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v4.17
   1/*
   2   SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
   3   file Documentation/scsi/st.txt for more information.
   4
   5   History:
   6   Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
   7   Contribution and ideas from several people including (in alphabetical
   8   order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
   9   Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
  10   Michael Schaefer, J"org Weule, and Eric Youngdale.
  11
  12   Copyright 1992 - 2016 Kai Makisara
  13   email Kai.Makisara@kolumbus.fi
  14
  15   Some small formal changes - aeb, 950809
  16
  17   Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  18 */
  19
  20static const char *verstr = "20160209";
  21
  22#include <linux/module.h>
  23
  24#include <linux/fs.h>
  25#include <linux/kernel.h>
  26#include <linux/sched/signal.h>
  27#include <linux/mm.h>
  28#include <linux/init.h>
  29#include <linux/string.h>
  30#include <linux/slab.h>
  31#include <linux/errno.h>
  32#include <linux/mtio.h>
  33#include <linux/cdrom.h>
  34#include <linux/ioctl.h>
  35#include <linux/fcntl.h>
  36#include <linux/spinlock.h>
  37#include <linux/blkdev.h>
  38#include <linux/moduleparam.h>
  39#include <linux/cdev.h>
  40#include <linux/idr.h>
  41#include <linux/delay.h>
  42#include <linux/mutex.h>
  43
  44#include <linux/uaccess.h>
  45#include <asm/dma.h>
  46
  47#include <scsi/scsi.h>
  48#include <scsi/scsi_dbg.h>
  49#include <scsi/scsi_device.h>
  50#include <scsi/scsi_driver.h>
  51#include <scsi/scsi_eh.h>
  52#include <scsi/scsi_host.h>
  53#include <scsi/scsi_ioctl.h>
  54#include <scsi/sg.h>
  55
  56
  57/* The driver prints some debugging information on the console if DEBUG
  58   is defined and non-zero. */
  59#define DEBUG 1
  60#define NO_DEBUG 0
  61
  62#define ST_DEB_MSG  KERN_NOTICE
  63#if DEBUG
  64/* The message level for the debug messages is currently set to KERN_NOTICE
  65   so that people can easily see the messages. Later when the debugging messages
  66   in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
  67#define DEB(a) a
  68#define DEBC(a) if (debugging) { a ; }
  69#else
  70#define DEB(a)
  71#define DEBC(a)
  72#endif
  73
  74#define ST_KILOBYTE 1024
  75
  76#include "st_options.h"
  77#include "st.h"
  78
  79static int buffer_kbs;
  80static int max_sg_segs;
  81static int try_direct_io = TRY_DIRECT_IO;
  82static int try_rdio = 1;
  83static int try_wdio = 1;
  84static int debug_flag;
  85
  86static struct class st_sysfs_class;
  87static const struct attribute_group *st_dev_groups[];
  88static const struct attribute_group *st_drv_groups[];
  89
  90MODULE_AUTHOR("Kai Makisara");
  91MODULE_DESCRIPTION("SCSI tape (st) driver");
  92MODULE_LICENSE("GPL");
  93MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
  94MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
  95
  96/* Set 'perm' (4th argument) to 0 to disable module_param's definition
  97 * of sysfs parameters (which module_param doesn't yet support).
  98 * Sysfs parameters defined explicitly later.
  99 */
 100module_param_named(buffer_kbs, buffer_kbs, int, 0);
 101MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
 102module_param_named(max_sg_segs, max_sg_segs, int, 0);
 103MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
 104module_param_named(try_direct_io, try_direct_io, int, 0);
 105MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
 106module_param_named(debug_flag, debug_flag, int, 0);
 107MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
 108
 109
 110/* Extra parameters for testing */
 111module_param_named(try_rdio, try_rdio, int, 0);
 112MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
 113module_param_named(try_wdio, try_wdio, int, 0);
 114MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
 115
 116#ifndef MODULE
 117static int write_threshold_kbs;  /* retained for compatibility */
 118static struct st_dev_parm {
 119	char *name;
 120	int *val;
 121} parms[] __initdata = {
 122	{
 123		"buffer_kbs", &buffer_kbs
 124	},
 125	{       /* Retained for compatibility with 2.4 */
 126		"write_threshold_kbs", &write_threshold_kbs
 127	},
 128	{
 129		"max_sg_segs", NULL
 130	},
 131	{
 132		"try_direct_io", &try_direct_io
 133	},
 134	{
 135		"debug_flag", &debug_flag
 136	}
 137};
 138#endif
 139
 140/* Restrict the number of modes so that names for all are assigned */
 141#if ST_NBR_MODES > 16
 142#error "Maximum number of modes is 16"
 143#endif
 144/* Bit reversed order to get same names for same minors with all
 145   mode counts */
 146static const char *st_formats[] = {
 147	"",  "r", "k", "s", "l", "t", "o", "u",
 148	"m", "v", "p", "x", "a", "y", "q", "z"}; 
 149
 150/* The default definitions have been moved to st_options.h */
 151
 152#define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
 153
 154/* The buffer size should fit into the 24 bits for length in the
 155   6-byte SCSI read and write commands. */
 156#if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
 157#error "Buffer size should not exceed (2 << 24 - 1) bytes!"
 158#endif
 159
 160static int debugging = DEBUG;
 161
 162#define MAX_RETRIES 0
 163#define MAX_WRITE_RETRIES 0
 164#define MAX_READY_RETRIES 0
 165#define NO_TAPE  NOT_READY
 166
 167#define ST_TIMEOUT (900 * HZ)
 168#define ST_LONG_TIMEOUT (14000 * HZ)
 169
 170/* Remove mode bits and auto-rewind bit (7) */
 171#define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
 172    (iminor(x) & ~(-1 << ST_MODE_SHIFT)) )
 173#define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
 174
 175/* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
 176#define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
 177  (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
 178
 179/* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 180   24 bits) */
 181#define SET_DENS_AND_BLK 0x10001
 182
 183static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
 184static int st_max_sg_segs = ST_MAX_SG;
 185
 186static int modes_defined;
 187
 188static int enlarge_buffer(struct st_buffer *, int, int);
 189static void clear_buffer(struct st_buffer *);
 190static void normalize_buffer(struct st_buffer *);
 191static int append_to_buffer(const char __user *, struct st_buffer *, int);
 192static int from_buffer(struct st_buffer *, char __user *, int);
 193static void move_buffer_data(struct st_buffer *, int);
 194
 195static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
 196			      unsigned long, size_t, int);
 197static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
 198
 199static int st_probe(struct device *);
 200static int st_remove(struct device *);
 201
 202static struct scsi_driver st_template = {
 203	.gendrv = {
 204		.name		= "st",
 205		.owner		= THIS_MODULE,
 206		.probe		= st_probe,
 207		.remove		= st_remove,
 208		.groups		= st_drv_groups,
 209	},
 210};
 211
 212static int st_compression(struct scsi_tape *, int);
 213
 214static int find_partition(struct scsi_tape *);
 215static int switch_partition(struct scsi_tape *);
 216
 217static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
 218
 219static void scsi_tape_release(struct kref *);
 220
 221#define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
 222
 223static DEFINE_MUTEX(st_ref_mutex);
 224static DEFINE_SPINLOCK(st_index_lock);
 225static DEFINE_SPINLOCK(st_use_lock);
 226static DEFINE_IDR(st_index_idr);
 227
 228
 229
 230#include "osst_detect.h"
 231#ifndef SIGS_FROM_OSST
 232#define SIGS_FROM_OSST \
 233	{"OnStream", "SC-", "", "osst"}, \
 234	{"OnStream", "DI-", "", "osst"}, \
 235	{"OnStream", "DP-", "", "osst"}, \
 236	{"OnStream", "USB", "", "osst"}, \
 237	{"OnStream", "FW-", "", "osst"}
 238#endif
 239
 240static struct scsi_tape *scsi_tape_get(int dev)
 241{
 242	struct scsi_tape *STp = NULL;
 243
 244	mutex_lock(&st_ref_mutex);
 245	spin_lock(&st_index_lock);
 246
 247	STp = idr_find(&st_index_idr, dev);
 248	if (!STp) goto out;
 249
 250	kref_get(&STp->kref);
 251
 252	if (!STp->device)
 253		goto out_put;
 254
 255	if (scsi_device_get(STp->device))
 256		goto out_put;
 257
 258	goto out;
 259
 260out_put:
 261	kref_put(&STp->kref, scsi_tape_release);
 262	STp = NULL;
 263out:
 264	spin_unlock(&st_index_lock);
 265	mutex_unlock(&st_ref_mutex);
 266	return STp;
 267}
 268
 269static void scsi_tape_put(struct scsi_tape *STp)
 270{
 271	struct scsi_device *sdev = STp->device;
 272
 273	mutex_lock(&st_ref_mutex);
 274	kref_put(&STp->kref, scsi_tape_release);
 275	scsi_device_put(sdev);
 276	mutex_unlock(&st_ref_mutex);
 277}
 278
 279struct st_reject_data {
 280	char *vendor;
 281	char *model;
 282	char *rev;
 283	char *driver_hint; /* Name of the correct driver, NULL if unknown */
 284};
 285
 286static struct st_reject_data reject_list[] = {
 287	/* {"XXX", "Yy-", "", NULL},  example */
 288	SIGS_FROM_OSST,
 289	{NULL, }};
 290
 291/* If the device signature is on the list of incompatible drives, the
 292   function returns a pointer to the name of the correct driver (if known) */
 293static char * st_incompatible(struct scsi_device* SDp)
 294{
 295	struct st_reject_data *rp;
 296
 297	for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
 298		if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
 299		    !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
 300		    !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
 301			if (rp->driver_hint)
 302				return rp->driver_hint;
 303			else
 304				return "unknown";
 305		}
 306	return NULL;
 307}
 308
 309
 310static inline char *tape_name(struct scsi_tape *tape)
 311{
 312	return tape->disk->disk_name;
 313}
 314
 315#define st_printk(prefix, t, fmt, a...) \
 316	sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
 317#ifdef DEBUG
 318#define DEBC_printk(t, fmt, a...) \
 319	if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
 320#else
 321#define DEBC_printk(t, fmt, a...)
 322#endif
 323
 324static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
 325{
 326	const u8 *ucp;
 327	const u8 *sense = SRpnt->sense;
 328
 329	s->have_sense = scsi_normalize_sense(SRpnt->sense,
 330				SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
 331	s->flags = 0;
 332
 333	if (s->have_sense) {
 334		s->deferred = 0;
 335		s->remainder_valid =
 336			scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
 337		switch (sense[0] & 0x7f) {
 338		case 0x71:
 339			s->deferred = 1;
 340		case 0x70:
 341			s->fixed_format = 1;
 342			s->flags = sense[2] & 0xe0;
 343			break;
 344		case 0x73:
 345			s->deferred = 1;
 346		case 0x72:
 347			s->fixed_format = 0;
 348			ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
 349			s->flags = ucp ? (ucp[3] & 0xe0) : 0;
 350			break;
 351		}
 352	}
 353}
 354
 355
 356/* Convert the result to success code */
 357static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 358{
 359	int result = SRpnt->result;
 360	u8 scode;
 361	DEB(const char *stp;)
 362	char *name = tape_name(STp);
 363	struct st_cmdstatus *cmdstatp;
 364
 365	if (!result)
 366		return 0;
 367
 368	cmdstatp = &STp->buffer->cmdstat;
 369	st_analyze_sense(SRpnt, cmdstatp);
 370
 371	if (cmdstatp->have_sense)
 372		scode = STp->buffer->cmdstat.sense_hdr.sense_key;
 373	else
 374		scode = 0;
 375
 376	DEB(
 377	if (debugging) {
 378		st_printk(ST_DEB_MSG, STp,
 379			    "Error: %x, cmd: %x %x %x %x %x %x\n", result,
 380			    SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 381			    SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 382		if (cmdstatp->have_sense)
 383			__scsi_print_sense(STp->device, name,
 384					   SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 385	} ) /* end DEB */
 386	if (!debugging) { /* Abnormal conditions for tape */
 387		if (!cmdstatp->have_sense)
 388			st_printk(KERN_WARNING, STp,
 389			       "Error %x (driver bt 0x%x, host bt 0x%x).\n",
 390			       result, driver_byte(result), host_byte(result));
 391		else if (cmdstatp->have_sense &&
 392			 scode != NO_SENSE &&
 393			 scode != RECOVERED_ERROR &&
 394			 /* scode != UNIT_ATTENTION && */
 395			 scode != BLANK_CHECK &&
 396			 scode != VOLUME_OVERFLOW &&
 397			 SRpnt->cmd[0] != MODE_SENSE &&
 398			 SRpnt->cmd[0] != TEST_UNIT_READY) {
 399
 400			__scsi_print_sense(STp->device, name,
 401					   SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 402		}
 403	}
 404
 405	if (cmdstatp->fixed_format &&
 406	    STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
 407		if (STp->cln_sense_value)
 408			STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 409					       STp->cln_sense_mask) == STp->cln_sense_value);
 410		else
 411			STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 412					       STp->cln_sense_mask) != 0);
 413	}
 414	if (cmdstatp->have_sense &&
 415	    cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 416		STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
 417
 418	STp->pos_unknown |= STp->device->was_reset;
 419
 420	if (cmdstatp->have_sense &&
 421	    scode == RECOVERED_ERROR
 422#if ST_RECOVERED_WRITE_FATAL
 423	    && SRpnt->cmd[0] != WRITE_6
 424	    && SRpnt->cmd[0] != WRITE_FILEMARKS
 425#endif
 426	    ) {
 427		STp->recover_count++;
 428		STp->recover_reg++;
 429
 430		DEB(
 431		if (debugging) {
 432			if (SRpnt->cmd[0] == READ_6)
 433				stp = "read";
 434			else if (SRpnt->cmd[0] == WRITE_6)
 435				stp = "write";
 436			else
 437				stp = "ioctl";
 438			st_printk(ST_DEB_MSG, STp,
 439				  "Recovered %s error (%d).\n",
 440				  stp, STp->recover_count);
 441		} ) /* end DEB */
 442
 443		if (cmdstatp->flags == 0)
 444			return 0;
 445	}
 446	return (-EIO);
 447}
 448
 449static struct st_request *st_allocate_request(struct scsi_tape *stp)
 450{
 451	struct st_request *streq;
 452
 453	streq = kzalloc(sizeof(*streq), GFP_KERNEL);
 454	if (streq)
 455		streq->stp = stp;
 456	else {
 457		st_printk(KERN_ERR, stp,
 458			  "Can't get SCSI request.\n");
 459		if (signal_pending(current))
 460			stp->buffer->syscall_result = -EINTR;
 461		else
 462			stp->buffer->syscall_result = -EBUSY;
 463	}
 464
 465	return streq;
 466}
 467
 468static void st_release_request(struct st_request *streq)
 469{
 470	kfree(streq);
 471}
 472
 473static void st_do_stats(struct scsi_tape *STp, struct request *req)
 474{
 475	ktime_t now;
 476
 477	now = ktime_get();
 478	if (scsi_req(req)->cmd[0] == WRITE_6) {
 479		now = ktime_sub(now, STp->stats->write_time);
 480		atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
 481		atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 482		atomic64_inc(&STp->stats->write_cnt);
 483		if (scsi_req(req)->result) {
 484			atomic64_add(atomic_read(&STp->stats->last_write_size)
 485				- STp->buffer->cmdstat.residual,
 486				&STp->stats->write_byte_cnt);
 487			if (STp->buffer->cmdstat.residual > 0)
 488				atomic64_inc(&STp->stats->resid_cnt);
 489		} else
 490			atomic64_add(atomic_read(&STp->stats->last_write_size),
 491				&STp->stats->write_byte_cnt);
 492	} else if (scsi_req(req)->cmd[0] == READ_6) {
 493		now = ktime_sub(now, STp->stats->read_time);
 494		atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
 495		atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 496		atomic64_inc(&STp->stats->read_cnt);
 497		if (scsi_req(req)->result) {
 498			atomic64_add(atomic_read(&STp->stats->last_read_size)
 499				- STp->buffer->cmdstat.residual,
 500				&STp->stats->read_byte_cnt);
 501			if (STp->buffer->cmdstat.residual > 0)
 502				atomic64_inc(&STp->stats->resid_cnt);
 503		} else
 504			atomic64_add(atomic_read(&STp->stats->last_read_size),
 505				&STp->stats->read_byte_cnt);
 506	} else {
 507		now = ktime_sub(now, STp->stats->other_time);
 508		atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 509		atomic64_inc(&STp->stats->other_cnt);
 510	}
 511	atomic64_dec(&STp->stats->in_flight);
 512}
 513
 514static void st_scsi_execute_end(struct request *req, blk_status_t status)
 515{
 516	struct st_request *SRpnt = req->end_io_data;
 517	struct scsi_request *rq = scsi_req(req);
 518	struct scsi_tape *STp = SRpnt->stp;
 519	struct bio *tmp;
 520
 521	STp->buffer->cmdstat.midlevel_result = SRpnt->result = rq->result;
 522	STp->buffer->cmdstat.residual = rq->resid_len;
 523
 524	st_do_stats(STp, req);
 525
 526	tmp = SRpnt->bio;
 527	if (rq->sense_len)
 528		memcpy(SRpnt->sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
 529	if (SRpnt->waiting)
 530		complete(SRpnt->waiting);
 531
 532	blk_rq_unmap_user(tmp);
 533	__blk_put_request(req->q, req);
 534}
 535
 536static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 537			   int data_direction, void *buffer, unsigned bufflen,
 538			   int timeout, int retries)
 539{
 540	struct request *req;
 541	struct scsi_request *rq;
 542	struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
 543	int err = 0;
 
 544	struct scsi_tape *STp = SRpnt->stp;
 545
 546	req = blk_get_request(SRpnt->stp->device->request_queue,
 547			data_direction == DMA_TO_DEVICE ?
 548			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, GFP_KERNEL);
 549	if (IS_ERR(req))
 550		return DRIVER_ERROR << 24;
 551	rq = scsi_req(req);
 552	req->rq_flags |= RQF_QUIET;
 
 553
 554	mdata->null_mapped = 1;
 555
 556	if (bufflen) {
 557		err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
 558				      GFP_KERNEL);
 559		if (err) {
 560			blk_put_request(req);
 561			return DRIVER_ERROR << 24;
 562		}
 563	}
 564
 565	atomic64_inc(&STp->stats->in_flight);
 566	if (cmd[0] == WRITE_6) {
 567		atomic_set(&STp->stats->last_write_size, bufflen);
 568		STp->stats->write_time = ktime_get();
 569	} else if (cmd[0] == READ_6) {
 570		atomic_set(&STp->stats->last_read_size, bufflen);
 571		STp->stats->read_time = ktime_get();
 572	} else {
 573		STp->stats->other_time = ktime_get();
 574	}
 575
 576	SRpnt->bio = req->bio;
 577	rq->cmd_len = COMMAND_SIZE(cmd[0]);
 578	memset(rq->cmd, 0, BLK_MAX_CDB);
 579	memcpy(rq->cmd, cmd, rq->cmd_len);
 
 
 580	req->timeout = timeout;
 581	rq->retries = retries;
 582	req->end_io_data = SRpnt;
 583
 584	blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
 585	return 0;
 586}
 587
 588/* Do the scsi command. Waits until command performed if do_wait is true.
 589   Otherwise write_behind_check() is used to check that the command
 590   has finished. */
 591static struct st_request *
 592st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
 593	   int bytes, int direction, int timeout, int retries, int do_wait)
 594{
 595	struct completion *waiting;
 596	struct rq_map_data *mdata = &STp->buffer->map_data;
 597	int ret;
 598
 599	/* if async, make sure there's no command outstanding */
 600	if (!do_wait && ((STp->buffer)->last_SRpnt)) {
 601		st_printk(KERN_ERR, STp,
 602			  "Async command already active.\n");
 603		if (signal_pending(current))
 604			(STp->buffer)->syscall_result = (-EINTR);
 605		else
 606			(STp->buffer)->syscall_result = (-EBUSY);
 607		return NULL;
 608	}
 609
 610	if (!SRpnt) {
 611		SRpnt = st_allocate_request(STp);
 612		if (!SRpnt)
 613			return NULL;
 614	}
 615
 616	/* If async IO, set last_SRpnt. This ptr tells write_behind_check
 617	   which IO is outstanding. It's nulled out when the IO completes. */
 618	if (!do_wait)
 619		(STp->buffer)->last_SRpnt = SRpnt;
 620
 621	waiting = &STp->wait;
 622	init_completion(waiting);
 623	SRpnt->waiting = waiting;
 624
 625	if (STp->buffer->do_dio) {
 626		mdata->page_order = 0;
 627		mdata->nr_entries = STp->buffer->sg_segs;
 628		mdata->pages = STp->buffer->mapped_pages;
 629	} else {
 630		mdata->page_order = STp->buffer->reserved_page_order;
 631		mdata->nr_entries =
 632			DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
 633		mdata->pages = STp->buffer->reserved_pages;
 634		mdata->offset = 0;
 635	}
 636
 637	memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
 638	STp->buffer->cmdstat.have_sense = 0;
 639	STp->buffer->syscall_result = 0;
 640
 641	ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
 642			      retries);
 643	if (ret) {
 644		/* could not allocate the buffer or request was too large */
 645		(STp->buffer)->syscall_result = (-EBUSY);
 646		(STp->buffer)->last_SRpnt = NULL;
 647	} else if (do_wait) {
 648		wait_for_completion(waiting);
 649		SRpnt->waiting = NULL;
 650		(STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 651	}
 652
 653	return SRpnt;
 654}
 655
 656
 657/* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
 658   write has been correct but EOM early warning reached, -EIO if write ended in
 659   error or zero if write successful. Asynchronous writes are used only in
 660   variable block mode. */
 661static int write_behind_check(struct scsi_tape * STp)
 662{
 663	int retval = 0;
 664	struct st_buffer *STbuffer;
 665	struct st_partstat *STps;
 666	struct st_cmdstatus *cmdstatp;
 667	struct st_request *SRpnt;
 668
 669	STbuffer = STp->buffer;
 670	if (!STbuffer->writing)
 671		return 0;
 672
 673	DEB(
 674	if (STp->write_pending)
 675		STp->nbr_waits++;
 676	else
 677		STp->nbr_finished++;
 678	) /* end DEB */
 679
 680	wait_for_completion(&(STp->wait));
 681	SRpnt = STbuffer->last_SRpnt;
 682	STbuffer->last_SRpnt = NULL;
 683	SRpnt->waiting = NULL;
 684
 685	(STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 686	st_release_request(SRpnt);
 687
 688	STbuffer->buffer_bytes -= STbuffer->writing;
 689	STps = &(STp->ps[STp->partition]);
 690	if (STps->drv_block >= 0) {
 691		if (STp->block_size == 0)
 692			STps->drv_block++;
 693		else
 694			STps->drv_block += STbuffer->writing / STp->block_size;
 695	}
 696
 697	cmdstatp = &STbuffer->cmdstat;
 698	if (STbuffer->syscall_result) {
 699		retval = -EIO;
 700		if (cmdstatp->have_sense && !cmdstatp->deferred &&
 701		    (cmdstatp->flags & SENSE_EOM) &&
 702		    (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 703		     cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
 704			/* EOM at write-behind, has all data been written? */
 705			if (!cmdstatp->remainder_valid ||
 706			    cmdstatp->uremainder64 == 0)
 707				retval = -ENOSPC;
 708		}
 709		if (retval == -EIO)
 710			STps->drv_block = -1;
 711	}
 712	STbuffer->writing = 0;
 713
 714	DEB(if (debugging && retval)
 715		    st_printk(ST_DEB_MSG, STp,
 716				"Async write error %x, return value %d.\n",
 717				STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
 718
 719	return retval;
 720}
 721
 722
 723/* Step over EOF if it has been inadvertently crossed (ioctl not used because
 724   it messes up the block number). */
 725static int cross_eof(struct scsi_tape * STp, int forward)
 726{
 727	struct st_request *SRpnt;
 728	unsigned char cmd[MAX_COMMAND_SIZE];
 729
 730	cmd[0] = SPACE;
 731	cmd[1] = 0x01;		/* Space FileMarks */
 732	if (forward) {
 733		cmd[2] = cmd[3] = 0;
 734		cmd[4] = 1;
 735	} else
 736		cmd[2] = cmd[3] = cmd[4] = 0xff;	/* -1 filemarks */
 737	cmd[5] = 0;
 738
 739	DEBC_printk(STp, "Stepping over filemark %s.\n",
 740		    forward ? "forward" : "backward");
 741
 742	SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
 743			   STp->device->request_queue->rq_timeout,
 744			   MAX_RETRIES, 1);
 745	if (!SRpnt)
 746		return (STp->buffer)->syscall_result;
 747
 748	st_release_request(SRpnt);
 749	SRpnt = NULL;
 750
 751	if ((STp->buffer)->cmdstat.midlevel_result != 0)
 752		st_printk(KERN_ERR, STp,
 753			  "Stepping over filemark %s failed.\n",
 754			  forward ? "forward" : "backward");
 755
 756	return (STp->buffer)->syscall_result;
 757}
 758
 759
 760/* Flush the write buffer (never need to write if variable blocksize). */
 761static int st_flush_write_buffer(struct scsi_tape * STp)
 762{
 763	int transfer, blks;
 764	int result;
 765	unsigned char cmd[MAX_COMMAND_SIZE];
 766	struct st_request *SRpnt;
 767	struct st_partstat *STps;
 768
 769	result = write_behind_check(STp);
 770	if (result)
 771		return result;
 772
 773	result = 0;
 774	if (STp->dirty == 1) {
 775
 776		transfer = STp->buffer->buffer_bytes;
 777		DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
 778
 779		memset(cmd, 0, MAX_COMMAND_SIZE);
 780		cmd[0] = WRITE_6;
 781		cmd[1] = 1;
 782		blks = transfer / STp->block_size;
 783		cmd[2] = blks >> 16;
 784		cmd[3] = blks >> 8;
 785		cmd[4] = blks;
 786
 787		SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
 788				   STp->device->request_queue->rq_timeout,
 789				   MAX_WRITE_RETRIES, 1);
 790		if (!SRpnt)
 791			return (STp->buffer)->syscall_result;
 792
 793		STps = &(STp->ps[STp->partition]);
 794		if ((STp->buffer)->syscall_result != 0) {
 795			struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 796
 797			if (cmdstatp->have_sense && !cmdstatp->deferred &&
 798			    (cmdstatp->flags & SENSE_EOM) &&
 799			    (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 800			     cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
 801			    (!cmdstatp->remainder_valid ||
 802			     cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
 803				STp->dirty = 0;
 804				(STp->buffer)->buffer_bytes = 0;
 805				if (STps->drv_block >= 0)
 806					STps->drv_block += blks;
 807				result = (-ENOSPC);
 808			} else {
 809				st_printk(KERN_ERR, STp, "Error on flush.\n");
 810				STps->drv_block = (-1);
 811				result = (-EIO);
 812			}
 813		} else {
 814			if (STps->drv_block >= 0)
 815				STps->drv_block += blks;
 816			STp->dirty = 0;
 817			(STp->buffer)->buffer_bytes = 0;
 818		}
 819		st_release_request(SRpnt);
 820		SRpnt = NULL;
 821	}
 822	return result;
 823}
 824
 825
 826/* Flush the tape buffer. The tape will be positioned correctly unless
 827   seek_next is true. */
 828static int flush_buffer(struct scsi_tape *STp, int seek_next)
 829{
 830	int backspace, result;
 831	struct st_buffer *STbuffer;
 832	struct st_partstat *STps;
 833
 834	STbuffer = STp->buffer;
 835
 836	/*
 837	 * If there was a bus reset, block further access
 838	 * to this device.
 839	 */
 840	if (STp->pos_unknown)
 841		return (-EIO);
 842
 843	if (STp->ready != ST_READY)
 844		return 0;
 845	STps = &(STp->ps[STp->partition]);
 846	if (STps->rw == ST_WRITING)	/* Writing */
 847		return st_flush_write_buffer(STp);
 848
 849	if (STp->block_size == 0)
 850		return 0;
 851
 852	backspace = ((STp->buffer)->buffer_bytes +
 853		     (STp->buffer)->read_pointer) / STp->block_size -
 854	    ((STp->buffer)->read_pointer + STp->block_size - 1) /
 855	    STp->block_size;
 856	(STp->buffer)->buffer_bytes = 0;
 857	(STp->buffer)->read_pointer = 0;
 858	result = 0;
 859	if (!seek_next) {
 860		if (STps->eof == ST_FM_HIT) {
 861			result = cross_eof(STp, 0);	/* Back over the EOF hit */
 862			if (!result)
 863				STps->eof = ST_NOEOF;
 864			else {
 865				if (STps->drv_file >= 0)
 866					STps->drv_file++;
 867				STps->drv_block = 0;
 868			}
 869		}
 870		if (!result && backspace > 0)
 871			result = st_int_ioctl(STp, MTBSR, backspace);
 872	} else if (STps->eof == ST_FM_HIT) {
 873		if (STps->drv_file >= 0)
 874			STps->drv_file++;
 875		STps->drv_block = 0;
 876		STps->eof = ST_NOEOF;
 877	}
 878	return result;
 879
 880}
 881
 882/* Set the mode parameters */
 883static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
 884{
 885	int set_it = 0;
 886	unsigned long arg;
 887
 888	if (!STp->density_changed &&
 889	    STm->default_density >= 0 &&
 890	    STm->default_density != STp->density) {
 891		arg = STm->default_density;
 892		set_it = 1;
 893	} else
 894		arg = STp->density;
 895	arg <<= MT_ST_DENSITY_SHIFT;
 896	if (!STp->blksize_changed &&
 897	    STm->default_blksize >= 0 &&
 898	    STm->default_blksize != STp->block_size) {
 899		arg |= STm->default_blksize;
 900		set_it = 1;
 901	} else
 902		arg |= STp->block_size;
 903	if (set_it &&
 904	    st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
 905		st_printk(KERN_WARNING, STp,
 906			  "Can't set default block size to %d bytes "
 907			  "and density %x.\n",
 908			  STm->default_blksize, STm->default_density);
 909		if (modes_defined)
 910			return (-EINVAL);
 911	}
 912	return 0;
 913}
 914
 915
 916/* Lock or unlock the drive door. Don't use when st_request allocated. */
 917static int do_door_lock(struct scsi_tape * STp, int do_lock)
 918{
 919	int retval;
 920
 921	DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
 922
 923	retval = scsi_set_medium_removal(STp->device,
 924			do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
 925	if (!retval)
 926		STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
 927	else
 928		STp->door_locked = ST_LOCK_FAILS;
 929	return retval;
 930}
 931
 932
 933/* Set the internal state after reset */
 934static void reset_state(struct scsi_tape *STp)
 935{
 936	int i;
 937	struct st_partstat *STps;
 938
 939	STp->pos_unknown = 0;
 940	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
 941		STps = &(STp->ps[i]);
 942		STps->rw = ST_IDLE;
 943		STps->eof = ST_NOEOF;
 944		STps->at_sm = 0;
 945		STps->last_block_valid = 0;
 946		STps->drv_block = -1;
 947		STps->drv_file = -1;
 948	}
 949	if (STp->can_partitions) {
 950		STp->partition = find_partition(STp);
 951		if (STp->partition < 0)
 952			STp->partition = 0;
 953		STp->new_partition = STp->partition;
 954	}
 955}
 956
 957/* Test if the drive is ready. Returns either one of the codes below or a negative system
 958   error code. */
 959#define CHKRES_READY       0
 960#define CHKRES_NEW_SESSION 1
 961#define CHKRES_NOT_READY   2
 962#define CHKRES_NO_TAPE     3
 963
 964#define MAX_ATTENTIONS    10
 965
 966static int test_ready(struct scsi_tape *STp, int do_wait)
 967{
 968	int attentions, waits, max_wait, scode;
 969	int retval = CHKRES_READY, new_session = 0;
 970	unsigned char cmd[MAX_COMMAND_SIZE];
 971	struct st_request *SRpnt = NULL;
 972	struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 973
 974	max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
 975
 976	for (attentions=waits=0; ; ) {
 977		memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
 978		cmd[0] = TEST_UNIT_READY;
 979		SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
 980				   STp->long_timeout, MAX_READY_RETRIES, 1);
 981
 982		if (!SRpnt) {
 983			retval = (STp->buffer)->syscall_result;
 984			break;
 985		}
 986
 987		if (cmdstatp->have_sense) {
 988
 989			scode = cmdstatp->sense_hdr.sense_key;
 990
 991			if (scode == UNIT_ATTENTION) { /* New media? */
 992				new_session = 1;
 993				if (attentions < MAX_ATTENTIONS) {
 994					attentions++;
 995					continue;
 996				}
 997				else {
 998					retval = (-EIO);
 999					break;
1000				}
1001			}
1002
1003			if (scode == NOT_READY) {
1004				if (waits < max_wait) {
1005					if (msleep_interruptible(1000)) {
1006						retval = (-EINTR);
1007						break;
1008					}
1009					waits++;
1010					continue;
1011				}
1012				else {
1013					if ((STp->device)->scsi_level >= SCSI_2 &&
1014					    cmdstatp->sense_hdr.asc == 0x3a)	/* Check ASC */
1015						retval = CHKRES_NO_TAPE;
1016					else
1017						retval = CHKRES_NOT_READY;
1018					break;
1019				}
1020			}
1021		}
1022
1023		retval = (STp->buffer)->syscall_result;
1024		if (!retval)
1025			retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
1026		break;
1027	}
1028
1029	if (SRpnt != NULL)
1030		st_release_request(SRpnt);
1031	return retval;
1032}
1033
1034
1035/* See if the drive is ready and gather information about the tape. Return values:
1036   < 0   negative error code from errno.h
1037   0     drive ready
1038   1     drive not ready (possibly no tape)
1039*/
1040static int check_tape(struct scsi_tape *STp, struct file *filp)
1041{
1042	int i, retval, new_session = 0, do_wait;
1043	unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
1044	unsigned short st_flags = filp->f_flags;
1045	struct st_request *SRpnt = NULL;
1046	struct st_modedef *STm;
1047	struct st_partstat *STps;
1048	struct inode *inode = file_inode(filp);
1049	int mode = TAPE_MODE(inode);
1050
1051	STp->ready = ST_READY;
1052
1053	if (mode != STp->current_mode) {
1054		DEBC_printk(STp, "Mode change from %d to %d.\n",
1055			    STp->current_mode, mode);
1056		new_session = 1;
1057		STp->current_mode = mode;
1058	}
1059	STm = &(STp->modes[STp->current_mode]);
1060
1061	saved_cleaning = STp->cleaning_req;
1062	STp->cleaning_req = 0;
1063
1064	do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1065	retval = test_ready(STp, do_wait);
1066
1067	if (retval < 0)
1068	    goto err_out;
1069
1070	if (retval == CHKRES_NEW_SESSION) {
1071		STp->pos_unknown = 0;
1072		STp->partition = STp->new_partition = 0;
1073		if (STp->can_partitions)
1074			STp->nbr_partitions = 1; /* This guess will be updated later
1075                                                    if necessary */
1076		for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1077			STps = &(STp->ps[i]);
1078			STps->rw = ST_IDLE;
1079			STps->eof = ST_NOEOF;
1080			STps->at_sm = 0;
1081			STps->last_block_valid = 0;
1082			STps->drv_block = 0;
1083			STps->drv_file = 0;
1084		}
1085		new_session = 1;
1086	}
1087	else {
1088		STp->cleaning_req |= saved_cleaning;
1089
1090		if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1091			if (retval == CHKRES_NO_TAPE)
1092				STp->ready = ST_NO_TAPE;
1093			else
1094				STp->ready = ST_NOT_READY;
1095
1096			STp->density = 0;	/* Clear the erroneous "residue" */
1097			STp->write_prot = 0;
1098			STp->block_size = 0;
1099			STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1100			STp->partition = STp->new_partition = 0;
1101			STp->door_locked = ST_UNLOCKED;
1102			return CHKRES_NOT_READY;
1103		}
1104	}
1105
1106	if (STp->omit_blklims)
1107		STp->min_block = STp->max_block = (-1);
1108	else {
1109		memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1110		cmd[0] = READ_BLOCK_LIMITS;
1111
1112		SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1113				   STp->device->request_queue->rq_timeout,
1114				   MAX_READY_RETRIES, 1);
1115		if (!SRpnt) {
1116			retval = (STp->buffer)->syscall_result;
1117			goto err_out;
1118		}
1119
1120		if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1121			STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1122			    ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1123			STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1124			    (STp->buffer)->b_data[5];
1125			if ( DEB( debugging || ) !STp->inited)
1126				st_printk(KERN_INFO, STp,
1127					  "Block limits %d - %d bytes.\n",
1128					  STp->min_block, STp->max_block);
1129		} else {
1130			STp->min_block = STp->max_block = (-1);
1131			DEBC_printk(STp, "Can't read block limits.\n");
1132		}
1133	}
1134
1135	memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1136	cmd[0] = MODE_SENSE;
1137	cmd[4] = 12;
1138
1139	SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1140			   STp->device->request_queue->rq_timeout,
1141			   MAX_READY_RETRIES, 1);
1142	if (!SRpnt) {
1143		retval = (STp->buffer)->syscall_result;
1144		goto err_out;
1145	}
1146
1147	if ((STp->buffer)->syscall_result != 0) {
1148		DEBC_printk(STp, "No Mode Sense.\n");
1149		STp->block_size = ST_DEFAULT_BLOCK;	/* Educated guess (?) */
1150		(STp->buffer)->syscall_result = 0;	/* Prevent error propagation */
1151		STp->drv_write_prot = 0;
1152	} else {
1153		DEBC_printk(STp,"Mode sense. Length %d, "
1154			    "medium %x, WBS %x, BLL %d\n",
1155			    (STp->buffer)->b_data[0],
1156			    (STp->buffer)->b_data[1],
1157			    (STp->buffer)->b_data[2],
1158			    (STp->buffer)->b_data[3]);
1159
1160		if ((STp->buffer)->b_data[3] >= 8) {
1161			STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1162			STp->density = (STp->buffer)->b_data[4];
1163			STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1164			    (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1165			DEBC_printk(STp, "Density %x, tape length: %x, "
1166				    "drv buffer: %d\n",
1167				    STp->density,
1168				    (STp->buffer)->b_data[5] * 65536 +
1169				    (STp->buffer)->b_data[6] * 256 +
1170				    (STp->buffer)->b_data[7],
1171				    STp->drv_buffer);
1172		}
1173		STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1174		if (!STp->drv_buffer && STp->immediate_filemark) {
1175			st_printk(KERN_WARNING, STp,
1176				  "non-buffered tape: disabling "
1177				  "writing immediate filemarks\n");
1178			STp->immediate_filemark = 0;
1179		}
1180	}
1181	st_release_request(SRpnt);
1182	SRpnt = NULL;
1183	STp->inited = 1;
1184
1185	if (STp->block_size > 0)
1186		(STp->buffer)->buffer_blocks =
1187			(STp->buffer)->buffer_size / STp->block_size;
1188	else
1189		(STp->buffer)->buffer_blocks = 1;
1190	(STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1191
1192	DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1193		    STp->block_size, (STp->buffer)->buffer_size,
1194		    (STp->buffer)->buffer_blocks);
1195
1196	if (STp->drv_write_prot) {
1197		STp->write_prot = 1;
1198
1199		DEBC_printk(STp, "Write protected\n");
1200
1201		if (do_wait &&
1202		    ((st_flags & O_ACCMODE) == O_WRONLY ||
1203		     (st_flags & O_ACCMODE) == O_RDWR)) {
1204			retval = (-EROFS);
1205			goto err_out;
1206		}
1207	}
1208
1209	if (STp->can_partitions && STp->nbr_partitions < 1) {
1210		/* This code is reached when the device is opened for the first time
1211		   after the driver has been initialized with tape in the drive and the
1212		   partition support has been enabled. */
1213		DEBC_printk(STp, "Updating partition number in status.\n");
1214		if ((STp->partition = find_partition(STp)) < 0) {
1215			retval = STp->partition;
1216			goto err_out;
1217		}
1218		STp->new_partition = STp->partition;
1219		STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1220	}
1221
1222	if (new_session) {	/* Change the drive parameters for the new mode */
1223		STp->density_changed = STp->blksize_changed = 0;
1224		STp->compression_changed = 0;
1225		if (!(STm->defaults_for_writes) &&
1226		    (retval = set_mode_densblk(STp, STm)) < 0)
1227		    goto err_out;
1228
1229		if (STp->default_drvbuffer != 0xff) {
1230			if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1231				st_printk(KERN_WARNING, STp,
1232					  "Can't set default drive "
1233					  "buffering to %d.\n",
1234					  STp->default_drvbuffer);
1235		}
1236	}
1237
1238	return CHKRES_READY;
1239
1240 err_out:
1241	return retval;
1242}
1243
1244
1245/* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1246   module count. */
1247static int st_open(struct inode *inode, struct file *filp)
1248{
1249	int i, retval = (-EIO);
1250	int resumed = 0;
1251	struct scsi_tape *STp;
1252	struct st_partstat *STps;
1253	int dev = TAPE_NR(inode);
1254
1255	/*
1256	 * We really want to do nonseekable_open(inode, filp); here, but some
1257	 * versions of tar incorrectly call lseek on tapes and bail out if that
1258	 * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1259	 */
1260	filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1261
1262	if (!(STp = scsi_tape_get(dev))) {
1263		return -ENXIO;
1264	}
1265
1266	filp->private_data = STp;
1267
1268	spin_lock(&st_use_lock);
1269	if (STp->in_use) {
1270		spin_unlock(&st_use_lock);
1271		scsi_tape_put(STp);
1272		DEBC_printk(STp, "Device already in use.\n");
1273		return (-EBUSY);
1274	}
1275
1276	STp->in_use = 1;
1277	spin_unlock(&st_use_lock);
1278	STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1279
1280	if (scsi_autopm_get_device(STp->device) < 0) {
1281		retval = -EIO;
1282		goto err_out;
1283	}
1284	resumed = 1;
1285	if (!scsi_block_when_processing_errors(STp->device)) {
1286		retval = (-ENXIO);
1287		goto err_out;
1288	}
1289
1290	/* See that we have at least a one page buffer available */
1291	if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
1292		st_printk(KERN_WARNING, STp,
1293			  "Can't allocate one page tape buffer.\n");
1294		retval = (-EOVERFLOW);
1295		goto err_out;
1296	}
1297
1298	(STp->buffer)->cleared = 0;
1299	(STp->buffer)->writing = 0;
1300	(STp->buffer)->syscall_result = 0;
1301
1302	STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1303
1304	STp->dirty = 0;
1305	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1306		STps = &(STp->ps[i]);
1307		STps->rw = ST_IDLE;
1308	}
1309	STp->try_dio_now = STp->try_dio;
1310	STp->recover_count = 0;
1311	DEB( STp->nbr_waits = STp->nbr_finished = 0;
1312	     STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1313
1314	retval = check_tape(STp, filp);
1315	if (retval < 0)
1316		goto err_out;
1317	if ((filp->f_flags & O_NONBLOCK) == 0 &&
1318	    retval != CHKRES_READY) {
1319		if (STp->ready == NO_TAPE)
1320			retval = (-ENOMEDIUM);
1321		else
1322			retval = (-EIO);
1323		goto err_out;
1324	}
1325	return 0;
1326
1327 err_out:
1328	normalize_buffer(STp->buffer);
1329	spin_lock(&st_use_lock);
1330	STp->in_use = 0;
1331	spin_unlock(&st_use_lock);
1332	if (resumed)
1333		scsi_autopm_put_device(STp->device);
1334	scsi_tape_put(STp);
1335	return retval;
1336
1337}
1338
1339
1340/* Flush the tape buffer before close */
1341static int st_flush(struct file *filp, fl_owner_t id)
1342{
1343	int result = 0, result2;
1344	unsigned char cmd[MAX_COMMAND_SIZE];
1345	struct st_request *SRpnt;
1346	struct scsi_tape *STp = filp->private_data;
1347	struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1348	struct st_partstat *STps = &(STp->ps[STp->partition]);
1349
1350	if (file_count(filp) > 1)
1351		return 0;
1352
1353	if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1354		result = st_flush_write_buffer(STp);
1355		if (result != 0 && result != (-ENOSPC))
1356			goto out;
1357	}
1358
1359	if (STp->can_partitions &&
1360	    (result2 = switch_partition(STp)) < 0) {
1361		DEBC_printk(STp, "switch_partition at close failed.\n");
1362		if (result == 0)
1363			result = result2;
1364		goto out;
1365	}
1366
1367	DEBC( if (STp->nbr_requests)
1368		st_printk(KERN_DEBUG, STp,
1369			  "Number of r/w requests %d, dio used in %d, "
1370			  "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1371			  STp->nbr_pages));
1372
1373	if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1374		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1375
1376#if DEBUG
1377		DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1378			    STp->nbr_waits, STp->nbr_finished);
1379#endif
1380		memset(cmd, 0, MAX_COMMAND_SIZE);
1381		cmd[0] = WRITE_FILEMARKS;
1382		if (STp->immediate_filemark)
1383			cmd[1] = 1;
1384		cmd[4] = 1 + STp->two_fm;
1385
1386		SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1387				   STp->device->request_queue->rq_timeout,
1388				   MAX_WRITE_RETRIES, 1);
1389		if (!SRpnt) {
1390			result = (STp->buffer)->syscall_result;
1391			goto out;
1392		}
1393
1394		if (STp->buffer->syscall_result == 0 ||
1395		    (cmdstatp->have_sense && !cmdstatp->deferred &&
1396		     (cmdstatp->flags & SENSE_EOM) &&
1397		     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1398		      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1399		     (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1400			/* Write successful at EOM */
1401			st_release_request(SRpnt);
1402			SRpnt = NULL;
1403			if (STps->drv_file >= 0)
1404				STps->drv_file++;
1405			STps->drv_block = 0;
1406			if (STp->two_fm)
1407				cross_eof(STp, 0);
1408			STps->eof = ST_FM;
1409		}
1410		else { /* Write error */
1411			st_release_request(SRpnt);
1412			SRpnt = NULL;
1413			st_printk(KERN_ERR, STp,
1414				  "Error on write filemark.\n");
1415			if (result == 0)
1416				result = (-EIO);
1417		}
1418
1419		DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1420	} else if (!STp->rew_at_close) {
1421		STps = &(STp->ps[STp->partition]);
1422		if (!STm->sysv || STps->rw != ST_READING) {
1423			if (STp->can_bsr)
1424				result = flush_buffer(STp, 0);
1425			else if (STps->eof == ST_FM_HIT) {
1426				result = cross_eof(STp, 0);
1427				if (result) {
1428					if (STps->drv_file >= 0)
1429						STps->drv_file++;
1430					STps->drv_block = 0;
1431					STps->eof = ST_FM;
1432				} else
1433					STps->eof = ST_NOEOF;
1434			}
1435		} else if ((STps->eof == ST_NOEOF &&
1436			    !(result = cross_eof(STp, 1))) ||
1437			   STps->eof == ST_FM_HIT) {
1438			if (STps->drv_file >= 0)
1439				STps->drv_file++;
1440			STps->drv_block = 0;
1441			STps->eof = ST_FM;
1442		}
1443	}
1444
1445      out:
1446	if (STp->rew_at_close) {
1447		result2 = st_int_ioctl(STp, MTREW, 1);
1448		if (result == 0)
1449			result = result2;
1450	}
1451	return result;
1452}
1453
1454
1455/* Close the device and release it. BKL is not needed: this is the only thread
1456   accessing this tape. */
1457static int st_release(struct inode *inode, struct file *filp)
1458{
1459	int result = 0;
1460	struct scsi_tape *STp = filp->private_data;
1461
1462	if (STp->door_locked == ST_LOCKED_AUTO)
1463		do_door_lock(STp, 0);
1464
1465	normalize_buffer(STp->buffer);
1466	spin_lock(&st_use_lock);
1467	STp->in_use = 0;
1468	spin_unlock(&st_use_lock);
1469	scsi_autopm_put_device(STp->device);
1470	scsi_tape_put(STp);
1471
1472	return result;
1473}
1474
1475/* The checks common to both reading and writing */
1476static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1477{
1478	ssize_t retval = 0;
1479
1480	/*
1481	 * If we are in the middle of error recovery, don't let anyone
1482	 * else try and use this device.  Also, if error recovery fails, it
1483	 * may try and take the device offline, in which case all further
1484	 * access to the device is prohibited.
1485	 */
1486	if (!scsi_block_when_processing_errors(STp->device)) {
1487		retval = (-ENXIO);
1488		goto out;
1489	}
1490
1491	if (STp->ready != ST_READY) {
1492		if (STp->ready == ST_NO_TAPE)
1493			retval = (-ENOMEDIUM);
1494		else
1495			retval = (-EIO);
1496		goto out;
1497	}
1498
1499	if (! STp->modes[STp->current_mode].defined) {
1500		retval = (-ENXIO);
1501		goto out;
1502	}
1503
1504
1505	/*
1506	 * If there was a bus reset, block further access
1507	 * to this device.
1508	 */
1509	if (STp->pos_unknown) {
1510		retval = (-EIO);
1511		goto out;
1512	}
1513
1514	if (count == 0)
1515		goto out;
1516
1517	DEB(
1518	if (!STp->in_use) {
1519		st_printk(ST_DEB_MSG, STp,
1520			  "Incorrect device.\n");
1521		retval = (-EIO);
1522		goto out;
1523	} ) /* end DEB */
1524
1525	if (STp->can_partitions &&
1526	    (retval = switch_partition(STp)) < 0)
1527		goto out;
1528
1529	if (STp->block_size == 0 && STp->max_block > 0 &&
1530	    (count < STp->min_block || count > STp->max_block)) {
1531		retval = (-EINVAL);
1532		goto out;
1533	}
1534
1535	if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1536	    !do_door_lock(STp, 1))
1537		STp->door_locked = ST_LOCKED_AUTO;
1538
1539 out:
1540	return retval;
1541}
1542
1543
1544static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1545			   size_t count, int is_read)
1546{
1547	int i, bufsize, retval = 0;
1548	struct st_buffer *STbp = STp->buffer;
1549
1550	if (is_read)
1551		i = STp->try_dio_now && try_rdio;
1552	else
1553		i = STp->try_dio_now && try_wdio;
1554
1555	if (i && ((unsigned long)buf & queue_dma_alignment(
1556					STp->device->request_queue)) == 0) {
1557		i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1558				       count, (is_read ? READ : WRITE));
1559		if (i > 0) {
1560			STbp->do_dio = i;
1561			STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1562		}
1563		else
1564			STbp->do_dio = 0;  /* fall back to buffering with any error */
1565		STbp->sg_segs = STbp->do_dio;
1566		DEB(
1567		     if (STbp->do_dio) {
1568			STp->nbr_dio++;
1569			STp->nbr_pages += STbp->do_dio;
1570		     }
1571		)
1572	} else
1573		STbp->do_dio = 0;
1574	DEB( STp->nbr_requests++; )
1575
1576	if (!STbp->do_dio) {
1577		if (STp->block_size)
1578			bufsize = STp->block_size > st_fixed_buffer_size ?
1579				STp->block_size : st_fixed_buffer_size;
1580		else {
1581			bufsize = count;
1582			/* Make sure that data from previous user is not leaked even if
1583			   HBA does not return correct residual */
1584			if (is_read && STp->sili && !STbp->cleared)
1585				clear_buffer(STbp);
1586		}
1587
1588		if (bufsize > STbp->buffer_size &&
1589		    !enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
1590			st_printk(KERN_WARNING, STp,
1591				  "Can't allocate %d byte tape buffer.\n",
1592				  bufsize);
1593			retval = (-EOVERFLOW);
1594			goto out;
1595		}
1596		if (STp->block_size)
1597			STbp->buffer_blocks = bufsize / STp->block_size;
1598	}
1599
1600 out:
1601	return retval;
1602}
1603
1604
1605/* Can be called more than once after each setup_buffer() */
1606static void release_buffering(struct scsi_tape *STp, int is_read)
1607{
1608	struct st_buffer *STbp;
1609
1610	STbp = STp->buffer;
1611	if (STbp->do_dio) {
1612		sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1613		STbp->do_dio = 0;
1614		STbp->sg_segs = 0;
1615	}
1616}
1617
1618
1619/* Write command */
1620static ssize_t
1621st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1622{
1623	ssize_t total;
1624	ssize_t i, do_count, blks, transfer;
1625	ssize_t retval;
1626	int undone, retry_eot = 0, scode;
1627	int async_write;
1628	unsigned char cmd[MAX_COMMAND_SIZE];
1629	const char __user *b_point;
1630	struct st_request *SRpnt = NULL;
1631	struct scsi_tape *STp = filp->private_data;
1632	struct st_modedef *STm;
1633	struct st_partstat *STps;
1634	struct st_buffer *STbp;
1635
1636	if (mutex_lock_interruptible(&STp->lock))
1637		return -ERESTARTSYS;
1638
1639	retval = rw_checks(STp, filp, count);
1640	if (retval || count == 0)
1641		goto out;
1642
1643	/* Write must be integral number of blocks */
1644	if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1645		st_printk(KERN_WARNING, STp,
1646			  "Write not multiple of tape block size.\n");
1647		retval = (-EINVAL);
1648		goto out;
1649	}
1650
1651	STm = &(STp->modes[STp->current_mode]);
1652	STps = &(STp->ps[STp->partition]);
1653
1654	if (STp->write_prot) {
1655		retval = (-EACCES);
1656		goto out;
1657	}
1658
1659
1660	if (STps->rw == ST_READING) {
1661		retval = flush_buffer(STp, 0);
1662		if (retval)
1663			goto out;
1664		STps->rw = ST_WRITING;
1665	} else if (STps->rw != ST_WRITING &&
1666		   STps->drv_file == 0 && STps->drv_block == 0) {
1667		if ((retval = set_mode_densblk(STp, STm)) < 0)
1668			goto out;
1669		if (STm->default_compression != ST_DONT_TOUCH &&
1670		    !(STp->compression_changed)) {
1671			if (st_compression(STp, (STm->default_compression == ST_YES))) {
1672				st_printk(KERN_WARNING, STp,
1673					  "Can't set default compression.\n");
1674				if (modes_defined) {
1675					retval = (-EINVAL);
1676					goto out;
1677				}
1678			}
1679		}
1680	}
1681
1682	STbp = STp->buffer;
1683	i = write_behind_check(STp);
1684	if (i) {
1685		if (i == -ENOSPC)
1686			STps->eof = ST_EOM_OK;
1687		else
1688			STps->eof = ST_EOM_ERROR;
1689	}
1690
1691	if (STps->eof == ST_EOM_OK) {
1692		STps->eof = ST_EOD_1;  /* allow next write */
1693		retval = (-ENOSPC);
1694		goto out;
1695	}
1696	else if (STps->eof == ST_EOM_ERROR) {
1697		retval = (-EIO);
1698		goto out;
1699	}
1700
1701	/* Check the buffer readability in cases where copy_user might catch
1702	   the problems after some tape movement. */
1703	if (STp->block_size != 0 &&
1704	    !STbp->do_dio &&
1705	    (copy_from_user(&i, buf, 1) != 0 ||
1706	     copy_from_user(&i, buf + count - 1, 1) != 0)) {
1707		retval = (-EFAULT);
1708		goto out;
1709	}
1710
1711	retval = setup_buffering(STp, buf, count, 0);
1712	if (retval)
1713		goto out;
1714
1715	total = count;
1716
1717	memset(cmd, 0, MAX_COMMAND_SIZE);
1718	cmd[0] = WRITE_6;
1719	cmd[1] = (STp->block_size != 0);
1720
1721	STps->rw = ST_WRITING;
1722
1723	b_point = buf;
1724	while (count > 0 && !retry_eot) {
1725
1726		if (STbp->do_dio) {
1727			do_count = count;
1728		}
1729		else {
1730			if (STp->block_size == 0)
1731				do_count = count;
1732			else {
1733				do_count = STbp->buffer_blocks * STp->block_size -
1734					STbp->buffer_bytes;
1735				if (do_count > count)
1736					do_count = count;
1737			}
1738
1739			i = append_to_buffer(b_point, STbp, do_count);
1740			if (i) {
1741				retval = i;
1742				goto out;
1743			}
1744		}
1745		count -= do_count;
1746		b_point += do_count;
1747
1748		async_write = STp->block_size == 0 && !STbp->do_dio &&
1749			STm->do_async_writes && STps->eof < ST_EOM_OK;
1750
1751		if (STp->block_size != 0 && STm->do_buffer_writes &&
1752		    !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1753		    STbp->buffer_bytes < STbp->buffer_size) {
1754			STp->dirty = 1;
1755			/* Don't write a buffer that is not full enough. */
1756			if (!async_write && count == 0)
1757				break;
1758		}
1759
1760	retry_write:
1761		if (STp->block_size == 0)
1762			blks = transfer = do_count;
1763		else {
1764			if (!STbp->do_dio)
1765				blks = STbp->buffer_bytes;
1766			else
1767				blks = do_count;
1768			blks /= STp->block_size;
1769			transfer = blks * STp->block_size;
1770		}
1771		cmd[2] = blks >> 16;
1772		cmd[3] = blks >> 8;
1773		cmd[4] = blks;
1774
1775		SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1776				   STp->device->request_queue->rq_timeout,
1777				   MAX_WRITE_RETRIES, !async_write);
1778		if (!SRpnt) {
1779			retval = STbp->syscall_result;
1780			goto out;
1781		}
1782		if (async_write && !STbp->syscall_result) {
1783			STbp->writing = transfer;
1784			STp->dirty = !(STbp->writing ==
1785				       STbp->buffer_bytes);
1786			SRpnt = NULL;  /* Prevent releasing this request! */
1787			DEB( STp->write_pending = 1; )
1788			break;
1789		}
1790
1791		if (STbp->syscall_result != 0) {
1792			struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1793
1794			DEBC_printk(STp, "Error on write:\n");
1795			if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1796				scode = cmdstatp->sense_hdr.sense_key;
1797				if (cmdstatp->remainder_valid)
1798					undone = (int)cmdstatp->uremainder64;
1799				else if (STp->block_size == 0 &&
1800					 scode == VOLUME_OVERFLOW)
1801					undone = transfer;
1802				else
1803					undone = 0;
1804				if (STp->block_size != 0)
1805					undone *= STp->block_size;
1806				if (undone <= do_count) {
1807					/* Only data from this write is not written */
1808					count += undone;
1809					b_point -= undone;
1810					do_count -= undone;
1811					if (STp->block_size)
1812						blks = (transfer - undone) / STp->block_size;
1813					STps->eof = ST_EOM_OK;
1814					/* Continue in fixed block mode if all written
1815					   in this request but still something left to write
1816					   (retval left to zero)
1817					*/
1818					if (STp->block_size == 0 ||
1819					    undone > 0 || count == 0)
1820						retval = (-ENOSPC); /* EOM within current request */
1821					DEBC_printk(STp, "EOM with %d "
1822						    "bytes unwritten.\n",
1823						    (int)count);
1824				} else {
1825					/* EOT within data buffered earlier (possible only
1826					   in fixed block mode without direct i/o) */
1827					if (!retry_eot && !cmdstatp->deferred &&
1828					    (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1829						move_buffer_data(STp->buffer, transfer - undone);
1830						retry_eot = 1;
1831						if (STps->drv_block >= 0) {
1832							STps->drv_block += (transfer - undone) /
1833								STp->block_size;
1834						}
1835						STps->eof = ST_EOM_OK;
1836						DEBC_printk(STp, "Retry "
1837							    "write of %d "
1838							    "bytes at EOM.\n",
1839							    STp->buffer->buffer_bytes);
1840						goto retry_write;
1841					}
1842					else {
1843						/* Either error within data buffered by driver or
1844						   failed retry */
1845						count -= do_count;
1846						blks = do_count = 0;
1847						STps->eof = ST_EOM_ERROR;
1848						STps->drv_block = (-1); /* Too cautious? */
1849						retval = (-EIO);	/* EOM for old data */
1850						DEBC_printk(STp, "EOM with "
1851							    "lost data.\n");
1852					}
1853				}
1854			} else {
1855				count += do_count;
1856				STps->drv_block = (-1);		/* Too cautious? */
1857				retval = STbp->syscall_result;
1858			}
1859
1860		}
1861
1862		if (STps->drv_block >= 0) {
1863			if (STp->block_size == 0)
1864				STps->drv_block += (do_count > 0);
1865			else
1866				STps->drv_block += blks;
1867		}
1868
1869		STbp->buffer_bytes = 0;
1870		STp->dirty = 0;
1871
1872		if (retval || retry_eot) {
1873			if (count < total)
1874				retval = total - count;
1875			goto out;
1876		}
1877	}
1878
1879	if (STps->eof == ST_EOD_1)
1880		STps->eof = ST_EOM_OK;
1881	else if (STps->eof != ST_EOM_OK)
1882		STps->eof = ST_NOEOF;
1883	retval = total - count;
1884
1885 out:
1886	if (SRpnt != NULL)
1887		st_release_request(SRpnt);
1888	release_buffering(STp, 0);
1889	mutex_unlock(&STp->lock);
1890
1891	return retval;
1892}
1893
1894/* Read data from the tape. Returns zero in the normal case, one if the
1895   eof status has changed, and the negative error code in case of a
1896   fatal error. Otherwise updates the buffer and the eof state.
1897
1898   Does release user buffer mapping if it is set.
1899*/
1900static long read_tape(struct scsi_tape *STp, long count,
1901		      struct st_request ** aSRpnt)
1902{
1903	int transfer, blks, bytes;
1904	unsigned char cmd[MAX_COMMAND_SIZE];
1905	struct st_request *SRpnt;
1906	struct st_modedef *STm;
1907	struct st_partstat *STps;
1908	struct st_buffer *STbp;
1909	int retval = 0;
1910
1911	if (count == 0)
1912		return 0;
1913
1914	STm = &(STp->modes[STp->current_mode]);
1915	STps = &(STp->ps[STp->partition]);
1916	if (STps->eof == ST_FM_HIT)
1917		return 1;
1918	STbp = STp->buffer;
1919
1920	if (STp->block_size == 0)
1921		blks = bytes = count;
1922	else {
1923		if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1924			blks = (STp->buffer)->buffer_blocks;
1925			bytes = blks * STp->block_size;
1926		} else {
1927			bytes = count;
1928			if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1929				bytes = (STp->buffer)->buffer_size;
1930			blks = bytes / STp->block_size;
1931			bytes = blks * STp->block_size;
1932		}
1933	}
1934
1935	memset(cmd, 0, MAX_COMMAND_SIZE);
1936	cmd[0] = READ_6;
1937	cmd[1] = (STp->block_size != 0);
1938	if (!cmd[1] && STp->sili)
1939		cmd[1] |= 2;
1940	cmd[2] = blks >> 16;
1941	cmd[3] = blks >> 8;
1942	cmd[4] = blks;
1943
1944	SRpnt = *aSRpnt;
1945	SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1946			   STp->device->request_queue->rq_timeout,
1947			   MAX_RETRIES, 1);
1948	release_buffering(STp, 1);
1949	*aSRpnt = SRpnt;
1950	if (!SRpnt)
1951		return STbp->syscall_result;
1952
1953	STbp->read_pointer = 0;
1954	STps->at_sm = 0;
1955
1956	/* Something to check */
1957	if (STbp->syscall_result) {
1958		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1959
1960		retval = 1;
1961		DEBC_printk(STp,
1962			    "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1963			    SRpnt->sense[0], SRpnt->sense[1],
1964			    SRpnt->sense[2], SRpnt->sense[3],
1965			    SRpnt->sense[4], SRpnt->sense[5],
1966			    SRpnt->sense[6], SRpnt->sense[7]);
1967		if (cmdstatp->have_sense) {
1968
1969			if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1970				cmdstatp->flags &= 0xcf;	/* No need for EOM in this case */
1971
1972			if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1973				/* Compute the residual count */
1974				if (cmdstatp->remainder_valid)
1975					transfer = (int)cmdstatp->uremainder64;
1976				else
1977					transfer = 0;
1978				if (cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR) {
1979					if (STp->block_size == 0)
1980						transfer = bytes;
1981					/* Some drives set ILI with MEDIUM ERROR */
1982					cmdstatp->flags &= ~SENSE_ILI;
1983				}
1984
1985				if (cmdstatp->flags & SENSE_ILI) {	/* ILI */
1986					if (STp->block_size == 0 &&
1987					    transfer < 0) {
1988						st_printk(KERN_NOTICE, STp,
1989							  "Failed to read %d "
1990							  "byte block with %d "
1991							  "byte transfer.\n",
1992							  bytes - transfer,
1993							  bytes);
1994						if (STps->drv_block >= 0)
1995							STps->drv_block += 1;
1996						STbp->buffer_bytes = 0;
1997						return (-ENOMEM);
1998					} else if (STp->block_size == 0) {
1999						STbp->buffer_bytes = bytes - transfer;
2000					} else {
2001						st_release_request(SRpnt);
2002						SRpnt = *aSRpnt = NULL;
2003						if (transfer == blks) {	/* We did not get anything, error */
2004							st_printk(KERN_NOTICE, STp,
2005								  "Incorrect "
2006								  "block size.\n");
2007							if (STps->drv_block >= 0)
2008								STps->drv_block += blks - transfer + 1;
2009							st_int_ioctl(STp, MTBSR, 1);
2010							return (-EIO);
2011						}
2012						/* We have some data, deliver it */
2013						STbp->buffer_bytes = (blks - transfer) *
2014						    STp->block_size;
2015						DEBC_printk(STp, "ILI but "
2016							    "enough data "
2017							    "received %ld "
2018							    "%d.\n", count,
2019							    STbp->buffer_bytes);
2020						if (STps->drv_block >= 0)
2021							STps->drv_block += 1;
2022						if (st_int_ioctl(STp, MTBSR, 1))
2023							return (-EIO);
2024					}
2025				} else if (cmdstatp->flags & SENSE_FMK) {	/* FM overrides EOM */
2026					if (STps->eof != ST_FM_HIT)
2027						STps->eof = ST_FM_HIT;
2028					else
2029						STps->eof = ST_EOD_2;
2030					if (STp->block_size == 0)
2031						STbp->buffer_bytes = 0;
2032					else
2033						STbp->buffer_bytes =
2034						    bytes - transfer * STp->block_size;
2035					DEBC_printk(STp, "EOF detected (%d "
2036						    "bytes read).\n",
2037						    STbp->buffer_bytes);
2038				} else if (cmdstatp->flags & SENSE_EOM) {
2039					if (STps->eof == ST_FM)
2040						STps->eof = ST_EOD_1;
2041					else
2042						STps->eof = ST_EOM_OK;
2043					if (STp->block_size == 0)
2044						STbp->buffer_bytes = bytes - transfer;
2045					else
2046						STbp->buffer_bytes =
2047						    bytes - transfer * STp->block_size;
2048
2049					DEBC_printk(STp, "EOM detected (%d "
2050						    "bytes read).\n",
2051						    STbp->buffer_bytes);
2052				}
2053			}
2054			/* end of EOF, EOM, ILI test */
2055			else {	/* nonzero sense key */
2056				DEBC_printk(STp, "Tape error while reading.\n");
2057				STps->drv_block = (-1);
2058				if (STps->eof == ST_FM &&
2059				    cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2060					DEBC_printk(STp, "Zero returned for "
2061						    "first BLANK CHECK "
2062						    "after EOF.\n");
2063					STps->eof = ST_EOD_2;	/* First BLANK_CHECK after FM */
2064				} else	/* Some other extended sense code */
2065					retval = (-EIO);
2066			}
2067
2068			if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2069				STbp->buffer_bytes = 0;
2070		}
2071		/* End of extended sense test */
2072		else {		/* Non-extended sense */
2073			retval = STbp->syscall_result;
2074		}
2075
2076	}
2077	/* End of error handling */
2078	else {			/* Read successful */
2079		STbp->buffer_bytes = bytes;
2080		if (STp->sili) /* In fixed block mode residual is always zero here */
2081			STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2082	}
2083
2084	if (STps->drv_block >= 0) {
2085		if (STp->block_size == 0)
2086			STps->drv_block++;
2087		else
2088			STps->drv_block += STbp->buffer_bytes / STp->block_size;
2089	}
2090	return retval;
2091}
2092
2093
2094/* Read command */
2095static ssize_t
2096st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2097{
2098	ssize_t total;
2099	ssize_t retval = 0;
2100	ssize_t i, transfer;
2101	int special, do_dio = 0;
2102	struct st_request *SRpnt = NULL;
2103	struct scsi_tape *STp = filp->private_data;
2104	struct st_modedef *STm;
2105	struct st_partstat *STps;
2106	struct st_buffer *STbp = STp->buffer;
2107
2108	if (mutex_lock_interruptible(&STp->lock))
2109		return -ERESTARTSYS;
2110
2111	retval = rw_checks(STp, filp, count);
2112	if (retval || count == 0)
2113		goto out;
2114
2115	STm = &(STp->modes[STp->current_mode]);
2116	if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2117		if (!STm->do_read_ahead) {
2118			retval = (-EINVAL);	/* Read must be integral number of blocks */
2119			goto out;
2120		}
2121		STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2122	}
2123
2124	STps = &(STp->ps[STp->partition]);
2125	if (STps->rw == ST_WRITING) {
2126		retval = flush_buffer(STp, 0);
2127		if (retval)
2128			goto out;
2129		STps->rw = ST_READING;
2130	}
2131	DEB(
2132	if (debugging && STps->eof != ST_NOEOF)
2133		st_printk(ST_DEB_MSG, STp,
2134			  "EOF/EOM flag up (%d). Bytes %d\n",
2135			  STps->eof, STbp->buffer_bytes);
2136	) /* end DEB */
2137
2138	retval = setup_buffering(STp, buf, count, 1);
2139	if (retval)
2140		goto out;
2141	do_dio = STbp->do_dio;
2142
2143	if (STbp->buffer_bytes == 0 &&
2144	    STps->eof >= ST_EOD_1) {
2145		if (STps->eof < ST_EOD) {
2146			STps->eof += 1;
2147			retval = 0;
2148			goto out;
2149		}
2150		retval = (-EIO);	/* EOM or Blank Check */
2151		goto out;
2152	}
2153
2154	if (do_dio) {
2155		/* Check the buffer writability before any tape movement. Don't alter
2156		   buffer data. */
2157		if (copy_from_user(&i, buf, 1) != 0 ||
2158		    copy_to_user(buf, &i, 1) != 0 ||
2159		    copy_from_user(&i, buf + count - 1, 1) != 0 ||
2160		    copy_to_user(buf + count - 1, &i, 1) != 0) {
2161			retval = (-EFAULT);
2162			goto out;
2163		}
2164	}
2165
2166	STps->rw = ST_READING;
2167
2168
2169	/* Loop until enough data in buffer or a special condition found */
2170	for (total = 0, special = 0; total < count && !special;) {
2171
2172		/* Get new data if the buffer is empty */
2173		if (STbp->buffer_bytes == 0) {
2174			special = read_tape(STp, count - total, &SRpnt);
2175			if (special < 0) {	/* No need to continue read */
2176				retval = special;
2177				goto out;
2178			}
2179		}
2180
2181		/* Move the data from driver buffer to user buffer */
2182		if (STbp->buffer_bytes > 0) {
2183			DEB(
2184			if (debugging && STps->eof != ST_NOEOF)
2185				st_printk(ST_DEB_MSG, STp,
2186					  "EOF up (%d). Left %d, needed %d.\n",
2187					  STps->eof, STbp->buffer_bytes,
2188					  (int)(count - total));
2189			) /* end DEB */
2190			transfer = STbp->buffer_bytes < count - total ?
2191			    STbp->buffer_bytes : count - total;
2192			if (!do_dio) {
2193				i = from_buffer(STbp, buf, transfer);
2194				if (i) {
2195					retval = i;
2196					goto out;
2197				}
2198			}
2199			buf += transfer;
2200			total += transfer;
2201		}
2202
2203		if (STp->block_size == 0)
2204			break;	/* Read only one variable length block */
2205
2206	}			/* for (total = 0, special = 0;
2207                                   total < count && !special; ) */
2208
2209	/* Change the eof state if no data from tape or buffer */
2210	if (total == 0) {
2211		if (STps->eof == ST_FM_HIT) {
2212			STps->eof = ST_FM;
2213			STps->drv_block = 0;
2214			if (STps->drv_file >= 0)
2215				STps->drv_file++;
2216		} else if (STps->eof == ST_EOD_1) {
2217			STps->eof = ST_EOD_2;
2218			STps->drv_block = 0;
2219			if (STps->drv_file >= 0)
2220				STps->drv_file++;
2221		} else if (STps->eof == ST_EOD_2)
2222			STps->eof = ST_EOD;
2223	} else if (STps->eof == ST_FM)
2224		STps->eof = ST_NOEOF;
2225	retval = total;
2226
2227 out:
2228	if (SRpnt != NULL) {
2229		st_release_request(SRpnt);
2230		SRpnt = NULL;
2231	}
2232	if (do_dio) {
2233		release_buffering(STp, 1);
2234		STbp->buffer_bytes = 0;
2235	}
2236	mutex_unlock(&STp->lock);
2237
2238	return retval;
2239}
2240
2241
2242
2243DEB(
2244/* Set the driver options */
2245static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2246{
2247	if (debugging) {
2248		st_printk(KERN_INFO, STp,
2249			  "Mode %d options: buffer writes: %d, "
2250			  "async writes: %d, read ahead: %d\n",
2251			  STp->current_mode, STm->do_buffer_writes,
2252			  STm->do_async_writes, STm->do_read_ahead);
2253		st_printk(KERN_INFO, STp,
2254			  "    can bsr: %d, two FMs: %d, "
2255			  "fast mteom: %d, auto lock: %d,\n",
2256			  STp->can_bsr, STp->two_fm, STp->fast_mteom,
2257			  STp->do_auto_lock);
2258		st_printk(KERN_INFO, STp,
2259			  "    defs for wr: %d, no block limits: %d, "
2260			  "partitions: %d, s2 log: %d\n",
2261			  STm->defaults_for_writes, STp->omit_blklims,
2262			  STp->can_partitions, STp->scsi2_logical);
2263		st_printk(KERN_INFO, STp,
2264			  "    sysv: %d nowait: %d sili: %d "
2265			  "nowait_filemark: %d\n",
2266			  STm->sysv, STp->immediate, STp->sili,
2267			  STp->immediate_filemark);
2268		st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2269	}
2270}
2271	)
2272
2273
2274static int st_set_options(struct scsi_tape *STp, long options)
2275{
2276	int value;
2277	long code;
2278	struct st_modedef *STm;
2279	struct cdev *cd0, *cd1;
2280	struct device *d0, *d1;
2281
2282	STm = &(STp->modes[STp->current_mode]);
2283	if (!STm->defined) {
2284		cd0 = STm->cdevs[0];
2285		cd1 = STm->cdevs[1];
2286		d0  = STm->devs[0];
2287		d1  = STm->devs[1];
2288		memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2289		STm->cdevs[0] = cd0;
2290		STm->cdevs[1] = cd1;
2291		STm->devs[0]  = d0;
2292		STm->devs[1]  = d1;
2293		modes_defined = 1;
2294		DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2295			    STp->current_mode);
2296	}
2297
2298	code = options & MT_ST_OPTIONS;
2299	if (code == MT_ST_BOOLEANS) {
2300		STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2301		STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2302		STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2303		STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2304		STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2305		STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2306		STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2307		STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2308		STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2309		if ((STp->device)->scsi_level >= SCSI_2)
2310			STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2311		STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2312		STp->immediate = (options & MT_ST_NOWAIT) != 0;
2313		STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2314		STm->sysv = (options & MT_ST_SYSV) != 0;
2315		STp->sili = (options & MT_ST_SILI) != 0;
2316		DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2317		     st_log_options(STp, STm); )
2318	} else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2319		value = (code == MT_ST_SETBOOLEANS);
2320		if ((options & MT_ST_BUFFER_WRITES) != 0)
2321			STm->do_buffer_writes = value;
2322		if ((options & MT_ST_ASYNC_WRITES) != 0)
2323			STm->do_async_writes = value;
2324		if ((options & MT_ST_DEF_WRITES) != 0)
2325			STm->defaults_for_writes = value;
2326		if ((options & MT_ST_READ_AHEAD) != 0)
2327			STm->do_read_ahead = value;
2328		if ((options & MT_ST_TWO_FM) != 0)
2329			STp->two_fm = value;
2330		if ((options & MT_ST_FAST_MTEOM) != 0)
2331			STp->fast_mteom = value;
2332		if ((options & MT_ST_AUTO_LOCK) != 0)
2333			STp->do_auto_lock = value;
2334		if ((options & MT_ST_CAN_BSR) != 0)
2335			STp->can_bsr = value;
2336		if ((options & MT_ST_NO_BLKLIMS) != 0)
2337			STp->omit_blklims = value;
2338		if ((STp->device)->scsi_level >= SCSI_2 &&
2339		    (options & MT_ST_CAN_PARTITIONS) != 0)
2340			STp->can_partitions = value;
2341		if ((options & MT_ST_SCSI2LOGICAL) != 0)
2342			STp->scsi2_logical = value;
2343		if ((options & MT_ST_NOWAIT) != 0)
2344			STp->immediate = value;
2345		if ((options & MT_ST_NOWAIT_EOF) != 0)
2346			STp->immediate_filemark = value;
2347		if ((options & MT_ST_SYSV) != 0)
2348			STm->sysv = value;
2349		if ((options & MT_ST_SILI) != 0)
2350			STp->sili = value;
2351		DEB(
2352		if ((options & MT_ST_DEBUGGING) != 0)
2353			debugging = value;
2354			st_log_options(STp, STm); )
2355	} else if (code == MT_ST_WRITE_THRESHOLD) {
2356		/* Retained for compatibility */
2357	} else if (code == MT_ST_DEF_BLKSIZE) {
2358		value = (options & ~MT_ST_OPTIONS);
2359		if (value == ~MT_ST_OPTIONS) {
2360			STm->default_blksize = (-1);
2361			DEBC_printk(STp, "Default block size disabled.\n");
2362		} else {
2363			STm->default_blksize = value;
2364			DEBC_printk(STp,"Default block size set to "
2365				    "%d bytes.\n", STm->default_blksize);
2366			if (STp->ready == ST_READY) {
2367				STp->blksize_changed = 0;
2368				set_mode_densblk(STp, STm);
2369			}
2370		}
2371	} else if (code == MT_ST_TIMEOUTS) {
2372		value = (options & ~MT_ST_OPTIONS);
2373		if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2374			STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2375			DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2376				    (value & ~MT_ST_SET_LONG_TIMEOUT));
2377		} else {
2378			blk_queue_rq_timeout(STp->device->request_queue,
2379					     value * HZ);
2380			DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2381				    value);
2382		}
2383	} else if (code == MT_ST_SET_CLN) {
2384		value = (options & ~MT_ST_OPTIONS) & 0xff;
2385		if (value != 0 &&
2386			(value < EXTENDED_SENSE_START ||
2387				value >= SCSI_SENSE_BUFFERSIZE))
2388			return (-EINVAL);
2389		STp->cln_mode = value;
2390		STp->cln_sense_mask = (options >> 8) & 0xff;
2391		STp->cln_sense_value = (options >> 16) & 0xff;
2392		st_printk(KERN_INFO, STp,
2393			  "Cleaning request mode %d, mask %02x, value %02x\n",
2394			  value, STp->cln_sense_mask, STp->cln_sense_value);
2395	} else if (code == MT_ST_DEF_OPTIONS) {
2396		code = (options & ~MT_ST_CLEAR_DEFAULT);
2397		value = (options & MT_ST_CLEAR_DEFAULT);
2398		if (code == MT_ST_DEF_DENSITY) {
2399			if (value == MT_ST_CLEAR_DEFAULT) {
2400				STm->default_density = (-1);
2401				DEBC_printk(STp,
2402					    "Density default disabled.\n");
2403			} else {
2404				STm->default_density = value & 0xff;
2405				DEBC_printk(STp, "Density default set to %x\n",
2406					    STm->default_density);
2407				if (STp->ready == ST_READY) {
2408					STp->density_changed = 0;
2409					set_mode_densblk(STp, STm);
2410				}
2411			}
2412		} else if (code == MT_ST_DEF_DRVBUFFER) {
2413			if (value == MT_ST_CLEAR_DEFAULT) {
2414				STp->default_drvbuffer = 0xff;
2415				DEBC_printk(STp,
2416					    "Drive buffer default disabled.\n");
2417			} else {
2418				STp->default_drvbuffer = value & 7;
2419				DEBC_printk(STp,
2420					    "Drive buffer default set to %x\n",
2421					    STp->default_drvbuffer);
2422				if (STp->ready == ST_READY)
2423					st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2424			}
2425		} else if (code == MT_ST_DEF_COMPRESSION) {
2426			if (value == MT_ST_CLEAR_DEFAULT) {
2427				STm->default_compression = ST_DONT_TOUCH;
2428				DEBC_printk(STp,
2429					    "Compression default disabled.\n");
2430			} else {
2431				if ((value & 0xff00) != 0) {
2432					STp->c_algo = (value & 0xff00) >> 8;
2433					DEBC_printk(STp, "Compression "
2434						    "algorithm set to 0x%x.\n",
2435						    STp->c_algo);
2436				}
2437				if ((value & 0xff) != 0xff) {
2438					STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2439					DEBC_printk(STp, "Compression default "
2440						    "set to %x\n",
2441						    (value & 1));
2442					if (STp->ready == ST_READY) {
2443						STp->compression_changed = 0;
2444						st_compression(STp, (STm->default_compression == ST_YES));
2445					}
2446				}
2447			}
2448		}
2449	} else
2450		return (-EIO);
2451
2452	return 0;
2453}
2454
2455#define MODE_HEADER_LENGTH  4
2456
2457/* Mode header and page byte offsets */
2458#define MH_OFF_DATA_LENGTH     0
2459#define MH_OFF_MEDIUM_TYPE     1
2460#define MH_OFF_DEV_SPECIFIC    2
2461#define MH_OFF_BDESCS_LENGTH   3
2462#define MP_OFF_PAGE_NBR        0
2463#define MP_OFF_PAGE_LENGTH     1
2464
2465/* Mode header and page bit masks */
2466#define MH_BIT_WP              0x80
2467#define MP_MSK_PAGE_NBR        0x3f
2468
2469/* Don't return block descriptors */
2470#define MODE_SENSE_OMIT_BDESCS 0x08
2471
2472#define MODE_SELECT_PAGE_FORMAT 0x10
2473
2474/* Read a mode page into the tape buffer. The block descriptors are included
2475   if incl_block_descs is true. The page control is ored to the page number
2476   parameter, if necessary. */
2477static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2478{
2479	unsigned char cmd[MAX_COMMAND_SIZE];
2480	struct st_request *SRpnt;
2481
2482	memset(cmd, 0, MAX_COMMAND_SIZE);
2483	cmd[0] = MODE_SENSE;
2484	if (omit_block_descs)
2485		cmd[1] = MODE_SENSE_OMIT_BDESCS;
2486	cmd[2] = page;
2487	cmd[4] = 255;
2488
2489	SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2490			   STp->device->request_queue->rq_timeout, 0, 1);
2491	if (SRpnt == NULL)
2492		return (STp->buffer)->syscall_result;
2493
2494	st_release_request(SRpnt);
2495
2496	return STp->buffer->syscall_result;
2497}
2498
2499
2500/* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2501   in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2502static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2503{
2504	int pgo;
2505	unsigned char cmd[MAX_COMMAND_SIZE];
2506	struct st_request *SRpnt;
2507	int timeout;
2508
2509	memset(cmd, 0, MAX_COMMAND_SIZE);
2510	cmd[0] = MODE_SELECT;
2511	cmd[1] = MODE_SELECT_PAGE_FORMAT;
2512	pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2513	cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2514
2515	/* Clear reserved fields */
2516	(STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2517	(STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2518	(STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2519	(STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2520
2521	timeout = slow ?
2522		STp->long_timeout : STp->device->request_queue->rq_timeout;
2523	SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2524			   timeout, 0, 1);
2525	if (SRpnt == NULL)
2526		return (STp->buffer)->syscall_result;
2527
2528	st_release_request(SRpnt);
2529
2530	return STp->buffer->syscall_result;
2531}
2532
2533
2534#define COMPRESSION_PAGE        0x0f
2535#define COMPRESSION_PAGE_LENGTH 16
2536
2537#define CP_OFF_DCE_DCC          2
2538#define CP_OFF_C_ALGO           7
2539
2540#define DCE_MASK  0x80
2541#define DCC_MASK  0x40
2542#define RED_MASK  0x60
2543
2544
2545/* Control the compression with mode page 15. Algorithm not changed if zero.
2546
2547   The block descriptors are read and written because Sony SDT-7000 does not
2548   work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2549   Including block descriptors should not cause any harm to other drives. */
2550
2551static int st_compression(struct scsi_tape * STp, int state)
2552{
2553	int retval;
2554	int mpoffs;  /* Offset to mode page start */
2555	unsigned char *b_data = (STp->buffer)->b_data;
2556
2557	if (STp->ready != ST_READY)
2558		return (-EIO);
2559
2560	/* Read the current page contents */
2561	retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2562	if (retval) {
2563		DEBC_printk(STp, "Compression mode page not supported.\n");
2564		return (-EIO);
2565	}
2566
2567	mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2568	DEBC_printk(STp, "Compression state is %d.\n",
2569		    (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2570
2571	/* Check if compression can be changed */
2572	if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2573		DEBC_printk(STp, "Compression not supported.\n");
2574		return (-EIO);
2575	}
2576
2577	/* Do the change */
2578	if (state) {
2579		b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2580		if (STp->c_algo != 0)
2581			b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2582	}
2583	else {
2584		b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2585		if (STp->c_algo != 0)
2586			b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2587	}
2588
2589	retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2590	if (retval) {
2591		DEBC_printk(STp, "Compression change failed.\n");
2592		return (-EIO);
2593	}
2594	DEBC_printk(STp, "Compression state changed to %d.\n", state);
2595
2596	STp->compression_changed = 1;
2597	return 0;
2598}
2599
2600
2601/* Process the load and unload commands (does unload if the load code is zero) */
2602static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2603{
2604	int retval = (-EIO), timeout;
2605	unsigned char cmd[MAX_COMMAND_SIZE];
2606	struct st_partstat *STps;
2607	struct st_request *SRpnt;
2608
2609	if (STp->ready != ST_READY && !load_code) {
2610		if (STp->ready == ST_NO_TAPE)
2611			return (-ENOMEDIUM);
2612		else
2613			return (-EIO);
2614	}
2615
2616	memset(cmd, 0, MAX_COMMAND_SIZE);
2617	cmd[0] = START_STOP;
2618	if (load_code)
2619		cmd[4] |= 1;
2620	/*
2621	 * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2622	 */
2623	if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2624	    && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2625		DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2626			    (cmd[4]) ? "" : "un",
2627			    load_code - MT_ST_HPLOADER_OFFSET);
2628		cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2629	}
2630	if (STp->immediate) {
2631		cmd[1] = 1;	/* Don't wait for completion */
2632		timeout = STp->device->request_queue->rq_timeout;
2633	}
2634	else
2635		timeout = STp->long_timeout;
2636
2637	DEBC(
2638		if (!load_code)
2639			st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2640		else
2641			st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2642		);
2643
2644	SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2645			   timeout, MAX_RETRIES, 1);
2646	if (!SRpnt)
2647		return (STp->buffer)->syscall_result;
2648
2649	retval = (STp->buffer)->syscall_result;
2650	st_release_request(SRpnt);
2651
2652	if (!retval) {	/* SCSI command successful */
2653
2654		if (!load_code) {
2655			STp->rew_at_close = 0;
2656			STp->ready = ST_NO_TAPE;
2657		}
2658		else {
2659			STp->rew_at_close = STp->autorew_dev;
2660			retval = check_tape(STp, filp);
2661			if (retval > 0)
2662				retval = 0;
2663		}
2664	}
2665	else {
2666		STps = &(STp->ps[STp->partition]);
2667		STps->drv_file = STps->drv_block = (-1);
2668	}
2669
2670	return retval;
2671}
2672
2673#if DEBUG
2674#define ST_DEB_FORWARD  0
2675#define ST_DEB_BACKWARD 1
2676static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2677{
2678	s32 sc;
2679
2680	if (!debugging)
2681		return;
2682
2683	sc = cmd[2] & 0x80 ? 0xff000000 : 0;
2684	sc |= (cmd[2] << 16) | (cmd[3] << 8) | cmd[4];
2685	if (direction)
2686		sc = -sc;
2687	st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2688		  direction ? "backward" : "forward", sc, units);
2689}
2690#else
2691#define ST_DEB_FORWARD  0
2692#define ST_DEB_BACKWARD 1
2693static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2694#endif
2695
2696
2697/* Internal ioctl function */
2698static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2699{
2700	int timeout;
2701	long ltmp;
2702	int ioctl_result;
2703	int chg_eof = 1;
2704	unsigned char cmd[MAX_COMMAND_SIZE];
2705	struct st_request *SRpnt;
2706	struct st_partstat *STps;
2707	int fileno, blkno, at_sm, undone;
2708	int datalen = 0, direction = DMA_NONE;
2709
2710	WARN_ON(STp->buffer->do_dio != 0);
2711	if (STp->ready != ST_READY) {
2712		if (STp->ready == ST_NO_TAPE)
2713			return (-ENOMEDIUM);
2714		else
2715			return (-EIO);
2716	}
2717	timeout = STp->long_timeout;
2718	STps = &(STp->ps[STp->partition]);
2719	fileno = STps->drv_file;
2720	blkno = STps->drv_block;
2721	at_sm = STps->at_sm;
2722
2723	memset(cmd, 0, MAX_COMMAND_SIZE);
2724	switch (cmd_in) {
2725	case MTFSFM:
2726		chg_eof = 0;	/* Changed from the FSF after this */
2727	case MTFSF:
2728		cmd[0] = SPACE;
2729		cmd[1] = 0x01;	/* Space FileMarks */
2730		cmd[2] = (arg >> 16);
2731		cmd[3] = (arg >> 8);
2732		cmd[4] = arg;
2733		deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2734		if (fileno >= 0)
2735			fileno += arg;
2736		blkno = 0;
2737		at_sm &= (arg == 0);
2738		break;
2739	case MTBSFM:
2740		chg_eof = 0;	/* Changed from the FSF after this */
2741	case MTBSF:
2742		cmd[0] = SPACE;
2743		cmd[1] = 0x01;	/* Space FileMarks */
2744		ltmp = (-arg);
2745		cmd[2] = (ltmp >> 16);
2746		cmd[3] = (ltmp >> 8);
2747		cmd[4] = ltmp;
2748		deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2749		if (fileno >= 0)
2750			fileno -= arg;
2751		blkno = (-1);	/* We can't know the block number */
2752		at_sm &= (arg == 0);
2753		break;
2754	case MTFSR:
2755		cmd[0] = SPACE;
2756		cmd[1] = 0x00;	/* Space Blocks */
2757		cmd[2] = (arg >> 16);
2758		cmd[3] = (arg >> 8);
2759		cmd[4] = arg;
2760		deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2761		if (blkno >= 0)
2762			blkno += arg;
2763		at_sm &= (arg == 0);
2764		break;
2765	case MTBSR:
2766		cmd[0] = SPACE;
2767		cmd[1] = 0x00;	/* Space Blocks */
2768		ltmp = (-arg);
2769		cmd[2] = (ltmp >> 16);
2770		cmd[3] = (ltmp >> 8);
2771		cmd[4] = ltmp;
2772		deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2773		if (blkno >= 0)
2774			blkno -= arg;
2775		at_sm &= (arg == 0);
2776		break;
2777	case MTFSS:
2778		cmd[0] = SPACE;
2779		cmd[1] = 0x04;	/* Space Setmarks */
2780		cmd[2] = (arg >> 16);
2781		cmd[3] = (arg >> 8);
2782		cmd[4] = arg;
2783		deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2784		if (arg != 0) {
2785			blkno = fileno = (-1);
2786			at_sm = 1;
2787		}
2788		break;
2789	case MTBSS:
2790		cmd[0] = SPACE;
2791		cmd[1] = 0x04;	/* Space Setmarks */
2792		ltmp = (-arg);
2793		cmd[2] = (ltmp >> 16);
2794		cmd[3] = (ltmp >> 8);
2795		cmd[4] = ltmp;
2796		deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2797		if (arg != 0) {
2798			blkno = fileno = (-1);
2799			at_sm = 1;
2800		}
2801		break;
2802	case MTWEOF:
2803	case MTWEOFI:
2804	case MTWSM:
2805		if (STp->write_prot)
2806			return (-EACCES);
2807		cmd[0] = WRITE_FILEMARKS;
2808		if (cmd_in == MTWSM)
2809			cmd[1] = 2;
2810		if (cmd_in == MTWEOFI ||
2811		    (cmd_in == MTWEOF && STp->immediate_filemark))
2812			cmd[1] |= 1;
2813		cmd[2] = (arg >> 16);
2814		cmd[3] = (arg >> 8);
2815		cmd[4] = arg;
2816		timeout = STp->device->request_queue->rq_timeout;
2817		DEBC(
2818			if (cmd_in != MTWSM)
2819				st_printk(ST_DEB_MSG, STp,
2820					  "Writing %d filemarks.\n",
2821					  cmd[2] * 65536 +
2822					  cmd[3] * 256 +
2823					  cmd[4]);
2824			else
2825				st_printk(ST_DEB_MSG, STp,
2826					  "Writing %d setmarks.\n",
2827					  cmd[2] * 65536 +
2828					  cmd[3] * 256 +
2829					  cmd[4]);
2830		)
2831		if (fileno >= 0)
2832			fileno += arg;
2833		blkno = 0;
2834		at_sm = (cmd_in == MTWSM);
2835		break;
2836	case MTREW:
2837		cmd[0] = REZERO_UNIT;
2838		if (STp->immediate) {
2839			cmd[1] = 1;	/* Don't wait for completion */
2840			timeout = STp->device->request_queue->rq_timeout;
2841		}
2842		DEBC_printk(STp, "Rewinding tape.\n");
2843		fileno = blkno = at_sm = 0;
2844		break;
2845	case MTNOP:
2846		DEBC_printk(STp, "No op on tape.\n");
2847		return 0;	/* Should do something ? */
2848		break;
2849	case MTRETEN:
2850		cmd[0] = START_STOP;
2851		if (STp->immediate) {
2852			cmd[1] = 1;	/* Don't wait for completion */
2853			timeout = STp->device->request_queue->rq_timeout;
2854		}
2855		cmd[4] = 3;
2856		DEBC_printk(STp, "Retensioning tape.\n");
2857		fileno = blkno = at_sm = 0;
2858		break;
2859	case MTEOM:
2860		if (!STp->fast_mteom) {
2861			/* space to the end of tape */
2862			ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2863			fileno = STps->drv_file;
2864			if (STps->eof >= ST_EOD_1)
2865				return 0;
2866			/* The next lines would hide the number of spaced FileMarks
2867			   That's why I inserted the previous lines. I had no luck
2868			   with detecting EOM with FSF, so we go now to EOM.
2869			   Joerg Weule */
2870		} else
2871			fileno = (-1);
2872		cmd[0] = SPACE;
2873		cmd[1] = 3;
2874		DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2875		blkno = -1;
2876		at_sm = 0;
2877		break;
2878	case MTERASE:
2879		if (STp->write_prot)
2880			return (-EACCES);
2881		cmd[0] = ERASE;
2882		cmd[1] = (arg ? 1 : 0);	/* Long erase with non-zero argument */
2883		if (STp->immediate) {
2884			cmd[1] |= 2;	/* Don't wait for completion */
2885			timeout = STp->device->request_queue->rq_timeout;
2886		}
2887		else
2888			timeout = STp->long_timeout * 8;
2889
2890		DEBC_printk(STp, "Erasing tape.\n");
2891		fileno = blkno = at_sm = 0;
2892		break;
2893	case MTSETBLK:		/* Set block length */
2894	case MTSETDENSITY:	/* Set tape density */
2895	case MTSETDRVBUFFER:	/* Set drive buffering */
2896	case SET_DENS_AND_BLK:	/* Set density and block size */
2897		chg_eof = 0;
2898		if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2899			return (-EIO);	/* Not allowed if data in buffer */
2900		if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2901		    (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2902		    STp->max_block > 0 &&
2903		    ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2904		     (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2905			st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2906			return (-EINVAL);
2907		}
2908		cmd[0] = MODE_SELECT;
2909		if ((STp->use_pf & USE_PF))
2910			cmd[1] = MODE_SELECT_PAGE_FORMAT;
2911		cmd[4] = datalen = 12;
2912		direction = DMA_TO_DEVICE;
2913
2914		memset((STp->buffer)->b_data, 0, 12);
2915		if (cmd_in == MTSETDRVBUFFER)
2916			(STp->buffer)->b_data[2] = (arg & 7) << 4;
2917		else
2918			(STp->buffer)->b_data[2] =
2919			    STp->drv_buffer << 4;
2920		(STp->buffer)->b_data[3] = 8;	/* block descriptor length */
2921		if (cmd_in == MTSETDENSITY) {
2922			(STp->buffer)->b_data[4] = arg;
2923			STp->density_changed = 1;	/* At least we tried ;-) */
2924		} else if (cmd_in == SET_DENS_AND_BLK)
2925			(STp->buffer)->b_data[4] = arg >> 24;
2926		else
2927			(STp->buffer)->b_data[4] = STp->density;
2928		if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2929			ltmp = arg & MT_ST_BLKSIZE_MASK;
2930			if (cmd_in == MTSETBLK)
2931				STp->blksize_changed = 1; /* At least we tried ;-) */
2932		} else
2933			ltmp = STp->block_size;
2934		(STp->buffer)->b_data[9] = (ltmp >> 16);
2935		(STp->buffer)->b_data[10] = (ltmp >> 8);
2936		(STp->buffer)->b_data[11] = ltmp;
2937		timeout = STp->device->request_queue->rq_timeout;
2938		DEBC(
2939			if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2940				st_printk(ST_DEB_MSG, STp,
2941					  "Setting block size to %d bytes.\n",
2942					  (STp->buffer)->b_data[9] * 65536 +
2943					  (STp->buffer)->b_data[10] * 256 +
2944					  (STp->buffer)->b_data[11]);
2945			if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2946				st_printk(ST_DEB_MSG, STp,
2947					  "Setting density code to %x.\n",
2948					  (STp->buffer)->b_data[4]);
2949			if (cmd_in == MTSETDRVBUFFER)
2950				st_printk(ST_DEB_MSG, STp,
2951					  "Setting drive buffer code to %d.\n",
2952					  ((STp->buffer)->b_data[2] >> 4) & 7);
2953		)
2954		break;
2955	default:
2956		return (-ENOSYS);
2957	}
2958
2959	SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2960			   timeout, MAX_RETRIES, 1);
2961	if (!SRpnt)
2962		return (STp->buffer)->syscall_result;
2963
2964	ioctl_result = (STp->buffer)->syscall_result;
2965
2966	if (!ioctl_result) {	/* SCSI command successful */
2967		st_release_request(SRpnt);
2968		SRpnt = NULL;
2969		STps->drv_block = blkno;
2970		STps->drv_file = fileno;
2971		STps->at_sm = at_sm;
2972
2973		if (cmd_in == MTBSFM)
2974			ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2975		else if (cmd_in == MTFSFM)
2976			ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2977
2978		if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2979			STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2980			if (STp->block_size != 0) {
2981				(STp->buffer)->buffer_blocks =
2982				    (STp->buffer)->buffer_size / STp->block_size;
2983			}
2984			(STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2985			if (cmd_in == SET_DENS_AND_BLK)
2986				STp->density = arg >> MT_ST_DENSITY_SHIFT;
2987		} else if (cmd_in == MTSETDRVBUFFER)
2988			STp->drv_buffer = (arg & 7);
2989		else if (cmd_in == MTSETDENSITY)
2990			STp->density = arg;
2991
2992		if (cmd_in == MTEOM)
2993			STps->eof = ST_EOD;
2994		else if (cmd_in == MTFSF)
2995			STps->eof = ST_FM;
2996		else if (chg_eof)
2997			STps->eof = ST_NOEOF;
2998
2999		if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
3000			STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
3001	} else { /* SCSI command was not completely successful. Don't return
3002                    from this block without releasing the SCSI command block! */
3003		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3004
3005		if (cmdstatp->flags & SENSE_EOM) {
3006			if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3007			    cmd_in != MTBSR && cmd_in != MTBSS)
3008				STps->eof = ST_EOM_OK;
3009			STps->drv_block = 0;
3010		}
3011
3012		if (cmdstatp->remainder_valid)
3013			undone = (int)cmdstatp->uremainder64;
3014		else
3015			undone = 0;
3016
3017		if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3018		    cmdstatp->have_sense &&
3019		    (cmdstatp->flags & SENSE_EOM)) {
3020			if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3021			    cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3022				ioctl_result = 0;	/* EOF(s) written successfully at EOM */
3023				STps->eof = ST_NOEOF;
3024			} else {  /* Writing EOF(s) failed */
3025				if (fileno >= 0)
3026					fileno -= undone;
3027				if (undone < arg)
3028					STps->eof = ST_NOEOF;
3029			}
3030			STps->drv_file = fileno;
3031		} else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3032			if (fileno >= 0)
3033				STps->drv_file = fileno - undone;
3034			else
3035				STps->drv_file = fileno;
3036			STps->drv_block = -1;
3037			STps->eof = ST_NOEOF;
3038		} else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3039			if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3040				undone = (-undone);
3041			if (STps->drv_file >= 0)
3042				STps->drv_file = fileno + undone;
3043			STps->drv_block = 0;
3044			STps->eof = ST_NOEOF;
3045		} else if (cmd_in == MTFSR) {
3046			if (cmdstatp->flags & SENSE_FMK) {	/* Hit filemark */
3047				if (STps->drv_file >= 0)
3048					STps->drv_file++;
3049				STps->drv_block = 0;
3050				STps->eof = ST_FM;
3051			} else {
3052				if (blkno >= undone)
3053					STps->drv_block = blkno - undone;
3054				else
3055					STps->drv_block = (-1);
3056				STps->eof = ST_NOEOF;
3057			}
3058		} else if (cmd_in == MTBSR) {
3059			if (cmdstatp->flags & SENSE_FMK) {	/* Hit filemark */
3060				STps->drv_file--;
3061				STps->drv_block = (-1);
3062			} else {
3063				if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3064					undone = (-undone);
3065				if (STps->drv_block >= 0)
3066					STps->drv_block = blkno + undone;
3067			}
3068			STps->eof = ST_NOEOF;
3069		} else if (cmd_in == MTEOM) {
3070			STps->drv_file = (-1);
3071			STps->drv_block = (-1);
3072			STps->eof = ST_EOD;
3073		} else if (cmd_in == MTSETBLK ||
3074			   cmd_in == MTSETDENSITY ||
3075			   cmd_in == MTSETDRVBUFFER ||
3076			   cmd_in == SET_DENS_AND_BLK) {
3077			if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3078			    !(STp->use_pf & PF_TESTED)) {
3079				/* Try the other possible state of Page Format if not
3080				   already tried */
3081				STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3082				st_release_request(SRpnt);
3083				SRpnt = NULL;
3084				return st_int_ioctl(STp, cmd_in, arg);
3085			}
3086		} else if (chg_eof)
3087			STps->eof = ST_NOEOF;
3088
3089		if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3090			STps->eof = ST_EOD;
3091
3092		st_release_request(SRpnt);
3093		SRpnt = NULL;
3094	}
3095
3096	return ioctl_result;
3097}
3098
3099
3100/* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3101   structure. */
3102
3103static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3104			int logical)
3105{
3106	int result;
3107	unsigned char scmd[MAX_COMMAND_SIZE];
3108	struct st_request *SRpnt;
3109
3110	if (STp->ready != ST_READY)
3111		return (-EIO);
3112
3113	memset(scmd, 0, MAX_COMMAND_SIZE);
3114	if ((STp->device)->scsi_level < SCSI_2) {
3115		scmd[0] = QFA_REQUEST_BLOCK;
3116		scmd[4] = 3;
3117	} else {
3118		scmd[0] = READ_POSITION;
3119		if (!logical && !STp->scsi2_logical)
3120			scmd[1] = 1;
3121	}
3122	SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3123			   STp->device->request_queue->rq_timeout,
3124			   MAX_READY_RETRIES, 1);
3125	if (!SRpnt)
3126		return (STp->buffer)->syscall_result;
3127
3128	if ((STp->buffer)->syscall_result != 0 ||
3129	    (STp->device->scsi_level >= SCSI_2 &&
3130	     ((STp->buffer)->b_data[0] & 4) != 0)) {
3131		*block = *partition = 0;
3132		DEBC_printk(STp, " Can't read tape position.\n");
3133		result = (-EIO);
3134	} else {
3135		result = 0;
3136		if ((STp->device)->scsi_level < SCSI_2) {
3137			*block = ((STp->buffer)->b_data[0] << 16)
3138			    + ((STp->buffer)->b_data[1] << 8)
3139			    + (STp->buffer)->b_data[2];
3140			*partition = 0;
3141		} else {
3142			*block = ((STp->buffer)->b_data[4] << 24)
3143			    + ((STp->buffer)->b_data[5] << 16)
3144			    + ((STp->buffer)->b_data[6] << 8)
3145			    + (STp->buffer)->b_data[7];
3146			*partition = (STp->buffer)->b_data[1];
3147			if (((STp->buffer)->b_data[0] & 0x80) &&
3148			    (STp->buffer)->b_data[1] == 0)	/* BOP of partition 0 */
3149				STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3150		}
3151		DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3152			    *block, *partition);
3153	}
3154	st_release_request(SRpnt);
3155	SRpnt = NULL;
3156
3157	return result;
3158}
3159
3160
3161/* Set the tape block and partition. Negative partition means that only the
3162   block should be set in vendor specific way. */
3163static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3164			int logical)
3165{
3166	struct st_partstat *STps;
3167	int result, p;
3168	unsigned int blk;
3169	int timeout;
3170	unsigned char scmd[MAX_COMMAND_SIZE];
3171	struct st_request *SRpnt;
3172
3173	if (STp->ready != ST_READY)
3174		return (-EIO);
3175	timeout = STp->long_timeout;
3176	STps = &(STp->ps[STp->partition]);
3177
3178	DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3179		    block, partition);
3180	DEB(if (partition < 0)
3181		return (-EIO); )
3182
3183	/* Update the location at the partition we are leaving */
3184	if ((!STp->can_partitions && partition != 0) ||
3185	    partition >= ST_NBR_PARTITIONS)
3186		return (-EINVAL);
3187	if (partition != STp->partition) {
3188		if (get_location(STp, &blk, &p, 1))
3189			STps->last_block_valid = 0;
3190		else {
3191			STps->last_block_valid = 1;
3192			STps->last_block_visited = blk;
3193			DEBC_printk(STp, "Visited block %d for "
3194				    "partition %d saved.\n",
3195				    blk, STp->partition);
3196		}
3197	}
3198
3199	memset(scmd, 0, MAX_COMMAND_SIZE);
3200	if ((STp->device)->scsi_level < SCSI_2) {
3201		scmd[0] = QFA_SEEK_BLOCK;
3202		scmd[2] = (block >> 16);
3203		scmd[3] = (block >> 8);
3204		scmd[4] = block;
3205		scmd[5] = 0;
3206	} else {
3207		scmd[0] = SEEK_10;
3208		scmd[3] = (block >> 24);
3209		scmd[4] = (block >> 16);
3210		scmd[5] = (block >> 8);
3211		scmd[6] = block;
3212		if (!logical && !STp->scsi2_logical)
3213			scmd[1] = 4;
3214		if (STp->partition != partition) {
3215			scmd[1] |= 2;
3216			scmd[8] = partition;
3217			DEBC_printk(STp, "Trying to change partition "
3218				    "from %d to %d\n", STp->partition,
3219				    partition);
3220		}
3221	}
3222	if (STp->immediate) {
3223		scmd[1] |= 1;		/* Don't wait for completion */
3224		timeout = STp->device->request_queue->rq_timeout;
3225	}
3226
3227	SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3228			   timeout, MAX_READY_RETRIES, 1);
3229	if (!SRpnt)
3230		return (STp->buffer)->syscall_result;
3231
3232	STps->drv_block = STps->drv_file = (-1);
3233	STps->eof = ST_NOEOF;
3234	if ((STp->buffer)->syscall_result != 0) {
3235		result = (-EIO);
3236		if (STp->can_partitions &&
3237		    (STp->device)->scsi_level >= SCSI_2 &&
3238		    (p = find_partition(STp)) >= 0)
3239			STp->partition = p;
3240	} else {
3241		if (STp->can_partitions) {
3242			STp->partition = partition;
3243			STps = &(STp->ps[partition]);
3244			if (!STps->last_block_valid ||
3245			    STps->last_block_visited != block) {
3246				STps->at_sm = 0;
3247				STps->rw = ST_IDLE;
3248			}
3249		} else
3250			STps->at_sm = 0;
3251		if (block == 0)
3252			STps->drv_block = STps->drv_file = 0;
3253		result = 0;
3254	}
3255
3256	st_release_request(SRpnt);
3257	SRpnt = NULL;
3258
3259	return result;
3260}
3261
3262
3263/* Find the current partition number for the drive status. Called from open and
3264   returns either partition number of negative error code. */
3265static int find_partition(struct scsi_tape *STp)
3266{
3267	int i, partition;
3268	unsigned int block;
3269
3270	if ((i = get_location(STp, &block, &partition, 1)) < 0)
3271		return i;
3272	if (partition >= ST_NBR_PARTITIONS)
3273		return (-EIO);
3274	return partition;
3275}
3276
3277
3278/* Change the partition if necessary */
3279static int switch_partition(struct scsi_tape *STp)
3280{
3281	struct st_partstat *STps;
3282
3283	if (STp->partition == STp->new_partition)
3284		return 0;
3285	STps = &(STp->ps[STp->new_partition]);
3286	if (!STps->last_block_valid)
3287		STps->last_block_visited = 0;
3288	return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3289}
3290
3291/* Functions for reading and writing the medium partition mode page. */
3292
3293#define PART_PAGE   0x11
3294#define PART_PAGE_FIXED_LENGTH 8
3295
3296#define PP_OFF_MAX_ADD_PARTS   2
3297#define PP_OFF_NBR_ADD_PARTS   3
3298#define PP_OFF_FLAGS           4
3299#define PP_OFF_PART_UNITS      6
3300#define PP_OFF_RESERVED        7
3301
3302#define PP_BIT_IDP             0x20
3303#define PP_BIT_FDP             0x80
3304#define PP_MSK_PSUM_MB         0x10
3305#define PP_MSK_PSUM_UNITS      0x18
3306#define PP_MSK_POFM            0x04
3307
3308/* Get the number of partitions on the tape. As a side effect reads the
3309   mode page into the tape buffer. */
3310static int nbr_partitions(struct scsi_tape *STp)
3311{
3312	int result;
3313
3314	if (STp->ready != ST_READY)
3315		return (-EIO);
3316
3317	result = read_mode_page(STp, PART_PAGE, 1);
3318
3319	if (result) {
3320		DEBC_printk(STp, "Can't read medium partition page.\n");
3321		result = (-EIO);
3322	} else {
3323		result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3324					      PP_OFF_NBR_ADD_PARTS] + 1;
3325		DEBC_printk(STp, "Number of partitions %d.\n", result);
3326	}
3327
3328	return result;
3329}
3330
3331
3332static int format_medium(struct scsi_tape *STp, int format)
3333{
3334	int result = 0;
3335	int timeout = STp->long_timeout;
3336	unsigned char scmd[MAX_COMMAND_SIZE];
3337	struct st_request *SRpnt;
3338
3339	memset(scmd, 0, MAX_COMMAND_SIZE);
3340	scmd[0] = FORMAT_UNIT;
3341	scmd[2] = format;
3342	if (STp->immediate) {
3343		scmd[1] |= 1;		/* Don't wait for completion */
3344		timeout = STp->device->request_queue->rq_timeout;
3345	}
3346	DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
3347	SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3348			   timeout, MAX_RETRIES, 1);
3349	if (!SRpnt)
3350		result = STp->buffer->syscall_result;
3351	return result;
3352}
3353
3354
3355/* Partition the tape into two partitions if size > 0 or one partition if
3356   size == 0.
3357
3358   The block descriptors are read and written because Sony SDT-7000 does not
3359   work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3360
3361   My HP C1533A drive returns only one partition size field. This is used to
3362   set the size of partition 1. There is no size field for the default partition.
3363   Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3364   used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3365   The following algorithm is used to accommodate both drives: if the number of
3366   partition size fields is greater than the maximum number of additional partitions
3367   in the mode page, the second field is used. Otherwise the first field is used.
3368
3369   For Seagate DDS drives the page length must be 8 when no partitions is defined
3370   and 10 when 1 partition is defined (information from Eric Lee Green). This is
3371   is acceptable also to some other old drives and enforced if the first partition
3372   size field is used for the first additional partition size.
3373
3374   For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
3375 */
3376static int partition_tape(struct scsi_tape *STp, int size)
3377{
3378	int result;
3379	int target_partition;
3380	bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
3381	int pgo, psd_cnt, psdo;
3382	int psum = PP_MSK_PSUM_MB, units = 0;
3383	unsigned char *bp;
3384
3385	result = read_mode_page(STp, PART_PAGE, 0);
3386	if (result) {
3387		DEBC_printk(STp, "Can't read partition mode page.\n");
3388		return result;
3389	}
3390	target_partition = 1;
3391	if (size < 0) {
3392		target_partition = 0;
3393		size = -size;
3394	}
3395
3396	/* The mode page is in the buffer. Let's modify it and write it. */
3397	bp = (STp->buffer)->b_data;
3398	pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3399	DEBC_printk(STp, "Partition page length is %d bytes.\n",
3400		    bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3401
3402	psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3403
3404	if (scsi3) {
3405		needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
3406		if (needs_format && size == 0) {
3407			/* No need to write the mode page when clearing
3408			 *  partitioning
3409			 */
3410			DEBC_printk(STp, "Formatting tape with one partition.\n");
3411			result = format_medium(STp, 0);
3412			goto out;
3413		}
3414		if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
3415			psd_cnt = 2;
3416		if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
3417			/* Use units scaling for large partitions if the device
3418			 * suggests it and no precision lost. Required for IBM
3419			 * TS1140/50 drives that don't support MB units.
3420			 */
3421			if (size >= 1000 && (size % 1000) == 0) {
3422				size /= 1000;
3423				psum = PP_MSK_PSUM_UNITS;
3424				units = 9; /* GB */
3425			}
3426		}
3427		/* Try it anyway if too large to specify in MB */
3428		if (psum == PP_MSK_PSUM_MB && size >= 65534) {
3429			size /= 1000;
3430			psum = PP_MSK_PSUM_UNITS;
3431			units = 9;  /* GB */
3432		}
3433	}
3434
3435	if (size >= 65535 ||  /* Does not fit into two bytes */
3436	    (target_partition == 0 && psd_cnt < 2)) {
3437		result = -EINVAL;
3438		goto out;
3439	}
3440
3441	psdo = pgo + PART_PAGE_FIXED_LENGTH;
3442	/* The second condition is for HP DDS which use only one partition size
3443	 * descriptor
3444	 */
3445	if (target_partition > 0 &&
3446	    (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
3447	     bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
3448		bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
3449		psdo += 2;
3450	}
3451	memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3452
3453	DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3454		    psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3455		    bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3456
3457	if (size == 0) {
3458		bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3459		if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3460		    bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3461		DEBC_printk(STp, "Formatting tape with one partition.\n");
3462	} else {
3463		bp[psdo] = (size >> 8) & 0xff;
3464		bp[psdo + 1] = size & 0xff;
3465		if (target_partition == 0)
3466			bp[psdo + 2] = bp[psdo + 3] = 0xff;
3467		bp[pgo + 3] = 1;
3468		if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3469		    bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3470		DEBC_printk(STp,
3471			    "Formatting tape with two partitions (%i = %d MB).\n",
3472			    target_partition, units > 0 ? size * 1000 : size);
3473	}
3474	bp[pgo + PP_OFF_PART_UNITS] = 0;
3475	bp[pgo + PP_OFF_RESERVED] = 0;
3476	if (size != 1 || units != 0) {
3477		bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
3478			(bp[pgo + PP_OFF_FLAGS] & 0x07);
3479		bp[pgo + PP_OFF_PART_UNITS] = units;
3480	} else
3481		bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
3482			(bp[pgo + PP_OFF_FLAGS] & 0x1f);
3483	bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
3484
3485	result = write_mode_page(STp, PART_PAGE, 1);
3486
3487	if (!result && needs_format)
3488		result = format_medium(STp, 1);
3489
3490	if (result) {
3491		st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3492		result = (-EIO);
3493	}
3494
3495out:
3496	return result;
3497}
3498
3499
3500
3501/* The ioctl command */
3502static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3503{
3504	int i, cmd_nr, cmd_type, bt;
3505	int retval = 0;
3506	unsigned int blk;
3507	struct scsi_tape *STp = file->private_data;
3508	struct st_modedef *STm;
3509	struct st_partstat *STps;
3510	void __user *p = (void __user *)arg;
3511
3512	if (mutex_lock_interruptible(&STp->lock))
3513		return -ERESTARTSYS;
3514
3515	DEB(
3516	if (debugging && !STp->in_use) {
3517		st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3518		retval = (-EIO);
3519		goto out;
3520	} ) /* end DEB */
3521
3522	STm = &(STp->modes[STp->current_mode]);
3523	STps = &(STp->ps[STp->partition]);
3524
3525	/*
3526	 * If we are in the middle of error recovery, don't let anyone
3527	 * else try and use this device.  Also, if error recovery fails, it
3528	 * may try and take the device offline, in which case all further
3529	 * access to the device is prohibited.
3530	 */
3531	retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3532			file->f_flags & O_NDELAY);
3533	if (retval)
3534		goto out;
3535
3536	cmd_type = _IOC_TYPE(cmd_in);
3537	cmd_nr = _IOC_NR(cmd_in);
3538
3539	if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3540		struct mtop mtc;
3541
3542		if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3543			retval = (-EINVAL);
3544			goto out;
3545		}
3546
3547		i = copy_from_user(&mtc, p, sizeof(struct mtop));
3548		if (i) {
3549			retval = (-EFAULT);
3550			goto out;
3551		}
3552
3553		if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3554			st_printk(KERN_WARNING, STp,
3555				  "MTSETDRVBUFFER only allowed for root.\n");
3556			retval = (-EPERM);
3557			goto out;
3558		}
3559		if (!STm->defined &&
3560		    (mtc.mt_op != MTSETDRVBUFFER &&
3561		     (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3562			retval = (-ENXIO);
3563			goto out;
3564		}
3565
3566		if (!STp->pos_unknown) {
3567
3568			if (STps->eof == ST_FM_HIT) {
3569				if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3570                                    mtc.mt_op == MTEOM) {
3571					mtc.mt_count -= 1;
3572					if (STps->drv_file >= 0)
3573						STps->drv_file += 1;
3574				} else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3575					mtc.mt_count += 1;
3576					if (STps->drv_file >= 0)
3577						STps->drv_file += 1;
3578				}
3579			}
3580
3581			if (mtc.mt_op == MTSEEK) {
3582				/* Old position must be restored if partition will be
3583                                   changed */
3584				i = !STp->can_partitions ||
3585				    (STp->new_partition != STp->partition);
3586			} else {
3587				i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3588				    mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3589				    mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3590				    mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3591				    mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3592				    mtc.mt_op == MTCOMPRESSION;
3593			}
3594			i = flush_buffer(STp, i);
3595			if (i < 0) {
3596				retval = i;
3597				goto out;
3598			}
3599			if (STps->rw == ST_WRITING &&
3600			    (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3601			     mtc.mt_op == MTSEEK ||
3602			     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3603				i = st_int_ioctl(STp, MTWEOF, 1);
3604				if (i < 0) {
3605					retval = i;
3606					goto out;
3607				}
3608				if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3609					mtc.mt_count++;
3610				STps->rw = ST_IDLE;
3611			     }
3612
3613		} else {
3614			/*
3615			 * If there was a bus reset, block further access
3616			 * to this device.  If the user wants to rewind the tape,
3617			 * then reset the flag and allow access again.
3618			 */
3619			if (mtc.mt_op != MTREW &&
3620			    mtc.mt_op != MTOFFL &&
3621			    mtc.mt_op != MTRETEN &&
3622			    mtc.mt_op != MTERASE &&
3623			    mtc.mt_op != MTSEEK &&
3624			    mtc.mt_op != MTEOM) {
3625				retval = (-EIO);
3626				goto out;
3627			}
3628			reset_state(STp);
3629			/* remove this when the midlevel properly clears was_reset */
3630			STp->device->was_reset = 0;
3631		}
3632
3633		if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3634		    mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3635		    mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3636			STps->rw = ST_IDLE;	/* Prevent automatic WEOF and fsf */
3637
3638		if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3639			do_door_lock(STp, 0);	/* Ignore result! */
3640
3641		if (mtc.mt_op == MTSETDRVBUFFER &&
3642		    (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3643			retval = st_set_options(STp, mtc.mt_count);
3644			goto out;
3645		}
3646
3647		if (mtc.mt_op == MTSETPART) {
3648			if (!STp->can_partitions ||
3649			    mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3650				retval = (-EINVAL);
3651				goto out;
3652			}
3653			if (mtc.mt_count >= STp->nbr_partitions &&
3654			    (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3655				retval = (-EIO);
3656				goto out;
3657			}
3658			if (mtc.mt_count >= STp->nbr_partitions) {
3659				retval = (-EINVAL);
3660				goto out;
3661			}
3662			STp->new_partition = mtc.mt_count;
3663			retval = 0;
3664			goto out;
3665		}
3666
3667		if (mtc.mt_op == MTMKPART) {
3668			if (!STp->can_partitions) {
3669				retval = (-EINVAL);
3670				goto out;
3671			}
3672			i = do_load_unload(STp, file, 1);
3673			if (i < 0) {
3674				retval = i;
3675				goto out;
3676			}
3677			i = partition_tape(STp, mtc.mt_count);
3678			if (i < 0) {
3679				retval = i;
3680				goto out;
3681			}
3682			for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3683				STp->ps[i].rw = ST_IDLE;
3684				STp->ps[i].at_sm = 0;
3685				STp->ps[i].last_block_valid = 0;
3686			}
3687			STp->partition = STp->new_partition = 0;
3688			STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3689			STps->drv_block = STps->drv_file = 0;
3690			retval = 0;
3691			goto out;
3692		}
3693
3694		if (mtc.mt_op == MTSEEK) {
3695			i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3696			if (!STp->can_partitions)
3697				STp->ps[0].rw = ST_IDLE;
3698			retval = i;
3699			goto out;
3700		}
3701
3702		if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3703			retval = do_load_unload(STp, file, 0);
3704			goto out;
3705		}
3706
3707		if (mtc.mt_op == MTLOAD) {
3708			retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3709			goto out;
3710		}
3711
3712		if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3713			retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3714			goto out;
3715		}
3716
3717		if (STp->can_partitions && STp->ready == ST_READY &&
3718		    (i = switch_partition(STp)) < 0) {
3719			retval = i;
3720			goto out;
3721		}
3722
3723		if (mtc.mt_op == MTCOMPRESSION)
3724			retval = st_compression(STp, (mtc.mt_count & 1));
3725		else
3726			retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3727		goto out;
3728	}
3729	if (!STm->defined) {
3730		retval = (-ENXIO);
3731		goto out;
3732	}
3733
3734	if ((i = flush_buffer(STp, 0)) < 0) {
3735		retval = i;
3736		goto out;
3737	}
3738	if (STp->can_partitions &&
3739	    (i = switch_partition(STp)) < 0) {
3740		retval = i;
3741		goto out;
3742	}
3743
3744	if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3745		struct mtget mt_status;
3746
3747		if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3748			 retval = (-EINVAL);
3749			 goto out;
3750		}
3751
3752		mt_status.mt_type = STp->tape_type;
3753		mt_status.mt_dsreg =
3754		    ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3755		    ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3756		mt_status.mt_blkno = STps->drv_block;
3757		mt_status.mt_fileno = STps->drv_file;
3758		if (STp->block_size != 0) {
3759			if (STps->rw == ST_WRITING)
3760				mt_status.mt_blkno +=
3761				    (STp->buffer)->buffer_bytes / STp->block_size;
3762			else if (STps->rw == ST_READING)
3763				mt_status.mt_blkno -=
3764                                        ((STp->buffer)->buffer_bytes +
3765                                         STp->block_size - 1) / STp->block_size;
3766		}
3767
3768		mt_status.mt_gstat = 0;
3769		if (STp->drv_write_prot)
3770			mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3771		if (mt_status.mt_blkno == 0) {
3772			if (mt_status.mt_fileno == 0)
3773				mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3774			else
3775				mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3776		}
3777		mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3778		mt_status.mt_resid = STp->partition;
3779		if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3780			mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3781		else if (STps->eof >= ST_EOM_OK)
3782			mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3783		if (STp->density == 1)
3784			mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3785		else if (STp->density == 2)
3786			mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3787		else if (STp->density == 3)
3788			mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3789		if (STp->ready == ST_READY)
3790			mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3791		if (STp->ready == ST_NO_TAPE)
3792			mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3793		if (STps->at_sm)
3794			mt_status.mt_gstat |= GMT_SM(0xffffffff);
3795		if (STm->do_async_writes ||
3796                    (STm->do_buffer_writes && STp->block_size != 0) ||
3797		    STp->drv_buffer != 0)
3798			mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3799		if (STp->cleaning_req)
3800			mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3801
3802		i = copy_to_user(p, &mt_status, sizeof(struct mtget));
3803		if (i) {
3804			retval = (-EFAULT);
3805			goto out;
3806		}
3807
3808		STp->recover_reg = 0;		/* Clear after read */
3809		retval = 0;
3810		goto out;
3811	}			/* End of MTIOCGET */
3812	if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3813		struct mtpos mt_pos;
3814		if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3815			 retval = (-EINVAL);
3816			 goto out;
3817		}
3818		if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3819			retval = i;
3820			goto out;
3821		}
3822		mt_pos.mt_blkno = blk;
3823		i = copy_to_user(p, &mt_pos, sizeof(struct mtpos));
3824		if (i)
3825			retval = (-EFAULT);
3826		goto out;
3827	}
3828	mutex_unlock(&STp->lock);
3829	switch (cmd_in) {
3830		case SCSI_IOCTL_GET_IDLUN:
3831		case SCSI_IOCTL_GET_BUS_NUMBER:
3832			break;
3833		default:
3834			if ((cmd_in == SG_IO ||
3835			     cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3836			     cmd_in == CDROM_SEND_PACKET) &&
3837			    !capable(CAP_SYS_RAWIO))
3838				i = -EPERM;
3839			else
3840				i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3841						   file->f_mode, cmd_in, p);
3842			if (i != -ENOTTY)
3843				return i;
3844			break;
3845	}
3846	retval = scsi_ioctl(STp->device, cmd_in, p);
3847	if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) { /* unload */
3848		STp->rew_at_close = 0;
3849		STp->ready = ST_NO_TAPE;
3850	}
3851	return retval;
3852
3853 out:
3854	mutex_unlock(&STp->lock);
3855	return retval;
3856}
3857
3858#ifdef CONFIG_COMPAT
3859static long st_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3860{
3861	struct scsi_tape *STp = file->private_data;
3862	struct scsi_device *sdev = STp->device;
3863	int ret = -ENOIOCTLCMD;
3864	if (sdev->host->hostt->compat_ioctl) { 
3865
3866		ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
3867
3868	}
3869	return ret;
3870}
3871#endif
3872
3873
3874
3875/* Try to allocate a new tape buffer. Calling function must not hold
3876   dev_arr_lock. */
3877static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
3878{
3879	struct st_buffer *tb;
3880
3881	tb = kzalloc(sizeof(struct st_buffer), GFP_ATOMIC);
3882	if (!tb) {
3883		printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3884		return NULL;
3885	}
3886	tb->frp_segs = 0;
3887	tb->use_sg = max_sg;
3888	tb->dma = need_dma;
3889	tb->buffer_size = 0;
3890
3891	tb->reserved_pages = kzalloc(max_sg * sizeof(struct page *),
3892				     GFP_ATOMIC);
3893	if (!tb->reserved_pages) {
3894		kfree(tb);
3895		return NULL;
3896	}
3897
3898	return tb;
3899}
3900
3901
3902/* Try to allocate enough space in the tape buffer */
3903#define ST_MAX_ORDER 6
3904
3905static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3906{
3907	int segs, max_segs, b_size, order, got;
3908	gfp_t priority;
3909
3910	if (new_size <= STbuffer->buffer_size)
3911		return 1;
3912
3913	if (STbuffer->buffer_size <= PAGE_SIZE)
3914		normalize_buffer(STbuffer);  /* Avoid extra segment */
3915
3916	max_segs = STbuffer->use_sg;
3917
3918	priority = GFP_KERNEL | __GFP_NOWARN;
3919	if (need_dma)
3920		priority |= GFP_DMA;
3921
3922	if (STbuffer->cleared)
3923		priority |= __GFP_ZERO;
3924
3925	if (STbuffer->frp_segs) {
3926		order = STbuffer->reserved_page_order;
3927		b_size = PAGE_SIZE << order;
3928	} else {
3929		for (b_size = PAGE_SIZE, order = 0;
3930		     order < ST_MAX_ORDER &&
3931			     max_segs * (PAGE_SIZE << order) < new_size;
3932		     order++, b_size *= 2)
3933			;  /* empty */
3934		STbuffer->reserved_page_order = order;
3935	}
3936	if (max_segs * (PAGE_SIZE << order) < new_size) {
3937		if (order == ST_MAX_ORDER)
3938			return 0;
3939		normalize_buffer(STbuffer);
3940		return enlarge_buffer(STbuffer, new_size, need_dma);
3941	}
3942
3943	for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3944	     segs < max_segs && got < new_size;) {
3945		struct page *page;
3946
3947		page = alloc_pages(priority, order);
3948		if (!page) {
3949			DEB(STbuffer->buffer_size = got);
3950			normalize_buffer(STbuffer);
3951			return 0;
3952		}
3953
3954		STbuffer->frp_segs += 1;
3955		got += b_size;
3956		STbuffer->buffer_size = got;
3957		STbuffer->reserved_pages[segs] = page;
3958		segs++;
3959	}
3960	STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3961
3962	return 1;
3963}
3964
3965
3966/* Make sure that no data from previous user is in the internal buffer */
3967static void clear_buffer(struct st_buffer * st_bp)
3968{
3969	int i;
3970
3971	for (i=0; i < st_bp->frp_segs; i++)
3972		memset(page_address(st_bp->reserved_pages[i]), 0,
3973		       PAGE_SIZE << st_bp->reserved_page_order);
3974	st_bp->cleared = 1;
3975}
3976
3977
3978/* Release the extra buffer */
3979static void normalize_buffer(struct st_buffer * STbuffer)
3980{
3981	int i, order = STbuffer->reserved_page_order;
3982
3983	for (i = 0; i < STbuffer->frp_segs; i++) {
3984		__free_pages(STbuffer->reserved_pages[i], order);
3985		STbuffer->buffer_size -= (PAGE_SIZE << order);
3986	}
3987	STbuffer->frp_segs = 0;
3988	STbuffer->sg_segs = 0;
3989	STbuffer->reserved_page_order = 0;
3990	STbuffer->map_data.offset = 0;
3991}
3992
3993
3994/* Move data from the user buffer to the tape buffer. Returns zero (success) or
3995   negative error code. */
3996static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3997{
3998	int i, cnt, res, offset;
3999	int length = PAGE_SIZE << st_bp->reserved_page_order;
4000
4001	for (i = 0, offset = st_bp->buffer_bytes;
4002	     i < st_bp->frp_segs && offset >= length; i++)
4003		offset -= length;
4004	if (i == st_bp->frp_segs) {	/* Should never happen */
4005		printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
4006		return (-EIO);
4007	}
4008	for (; i < st_bp->frp_segs && do_count > 0; i++) {
4009		struct page *page = st_bp->reserved_pages[i];
4010		cnt = length - offset < do_count ? length - offset : do_count;
4011		res = copy_from_user(page_address(page) + offset, ubp, cnt);
4012		if (res)
4013			return (-EFAULT);
4014		do_count -= cnt;
4015		st_bp->buffer_bytes += cnt;
4016		ubp += cnt;
4017		offset = 0;
4018	}
4019	if (do_count) /* Should never happen */
4020		return (-EIO);
4021
4022	return 0;
4023}
4024
4025
4026/* Move data from the tape buffer to the user buffer. Returns zero (success) or
4027   negative error code. */
4028static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4029{
4030	int i, cnt, res, offset;
4031	int length = PAGE_SIZE << st_bp->reserved_page_order;
4032
4033	for (i = 0, offset = st_bp->read_pointer;
4034	     i < st_bp->frp_segs && offset >= length; i++)
4035		offset -= length;
4036	if (i == st_bp->frp_segs) {	/* Should never happen */
4037		printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4038		return (-EIO);
4039	}
4040	for (; i < st_bp->frp_segs && do_count > 0; i++) {
4041		struct page *page = st_bp->reserved_pages[i];
4042		cnt = length - offset < do_count ? length - offset : do_count;
4043		res = copy_to_user(ubp, page_address(page) + offset, cnt);
4044		if (res)
4045			return (-EFAULT);
4046		do_count -= cnt;
4047		st_bp->buffer_bytes -= cnt;
4048		st_bp->read_pointer += cnt;
4049		ubp += cnt;
4050		offset = 0;
4051	}
4052	if (do_count) /* Should never happen */
4053		return (-EIO);
4054
4055	return 0;
4056}
4057
4058
4059/* Move data towards start of buffer */
4060static void move_buffer_data(struct st_buffer * st_bp, int offset)
4061{
4062	int src_seg, dst_seg, src_offset = 0, dst_offset;
4063	int count, total;
4064	int length = PAGE_SIZE << st_bp->reserved_page_order;
4065
4066	if (offset == 0)
4067		return;
4068
4069	total=st_bp->buffer_bytes - offset;
4070	for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4071		src_offset = offset;
4072		if (src_offset < length)
4073			break;
4074		offset -= length;
4075	}
4076
4077	st_bp->buffer_bytes = st_bp->read_pointer = total;
4078	for (dst_seg=dst_offset=0; total > 0; ) {
4079		struct page *dpage = st_bp->reserved_pages[dst_seg];
4080		struct page *spage = st_bp->reserved_pages[src_seg];
4081
4082		count = min(length - dst_offset, length - src_offset);
4083		memmove(page_address(dpage) + dst_offset,
4084			page_address(spage) + src_offset, count);
4085		src_offset += count;
4086		if (src_offset >= length) {
4087			src_seg++;
4088			src_offset = 0;
4089		}
4090		dst_offset += count;
4091		if (dst_offset >= length) {
4092			dst_seg++;
4093			dst_offset = 0;
4094		}
4095		total -= count;
4096	}
4097}
4098
4099/* Validate the options from command line or module parameters */
4100static void validate_options(void)
4101{
4102	if (buffer_kbs > 0)
4103		st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4104	if (max_sg_segs >= ST_FIRST_SG)
4105		st_max_sg_segs = max_sg_segs;
4106}
4107
4108#ifndef MODULE
4109/* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4110 */
4111static int __init st_setup(char *str)
4112{
4113	int i, len, ints[5];
4114	char *stp;
4115
4116	stp = get_options(str, ARRAY_SIZE(ints), ints);
4117
4118	if (ints[0] > 0) {
4119		for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4120			if (parms[i].val)
4121				*parms[i].val = ints[i + 1];
4122	} else {
4123		while (stp != NULL) {
4124			for (i = 0; i < ARRAY_SIZE(parms); i++) {
4125				len = strlen(parms[i].name);
4126				if (!strncmp(stp, parms[i].name, len) &&
4127				    (*(stp + len) == ':' || *(stp + len) == '=')) {
4128					if (parms[i].val)
4129						*parms[i].val =
4130							simple_strtoul(stp + len + 1, NULL, 0);
4131					else
4132						printk(KERN_WARNING "st: Obsolete parameter %s\n",
4133						       parms[i].name);
4134					break;
4135				}
4136			}
4137			if (i >= ARRAY_SIZE(parms))
4138				 printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4139					stp);
4140			stp = strchr(stp, ',');
4141			if (stp)
4142				stp++;
4143		}
4144	}
4145
4146	validate_options();
4147
4148	return 1;
4149}
4150
4151__setup("st=", st_setup);
4152
4153#endif
4154
4155static const struct file_operations st_fops =
4156{
4157	.owner =	THIS_MODULE,
4158	.read =		st_read,
4159	.write =	st_write,
4160	.unlocked_ioctl = st_ioctl,
4161#ifdef CONFIG_COMPAT
4162	.compat_ioctl = st_compat_ioctl,
4163#endif
4164	.open =		st_open,
4165	.flush =	st_flush,
4166	.release =	st_release,
4167	.llseek =	noop_llseek,
4168};
4169
4170static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4171{
4172	int i, error;
4173	dev_t cdev_devno;
4174	struct cdev *cdev;
4175	struct device *dev;
4176	struct st_modedef *STm = &(tape->modes[mode]);
4177	char name[10];
4178	int dev_num = tape->index;
4179
4180	cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4181
4182	cdev = cdev_alloc();
4183	if (!cdev) {
4184		pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4185		error = -ENOMEM;
4186		goto out;
4187	}
4188	cdev->owner = THIS_MODULE;
4189	cdev->ops = &st_fops;
4190	STm->cdevs[rew] = cdev;
4191
4192	error = cdev_add(cdev, cdev_devno, 1);
4193	if (error) {
4194		pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4195		       rew ? "non" : "auto", mode);
4196		pr_err("st%d: Device not attached.\n", dev_num);
4197		goto out_free;
4198	}
4199
4200	i = mode << (4 - ST_NBR_MODE_BITS);
4201	snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4202		 tape->disk->disk_name, st_formats[i]);
4203
4204	dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4205			    cdev_devno, &tape->modes[mode], "%s", name);
4206	if (IS_ERR(dev)) {
4207		pr_err("st%d: device_create failed\n", dev_num);
4208		error = PTR_ERR(dev);
4209		goto out_free;
4210	}
4211
4212	STm->devs[rew] = dev;
4213
4214	return 0;
4215out_free:
4216	cdev_del(STm->cdevs[rew]);
4217out:
4218	STm->cdevs[rew] = NULL;
4219	STm->devs[rew] = NULL;
4220	return error;
4221}
4222
4223static int create_cdevs(struct scsi_tape *tape)
4224{
4225	int mode, error;
4226	for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4227		error = create_one_cdev(tape, mode, 0);
4228		if (error)
4229			return error;
4230		error = create_one_cdev(tape, mode, 1);
4231		if (error)
4232			return error;
4233	}
4234
4235	return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4236				 &tape->modes[0].devs[0]->kobj, "tape");
4237}
4238
4239static void remove_cdevs(struct scsi_tape *tape)
4240{
4241	int mode, rew;
4242	sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4243	for (mode = 0; mode < ST_NBR_MODES; mode++) {
4244		struct st_modedef *STm = &(tape->modes[mode]);
4245		for (rew = 0; rew < 2; rew++) {
4246			if (STm->cdevs[rew])
4247				cdev_del(STm->cdevs[rew]);
4248			if (STm->devs[rew])
4249				device_unregister(STm->devs[rew]);
4250		}
4251	}
4252}
4253
4254static int st_probe(struct device *dev)
4255{
4256	struct scsi_device *SDp = to_scsi_device(dev);
4257	struct gendisk *disk = NULL;
4258	struct scsi_tape *tpnt = NULL;
4259	struct st_modedef *STm;
4260	struct st_partstat *STps;
4261	struct st_buffer *buffer;
4262	int i, error;
4263	char *stp;
4264
4265	if (SDp->type != TYPE_TAPE)
4266		return -ENODEV;
4267	if ((stp = st_incompatible(SDp))) {
4268		sdev_printk(KERN_INFO, SDp, "Found incompatible tape\n");
4269		sdev_printk(KERN_INFO, SDp,
4270			    "st: The suggested driver is %s.\n", stp);
4271		return -ENODEV;
4272	}
4273
4274	scsi_autopm_get_device(SDp);
4275	i = queue_max_segments(SDp->request_queue);
4276	if (st_max_sg_segs < i)
4277		i = st_max_sg_segs;
4278	buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);
4279	if (buffer == NULL) {
4280		sdev_printk(KERN_ERR, SDp,
4281			    "st: Can't allocate new tape buffer. "
4282			    "Device not attached.\n");
4283		goto out;
4284	}
4285
4286	disk = alloc_disk(1);
4287	if (!disk) {
4288		sdev_printk(KERN_ERR, SDp,
4289			    "st: out of memory. Device not attached.\n");
4290		goto out_buffer_free;
4291	}
4292
4293	tpnt = kzalloc(sizeof(struct scsi_tape), GFP_ATOMIC);
4294	if (tpnt == NULL) {
4295		sdev_printk(KERN_ERR, SDp,
4296			    "st: Can't allocate device descriptor.\n");
4297		goto out_put_disk;
4298	}
4299	kref_init(&tpnt->kref);
4300	tpnt->disk = disk;
4301	disk->private_data = &tpnt->driver;
 
4302	/* SCSI tape doesn't register this gendisk via add_disk().  Manually
4303	 * take queue reference that release_disk() expects. */
4304	if (!blk_get_queue(SDp->request_queue))
4305		goto out_put_disk;
4306	disk->queue = SDp->request_queue;
4307	tpnt->driver = &st_template;
4308
4309	tpnt->device = SDp;
4310	if (SDp->scsi_level <= 2)
4311		tpnt->tape_type = MT_ISSCSI1;
4312	else
4313		tpnt->tape_type = MT_ISSCSI2;
4314
4315	tpnt->buffer = buffer;
4316	tpnt->buffer->last_SRpnt = NULL;
4317
4318	tpnt->inited = 0;
4319	tpnt->dirty = 0;
4320	tpnt->in_use = 0;
4321	tpnt->drv_buffer = 1;	/* Try buffering if no mode sense */
4322	tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
4323	tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4324	tpnt->density = 0;
4325	tpnt->do_auto_lock = ST_AUTO_LOCK;
4326	tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4327	tpnt->can_partitions = 0;
4328	tpnt->two_fm = ST_TWO_FM;
4329	tpnt->fast_mteom = ST_FAST_MTEOM;
4330	tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4331	tpnt->sili = ST_SILI;
4332	tpnt->immediate = ST_NOWAIT;
4333	tpnt->immediate_filemark = 0;
4334	tpnt->default_drvbuffer = 0xff;		/* No forced buffering */
4335	tpnt->partition = 0;
4336	tpnt->new_partition = 0;
4337	tpnt->nbr_partitions = 0;
4338	blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4339	tpnt->long_timeout = ST_LONG_TIMEOUT;
4340	tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4341
4342	for (i = 0; i < ST_NBR_MODES; i++) {
4343		STm = &(tpnt->modes[i]);
4344		STm->defined = 0;
4345		STm->sysv = ST_SYSV;
4346		STm->defaults_for_writes = 0;
4347		STm->do_async_writes = ST_ASYNC_WRITES;
4348		STm->do_buffer_writes = ST_BUFFER_WRITES;
4349		STm->do_read_ahead = ST_READ_AHEAD;
4350		STm->default_compression = ST_DONT_TOUCH;
4351		STm->default_blksize = (-1);	/* No forced size */
4352		STm->default_density = (-1);	/* No forced density */
4353		STm->tape = tpnt;
4354	}
4355
4356	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4357		STps = &(tpnt->ps[i]);
4358		STps->rw = ST_IDLE;
4359		STps->eof = ST_NOEOF;
4360		STps->at_sm = 0;
4361		STps->last_block_valid = 0;
4362		STps->drv_block = (-1);
4363		STps->drv_file = (-1);
4364	}
4365
4366	tpnt->current_mode = 0;
4367	tpnt->modes[0].defined = 1;
4368
4369	tpnt->density_changed = tpnt->compression_changed =
4370	    tpnt->blksize_changed = 0;
4371	mutex_init(&tpnt->lock);
4372
4373	idr_preload(GFP_KERNEL);
4374	spin_lock(&st_index_lock);
4375	error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4376	spin_unlock(&st_index_lock);
4377	idr_preload_end();
4378	if (error < 0) {
4379		pr_warn("st: idr allocation failed: %d\n", error);
4380		goto out_put_queue;
4381	}
4382	tpnt->index = error;
4383	sprintf(disk->disk_name, "st%d", tpnt->index);
4384	tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4385	if (tpnt->stats == NULL) {
4386		sdev_printk(KERN_ERR, SDp,
4387			    "st: Can't allocate statistics.\n");
4388		goto out_idr_remove;
4389	}
4390
4391	dev_set_drvdata(dev, tpnt);
4392
4393
4394	error = create_cdevs(tpnt);
4395	if (error)
4396		goto out_remove_devs;
4397	scsi_autopm_put_device(SDp);
4398
4399	sdev_printk(KERN_NOTICE, SDp,
4400		    "Attached scsi tape %s\n", tape_name(tpnt));
4401	sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4402		    tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4403		    queue_dma_alignment(SDp->request_queue) + 1);
4404
4405	return 0;
4406
4407out_remove_devs:
4408	remove_cdevs(tpnt);
4409	kfree(tpnt->stats);
4410out_idr_remove:
4411	spin_lock(&st_index_lock);
4412	idr_remove(&st_index_idr, tpnt->index);
4413	spin_unlock(&st_index_lock);
4414out_put_queue:
4415	blk_put_queue(disk->queue);
4416out_put_disk:
4417	put_disk(disk);
4418	kfree(tpnt);
4419out_buffer_free:
4420	kfree(buffer);
4421out:
4422	scsi_autopm_put_device(SDp);
4423	return -ENODEV;
4424};
4425
4426
4427static int st_remove(struct device *dev)
4428{
4429	struct scsi_tape *tpnt = dev_get_drvdata(dev);
4430	int index = tpnt->index;
4431
4432	scsi_autopm_get_device(to_scsi_device(dev));
4433	remove_cdevs(tpnt);
4434
4435	mutex_lock(&st_ref_mutex);
4436	kref_put(&tpnt->kref, scsi_tape_release);
4437	mutex_unlock(&st_ref_mutex);
4438	spin_lock(&st_index_lock);
4439	idr_remove(&st_index_idr, index);
4440	spin_unlock(&st_index_lock);
4441	return 0;
4442}
4443
4444/**
4445 *      scsi_tape_release - Called to free the Scsi_Tape structure
4446 *      @kref: pointer to embedded kref
4447 *
4448 *      st_ref_mutex must be held entering this routine.  Because it is
4449 *      called on last put, you should always use the scsi_tape_get()
4450 *      scsi_tape_put() helpers which manipulate the semaphore directly
4451 *      and never do a direct kref_put().
4452 **/
4453static void scsi_tape_release(struct kref *kref)
4454{
4455	struct scsi_tape *tpnt = to_scsi_tape(kref);
4456	struct gendisk *disk = tpnt->disk;
4457
4458	tpnt->device = NULL;
4459
4460	if (tpnt->buffer) {
4461		normalize_buffer(tpnt->buffer);
4462		kfree(tpnt->buffer->reserved_pages);
4463		kfree(tpnt->buffer);
4464	}
4465
4466	disk->private_data = NULL;
4467	put_disk(disk);
4468	kfree(tpnt->stats);
4469	kfree(tpnt);
4470	return;
4471}
4472
4473static struct class st_sysfs_class = {
4474	.name = "scsi_tape",
4475	.dev_groups = st_dev_groups,
4476};
4477
4478static int __init init_st(void)
4479{
4480	int err;
4481
4482	validate_options();
4483
4484	printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4485		verstr, st_fixed_buffer_size, st_max_sg_segs);
4486
4487	debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4488	if (debugging) {
4489		printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4490			debugging);
4491	}
4492
4493	err = class_register(&st_sysfs_class);
4494	if (err) {
4495		pr_err("Unable register sysfs class for SCSI tapes\n");
4496		return err;
4497	}
4498
4499	err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4500				     ST_MAX_TAPE_ENTRIES, "st");
4501	if (err) {
4502		printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4503		       SCSI_TAPE_MAJOR);
4504		goto err_class;
4505	}
4506
4507	err = scsi_register_driver(&st_template.gendrv);
4508	if (err)
4509		goto err_chrdev;
4510
4511	return 0;
4512
4513err_chrdev:
4514	unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4515				 ST_MAX_TAPE_ENTRIES);
4516err_class:
4517	class_unregister(&st_sysfs_class);
4518	return err;
4519}
4520
4521static void __exit exit_st(void)
4522{
4523	scsi_unregister_driver(&st_template.gendrv);
4524	unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4525				 ST_MAX_TAPE_ENTRIES);
4526	class_unregister(&st_sysfs_class);
4527	idr_destroy(&st_index_idr);
4528	printk(KERN_INFO "st: Unloaded.\n");
4529}
4530
4531module_init(init_st);
4532module_exit(exit_st);
4533
4534
4535/* The sysfs driver interface. Read-only at the moment */
4536static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4537{
4538	return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4539}
4540static DRIVER_ATTR_RO(try_direct_io);
4541
4542static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4543{
4544	return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4545}
4546static DRIVER_ATTR_RO(fixed_buffer_size);
4547
4548static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4549{
4550	return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4551}
4552static DRIVER_ATTR_RO(max_sg_segs);
4553
4554static ssize_t version_show(struct device_driver *ddd, char *buf)
4555{
4556	return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4557}
4558static DRIVER_ATTR_RO(version);
4559
4560#if DEBUG
4561static ssize_t debug_flag_store(struct device_driver *ddp,
4562	const char *buf, size_t count)
4563{
4564/* We only care what the first byte of the data is the rest is unused.
4565 * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4566 * other values have -EINVAL returned if they are passed in.
4567 */
4568	if (count > 0) {
4569		if (buf[0] == '0') {
4570			debugging = NO_DEBUG;
4571			return count;
4572		} else if (buf[0] == '1') {
4573			debugging = 1;
4574			return count;
4575		}
4576	}
4577	return -EINVAL;
4578}
4579
4580static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4581{
4582	return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4583}
4584static DRIVER_ATTR_RW(debug_flag);
4585#endif
4586
4587static struct attribute *st_drv_attrs[] = {
4588	&driver_attr_try_direct_io.attr,
4589	&driver_attr_fixed_buffer_size.attr,
4590	&driver_attr_max_sg_segs.attr,
4591	&driver_attr_version.attr,
4592#if DEBUG
4593	&driver_attr_debug_flag.attr,
4594#endif
4595	NULL,
4596};
4597ATTRIBUTE_GROUPS(st_drv);
4598
4599/* The sysfs simple class interface */
4600static ssize_t
4601defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4602{
4603	struct st_modedef *STm = dev_get_drvdata(dev);
4604	ssize_t l = 0;
4605
4606	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4607	return l;
4608}
4609static DEVICE_ATTR_RO(defined);
4610
4611static ssize_t
4612default_blksize_show(struct device *dev, struct device_attribute *attr,
4613		     char *buf)
4614{
4615	struct st_modedef *STm = dev_get_drvdata(dev);
4616	ssize_t l = 0;
4617
4618	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4619	return l;
4620}
4621static DEVICE_ATTR_RO(default_blksize);
4622
4623static ssize_t
4624default_density_show(struct device *dev, struct device_attribute *attr,
4625		     char *buf)
4626{
4627	struct st_modedef *STm = dev_get_drvdata(dev);
4628	ssize_t l = 0;
4629	char *fmt;
4630
4631	fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4632	l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4633	return l;
4634}
4635static DEVICE_ATTR_RO(default_density);
4636
4637static ssize_t
4638default_compression_show(struct device *dev, struct device_attribute *attr,
4639			 char *buf)
4640{
4641	struct st_modedef *STm = dev_get_drvdata(dev);
4642	ssize_t l = 0;
4643
4644	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4645	return l;
4646}
4647static DEVICE_ATTR_RO(default_compression);
4648
4649static ssize_t
4650options_show(struct device *dev, struct device_attribute *attr, char *buf)
4651{
4652	struct st_modedef *STm = dev_get_drvdata(dev);
4653	struct scsi_tape *STp = STm->tape;
4654	int options;
4655	ssize_t l = 0;
4656
4657	options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4658	options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4659	options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4660	DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4661	options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4662	options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4663	options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4664	options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4665	options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4666	options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4667	options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4668	options |= STm->sysv ? MT_ST_SYSV : 0;
4669	options |= STp->immediate ? MT_ST_NOWAIT : 0;
4670	options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4671	options |= STp->sili ? MT_ST_SILI : 0;
4672
4673	l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4674	return l;
4675}
4676static DEVICE_ATTR_RO(options);
4677
4678/* Support for tape stats */
4679
4680/**
4681 * read_cnt_show - return read count - count of reads made from tape drive
4682 * @dev: struct device
4683 * @attr: attribute structure
4684 * @buf: buffer to return formatted data in
4685 */
4686static ssize_t read_cnt_show(struct device *dev,
4687	struct device_attribute *attr, char *buf)
4688{
4689	struct st_modedef *STm = dev_get_drvdata(dev);
4690
4691	return sprintf(buf, "%lld",
4692		       (long long)atomic64_read(&STm->tape->stats->read_cnt));
4693}
4694static DEVICE_ATTR_RO(read_cnt);
4695
4696/**
4697 * read_byte_cnt_show - return read byte count - tape drives
4698 * may use blocks less than 512 bytes this gives the raw byte count of
4699 * of data read from the tape drive.
4700 * @dev: struct device
4701 * @attr: attribute structure
4702 * @buf: buffer to return formatted data in
4703 */
4704static ssize_t read_byte_cnt_show(struct device *dev,
4705	struct device_attribute *attr, char *buf)
4706{
4707	struct st_modedef *STm = dev_get_drvdata(dev);
4708
4709	return sprintf(buf, "%lld",
4710		       (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4711}
4712static DEVICE_ATTR_RO(read_byte_cnt);
4713
4714/**
4715 * read_ns_show - return read ns - overall time spent waiting on reads in ns.
4716 * @dev: struct device
4717 * @attr: attribute structure
4718 * @buf: buffer to return formatted data in
4719 */
4720static ssize_t read_ns_show(struct device *dev,
4721	struct device_attribute *attr, char *buf)
4722{
4723	struct st_modedef *STm = dev_get_drvdata(dev);
4724
4725	return sprintf(buf, "%lld",
4726		       (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4727}
4728static DEVICE_ATTR_RO(read_ns);
4729
4730/**
4731 * write_cnt_show - write count - number of user calls
4732 * to write(2) that have written data to tape.
4733 * @dev: struct device
4734 * @attr: attribute structure
4735 * @buf: buffer to return formatted data in
4736 */
4737static ssize_t write_cnt_show(struct device *dev,
4738	struct device_attribute *attr, char *buf)
4739{
4740	struct st_modedef *STm = dev_get_drvdata(dev);
4741
4742	return sprintf(buf, "%lld",
4743		       (long long)atomic64_read(&STm->tape->stats->write_cnt));
4744}
4745static DEVICE_ATTR_RO(write_cnt);
4746
4747/**
4748 * write_byte_cnt_show - write byte count - raw count of
4749 * bytes written to tape.
4750 * @dev: struct device
4751 * @attr: attribute structure
4752 * @buf: buffer to return formatted data in
4753 */
4754static ssize_t write_byte_cnt_show(struct device *dev,
4755	struct device_attribute *attr, char *buf)
4756{
4757	struct st_modedef *STm = dev_get_drvdata(dev);
4758
4759	return sprintf(buf, "%lld",
4760		       (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4761}
4762static DEVICE_ATTR_RO(write_byte_cnt);
4763
4764/**
4765 * write_ns_show - write ns - number of nanoseconds waiting on write
4766 * requests to complete.
4767 * @dev: struct device
4768 * @attr: attribute structure
4769 * @buf: buffer to return formatted data in
4770 */
4771static ssize_t write_ns_show(struct device *dev,
4772	struct device_attribute *attr, char *buf)
4773{
4774	struct st_modedef *STm = dev_get_drvdata(dev);
4775
4776	return sprintf(buf, "%lld",
4777		       (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4778}
4779static DEVICE_ATTR_RO(write_ns);
4780
4781/**
4782 * in_flight_show - number of I/Os currently in flight -
4783 * in most cases this will be either 0 or 1. It may be higher if someone
4784 * has also issued other SCSI commands such as via an ioctl.
4785 * @dev: struct device
4786 * @attr: attribute structure
4787 * @buf: buffer to return formatted data in
4788 */
4789static ssize_t in_flight_show(struct device *dev,
4790	struct device_attribute *attr, char *buf)
4791{
4792	struct st_modedef *STm = dev_get_drvdata(dev);
4793
4794	return sprintf(buf, "%lld",
4795		       (long long)atomic64_read(&STm->tape->stats->in_flight));
4796}
4797static DEVICE_ATTR_RO(in_flight);
4798
4799/**
4800 * io_ns_show - io wait ns - this is the number of ns spent
4801 * waiting on all I/O to complete. This includes tape movement commands
4802 * such as rewinding, seeking to end of file or tape, it also includes
4803 * read and write. To determine the time spent on tape movement
4804 * subtract the read and write ns from this value.
4805 * @dev: struct device
4806 * @attr: attribute structure
4807 * @buf: buffer to return formatted data in
4808 */
4809static ssize_t io_ns_show(struct device *dev,
4810	struct device_attribute *attr, char *buf)
4811{
4812	struct st_modedef *STm = dev_get_drvdata(dev);
4813
4814	return sprintf(buf, "%lld",
4815		       (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4816}
4817static DEVICE_ATTR_RO(io_ns);
4818
4819/**
4820 * other_cnt_show - other io count - this is the number of
4821 * I/O requests other than read and write requests.
4822 * Typically these are tape movement requests but will include driver
4823 * tape movement. This includes only requests issued by the st driver.
4824 * @dev: struct device
4825 * @attr: attribute structure
4826 * @buf: buffer to return formatted data in
4827 */
4828static ssize_t other_cnt_show(struct device *dev,
4829	struct device_attribute *attr, char *buf)
4830{
4831	struct st_modedef *STm = dev_get_drvdata(dev);
4832
4833	return sprintf(buf, "%lld",
4834		       (long long)atomic64_read(&STm->tape->stats->other_cnt));
4835}
4836static DEVICE_ATTR_RO(other_cnt);
4837
4838/**
4839 * resid_cnt_show - A count of the number of times we get a residual
4840 * count - this should indicate someone issuing reads larger than the
4841 * block size on tape.
4842 * @dev: struct device
4843 * @attr: attribute structure
4844 * @buf: buffer to return formatted data in
4845 */
4846static ssize_t resid_cnt_show(struct device *dev,
4847	struct device_attribute *attr, char *buf)
4848{
4849	struct st_modedef *STm = dev_get_drvdata(dev);
4850
4851	return sprintf(buf, "%lld",
4852		       (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4853}
4854static DEVICE_ATTR_RO(resid_cnt);
4855
4856static struct attribute *st_dev_attrs[] = {
4857	&dev_attr_defined.attr,
4858	&dev_attr_default_blksize.attr,
4859	&dev_attr_default_density.attr,
4860	&dev_attr_default_compression.attr,
4861	&dev_attr_options.attr,
4862	NULL,
4863};
4864
4865static struct attribute *st_stats_attrs[] = {
4866	&dev_attr_read_cnt.attr,
4867	&dev_attr_read_byte_cnt.attr,
4868	&dev_attr_read_ns.attr,
4869	&dev_attr_write_cnt.attr,
4870	&dev_attr_write_byte_cnt.attr,
4871	&dev_attr_write_ns.attr,
4872	&dev_attr_in_flight.attr,
4873	&dev_attr_io_ns.attr,
4874	&dev_attr_other_cnt.attr,
4875	&dev_attr_resid_cnt.attr,
4876	NULL,
4877};
4878
4879static struct attribute_group stats_group = {
4880	.name = "stats",
4881	.attrs = st_stats_attrs,
4882};
4883
4884static struct attribute_group st_group = {
4885	.attrs = st_dev_attrs,
4886};
4887
4888static const struct attribute_group *st_dev_groups[] = {
4889	&st_group,
4890	&stats_group,
4891	NULL,
4892};
4893
4894/* The following functions may be useful for a larger audience. */
4895static int sgl_map_user_pages(struct st_buffer *STbp,
4896			      const unsigned int max_pages, unsigned long uaddr,
4897			      size_t count, int rw)
4898{
4899	unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4900	unsigned long start = uaddr >> PAGE_SHIFT;
4901	const int nr_pages = end - start;
4902	int res, i, j;
4903	struct page **pages;
4904	struct rq_map_data *mdata = &STbp->map_data;
4905
4906	/* User attempted Overflow! */
4907	if ((uaddr + count) < uaddr)
4908		return -EINVAL;
4909
4910	/* Too big */
4911        if (nr_pages > max_pages)
4912		return -ENOMEM;
4913
4914	/* Hmm? */
4915	if (count == 0)
4916		return 0;
4917
4918	if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_KERNEL)) == NULL)
4919		return -ENOMEM;
4920
4921        /* Try to fault in all of the necessary pages */
4922        /* rw==READ means read from drive, write into memory area */
4923	res = get_user_pages_fast(uaddr, nr_pages, rw == READ, pages);
 
 
 
 
 
4924
4925	/* Errors and no page mapped should return here */
4926	if (res < nr_pages)
4927		goto out_unmap;
4928
4929        for (i=0; i < nr_pages; i++) {
4930                /* FIXME: flush superflous for rw==READ,
4931                 * probably wrong function for rw==WRITE
4932                 */
4933		flush_dcache_page(pages[i]);
4934        }
4935
4936	mdata->offset = uaddr & ~PAGE_MASK;
4937	STbp->mapped_pages = pages;
4938
4939	return nr_pages;
4940 out_unmap:
4941	if (res > 0) {
4942		for (j=0; j < res; j++)
4943			put_page(pages[j]);
4944		res = 0;
4945	}
4946	kfree(pages);
4947	return res;
4948}
4949
4950
4951/* And unmap them... */
4952static int sgl_unmap_user_pages(struct st_buffer *STbp,
4953				const unsigned int nr_pages, int dirtied)
4954{
4955	int i;
4956
4957	for (i=0; i < nr_pages; i++) {
4958		struct page *page = STbp->mapped_pages[i];
4959
4960		if (dirtied)
4961			SetPageDirty(page);
4962		/* FIXME: cache flush missing for rw==READ
4963		 * FIXME: call the correct reference counting function
4964		 */
4965		put_page(page);
4966	}
4967	kfree(STbp->mapped_pages);
4968	STbp->mapped_pages = NULL;
4969
4970	return 0;
4971}
v4.6
   1/*
   2   SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
   3   file Documentation/scsi/st.txt for more information.
   4
   5   History:
   6   Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
   7   Contribution and ideas from several people including (in alphabetical
   8   order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
   9   Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
  10   Michael Schaefer, J"org Weule, and Eric Youngdale.
  11
  12   Copyright 1992 - 2016 Kai Makisara
  13   email Kai.Makisara@kolumbus.fi
  14
  15   Some small formal changes - aeb, 950809
  16
  17   Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  18 */
  19
  20static const char *verstr = "20160209";
  21
  22#include <linux/module.h>
  23
  24#include <linux/fs.h>
  25#include <linux/kernel.h>
  26#include <linux/sched.h>
  27#include <linux/mm.h>
  28#include <linux/init.h>
  29#include <linux/string.h>
  30#include <linux/slab.h>
  31#include <linux/errno.h>
  32#include <linux/mtio.h>
  33#include <linux/cdrom.h>
  34#include <linux/ioctl.h>
  35#include <linux/fcntl.h>
  36#include <linux/spinlock.h>
  37#include <linux/blkdev.h>
  38#include <linux/moduleparam.h>
  39#include <linux/cdev.h>
  40#include <linux/idr.h>
  41#include <linux/delay.h>
  42#include <linux/mutex.h>
  43
  44#include <asm/uaccess.h>
  45#include <asm/dma.h>
  46
  47#include <scsi/scsi.h>
  48#include <scsi/scsi_dbg.h>
  49#include <scsi/scsi_device.h>
  50#include <scsi/scsi_driver.h>
  51#include <scsi/scsi_eh.h>
  52#include <scsi/scsi_host.h>
  53#include <scsi/scsi_ioctl.h>
  54#include <scsi/sg.h>
  55
  56
  57/* The driver prints some debugging information on the console if DEBUG
  58   is defined and non-zero. */
  59#define DEBUG 1
  60#define NO_DEBUG 0
  61
  62#define ST_DEB_MSG  KERN_NOTICE
  63#if DEBUG
  64/* The message level for the debug messages is currently set to KERN_NOTICE
  65   so that people can easily see the messages. Later when the debugging messages
  66   in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
  67#define DEB(a) a
  68#define DEBC(a) if (debugging) { a ; }
  69#else
  70#define DEB(a)
  71#define DEBC(a)
  72#endif
  73
  74#define ST_KILOBYTE 1024
  75
  76#include "st_options.h"
  77#include "st.h"
  78
  79static int buffer_kbs;
  80static int max_sg_segs;
  81static int try_direct_io = TRY_DIRECT_IO;
  82static int try_rdio = 1;
  83static int try_wdio = 1;
  84static int debug_flag;
  85
  86static struct class st_sysfs_class;
  87static const struct attribute_group *st_dev_groups[];
  88static const struct attribute_group *st_drv_groups[];
  89
  90MODULE_AUTHOR("Kai Makisara");
  91MODULE_DESCRIPTION("SCSI tape (st) driver");
  92MODULE_LICENSE("GPL");
  93MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
  94MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
  95
  96/* Set 'perm' (4th argument) to 0 to disable module_param's definition
  97 * of sysfs parameters (which module_param doesn't yet support).
  98 * Sysfs parameters defined explicitly later.
  99 */
 100module_param_named(buffer_kbs, buffer_kbs, int, 0);
 101MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
 102module_param_named(max_sg_segs, max_sg_segs, int, 0);
 103MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
 104module_param_named(try_direct_io, try_direct_io, int, 0);
 105MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
 106module_param_named(debug_flag, debug_flag, int, 0);
 107MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
 108
 109
 110/* Extra parameters for testing */
 111module_param_named(try_rdio, try_rdio, int, 0);
 112MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
 113module_param_named(try_wdio, try_wdio, int, 0);
 114MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
 115
 116#ifndef MODULE
 117static int write_threshold_kbs;  /* retained for compatibility */
 118static struct st_dev_parm {
 119	char *name;
 120	int *val;
 121} parms[] __initdata = {
 122	{
 123		"buffer_kbs", &buffer_kbs
 124	},
 125	{       /* Retained for compatibility with 2.4 */
 126		"write_threshold_kbs", &write_threshold_kbs
 127	},
 128	{
 129		"max_sg_segs", NULL
 130	},
 131	{
 132		"try_direct_io", &try_direct_io
 133	},
 134	{
 135		"debug_flag", &debug_flag
 136	}
 137};
 138#endif
 139
 140/* Restrict the number of modes so that names for all are assigned */
 141#if ST_NBR_MODES > 16
 142#error "Maximum number of modes is 16"
 143#endif
 144/* Bit reversed order to get same names for same minors with all
 145   mode counts */
 146static const char *st_formats[] = {
 147	"",  "r", "k", "s", "l", "t", "o", "u",
 148	"m", "v", "p", "x", "a", "y", "q", "z"}; 
 149
 150/* The default definitions have been moved to st_options.h */
 151
 152#define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
 153
 154/* The buffer size should fit into the 24 bits for length in the
 155   6-byte SCSI read and write commands. */
 156#if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
 157#error "Buffer size should not exceed (2 << 24 - 1) bytes!"
 158#endif
 159
 160static int debugging = DEBUG;
 161
 162#define MAX_RETRIES 0
 163#define MAX_WRITE_RETRIES 0
 164#define MAX_READY_RETRIES 0
 165#define NO_TAPE  NOT_READY
 166
 167#define ST_TIMEOUT (900 * HZ)
 168#define ST_LONG_TIMEOUT (14000 * HZ)
 169
 170/* Remove mode bits and auto-rewind bit (7) */
 171#define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
 172    (iminor(x) & ~(-1 << ST_MODE_SHIFT)) )
 173#define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
 174
 175/* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
 176#define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
 177  (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
 178
 179/* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 180   24 bits) */
 181#define SET_DENS_AND_BLK 0x10001
 182
 183static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
 184static int st_max_sg_segs = ST_MAX_SG;
 185
 186static int modes_defined;
 187
 188static int enlarge_buffer(struct st_buffer *, int, int);
 189static void clear_buffer(struct st_buffer *);
 190static void normalize_buffer(struct st_buffer *);
 191static int append_to_buffer(const char __user *, struct st_buffer *, int);
 192static int from_buffer(struct st_buffer *, char __user *, int);
 193static void move_buffer_data(struct st_buffer *, int);
 194
 195static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
 196			      unsigned long, size_t, int);
 197static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
 198
 199static int st_probe(struct device *);
 200static int st_remove(struct device *);
 201
 202static struct scsi_driver st_template = {
 203	.gendrv = {
 204		.name		= "st",
 205		.owner		= THIS_MODULE,
 206		.probe		= st_probe,
 207		.remove		= st_remove,
 208		.groups		= st_drv_groups,
 209	},
 210};
 211
 212static int st_compression(struct scsi_tape *, int);
 213
 214static int find_partition(struct scsi_tape *);
 215static int switch_partition(struct scsi_tape *);
 216
 217static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
 218
 219static void scsi_tape_release(struct kref *);
 220
 221#define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
 222
 223static DEFINE_MUTEX(st_ref_mutex);
 224static DEFINE_SPINLOCK(st_index_lock);
 225static DEFINE_SPINLOCK(st_use_lock);
 226static DEFINE_IDR(st_index_idr);
 227
 228
 229
 230#include "osst_detect.h"
 231#ifndef SIGS_FROM_OSST
 232#define SIGS_FROM_OSST \
 233	{"OnStream", "SC-", "", "osst"}, \
 234	{"OnStream", "DI-", "", "osst"}, \
 235	{"OnStream", "DP-", "", "osst"}, \
 236	{"OnStream", "USB", "", "osst"}, \
 237	{"OnStream", "FW-", "", "osst"}
 238#endif
 239
 240static struct scsi_tape *scsi_tape_get(int dev)
 241{
 242	struct scsi_tape *STp = NULL;
 243
 244	mutex_lock(&st_ref_mutex);
 245	spin_lock(&st_index_lock);
 246
 247	STp = idr_find(&st_index_idr, dev);
 248	if (!STp) goto out;
 249
 250	kref_get(&STp->kref);
 251
 252	if (!STp->device)
 253		goto out_put;
 254
 255	if (scsi_device_get(STp->device))
 256		goto out_put;
 257
 258	goto out;
 259
 260out_put:
 261	kref_put(&STp->kref, scsi_tape_release);
 262	STp = NULL;
 263out:
 264	spin_unlock(&st_index_lock);
 265	mutex_unlock(&st_ref_mutex);
 266	return STp;
 267}
 268
 269static void scsi_tape_put(struct scsi_tape *STp)
 270{
 271	struct scsi_device *sdev = STp->device;
 272
 273	mutex_lock(&st_ref_mutex);
 274	kref_put(&STp->kref, scsi_tape_release);
 275	scsi_device_put(sdev);
 276	mutex_unlock(&st_ref_mutex);
 277}
 278
 279struct st_reject_data {
 280	char *vendor;
 281	char *model;
 282	char *rev;
 283	char *driver_hint; /* Name of the correct driver, NULL if unknown */
 284};
 285
 286static struct st_reject_data reject_list[] = {
 287	/* {"XXX", "Yy-", "", NULL},  example */
 288	SIGS_FROM_OSST,
 289	{NULL, }};
 290
 291/* If the device signature is on the list of incompatible drives, the
 292   function returns a pointer to the name of the correct driver (if known) */
 293static char * st_incompatible(struct scsi_device* SDp)
 294{
 295	struct st_reject_data *rp;
 296
 297	for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
 298		if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
 299		    !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
 300		    !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
 301			if (rp->driver_hint)
 302				return rp->driver_hint;
 303			else
 304				return "unknown";
 305		}
 306	return NULL;
 307}
 308
 309
 310static inline char *tape_name(struct scsi_tape *tape)
 311{
 312	return tape->disk->disk_name;
 313}
 314
 315#define st_printk(prefix, t, fmt, a...) \
 316	sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
 317#ifdef DEBUG
 318#define DEBC_printk(t, fmt, a...) \
 319	if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
 320#else
 321#define DEBC_printk(t, fmt, a...)
 322#endif
 323
 324static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
 325{
 326	const u8 *ucp;
 327	const u8 *sense = SRpnt->sense;
 328
 329	s->have_sense = scsi_normalize_sense(SRpnt->sense,
 330				SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
 331	s->flags = 0;
 332
 333	if (s->have_sense) {
 334		s->deferred = 0;
 335		s->remainder_valid =
 336			scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
 337		switch (sense[0] & 0x7f) {
 338		case 0x71:
 339			s->deferred = 1;
 340		case 0x70:
 341			s->fixed_format = 1;
 342			s->flags = sense[2] & 0xe0;
 343			break;
 344		case 0x73:
 345			s->deferred = 1;
 346		case 0x72:
 347			s->fixed_format = 0;
 348			ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
 349			s->flags = ucp ? (ucp[3] & 0xe0) : 0;
 350			break;
 351		}
 352	}
 353}
 354
 355
 356/* Convert the result to success code */
 357static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 358{
 359	int result = SRpnt->result;
 360	u8 scode;
 361	DEB(const char *stp;)
 362	char *name = tape_name(STp);
 363	struct st_cmdstatus *cmdstatp;
 364
 365	if (!result)
 366		return 0;
 367
 368	cmdstatp = &STp->buffer->cmdstat;
 369	st_analyze_sense(SRpnt, cmdstatp);
 370
 371	if (cmdstatp->have_sense)
 372		scode = STp->buffer->cmdstat.sense_hdr.sense_key;
 373	else
 374		scode = 0;
 375
 376	DEB(
 377	if (debugging) {
 378		st_printk(ST_DEB_MSG, STp,
 379			    "Error: %x, cmd: %x %x %x %x %x %x\n", result,
 380			    SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 381			    SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 382		if (cmdstatp->have_sense)
 383			__scsi_print_sense(STp->device, name,
 384					   SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 385	} ) /* end DEB */
 386	if (!debugging) { /* Abnormal conditions for tape */
 387		if (!cmdstatp->have_sense)
 388			st_printk(KERN_WARNING, STp,
 389			       "Error %x (driver bt 0x%x, host bt 0x%x).\n",
 390			       result, driver_byte(result), host_byte(result));
 391		else if (cmdstatp->have_sense &&
 392			 scode != NO_SENSE &&
 393			 scode != RECOVERED_ERROR &&
 394			 /* scode != UNIT_ATTENTION && */
 395			 scode != BLANK_CHECK &&
 396			 scode != VOLUME_OVERFLOW &&
 397			 SRpnt->cmd[0] != MODE_SENSE &&
 398			 SRpnt->cmd[0] != TEST_UNIT_READY) {
 399
 400			__scsi_print_sense(STp->device, name,
 401					   SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 402		}
 403	}
 404
 405	if (cmdstatp->fixed_format &&
 406	    STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
 407		if (STp->cln_sense_value)
 408			STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 409					       STp->cln_sense_mask) == STp->cln_sense_value);
 410		else
 411			STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 412					       STp->cln_sense_mask) != 0);
 413	}
 414	if (cmdstatp->have_sense &&
 415	    cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 416		STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
 417
 418	STp->pos_unknown |= STp->device->was_reset;
 419
 420	if (cmdstatp->have_sense &&
 421	    scode == RECOVERED_ERROR
 422#if ST_RECOVERED_WRITE_FATAL
 423	    && SRpnt->cmd[0] != WRITE_6
 424	    && SRpnt->cmd[0] != WRITE_FILEMARKS
 425#endif
 426	    ) {
 427		STp->recover_count++;
 428		STp->recover_reg++;
 429
 430		DEB(
 431		if (debugging) {
 432			if (SRpnt->cmd[0] == READ_6)
 433				stp = "read";
 434			else if (SRpnt->cmd[0] == WRITE_6)
 435				stp = "write";
 436			else
 437				stp = "ioctl";
 438			st_printk(ST_DEB_MSG, STp,
 439				  "Recovered %s error (%d).\n",
 440				  stp, STp->recover_count);
 441		} ) /* end DEB */
 442
 443		if (cmdstatp->flags == 0)
 444			return 0;
 445	}
 446	return (-EIO);
 447}
 448
 449static struct st_request *st_allocate_request(struct scsi_tape *stp)
 450{
 451	struct st_request *streq;
 452
 453	streq = kzalloc(sizeof(*streq), GFP_KERNEL);
 454	if (streq)
 455		streq->stp = stp;
 456	else {
 457		st_printk(KERN_ERR, stp,
 458			  "Can't get SCSI request.\n");
 459		if (signal_pending(current))
 460			stp->buffer->syscall_result = -EINTR;
 461		else
 462			stp->buffer->syscall_result = -EBUSY;
 463	}
 464
 465	return streq;
 466}
 467
 468static void st_release_request(struct st_request *streq)
 469{
 470	kfree(streq);
 471}
 472
 473static void st_do_stats(struct scsi_tape *STp, struct request *req)
 474{
 475	ktime_t now;
 476
 477	now = ktime_get();
 478	if (req->cmd[0] == WRITE_6) {
 479		now = ktime_sub(now, STp->stats->write_time);
 480		atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
 481		atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 482		atomic64_inc(&STp->stats->write_cnt);
 483		if (req->errors) {
 484			atomic64_add(atomic_read(&STp->stats->last_write_size)
 485				- STp->buffer->cmdstat.residual,
 486				&STp->stats->write_byte_cnt);
 487			if (STp->buffer->cmdstat.residual > 0)
 488				atomic64_inc(&STp->stats->resid_cnt);
 489		} else
 490			atomic64_add(atomic_read(&STp->stats->last_write_size),
 491				&STp->stats->write_byte_cnt);
 492	} else if (req->cmd[0] == READ_6) {
 493		now = ktime_sub(now, STp->stats->read_time);
 494		atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
 495		atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 496		atomic64_inc(&STp->stats->read_cnt);
 497		if (req->errors) {
 498			atomic64_add(atomic_read(&STp->stats->last_read_size)
 499				- STp->buffer->cmdstat.residual,
 500				&STp->stats->read_byte_cnt);
 501			if (STp->buffer->cmdstat.residual > 0)
 502				atomic64_inc(&STp->stats->resid_cnt);
 503		} else
 504			atomic64_add(atomic_read(&STp->stats->last_read_size),
 505				&STp->stats->read_byte_cnt);
 506	} else {
 507		now = ktime_sub(now, STp->stats->other_time);
 508		atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 509		atomic64_inc(&STp->stats->other_cnt);
 510	}
 511	atomic64_dec(&STp->stats->in_flight);
 512}
 513
 514static void st_scsi_execute_end(struct request *req, int uptodate)
 515{
 516	struct st_request *SRpnt = req->end_io_data;
 
 517	struct scsi_tape *STp = SRpnt->stp;
 518	struct bio *tmp;
 519
 520	STp->buffer->cmdstat.midlevel_result = SRpnt->result = req->errors;
 521	STp->buffer->cmdstat.residual = req->resid_len;
 522
 523	st_do_stats(STp, req);
 524
 525	tmp = SRpnt->bio;
 
 
 526	if (SRpnt->waiting)
 527		complete(SRpnt->waiting);
 528
 529	blk_rq_unmap_user(tmp);
 530	__blk_put_request(req->q, req);
 531}
 532
 533static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 534			   int data_direction, void *buffer, unsigned bufflen,
 535			   int timeout, int retries)
 536{
 537	struct request *req;
 
 538	struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
 539	int err = 0;
 540	int write = (data_direction == DMA_TO_DEVICE);
 541	struct scsi_tape *STp = SRpnt->stp;
 542
 543	req = blk_get_request(SRpnt->stp->device->request_queue, write,
 544			      GFP_KERNEL);
 
 545	if (IS_ERR(req))
 546		return DRIVER_ERROR << 24;
 547
 548	blk_rq_set_block_pc(req);
 549	req->cmd_flags |= REQ_QUIET;
 550
 551	mdata->null_mapped = 1;
 552
 553	if (bufflen) {
 554		err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
 555				      GFP_KERNEL);
 556		if (err) {
 557			blk_put_request(req);
 558			return DRIVER_ERROR << 24;
 559		}
 560	}
 561
 562	atomic64_inc(&STp->stats->in_flight);
 563	if (cmd[0] == WRITE_6) {
 564		atomic_set(&STp->stats->last_write_size, bufflen);
 565		STp->stats->write_time = ktime_get();
 566	} else if (cmd[0] == READ_6) {
 567		atomic_set(&STp->stats->last_read_size, bufflen);
 568		STp->stats->read_time = ktime_get();
 569	} else {
 570		STp->stats->other_time = ktime_get();
 571	}
 572
 573	SRpnt->bio = req->bio;
 574	req->cmd_len = COMMAND_SIZE(cmd[0]);
 575	memset(req->cmd, 0, BLK_MAX_CDB);
 576	memcpy(req->cmd, cmd, req->cmd_len);
 577	req->sense = SRpnt->sense;
 578	req->sense_len = 0;
 579	req->timeout = timeout;
 580	req->retries = retries;
 581	req->end_io_data = SRpnt;
 582
 583	blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
 584	return 0;
 585}
 586
 587/* Do the scsi command. Waits until command performed if do_wait is true.
 588   Otherwise write_behind_check() is used to check that the command
 589   has finished. */
 590static struct st_request *
 591st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
 592	   int bytes, int direction, int timeout, int retries, int do_wait)
 593{
 594	struct completion *waiting;
 595	struct rq_map_data *mdata = &STp->buffer->map_data;
 596	int ret;
 597
 598	/* if async, make sure there's no command outstanding */
 599	if (!do_wait && ((STp->buffer)->last_SRpnt)) {
 600		st_printk(KERN_ERR, STp,
 601			  "Async command already active.\n");
 602		if (signal_pending(current))
 603			(STp->buffer)->syscall_result = (-EINTR);
 604		else
 605			(STp->buffer)->syscall_result = (-EBUSY);
 606		return NULL;
 607	}
 608
 609	if (!SRpnt) {
 610		SRpnt = st_allocate_request(STp);
 611		if (!SRpnt)
 612			return NULL;
 613	}
 614
 615	/* If async IO, set last_SRpnt. This ptr tells write_behind_check
 616	   which IO is outstanding. It's nulled out when the IO completes. */
 617	if (!do_wait)
 618		(STp->buffer)->last_SRpnt = SRpnt;
 619
 620	waiting = &STp->wait;
 621	init_completion(waiting);
 622	SRpnt->waiting = waiting;
 623
 624	if (STp->buffer->do_dio) {
 625		mdata->page_order = 0;
 626		mdata->nr_entries = STp->buffer->sg_segs;
 627		mdata->pages = STp->buffer->mapped_pages;
 628	} else {
 629		mdata->page_order = STp->buffer->reserved_page_order;
 630		mdata->nr_entries =
 631			DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
 632		mdata->pages = STp->buffer->reserved_pages;
 633		mdata->offset = 0;
 634	}
 635
 636	memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
 637	STp->buffer->cmdstat.have_sense = 0;
 638	STp->buffer->syscall_result = 0;
 639
 640	ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
 641			      retries);
 642	if (ret) {
 643		/* could not allocate the buffer or request was too large */
 644		(STp->buffer)->syscall_result = (-EBUSY);
 645		(STp->buffer)->last_SRpnt = NULL;
 646	} else if (do_wait) {
 647		wait_for_completion(waiting);
 648		SRpnt->waiting = NULL;
 649		(STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 650	}
 651
 652	return SRpnt;
 653}
 654
 655
 656/* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
 657   write has been correct but EOM early warning reached, -EIO if write ended in
 658   error or zero if write successful. Asynchronous writes are used only in
 659   variable block mode. */
 660static int write_behind_check(struct scsi_tape * STp)
 661{
 662	int retval = 0;
 663	struct st_buffer *STbuffer;
 664	struct st_partstat *STps;
 665	struct st_cmdstatus *cmdstatp;
 666	struct st_request *SRpnt;
 667
 668	STbuffer = STp->buffer;
 669	if (!STbuffer->writing)
 670		return 0;
 671
 672	DEB(
 673	if (STp->write_pending)
 674		STp->nbr_waits++;
 675	else
 676		STp->nbr_finished++;
 677	) /* end DEB */
 678
 679	wait_for_completion(&(STp->wait));
 680	SRpnt = STbuffer->last_SRpnt;
 681	STbuffer->last_SRpnt = NULL;
 682	SRpnt->waiting = NULL;
 683
 684	(STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 685	st_release_request(SRpnt);
 686
 687	STbuffer->buffer_bytes -= STbuffer->writing;
 688	STps = &(STp->ps[STp->partition]);
 689	if (STps->drv_block >= 0) {
 690		if (STp->block_size == 0)
 691			STps->drv_block++;
 692		else
 693			STps->drv_block += STbuffer->writing / STp->block_size;
 694	}
 695
 696	cmdstatp = &STbuffer->cmdstat;
 697	if (STbuffer->syscall_result) {
 698		retval = -EIO;
 699		if (cmdstatp->have_sense && !cmdstatp->deferred &&
 700		    (cmdstatp->flags & SENSE_EOM) &&
 701		    (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 702		     cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
 703			/* EOM at write-behind, has all data been written? */
 704			if (!cmdstatp->remainder_valid ||
 705			    cmdstatp->uremainder64 == 0)
 706				retval = -ENOSPC;
 707		}
 708		if (retval == -EIO)
 709			STps->drv_block = -1;
 710	}
 711	STbuffer->writing = 0;
 712
 713	DEB(if (debugging && retval)
 714		    st_printk(ST_DEB_MSG, STp,
 715				"Async write error %x, return value %d.\n",
 716				STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
 717
 718	return retval;
 719}
 720
 721
 722/* Step over EOF if it has been inadvertently crossed (ioctl not used because
 723   it messes up the block number). */
 724static int cross_eof(struct scsi_tape * STp, int forward)
 725{
 726	struct st_request *SRpnt;
 727	unsigned char cmd[MAX_COMMAND_SIZE];
 728
 729	cmd[0] = SPACE;
 730	cmd[1] = 0x01;		/* Space FileMarks */
 731	if (forward) {
 732		cmd[2] = cmd[3] = 0;
 733		cmd[4] = 1;
 734	} else
 735		cmd[2] = cmd[3] = cmd[4] = 0xff;	/* -1 filemarks */
 736	cmd[5] = 0;
 737
 738	DEBC_printk(STp, "Stepping over filemark %s.\n",
 739		    forward ? "forward" : "backward");
 740
 741	SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
 742			   STp->device->request_queue->rq_timeout,
 743			   MAX_RETRIES, 1);
 744	if (!SRpnt)
 745		return (STp->buffer)->syscall_result;
 746
 747	st_release_request(SRpnt);
 748	SRpnt = NULL;
 749
 750	if ((STp->buffer)->cmdstat.midlevel_result != 0)
 751		st_printk(KERN_ERR, STp,
 752			  "Stepping over filemark %s failed.\n",
 753			  forward ? "forward" : "backward");
 754
 755	return (STp->buffer)->syscall_result;
 756}
 757
 758
 759/* Flush the write buffer (never need to write if variable blocksize). */
 760static int st_flush_write_buffer(struct scsi_tape * STp)
 761{
 762	int transfer, blks;
 763	int result;
 764	unsigned char cmd[MAX_COMMAND_SIZE];
 765	struct st_request *SRpnt;
 766	struct st_partstat *STps;
 767
 768	result = write_behind_check(STp);
 769	if (result)
 770		return result;
 771
 772	result = 0;
 773	if (STp->dirty == 1) {
 774
 775		transfer = STp->buffer->buffer_bytes;
 776		DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
 777
 778		memset(cmd, 0, MAX_COMMAND_SIZE);
 779		cmd[0] = WRITE_6;
 780		cmd[1] = 1;
 781		blks = transfer / STp->block_size;
 782		cmd[2] = blks >> 16;
 783		cmd[3] = blks >> 8;
 784		cmd[4] = blks;
 785
 786		SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
 787				   STp->device->request_queue->rq_timeout,
 788				   MAX_WRITE_RETRIES, 1);
 789		if (!SRpnt)
 790			return (STp->buffer)->syscall_result;
 791
 792		STps = &(STp->ps[STp->partition]);
 793		if ((STp->buffer)->syscall_result != 0) {
 794			struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 795
 796			if (cmdstatp->have_sense && !cmdstatp->deferred &&
 797			    (cmdstatp->flags & SENSE_EOM) &&
 798			    (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 799			     cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
 800			    (!cmdstatp->remainder_valid ||
 801			     cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
 802				STp->dirty = 0;
 803				(STp->buffer)->buffer_bytes = 0;
 804				if (STps->drv_block >= 0)
 805					STps->drv_block += blks;
 806				result = (-ENOSPC);
 807			} else {
 808				st_printk(KERN_ERR, STp, "Error on flush.\n");
 809				STps->drv_block = (-1);
 810				result = (-EIO);
 811			}
 812		} else {
 813			if (STps->drv_block >= 0)
 814				STps->drv_block += blks;
 815			STp->dirty = 0;
 816			(STp->buffer)->buffer_bytes = 0;
 817		}
 818		st_release_request(SRpnt);
 819		SRpnt = NULL;
 820	}
 821	return result;
 822}
 823
 824
 825/* Flush the tape buffer. The tape will be positioned correctly unless
 826   seek_next is true. */
 827static int flush_buffer(struct scsi_tape *STp, int seek_next)
 828{
 829	int backspace, result;
 830	struct st_buffer *STbuffer;
 831	struct st_partstat *STps;
 832
 833	STbuffer = STp->buffer;
 834
 835	/*
 836	 * If there was a bus reset, block further access
 837	 * to this device.
 838	 */
 839	if (STp->pos_unknown)
 840		return (-EIO);
 841
 842	if (STp->ready != ST_READY)
 843		return 0;
 844	STps = &(STp->ps[STp->partition]);
 845	if (STps->rw == ST_WRITING)	/* Writing */
 846		return st_flush_write_buffer(STp);
 847
 848	if (STp->block_size == 0)
 849		return 0;
 850
 851	backspace = ((STp->buffer)->buffer_bytes +
 852		     (STp->buffer)->read_pointer) / STp->block_size -
 853	    ((STp->buffer)->read_pointer + STp->block_size - 1) /
 854	    STp->block_size;
 855	(STp->buffer)->buffer_bytes = 0;
 856	(STp->buffer)->read_pointer = 0;
 857	result = 0;
 858	if (!seek_next) {
 859		if (STps->eof == ST_FM_HIT) {
 860			result = cross_eof(STp, 0);	/* Back over the EOF hit */
 861			if (!result)
 862				STps->eof = ST_NOEOF;
 863			else {
 864				if (STps->drv_file >= 0)
 865					STps->drv_file++;
 866				STps->drv_block = 0;
 867			}
 868		}
 869		if (!result && backspace > 0)
 870			result = st_int_ioctl(STp, MTBSR, backspace);
 871	} else if (STps->eof == ST_FM_HIT) {
 872		if (STps->drv_file >= 0)
 873			STps->drv_file++;
 874		STps->drv_block = 0;
 875		STps->eof = ST_NOEOF;
 876	}
 877	return result;
 878
 879}
 880
 881/* Set the mode parameters */
 882static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
 883{
 884	int set_it = 0;
 885	unsigned long arg;
 886
 887	if (!STp->density_changed &&
 888	    STm->default_density >= 0 &&
 889	    STm->default_density != STp->density) {
 890		arg = STm->default_density;
 891		set_it = 1;
 892	} else
 893		arg = STp->density;
 894	arg <<= MT_ST_DENSITY_SHIFT;
 895	if (!STp->blksize_changed &&
 896	    STm->default_blksize >= 0 &&
 897	    STm->default_blksize != STp->block_size) {
 898		arg |= STm->default_blksize;
 899		set_it = 1;
 900	} else
 901		arg |= STp->block_size;
 902	if (set_it &&
 903	    st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
 904		st_printk(KERN_WARNING, STp,
 905			  "Can't set default block size to %d bytes "
 906			  "and density %x.\n",
 907			  STm->default_blksize, STm->default_density);
 908		if (modes_defined)
 909			return (-EINVAL);
 910	}
 911	return 0;
 912}
 913
 914
 915/* Lock or unlock the drive door. Don't use when st_request allocated. */
 916static int do_door_lock(struct scsi_tape * STp, int do_lock)
 917{
 918	int retval;
 919
 920	DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
 921
 922	retval = scsi_set_medium_removal(STp->device,
 923			do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
 924	if (!retval)
 925		STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
 926	else
 927		STp->door_locked = ST_LOCK_FAILS;
 928	return retval;
 929}
 930
 931
 932/* Set the internal state after reset */
 933static void reset_state(struct scsi_tape *STp)
 934{
 935	int i;
 936	struct st_partstat *STps;
 937
 938	STp->pos_unknown = 0;
 939	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
 940		STps = &(STp->ps[i]);
 941		STps->rw = ST_IDLE;
 942		STps->eof = ST_NOEOF;
 943		STps->at_sm = 0;
 944		STps->last_block_valid = 0;
 945		STps->drv_block = -1;
 946		STps->drv_file = -1;
 947	}
 948	if (STp->can_partitions) {
 949		STp->partition = find_partition(STp);
 950		if (STp->partition < 0)
 951			STp->partition = 0;
 952		STp->new_partition = STp->partition;
 953	}
 954}
 955
 956/* Test if the drive is ready. Returns either one of the codes below or a negative system
 957   error code. */
 958#define CHKRES_READY       0
 959#define CHKRES_NEW_SESSION 1
 960#define CHKRES_NOT_READY   2
 961#define CHKRES_NO_TAPE     3
 962
 963#define MAX_ATTENTIONS    10
 964
 965static int test_ready(struct scsi_tape *STp, int do_wait)
 966{
 967	int attentions, waits, max_wait, scode;
 968	int retval = CHKRES_READY, new_session = 0;
 969	unsigned char cmd[MAX_COMMAND_SIZE];
 970	struct st_request *SRpnt = NULL;
 971	struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 972
 973	max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
 974
 975	for (attentions=waits=0; ; ) {
 976		memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
 977		cmd[0] = TEST_UNIT_READY;
 978		SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
 979				   STp->long_timeout, MAX_READY_RETRIES, 1);
 980
 981		if (!SRpnt) {
 982			retval = (STp->buffer)->syscall_result;
 983			break;
 984		}
 985
 986		if (cmdstatp->have_sense) {
 987
 988			scode = cmdstatp->sense_hdr.sense_key;
 989
 990			if (scode == UNIT_ATTENTION) { /* New media? */
 991				new_session = 1;
 992				if (attentions < MAX_ATTENTIONS) {
 993					attentions++;
 994					continue;
 995				}
 996				else {
 997					retval = (-EIO);
 998					break;
 999				}
1000			}
1001
1002			if (scode == NOT_READY) {
1003				if (waits < max_wait) {
1004					if (msleep_interruptible(1000)) {
1005						retval = (-EINTR);
1006						break;
1007					}
1008					waits++;
1009					continue;
1010				}
1011				else {
1012					if ((STp->device)->scsi_level >= SCSI_2 &&
1013					    cmdstatp->sense_hdr.asc == 0x3a)	/* Check ASC */
1014						retval = CHKRES_NO_TAPE;
1015					else
1016						retval = CHKRES_NOT_READY;
1017					break;
1018				}
1019			}
1020		}
1021
1022		retval = (STp->buffer)->syscall_result;
1023		if (!retval)
1024			retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
1025		break;
1026	}
1027
1028	if (SRpnt != NULL)
1029		st_release_request(SRpnt);
1030	return retval;
1031}
1032
1033
1034/* See if the drive is ready and gather information about the tape. Return values:
1035   < 0   negative error code from errno.h
1036   0     drive ready
1037   1     drive not ready (possibly no tape)
1038*/
1039static int check_tape(struct scsi_tape *STp, struct file *filp)
1040{
1041	int i, retval, new_session = 0, do_wait;
1042	unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
1043	unsigned short st_flags = filp->f_flags;
1044	struct st_request *SRpnt = NULL;
1045	struct st_modedef *STm;
1046	struct st_partstat *STps;
1047	struct inode *inode = file_inode(filp);
1048	int mode = TAPE_MODE(inode);
1049
1050	STp->ready = ST_READY;
1051
1052	if (mode != STp->current_mode) {
1053		DEBC_printk(STp, "Mode change from %d to %d.\n",
1054			    STp->current_mode, mode);
1055		new_session = 1;
1056		STp->current_mode = mode;
1057	}
1058	STm = &(STp->modes[STp->current_mode]);
1059
1060	saved_cleaning = STp->cleaning_req;
1061	STp->cleaning_req = 0;
1062
1063	do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1064	retval = test_ready(STp, do_wait);
1065
1066	if (retval < 0)
1067	    goto err_out;
1068
1069	if (retval == CHKRES_NEW_SESSION) {
1070		STp->pos_unknown = 0;
1071		STp->partition = STp->new_partition = 0;
1072		if (STp->can_partitions)
1073			STp->nbr_partitions = 1; /* This guess will be updated later
1074                                                    if necessary */
1075		for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1076			STps = &(STp->ps[i]);
1077			STps->rw = ST_IDLE;
1078			STps->eof = ST_NOEOF;
1079			STps->at_sm = 0;
1080			STps->last_block_valid = 0;
1081			STps->drv_block = 0;
1082			STps->drv_file = 0;
1083		}
1084		new_session = 1;
1085	}
1086	else {
1087		STp->cleaning_req |= saved_cleaning;
1088
1089		if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1090			if (retval == CHKRES_NO_TAPE)
1091				STp->ready = ST_NO_TAPE;
1092			else
1093				STp->ready = ST_NOT_READY;
1094
1095			STp->density = 0;	/* Clear the erroneous "residue" */
1096			STp->write_prot = 0;
1097			STp->block_size = 0;
1098			STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1099			STp->partition = STp->new_partition = 0;
1100			STp->door_locked = ST_UNLOCKED;
1101			return CHKRES_NOT_READY;
1102		}
1103	}
1104
1105	if (STp->omit_blklims)
1106		STp->min_block = STp->max_block = (-1);
1107	else {
1108		memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1109		cmd[0] = READ_BLOCK_LIMITS;
1110
1111		SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1112				   STp->device->request_queue->rq_timeout,
1113				   MAX_READY_RETRIES, 1);
1114		if (!SRpnt) {
1115			retval = (STp->buffer)->syscall_result;
1116			goto err_out;
1117		}
1118
1119		if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1120			STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1121			    ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1122			STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1123			    (STp->buffer)->b_data[5];
1124			if ( DEB( debugging || ) !STp->inited)
1125				st_printk(KERN_INFO, STp,
1126					  "Block limits %d - %d bytes.\n",
1127					  STp->min_block, STp->max_block);
1128		} else {
1129			STp->min_block = STp->max_block = (-1);
1130			DEBC_printk(STp, "Can't read block limits.\n");
1131		}
1132	}
1133
1134	memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1135	cmd[0] = MODE_SENSE;
1136	cmd[4] = 12;
1137
1138	SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1139			   STp->device->request_queue->rq_timeout,
1140			   MAX_READY_RETRIES, 1);
1141	if (!SRpnt) {
1142		retval = (STp->buffer)->syscall_result;
1143		goto err_out;
1144	}
1145
1146	if ((STp->buffer)->syscall_result != 0) {
1147		DEBC_printk(STp, "No Mode Sense.\n");
1148		STp->block_size = ST_DEFAULT_BLOCK;	/* Educated guess (?) */
1149		(STp->buffer)->syscall_result = 0;	/* Prevent error propagation */
1150		STp->drv_write_prot = 0;
1151	} else {
1152		DEBC_printk(STp,"Mode sense. Length %d, "
1153			    "medium %x, WBS %x, BLL %d\n",
1154			    (STp->buffer)->b_data[0],
1155			    (STp->buffer)->b_data[1],
1156			    (STp->buffer)->b_data[2],
1157			    (STp->buffer)->b_data[3]);
1158
1159		if ((STp->buffer)->b_data[3] >= 8) {
1160			STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1161			STp->density = (STp->buffer)->b_data[4];
1162			STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1163			    (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1164			DEBC_printk(STp, "Density %x, tape length: %x, "
1165				    "drv buffer: %d\n",
1166				    STp->density,
1167				    (STp->buffer)->b_data[5] * 65536 +
1168				    (STp->buffer)->b_data[6] * 256 +
1169				    (STp->buffer)->b_data[7],
1170				    STp->drv_buffer);
1171		}
1172		STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1173		if (!STp->drv_buffer && STp->immediate_filemark) {
1174			st_printk(KERN_WARNING, STp,
1175				  "non-buffered tape: disabling "
1176				  "writing immediate filemarks\n");
1177			STp->immediate_filemark = 0;
1178		}
1179	}
1180	st_release_request(SRpnt);
1181	SRpnt = NULL;
1182	STp->inited = 1;
1183
1184	if (STp->block_size > 0)
1185		(STp->buffer)->buffer_blocks =
1186			(STp->buffer)->buffer_size / STp->block_size;
1187	else
1188		(STp->buffer)->buffer_blocks = 1;
1189	(STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1190
1191	DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1192		    STp->block_size, (STp->buffer)->buffer_size,
1193		    (STp->buffer)->buffer_blocks);
1194
1195	if (STp->drv_write_prot) {
1196		STp->write_prot = 1;
1197
1198		DEBC_printk(STp, "Write protected\n");
1199
1200		if (do_wait &&
1201		    ((st_flags & O_ACCMODE) == O_WRONLY ||
1202		     (st_flags & O_ACCMODE) == O_RDWR)) {
1203			retval = (-EROFS);
1204			goto err_out;
1205		}
1206	}
1207
1208	if (STp->can_partitions && STp->nbr_partitions < 1) {
1209		/* This code is reached when the device is opened for the first time
1210		   after the driver has been initialized with tape in the drive and the
1211		   partition support has been enabled. */
1212		DEBC_printk(STp, "Updating partition number in status.\n");
1213		if ((STp->partition = find_partition(STp)) < 0) {
1214			retval = STp->partition;
1215			goto err_out;
1216		}
1217		STp->new_partition = STp->partition;
1218		STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1219	}
1220
1221	if (new_session) {	/* Change the drive parameters for the new mode */
1222		STp->density_changed = STp->blksize_changed = 0;
1223		STp->compression_changed = 0;
1224		if (!(STm->defaults_for_writes) &&
1225		    (retval = set_mode_densblk(STp, STm)) < 0)
1226		    goto err_out;
1227
1228		if (STp->default_drvbuffer != 0xff) {
1229			if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1230				st_printk(KERN_WARNING, STp,
1231					  "Can't set default drive "
1232					  "buffering to %d.\n",
1233					  STp->default_drvbuffer);
1234		}
1235	}
1236
1237	return CHKRES_READY;
1238
1239 err_out:
1240	return retval;
1241}
1242
1243
1244/* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1245   module count. */
1246static int st_open(struct inode *inode, struct file *filp)
1247{
1248	int i, retval = (-EIO);
1249	int resumed = 0;
1250	struct scsi_tape *STp;
1251	struct st_partstat *STps;
1252	int dev = TAPE_NR(inode);
1253
1254	/*
1255	 * We really want to do nonseekable_open(inode, filp); here, but some
1256	 * versions of tar incorrectly call lseek on tapes and bail out if that
1257	 * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1258	 */
1259	filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1260
1261	if (!(STp = scsi_tape_get(dev))) {
1262		return -ENXIO;
1263	}
1264
1265	filp->private_data = STp;
1266
1267	spin_lock(&st_use_lock);
1268	if (STp->in_use) {
1269		spin_unlock(&st_use_lock);
1270		scsi_tape_put(STp);
1271		DEBC_printk(STp, "Device already in use.\n");
1272		return (-EBUSY);
1273	}
1274
1275	STp->in_use = 1;
1276	spin_unlock(&st_use_lock);
1277	STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1278
1279	if (scsi_autopm_get_device(STp->device) < 0) {
1280		retval = -EIO;
1281		goto err_out;
1282	}
1283	resumed = 1;
1284	if (!scsi_block_when_processing_errors(STp->device)) {
1285		retval = (-ENXIO);
1286		goto err_out;
1287	}
1288
1289	/* See that we have at least a one page buffer available */
1290	if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
1291		st_printk(KERN_WARNING, STp,
1292			  "Can't allocate one page tape buffer.\n");
1293		retval = (-EOVERFLOW);
1294		goto err_out;
1295	}
1296
1297	(STp->buffer)->cleared = 0;
1298	(STp->buffer)->writing = 0;
1299	(STp->buffer)->syscall_result = 0;
1300
1301	STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1302
1303	STp->dirty = 0;
1304	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1305		STps = &(STp->ps[i]);
1306		STps->rw = ST_IDLE;
1307	}
1308	STp->try_dio_now = STp->try_dio;
1309	STp->recover_count = 0;
1310	DEB( STp->nbr_waits = STp->nbr_finished = 0;
1311	     STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1312
1313	retval = check_tape(STp, filp);
1314	if (retval < 0)
1315		goto err_out;
1316	if ((filp->f_flags & O_NONBLOCK) == 0 &&
1317	    retval != CHKRES_READY) {
1318		if (STp->ready == NO_TAPE)
1319			retval = (-ENOMEDIUM);
1320		else
1321			retval = (-EIO);
1322		goto err_out;
1323	}
1324	return 0;
1325
1326 err_out:
1327	normalize_buffer(STp->buffer);
1328	spin_lock(&st_use_lock);
1329	STp->in_use = 0;
1330	spin_unlock(&st_use_lock);
1331	if (resumed)
1332		scsi_autopm_put_device(STp->device);
1333	scsi_tape_put(STp);
1334	return retval;
1335
1336}
1337
1338
1339/* Flush the tape buffer before close */
1340static int st_flush(struct file *filp, fl_owner_t id)
1341{
1342	int result = 0, result2;
1343	unsigned char cmd[MAX_COMMAND_SIZE];
1344	struct st_request *SRpnt;
1345	struct scsi_tape *STp = filp->private_data;
1346	struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1347	struct st_partstat *STps = &(STp->ps[STp->partition]);
1348
1349	if (file_count(filp) > 1)
1350		return 0;
1351
1352	if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1353		result = st_flush_write_buffer(STp);
1354		if (result != 0 && result != (-ENOSPC))
1355			goto out;
1356	}
1357
1358	if (STp->can_partitions &&
1359	    (result2 = switch_partition(STp)) < 0) {
1360		DEBC_printk(STp, "switch_partition at close failed.\n");
1361		if (result == 0)
1362			result = result2;
1363		goto out;
1364	}
1365
1366	DEBC( if (STp->nbr_requests)
1367		st_printk(KERN_DEBUG, STp,
1368			  "Number of r/w requests %d, dio used in %d, "
1369			  "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1370			  STp->nbr_pages));
1371
1372	if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1373		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1374
1375#if DEBUG
1376		DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1377			    STp->nbr_waits, STp->nbr_finished);
1378#endif
1379		memset(cmd, 0, MAX_COMMAND_SIZE);
1380		cmd[0] = WRITE_FILEMARKS;
1381		if (STp->immediate_filemark)
1382			cmd[1] = 1;
1383		cmd[4] = 1 + STp->two_fm;
1384
1385		SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1386				   STp->device->request_queue->rq_timeout,
1387				   MAX_WRITE_RETRIES, 1);
1388		if (!SRpnt) {
1389			result = (STp->buffer)->syscall_result;
1390			goto out;
1391		}
1392
1393		if (STp->buffer->syscall_result == 0 ||
1394		    (cmdstatp->have_sense && !cmdstatp->deferred &&
1395		     (cmdstatp->flags & SENSE_EOM) &&
1396		     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1397		      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1398		     (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1399			/* Write successful at EOM */
1400			st_release_request(SRpnt);
1401			SRpnt = NULL;
1402			if (STps->drv_file >= 0)
1403				STps->drv_file++;
1404			STps->drv_block = 0;
1405			if (STp->two_fm)
1406				cross_eof(STp, 0);
1407			STps->eof = ST_FM;
1408		}
1409		else { /* Write error */
1410			st_release_request(SRpnt);
1411			SRpnt = NULL;
1412			st_printk(KERN_ERR, STp,
1413				  "Error on write filemark.\n");
1414			if (result == 0)
1415				result = (-EIO);
1416		}
1417
1418		DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1419	} else if (!STp->rew_at_close) {
1420		STps = &(STp->ps[STp->partition]);
1421		if (!STm->sysv || STps->rw != ST_READING) {
1422			if (STp->can_bsr)
1423				result = flush_buffer(STp, 0);
1424			else if (STps->eof == ST_FM_HIT) {
1425				result = cross_eof(STp, 0);
1426				if (result) {
1427					if (STps->drv_file >= 0)
1428						STps->drv_file++;
1429					STps->drv_block = 0;
1430					STps->eof = ST_FM;
1431				} else
1432					STps->eof = ST_NOEOF;
1433			}
1434		} else if ((STps->eof == ST_NOEOF &&
1435			    !(result = cross_eof(STp, 1))) ||
1436			   STps->eof == ST_FM_HIT) {
1437			if (STps->drv_file >= 0)
1438				STps->drv_file++;
1439			STps->drv_block = 0;
1440			STps->eof = ST_FM;
1441		}
1442	}
1443
1444      out:
1445	if (STp->rew_at_close) {
1446		result2 = st_int_ioctl(STp, MTREW, 1);
1447		if (result == 0)
1448			result = result2;
1449	}
1450	return result;
1451}
1452
1453
1454/* Close the device and release it. BKL is not needed: this is the only thread
1455   accessing this tape. */
1456static int st_release(struct inode *inode, struct file *filp)
1457{
1458	int result = 0;
1459	struct scsi_tape *STp = filp->private_data;
1460
1461	if (STp->door_locked == ST_LOCKED_AUTO)
1462		do_door_lock(STp, 0);
1463
1464	normalize_buffer(STp->buffer);
1465	spin_lock(&st_use_lock);
1466	STp->in_use = 0;
1467	spin_unlock(&st_use_lock);
1468	scsi_autopm_put_device(STp->device);
1469	scsi_tape_put(STp);
1470
1471	return result;
1472}
1473
1474/* The checks common to both reading and writing */
1475static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1476{
1477	ssize_t retval = 0;
1478
1479	/*
1480	 * If we are in the middle of error recovery, don't let anyone
1481	 * else try and use this device.  Also, if error recovery fails, it
1482	 * may try and take the device offline, in which case all further
1483	 * access to the device is prohibited.
1484	 */
1485	if (!scsi_block_when_processing_errors(STp->device)) {
1486		retval = (-ENXIO);
1487		goto out;
1488	}
1489
1490	if (STp->ready != ST_READY) {
1491		if (STp->ready == ST_NO_TAPE)
1492			retval = (-ENOMEDIUM);
1493		else
1494			retval = (-EIO);
1495		goto out;
1496	}
1497
1498	if (! STp->modes[STp->current_mode].defined) {
1499		retval = (-ENXIO);
1500		goto out;
1501	}
1502
1503
1504	/*
1505	 * If there was a bus reset, block further access
1506	 * to this device.
1507	 */
1508	if (STp->pos_unknown) {
1509		retval = (-EIO);
1510		goto out;
1511	}
1512
1513	if (count == 0)
1514		goto out;
1515
1516	DEB(
1517	if (!STp->in_use) {
1518		st_printk(ST_DEB_MSG, STp,
1519			  "Incorrect device.\n");
1520		retval = (-EIO);
1521		goto out;
1522	} ) /* end DEB */
1523
1524	if (STp->can_partitions &&
1525	    (retval = switch_partition(STp)) < 0)
1526		goto out;
1527
1528	if (STp->block_size == 0 && STp->max_block > 0 &&
1529	    (count < STp->min_block || count > STp->max_block)) {
1530		retval = (-EINVAL);
1531		goto out;
1532	}
1533
1534	if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1535	    !do_door_lock(STp, 1))
1536		STp->door_locked = ST_LOCKED_AUTO;
1537
1538 out:
1539	return retval;
1540}
1541
1542
1543static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1544			   size_t count, int is_read)
1545{
1546	int i, bufsize, retval = 0;
1547	struct st_buffer *STbp = STp->buffer;
1548
1549	if (is_read)
1550		i = STp->try_dio_now && try_rdio;
1551	else
1552		i = STp->try_dio_now && try_wdio;
1553
1554	if (i && ((unsigned long)buf & queue_dma_alignment(
1555					STp->device->request_queue)) == 0) {
1556		i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1557				       count, (is_read ? READ : WRITE));
1558		if (i > 0) {
1559			STbp->do_dio = i;
1560			STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1561		}
1562		else
1563			STbp->do_dio = 0;  /* fall back to buffering with any error */
1564		STbp->sg_segs = STbp->do_dio;
1565		DEB(
1566		     if (STbp->do_dio) {
1567			STp->nbr_dio++;
1568			STp->nbr_pages += STbp->do_dio;
1569		     }
1570		)
1571	} else
1572		STbp->do_dio = 0;
1573	DEB( STp->nbr_requests++; )
1574
1575	if (!STbp->do_dio) {
1576		if (STp->block_size)
1577			bufsize = STp->block_size > st_fixed_buffer_size ?
1578				STp->block_size : st_fixed_buffer_size;
1579		else {
1580			bufsize = count;
1581			/* Make sure that data from previous user is not leaked even if
1582			   HBA does not return correct residual */
1583			if (is_read && STp->sili && !STbp->cleared)
1584				clear_buffer(STbp);
1585		}
1586
1587		if (bufsize > STbp->buffer_size &&
1588		    !enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
1589			st_printk(KERN_WARNING, STp,
1590				  "Can't allocate %d byte tape buffer.\n",
1591				  bufsize);
1592			retval = (-EOVERFLOW);
1593			goto out;
1594		}
1595		if (STp->block_size)
1596			STbp->buffer_blocks = bufsize / STp->block_size;
1597	}
1598
1599 out:
1600	return retval;
1601}
1602
1603
1604/* Can be called more than once after each setup_buffer() */
1605static void release_buffering(struct scsi_tape *STp, int is_read)
1606{
1607	struct st_buffer *STbp;
1608
1609	STbp = STp->buffer;
1610	if (STbp->do_dio) {
1611		sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1612		STbp->do_dio = 0;
1613		STbp->sg_segs = 0;
1614	}
1615}
1616
1617
1618/* Write command */
1619static ssize_t
1620st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1621{
1622	ssize_t total;
1623	ssize_t i, do_count, blks, transfer;
1624	ssize_t retval;
1625	int undone, retry_eot = 0, scode;
1626	int async_write;
1627	unsigned char cmd[MAX_COMMAND_SIZE];
1628	const char __user *b_point;
1629	struct st_request *SRpnt = NULL;
1630	struct scsi_tape *STp = filp->private_data;
1631	struct st_modedef *STm;
1632	struct st_partstat *STps;
1633	struct st_buffer *STbp;
1634
1635	if (mutex_lock_interruptible(&STp->lock))
1636		return -ERESTARTSYS;
1637
1638	retval = rw_checks(STp, filp, count);
1639	if (retval || count == 0)
1640		goto out;
1641
1642	/* Write must be integral number of blocks */
1643	if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1644		st_printk(KERN_WARNING, STp,
1645			  "Write not multiple of tape block size.\n");
1646		retval = (-EINVAL);
1647		goto out;
1648	}
1649
1650	STm = &(STp->modes[STp->current_mode]);
1651	STps = &(STp->ps[STp->partition]);
1652
1653	if (STp->write_prot) {
1654		retval = (-EACCES);
1655		goto out;
1656	}
1657
1658
1659	if (STps->rw == ST_READING) {
1660		retval = flush_buffer(STp, 0);
1661		if (retval)
1662			goto out;
1663		STps->rw = ST_WRITING;
1664	} else if (STps->rw != ST_WRITING &&
1665		   STps->drv_file == 0 && STps->drv_block == 0) {
1666		if ((retval = set_mode_densblk(STp, STm)) < 0)
1667			goto out;
1668		if (STm->default_compression != ST_DONT_TOUCH &&
1669		    !(STp->compression_changed)) {
1670			if (st_compression(STp, (STm->default_compression == ST_YES))) {
1671				st_printk(KERN_WARNING, STp,
1672					  "Can't set default compression.\n");
1673				if (modes_defined) {
1674					retval = (-EINVAL);
1675					goto out;
1676				}
1677			}
1678		}
1679	}
1680
1681	STbp = STp->buffer;
1682	i = write_behind_check(STp);
1683	if (i) {
1684		if (i == -ENOSPC)
1685			STps->eof = ST_EOM_OK;
1686		else
1687			STps->eof = ST_EOM_ERROR;
1688	}
1689
1690	if (STps->eof == ST_EOM_OK) {
1691		STps->eof = ST_EOD_1;  /* allow next write */
1692		retval = (-ENOSPC);
1693		goto out;
1694	}
1695	else if (STps->eof == ST_EOM_ERROR) {
1696		retval = (-EIO);
1697		goto out;
1698	}
1699
1700	/* Check the buffer readability in cases where copy_user might catch
1701	   the problems after some tape movement. */
1702	if (STp->block_size != 0 &&
1703	    !STbp->do_dio &&
1704	    (copy_from_user(&i, buf, 1) != 0 ||
1705	     copy_from_user(&i, buf + count - 1, 1) != 0)) {
1706		retval = (-EFAULT);
1707		goto out;
1708	}
1709
1710	retval = setup_buffering(STp, buf, count, 0);
1711	if (retval)
1712		goto out;
1713
1714	total = count;
1715
1716	memset(cmd, 0, MAX_COMMAND_SIZE);
1717	cmd[0] = WRITE_6;
1718	cmd[1] = (STp->block_size != 0);
1719
1720	STps->rw = ST_WRITING;
1721
1722	b_point = buf;
1723	while (count > 0 && !retry_eot) {
1724
1725		if (STbp->do_dio) {
1726			do_count = count;
1727		}
1728		else {
1729			if (STp->block_size == 0)
1730				do_count = count;
1731			else {
1732				do_count = STbp->buffer_blocks * STp->block_size -
1733					STbp->buffer_bytes;
1734				if (do_count > count)
1735					do_count = count;
1736			}
1737
1738			i = append_to_buffer(b_point, STbp, do_count);
1739			if (i) {
1740				retval = i;
1741				goto out;
1742			}
1743		}
1744		count -= do_count;
1745		b_point += do_count;
1746
1747		async_write = STp->block_size == 0 && !STbp->do_dio &&
1748			STm->do_async_writes && STps->eof < ST_EOM_OK;
1749
1750		if (STp->block_size != 0 && STm->do_buffer_writes &&
1751		    !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1752		    STbp->buffer_bytes < STbp->buffer_size) {
1753			STp->dirty = 1;
1754			/* Don't write a buffer that is not full enough. */
1755			if (!async_write && count == 0)
1756				break;
1757		}
1758
1759	retry_write:
1760		if (STp->block_size == 0)
1761			blks = transfer = do_count;
1762		else {
1763			if (!STbp->do_dio)
1764				blks = STbp->buffer_bytes;
1765			else
1766				blks = do_count;
1767			blks /= STp->block_size;
1768			transfer = blks * STp->block_size;
1769		}
1770		cmd[2] = blks >> 16;
1771		cmd[3] = blks >> 8;
1772		cmd[4] = blks;
1773
1774		SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1775				   STp->device->request_queue->rq_timeout,
1776				   MAX_WRITE_RETRIES, !async_write);
1777		if (!SRpnt) {
1778			retval = STbp->syscall_result;
1779			goto out;
1780		}
1781		if (async_write && !STbp->syscall_result) {
1782			STbp->writing = transfer;
1783			STp->dirty = !(STbp->writing ==
1784				       STbp->buffer_bytes);
1785			SRpnt = NULL;  /* Prevent releasing this request! */
1786			DEB( STp->write_pending = 1; )
1787			break;
1788		}
1789
1790		if (STbp->syscall_result != 0) {
1791			struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1792
1793			DEBC_printk(STp, "Error on write:\n");
1794			if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1795				scode = cmdstatp->sense_hdr.sense_key;
1796				if (cmdstatp->remainder_valid)
1797					undone = (int)cmdstatp->uremainder64;
1798				else if (STp->block_size == 0 &&
1799					 scode == VOLUME_OVERFLOW)
1800					undone = transfer;
1801				else
1802					undone = 0;
1803				if (STp->block_size != 0)
1804					undone *= STp->block_size;
1805				if (undone <= do_count) {
1806					/* Only data from this write is not written */
1807					count += undone;
1808					b_point -= undone;
1809					do_count -= undone;
1810					if (STp->block_size)
1811						blks = (transfer - undone) / STp->block_size;
1812					STps->eof = ST_EOM_OK;
1813					/* Continue in fixed block mode if all written
1814					   in this request but still something left to write
1815					   (retval left to zero)
1816					*/
1817					if (STp->block_size == 0 ||
1818					    undone > 0 || count == 0)
1819						retval = (-ENOSPC); /* EOM within current request */
1820					DEBC_printk(STp, "EOM with %d "
1821						    "bytes unwritten.\n",
1822						    (int)count);
1823				} else {
1824					/* EOT within data buffered earlier (possible only
1825					   in fixed block mode without direct i/o) */
1826					if (!retry_eot && !cmdstatp->deferred &&
1827					    (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1828						move_buffer_data(STp->buffer, transfer - undone);
1829						retry_eot = 1;
1830						if (STps->drv_block >= 0) {
1831							STps->drv_block += (transfer - undone) /
1832								STp->block_size;
1833						}
1834						STps->eof = ST_EOM_OK;
1835						DEBC_printk(STp, "Retry "
1836							    "write of %d "
1837							    "bytes at EOM.\n",
1838							    STp->buffer->buffer_bytes);
1839						goto retry_write;
1840					}
1841					else {
1842						/* Either error within data buffered by driver or
1843						   failed retry */
1844						count -= do_count;
1845						blks = do_count = 0;
1846						STps->eof = ST_EOM_ERROR;
1847						STps->drv_block = (-1); /* Too cautious? */
1848						retval = (-EIO);	/* EOM for old data */
1849						DEBC_printk(STp, "EOM with "
1850							    "lost data.\n");
1851					}
1852				}
1853			} else {
1854				count += do_count;
1855				STps->drv_block = (-1);		/* Too cautious? */
1856				retval = STbp->syscall_result;
1857			}
1858
1859		}
1860
1861		if (STps->drv_block >= 0) {
1862			if (STp->block_size == 0)
1863				STps->drv_block += (do_count > 0);
1864			else
1865				STps->drv_block += blks;
1866		}
1867
1868		STbp->buffer_bytes = 0;
1869		STp->dirty = 0;
1870
1871		if (retval || retry_eot) {
1872			if (count < total)
1873				retval = total - count;
1874			goto out;
1875		}
1876	}
1877
1878	if (STps->eof == ST_EOD_1)
1879		STps->eof = ST_EOM_OK;
1880	else if (STps->eof != ST_EOM_OK)
1881		STps->eof = ST_NOEOF;
1882	retval = total - count;
1883
1884 out:
1885	if (SRpnt != NULL)
1886		st_release_request(SRpnt);
1887	release_buffering(STp, 0);
1888	mutex_unlock(&STp->lock);
1889
1890	return retval;
1891}
1892
1893/* Read data from the tape. Returns zero in the normal case, one if the
1894   eof status has changed, and the negative error code in case of a
1895   fatal error. Otherwise updates the buffer and the eof state.
1896
1897   Does release user buffer mapping if it is set.
1898*/
1899static long read_tape(struct scsi_tape *STp, long count,
1900		      struct st_request ** aSRpnt)
1901{
1902	int transfer, blks, bytes;
1903	unsigned char cmd[MAX_COMMAND_SIZE];
1904	struct st_request *SRpnt;
1905	struct st_modedef *STm;
1906	struct st_partstat *STps;
1907	struct st_buffer *STbp;
1908	int retval = 0;
1909
1910	if (count == 0)
1911		return 0;
1912
1913	STm = &(STp->modes[STp->current_mode]);
1914	STps = &(STp->ps[STp->partition]);
1915	if (STps->eof == ST_FM_HIT)
1916		return 1;
1917	STbp = STp->buffer;
1918
1919	if (STp->block_size == 0)
1920		blks = bytes = count;
1921	else {
1922		if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1923			blks = (STp->buffer)->buffer_blocks;
1924			bytes = blks * STp->block_size;
1925		} else {
1926			bytes = count;
1927			if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1928				bytes = (STp->buffer)->buffer_size;
1929			blks = bytes / STp->block_size;
1930			bytes = blks * STp->block_size;
1931		}
1932	}
1933
1934	memset(cmd, 0, MAX_COMMAND_SIZE);
1935	cmd[0] = READ_6;
1936	cmd[1] = (STp->block_size != 0);
1937	if (!cmd[1] && STp->sili)
1938		cmd[1] |= 2;
1939	cmd[2] = blks >> 16;
1940	cmd[3] = blks >> 8;
1941	cmd[4] = blks;
1942
1943	SRpnt = *aSRpnt;
1944	SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1945			   STp->device->request_queue->rq_timeout,
1946			   MAX_RETRIES, 1);
1947	release_buffering(STp, 1);
1948	*aSRpnt = SRpnt;
1949	if (!SRpnt)
1950		return STbp->syscall_result;
1951
1952	STbp->read_pointer = 0;
1953	STps->at_sm = 0;
1954
1955	/* Something to check */
1956	if (STbp->syscall_result) {
1957		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1958
1959		retval = 1;
1960		DEBC_printk(STp,
1961			    "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1962			    SRpnt->sense[0], SRpnt->sense[1],
1963			    SRpnt->sense[2], SRpnt->sense[3],
1964			    SRpnt->sense[4], SRpnt->sense[5],
1965			    SRpnt->sense[6], SRpnt->sense[7]);
1966		if (cmdstatp->have_sense) {
1967
1968			if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1969				cmdstatp->flags &= 0xcf;	/* No need for EOM in this case */
1970
1971			if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1972				/* Compute the residual count */
1973				if (cmdstatp->remainder_valid)
1974					transfer = (int)cmdstatp->uremainder64;
1975				else
1976					transfer = 0;
1977				if (STp->block_size == 0 &&
1978				    cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR)
1979					transfer = bytes;
 
 
 
1980
1981				if (cmdstatp->flags & SENSE_ILI) {	/* ILI */
1982					if (STp->block_size == 0 &&
1983					    transfer < 0) {
1984						st_printk(KERN_NOTICE, STp,
1985							  "Failed to read %d "
1986							  "byte block with %d "
1987							  "byte transfer.\n",
1988							  bytes - transfer,
1989							  bytes);
1990						if (STps->drv_block >= 0)
1991							STps->drv_block += 1;
1992						STbp->buffer_bytes = 0;
1993						return (-ENOMEM);
1994					} else if (STp->block_size == 0) {
1995						STbp->buffer_bytes = bytes - transfer;
1996					} else {
1997						st_release_request(SRpnt);
1998						SRpnt = *aSRpnt = NULL;
1999						if (transfer == blks) {	/* We did not get anything, error */
2000							st_printk(KERN_NOTICE, STp,
2001								  "Incorrect "
2002								  "block size.\n");
2003							if (STps->drv_block >= 0)
2004								STps->drv_block += blks - transfer + 1;
2005							st_int_ioctl(STp, MTBSR, 1);
2006							return (-EIO);
2007						}
2008						/* We have some data, deliver it */
2009						STbp->buffer_bytes = (blks - transfer) *
2010						    STp->block_size;
2011						DEBC_printk(STp, "ILI but "
2012							    "enough data "
2013							    "received %ld "
2014							    "%d.\n", count,
2015							    STbp->buffer_bytes);
2016						if (STps->drv_block >= 0)
2017							STps->drv_block += 1;
2018						if (st_int_ioctl(STp, MTBSR, 1))
2019							return (-EIO);
2020					}
2021				} else if (cmdstatp->flags & SENSE_FMK) {	/* FM overrides EOM */
2022					if (STps->eof != ST_FM_HIT)
2023						STps->eof = ST_FM_HIT;
2024					else
2025						STps->eof = ST_EOD_2;
2026					if (STp->block_size == 0)
2027						STbp->buffer_bytes = 0;
2028					else
2029						STbp->buffer_bytes =
2030						    bytes - transfer * STp->block_size;
2031					DEBC_printk(STp, "EOF detected (%d "
2032						    "bytes read).\n",
2033						    STbp->buffer_bytes);
2034				} else if (cmdstatp->flags & SENSE_EOM) {
2035					if (STps->eof == ST_FM)
2036						STps->eof = ST_EOD_1;
2037					else
2038						STps->eof = ST_EOM_OK;
2039					if (STp->block_size == 0)
2040						STbp->buffer_bytes = bytes - transfer;
2041					else
2042						STbp->buffer_bytes =
2043						    bytes - transfer * STp->block_size;
2044
2045					DEBC_printk(STp, "EOM detected (%d "
2046						    "bytes read).\n",
2047						    STbp->buffer_bytes);
2048				}
2049			}
2050			/* end of EOF, EOM, ILI test */
2051			else {	/* nonzero sense key */
2052				DEBC_printk(STp, "Tape error while reading.\n");
2053				STps->drv_block = (-1);
2054				if (STps->eof == ST_FM &&
2055				    cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2056					DEBC_printk(STp, "Zero returned for "
2057						    "first BLANK CHECK "
2058						    "after EOF.\n");
2059					STps->eof = ST_EOD_2;	/* First BLANK_CHECK after FM */
2060				} else	/* Some other extended sense code */
2061					retval = (-EIO);
2062			}
2063
2064			if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2065				STbp->buffer_bytes = 0;
2066		}
2067		/* End of extended sense test */
2068		else {		/* Non-extended sense */
2069			retval = STbp->syscall_result;
2070		}
2071
2072	}
2073	/* End of error handling */
2074	else {			/* Read successful */
2075		STbp->buffer_bytes = bytes;
2076		if (STp->sili) /* In fixed block mode residual is always zero here */
2077			STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2078	}
2079
2080	if (STps->drv_block >= 0) {
2081		if (STp->block_size == 0)
2082			STps->drv_block++;
2083		else
2084			STps->drv_block += STbp->buffer_bytes / STp->block_size;
2085	}
2086	return retval;
2087}
2088
2089
2090/* Read command */
2091static ssize_t
2092st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2093{
2094	ssize_t total;
2095	ssize_t retval = 0;
2096	ssize_t i, transfer;
2097	int special, do_dio = 0;
2098	struct st_request *SRpnt = NULL;
2099	struct scsi_tape *STp = filp->private_data;
2100	struct st_modedef *STm;
2101	struct st_partstat *STps;
2102	struct st_buffer *STbp = STp->buffer;
2103
2104	if (mutex_lock_interruptible(&STp->lock))
2105		return -ERESTARTSYS;
2106
2107	retval = rw_checks(STp, filp, count);
2108	if (retval || count == 0)
2109		goto out;
2110
2111	STm = &(STp->modes[STp->current_mode]);
2112	if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2113		if (!STm->do_read_ahead) {
2114			retval = (-EINVAL);	/* Read must be integral number of blocks */
2115			goto out;
2116		}
2117		STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2118	}
2119
2120	STps = &(STp->ps[STp->partition]);
2121	if (STps->rw == ST_WRITING) {
2122		retval = flush_buffer(STp, 0);
2123		if (retval)
2124			goto out;
2125		STps->rw = ST_READING;
2126	}
2127	DEB(
2128	if (debugging && STps->eof != ST_NOEOF)
2129		st_printk(ST_DEB_MSG, STp,
2130			  "EOF/EOM flag up (%d). Bytes %d\n",
2131			  STps->eof, STbp->buffer_bytes);
2132	) /* end DEB */
2133
2134	retval = setup_buffering(STp, buf, count, 1);
2135	if (retval)
2136		goto out;
2137	do_dio = STbp->do_dio;
2138
2139	if (STbp->buffer_bytes == 0 &&
2140	    STps->eof >= ST_EOD_1) {
2141		if (STps->eof < ST_EOD) {
2142			STps->eof += 1;
2143			retval = 0;
2144			goto out;
2145		}
2146		retval = (-EIO);	/* EOM or Blank Check */
2147		goto out;
2148	}
2149
2150	if (do_dio) {
2151		/* Check the buffer writability before any tape movement. Don't alter
2152		   buffer data. */
2153		if (copy_from_user(&i, buf, 1) != 0 ||
2154		    copy_to_user(buf, &i, 1) != 0 ||
2155		    copy_from_user(&i, buf + count - 1, 1) != 0 ||
2156		    copy_to_user(buf + count - 1, &i, 1) != 0) {
2157			retval = (-EFAULT);
2158			goto out;
2159		}
2160	}
2161
2162	STps->rw = ST_READING;
2163
2164
2165	/* Loop until enough data in buffer or a special condition found */
2166	for (total = 0, special = 0; total < count && !special;) {
2167
2168		/* Get new data if the buffer is empty */
2169		if (STbp->buffer_bytes == 0) {
2170			special = read_tape(STp, count - total, &SRpnt);
2171			if (special < 0) {	/* No need to continue read */
2172				retval = special;
2173				goto out;
2174			}
2175		}
2176
2177		/* Move the data from driver buffer to user buffer */
2178		if (STbp->buffer_bytes > 0) {
2179			DEB(
2180			if (debugging && STps->eof != ST_NOEOF)
2181				st_printk(ST_DEB_MSG, STp,
2182					  "EOF up (%d). Left %d, needed %d.\n",
2183					  STps->eof, STbp->buffer_bytes,
2184					  (int)(count - total));
2185			) /* end DEB */
2186			transfer = STbp->buffer_bytes < count - total ?
2187			    STbp->buffer_bytes : count - total;
2188			if (!do_dio) {
2189				i = from_buffer(STbp, buf, transfer);
2190				if (i) {
2191					retval = i;
2192					goto out;
2193				}
2194			}
2195			buf += transfer;
2196			total += transfer;
2197		}
2198
2199		if (STp->block_size == 0)
2200			break;	/* Read only one variable length block */
2201
2202	}			/* for (total = 0, special = 0;
2203                                   total < count && !special; ) */
2204
2205	/* Change the eof state if no data from tape or buffer */
2206	if (total == 0) {
2207		if (STps->eof == ST_FM_HIT) {
2208			STps->eof = ST_FM;
2209			STps->drv_block = 0;
2210			if (STps->drv_file >= 0)
2211				STps->drv_file++;
2212		} else if (STps->eof == ST_EOD_1) {
2213			STps->eof = ST_EOD_2;
2214			STps->drv_block = 0;
2215			if (STps->drv_file >= 0)
2216				STps->drv_file++;
2217		} else if (STps->eof == ST_EOD_2)
2218			STps->eof = ST_EOD;
2219	} else if (STps->eof == ST_FM)
2220		STps->eof = ST_NOEOF;
2221	retval = total;
2222
2223 out:
2224	if (SRpnt != NULL) {
2225		st_release_request(SRpnt);
2226		SRpnt = NULL;
2227	}
2228	if (do_dio) {
2229		release_buffering(STp, 1);
2230		STbp->buffer_bytes = 0;
2231	}
2232	mutex_unlock(&STp->lock);
2233
2234	return retval;
2235}
2236
2237
2238
2239DEB(
2240/* Set the driver options */
2241static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2242{
2243	if (debugging) {
2244		st_printk(KERN_INFO, STp,
2245			  "Mode %d options: buffer writes: %d, "
2246			  "async writes: %d, read ahead: %d\n",
2247			  STp->current_mode, STm->do_buffer_writes,
2248			  STm->do_async_writes, STm->do_read_ahead);
2249		st_printk(KERN_INFO, STp,
2250			  "    can bsr: %d, two FMs: %d, "
2251			  "fast mteom: %d, auto lock: %d,\n",
2252			  STp->can_bsr, STp->two_fm, STp->fast_mteom,
2253			  STp->do_auto_lock);
2254		st_printk(KERN_INFO, STp,
2255			  "    defs for wr: %d, no block limits: %d, "
2256			  "partitions: %d, s2 log: %d\n",
2257			  STm->defaults_for_writes, STp->omit_blklims,
2258			  STp->can_partitions, STp->scsi2_logical);
2259		st_printk(KERN_INFO, STp,
2260			  "    sysv: %d nowait: %d sili: %d "
2261			  "nowait_filemark: %d\n",
2262			  STm->sysv, STp->immediate, STp->sili,
2263			  STp->immediate_filemark);
2264		st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2265	}
2266}
2267	)
2268
2269
2270static int st_set_options(struct scsi_tape *STp, long options)
2271{
2272	int value;
2273	long code;
2274	struct st_modedef *STm;
2275	struct cdev *cd0, *cd1;
2276	struct device *d0, *d1;
2277
2278	STm = &(STp->modes[STp->current_mode]);
2279	if (!STm->defined) {
2280		cd0 = STm->cdevs[0];
2281		cd1 = STm->cdevs[1];
2282		d0  = STm->devs[0];
2283		d1  = STm->devs[1];
2284		memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2285		STm->cdevs[0] = cd0;
2286		STm->cdevs[1] = cd1;
2287		STm->devs[0]  = d0;
2288		STm->devs[1]  = d1;
2289		modes_defined = 1;
2290		DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2291			    STp->current_mode);
2292	}
2293
2294	code = options & MT_ST_OPTIONS;
2295	if (code == MT_ST_BOOLEANS) {
2296		STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2297		STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2298		STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2299		STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2300		STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2301		STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2302		STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2303		STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2304		STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2305		if ((STp->device)->scsi_level >= SCSI_2)
2306			STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2307		STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2308		STp->immediate = (options & MT_ST_NOWAIT) != 0;
2309		STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2310		STm->sysv = (options & MT_ST_SYSV) != 0;
2311		STp->sili = (options & MT_ST_SILI) != 0;
2312		DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2313		     st_log_options(STp, STm); )
2314	} else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2315		value = (code == MT_ST_SETBOOLEANS);
2316		if ((options & MT_ST_BUFFER_WRITES) != 0)
2317			STm->do_buffer_writes = value;
2318		if ((options & MT_ST_ASYNC_WRITES) != 0)
2319			STm->do_async_writes = value;
2320		if ((options & MT_ST_DEF_WRITES) != 0)
2321			STm->defaults_for_writes = value;
2322		if ((options & MT_ST_READ_AHEAD) != 0)
2323			STm->do_read_ahead = value;
2324		if ((options & MT_ST_TWO_FM) != 0)
2325			STp->two_fm = value;
2326		if ((options & MT_ST_FAST_MTEOM) != 0)
2327			STp->fast_mteom = value;
2328		if ((options & MT_ST_AUTO_LOCK) != 0)
2329			STp->do_auto_lock = value;
2330		if ((options & MT_ST_CAN_BSR) != 0)
2331			STp->can_bsr = value;
2332		if ((options & MT_ST_NO_BLKLIMS) != 0)
2333			STp->omit_blklims = value;
2334		if ((STp->device)->scsi_level >= SCSI_2 &&
2335		    (options & MT_ST_CAN_PARTITIONS) != 0)
2336			STp->can_partitions = value;
2337		if ((options & MT_ST_SCSI2LOGICAL) != 0)
2338			STp->scsi2_logical = value;
2339		if ((options & MT_ST_NOWAIT) != 0)
2340			STp->immediate = value;
2341		if ((options & MT_ST_NOWAIT_EOF) != 0)
2342			STp->immediate_filemark = value;
2343		if ((options & MT_ST_SYSV) != 0)
2344			STm->sysv = value;
2345		if ((options & MT_ST_SILI) != 0)
2346			STp->sili = value;
2347		DEB(
2348		if ((options & MT_ST_DEBUGGING) != 0)
2349			debugging = value;
2350			st_log_options(STp, STm); )
2351	} else if (code == MT_ST_WRITE_THRESHOLD) {
2352		/* Retained for compatibility */
2353	} else if (code == MT_ST_DEF_BLKSIZE) {
2354		value = (options & ~MT_ST_OPTIONS);
2355		if (value == ~MT_ST_OPTIONS) {
2356			STm->default_blksize = (-1);
2357			DEBC_printk(STp, "Default block size disabled.\n");
2358		} else {
2359			STm->default_blksize = value;
2360			DEBC_printk(STp,"Default block size set to "
2361				    "%d bytes.\n", STm->default_blksize);
2362			if (STp->ready == ST_READY) {
2363				STp->blksize_changed = 0;
2364				set_mode_densblk(STp, STm);
2365			}
2366		}
2367	} else if (code == MT_ST_TIMEOUTS) {
2368		value = (options & ~MT_ST_OPTIONS);
2369		if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2370			STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2371			DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2372				    (value & ~MT_ST_SET_LONG_TIMEOUT));
2373		} else {
2374			blk_queue_rq_timeout(STp->device->request_queue,
2375					     value * HZ);
2376			DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2377				    value);
2378		}
2379	} else if (code == MT_ST_SET_CLN) {
2380		value = (options & ~MT_ST_OPTIONS) & 0xff;
2381		if (value != 0 &&
2382			(value < EXTENDED_SENSE_START ||
2383				value >= SCSI_SENSE_BUFFERSIZE))
2384			return (-EINVAL);
2385		STp->cln_mode = value;
2386		STp->cln_sense_mask = (options >> 8) & 0xff;
2387		STp->cln_sense_value = (options >> 16) & 0xff;
2388		st_printk(KERN_INFO, STp,
2389			  "Cleaning request mode %d, mask %02x, value %02x\n",
2390			  value, STp->cln_sense_mask, STp->cln_sense_value);
2391	} else if (code == MT_ST_DEF_OPTIONS) {
2392		code = (options & ~MT_ST_CLEAR_DEFAULT);
2393		value = (options & MT_ST_CLEAR_DEFAULT);
2394		if (code == MT_ST_DEF_DENSITY) {
2395			if (value == MT_ST_CLEAR_DEFAULT) {
2396				STm->default_density = (-1);
2397				DEBC_printk(STp,
2398					    "Density default disabled.\n");
2399			} else {
2400				STm->default_density = value & 0xff;
2401				DEBC_printk(STp, "Density default set to %x\n",
2402					    STm->default_density);
2403				if (STp->ready == ST_READY) {
2404					STp->density_changed = 0;
2405					set_mode_densblk(STp, STm);
2406				}
2407			}
2408		} else if (code == MT_ST_DEF_DRVBUFFER) {
2409			if (value == MT_ST_CLEAR_DEFAULT) {
2410				STp->default_drvbuffer = 0xff;
2411				DEBC_printk(STp,
2412					    "Drive buffer default disabled.\n");
2413			} else {
2414				STp->default_drvbuffer = value & 7;
2415				DEBC_printk(STp,
2416					    "Drive buffer default set to %x\n",
2417					    STp->default_drvbuffer);
2418				if (STp->ready == ST_READY)
2419					st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2420			}
2421		} else if (code == MT_ST_DEF_COMPRESSION) {
2422			if (value == MT_ST_CLEAR_DEFAULT) {
2423				STm->default_compression = ST_DONT_TOUCH;
2424				DEBC_printk(STp,
2425					    "Compression default disabled.\n");
2426			} else {
2427				if ((value & 0xff00) != 0) {
2428					STp->c_algo = (value & 0xff00) >> 8;
2429					DEBC_printk(STp, "Compression "
2430						    "algorithm set to 0x%x.\n",
2431						    STp->c_algo);
2432				}
2433				if ((value & 0xff) != 0xff) {
2434					STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2435					DEBC_printk(STp, "Compression default "
2436						    "set to %x\n",
2437						    (value & 1));
2438					if (STp->ready == ST_READY) {
2439						STp->compression_changed = 0;
2440						st_compression(STp, (STm->default_compression == ST_YES));
2441					}
2442				}
2443			}
2444		}
2445	} else
2446		return (-EIO);
2447
2448	return 0;
2449}
2450
2451#define MODE_HEADER_LENGTH  4
2452
2453/* Mode header and page byte offsets */
2454#define MH_OFF_DATA_LENGTH     0
2455#define MH_OFF_MEDIUM_TYPE     1
2456#define MH_OFF_DEV_SPECIFIC    2
2457#define MH_OFF_BDESCS_LENGTH   3
2458#define MP_OFF_PAGE_NBR        0
2459#define MP_OFF_PAGE_LENGTH     1
2460
2461/* Mode header and page bit masks */
2462#define MH_BIT_WP              0x80
2463#define MP_MSK_PAGE_NBR        0x3f
2464
2465/* Don't return block descriptors */
2466#define MODE_SENSE_OMIT_BDESCS 0x08
2467
2468#define MODE_SELECT_PAGE_FORMAT 0x10
2469
2470/* Read a mode page into the tape buffer. The block descriptors are included
2471   if incl_block_descs is true. The page control is ored to the page number
2472   parameter, if necessary. */
2473static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2474{
2475	unsigned char cmd[MAX_COMMAND_SIZE];
2476	struct st_request *SRpnt;
2477
2478	memset(cmd, 0, MAX_COMMAND_SIZE);
2479	cmd[0] = MODE_SENSE;
2480	if (omit_block_descs)
2481		cmd[1] = MODE_SENSE_OMIT_BDESCS;
2482	cmd[2] = page;
2483	cmd[4] = 255;
2484
2485	SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2486			   STp->device->request_queue->rq_timeout, 0, 1);
2487	if (SRpnt == NULL)
2488		return (STp->buffer)->syscall_result;
2489
2490	st_release_request(SRpnt);
2491
2492	return STp->buffer->syscall_result;
2493}
2494
2495
2496/* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2497   in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2498static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2499{
2500	int pgo;
2501	unsigned char cmd[MAX_COMMAND_SIZE];
2502	struct st_request *SRpnt;
2503	int timeout;
2504
2505	memset(cmd, 0, MAX_COMMAND_SIZE);
2506	cmd[0] = MODE_SELECT;
2507	cmd[1] = MODE_SELECT_PAGE_FORMAT;
2508	pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2509	cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2510
2511	/* Clear reserved fields */
2512	(STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2513	(STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2514	(STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2515	(STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2516
2517	timeout = slow ?
2518		STp->long_timeout : STp->device->request_queue->rq_timeout;
2519	SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2520			   timeout, 0, 1);
2521	if (SRpnt == NULL)
2522		return (STp->buffer)->syscall_result;
2523
2524	st_release_request(SRpnt);
2525
2526	return STp->buffer->syscall_result;
2527}
2528
2529
2530#define COMPRESSION_PAGE        0x0f
2531#define COMPRESSION_PAGE_LENGTH 16
2532
2533#define CP_OFF_DCE_DCC          2
2534#define CP_OFF_C_ALGO           7
2535
2536#define DCE_MASK  0x80
2537#define DCC_MASK  0x40
2538#define RED_MASK  0x60
2539
2540
2541/* Control the compression with mode page 15. Algorithm not changed if zero.
2542
2543   The block descriptors are read and written because Sony SDT-7000 does not
2544   work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2545   Including block descriptors should not cause any harm to other drives. */
2546
2547static int st_compression(struct scsi_tape * STp, int state)
2548{
2549	int retval;
2550	int mpoffs;  /* Offset to mode page start */
2551	unsigned char *b_data = (STp->buffer)->b_data;
2552
2553	if (STp->ready != ST_READY)
2554		return (-EIO);
2555
2556	/* Read the current page contents */
2557	retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2558	if (retval) {
2559		DEBC_printk(STp, "Compression mode page not supported.\n");
2560		return (-EIO);
2561	}
2562
2563	mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2564	DEBC_printk(STp, "Compression state is %d.\n",
2565		    (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2566
2567	/* Check if compression can be changed */
2568	if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2569		DEBC_printk(STp, "Compression not supported.\n");
2570		return (-EIO);
2571	}
2572
2573	/* Do the change */
2574	if (state) {
2575		b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2576		if (STp->c_algo != 0)
2577			b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2578	}
2579	else {
2580		b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2581		if (STp->c_algo != 0)
2582			b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2583	}
2584
2585	retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2586	if (retval) {
2587		DEBC_printk(STp, "Compression change failed.\n");
2588		return (-EIO);
2589	}
2590	DEBC_printk(STp, "Compression state changed to %d.\n", state);
2591
2592	STp->compression_changed = 1;
2593	return 0;
2594}
2595
2596
2597/* Process the load and unload commands (does unload if the load code is zero) */
2598static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2599{
2600	int retval = (-EIO), timeout;
2601	unsigned char cmd[MAX_COMMAND_SIZE];
2602	struct st_partstat *STps;
2603	struct st_request *SRpnt;
2604
2605	if (STp->ready != ST_READY && !load_code) {
2606		if (STp->ready == ST_NO_TAPE)
2607			return (-ENOMEDIUM);
2608		else
2609			return (-EIO);
2610	}
2611
2612	memset(cmd, 0, MAX_COMMAND_SIZE);
2613	cmd[0] = START_STOP;
2614	if (load_code)
2615		cmd[4] |= 1;
2616	/*
2617	 * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2618	 */
2619	if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2620	    && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2621		DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2622			    (cmd[4]) ? "" : "un",
2623			    load_code - MT_ST_HPLOADER_OFFSET);
2624		cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2625	}
2626	if (STp->immediate) {
2627		cmd[1] = 1;	/* Don't wait for completion */
2628		timeout = STp->device->request_queue->rq_timeout;
2629	}
2630	else
2631		timeout = STp->long_timeout;
2632
2633	DEBC(
2634		if (!load_code)
2635			st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2636		else
2637			st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2638		);
2639
2640	SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2641			   timeout, MAX_RETRIES, 1);
2642	if (!SRpnt)
2643		return (STp->buffer)->syscall_result;
2644
2645	retval = (STp->buffer)->syscall_result;
2646	st_release_request(SRpnt);
2647
2648	if (!retval) {	/* SCSI command successful */
2649
2650		if (!load_code) {
2651			STp->rew_at_close = 0;
2652			STp->ready = ST_NO_TAPE;
2653		}
2654		else {
2655			STp->rew_at_close = STp->autorew_dev;
2656			retval = check_tape(STp, filp);
2657			if (retval > 0)
2658				retval = 0;
2659		}
2660	}
2661	else {
2662		STps = &(STp->ps[STp->partition]);
2663		STps->drv_file = STps->drv_block = (-1);
2664	}
2665
2666	return retval;
2667}
2668
2669#if DEBUG
2670#define ST_DEB_FORWARD  0
2671#define ST_DEB_BACKWARD 1
2672static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2673{
2674	s32 sc;
2675
2676	if (!debugging)
2677		return;
2678
2679	sc = cmd[2] & 0x80 ? 0xff000000 : 0;
2680	sc |= (cmd[2] << 16) | (cmd[3] << 8) | cmd[4];
2681	if (direction)
2682		sc = -sc;
2683	st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2684		  direction ? "backward" : "forward", sc, units);
2685}
2686#else
2687#define ST_DEB_FORWARD  0
2688#define ST_DEB_BACKWARD 1
2689static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2690#endif
2691
2692
2693/* Internal ioctl function */
2694static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2695{
2696	int timeout;
2697	long ltmp;
2698	int ioctl_result;
2699	int chg_eof = 1;
2700	unsigned char cmd[MAX_COMMAND_SIZE];
2701	struct st_request *SRpnt;
2702	struct st_partstat *STps;
2703	int fileno, blkno, at_sm, undone;
2704	int datalen = 0, direction = DMA_NONE;
2705
2706	WARN_ON(STp->buffer->do_dio != 0);
2707	if (STp->ready != ST_READY) {
2708		if (STp->ready == ST_NO_TAPE)
2709			return (-ENOMEDIUM);
2710		else
2711			return (-EIO);
2712	}
2713	timeout = STp->long_timeout;
2714	STps = &(STp->ps[STp->partition]);
2715	fileno = STps->drv_file;
2716	blkno = STps->drv_block;
2717	at_sm = STps->at_sm;
2718
2719	memset(cmd, 0, MAX_COMMAND_SIZE);
2720	switch (cmd_in) {
2721	case MTFSFM:
2722		chg_eof = 0;	/* Changed from the FSF after this */
2723	case MTFSF:
2724		cmd[0] = SPACE;
2725		cmd[1] = 0x01;	/* Space FileMarks */
2726		cmd[2] = (arg >> 16);
2727		cmd[3] = (arg >> 8);
2728		cmd[4] = arg;
2729		deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2730		if (fileno >= 0)
2731			fileno += arg;
2732		blkno = 0;
2733		at_sm &= (arg == 0);
2734		break;
2735	case MTBSFM:
2736		chg_eof = 0;	/* Changed from the FSF after this */
2737	case MTBSF:
2738		cmd[0] = SPACE;
2739		cmd[1] = 0x01;	/* Space FileMarks */
2740		ltmp = (-arg);
2741		cmd[2] = (ltmp >> 16);
2742		cmd[3] = (ltmp >> 8);
2743		cmd[4] = ltmp;
2744		deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2745		if (fileno >= 0)
2746			fileno -= arg;
2747		blkno = (-1);	/* We can't know the block number */
2748		at_sm &= (arg == 0);
2749		break;
2750	case MTFSR:
2751		cmd[0] = SPACE;
2752		cmd[1] = 0x00;	/* Space Blocks */
2753		cmd[2] = (arg >> 16);
2754		cmd[3] = (arg >> 8);
2755		cmd[4] = arg;
2756		deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2757		if (blkno >= 0)
2758			blkno += arg;
2759		at_sm &= (arg == 0);
2760		break;
2761	case MTBSR:
2762		cmd[0] = SPACE;
2763		cmd[1] = 0x00;	/* Space Blocks */
2764		ltmp = (-arg);
2765		cmd[2] = (ltmp >> 16);
2766		cmd[3] = (ltmp >> 8);
2767		cmd[4] = ltmp;
2768		deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2769		if (blkno >= 0)
2770			blkno -= arg;
2771		at_sm &= (arg == 0);
2772		break;
2773	case MTFSS:
2774		cmd[0] = SPACE;
2775		cmd[1] = 0x04;	/* Space Setmarks */
2776		cmd[2] = (arg >> 16);
2777		cmd[3] = (arg >> 8);
2778		cmd[4] = arg;
2779		deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2780		if (arg != 0) {
2781			blkno = fileno = (-1);
2782			at_sm = 1;
2783		}
2784		break;
2785	case MTBSS:
2786		cmd[0] = SPACE;
2787		cmd[1] = 0x04;	/* Space Setmarks */
2788		ltmp = (-arg);
2789		cmd[2] = (ltmp >> 16);
2790		cmd[3] = (ltmp >> 8);
2791		cmd[4] = ltmp;
2792		deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2793		if (arg != 0) {
2794			blkno = fileno = (-1);
2795			at_sm = 1;
2796		}
2797		break;
2798	case MTWEOF:
2799	case MTWEOFI:
2800	case MTWSM:
2801		if (STp->write_prot)
2802			return (-EACCES);
2803		cmd[0] = WRITE_FILEMARKS;
2804		if (cmd_in == MTWSM)
2805			cmd[1] = 2;
2806		if (cmd_in == MTWEOFI ||
2807		    (cmd_in == MTWEOF && STp->immediate_filemark))
2808			cmd[1] |= 1;
2809		cmd[2] = (arg >> 16);
2810		cmd[3] = (arg >> 8);
2811		cmd[4] = arg;
2812		timeout = STp->device->request_queue->rq_timeout;
2813		DEBC(
2814			if (cmd_in != MTWSM)
2815				st_printk(ST_DEB_MSG, STp,
2816					  "Writing %d filemarks.\n",
2817					  cmd[2] * 65536 +
2818					  cmd[3] * 256 +
2819					  cmd[4]);
2820			else
2821				st_printk(ST_DEB_MSG, STp,
2822					  "Writing %d setmarks.\n",
2823					  cmd[2] * 65536 +
2824					  cmd[3] * 256 +
2825					  cmd[4]);
2826		)
2827		if (fileno >= 0)
2828			fileno += arg;
2829		blkno = 0;
2830		at_sm = (cmd_in == MTWSM);
2831		break;
2832	case MTREW:
2833		cmd[0] = REZERO_UNIT;
2834		if (STp->immediate) {
2835			cmd[1] = 1;	/* Don't wait for completion */
2836			timeout = STp->device->request_queue->rq_timeout;
2837		}
2838		DEBC_printk(STp, "Rewinding tape.\n");
2839		fileno = blkno = at_sm = 0;
2840		break;
2841	case MTNOP:
2842		DEBC_printk(STp, "No op on tape.\n");
2843		return 0;	/* Should do something ? */
2844		break;
2845	case MTRETEN:
2846		cmd[0] = START_STOP;
2847		if (STp->immediate) {
2848			cmd[1] = 1;	/* Don't wait for completion */
2849			timeout = STp->device->request_queue->rq_timeout;
2850		}
2851		cmd[4] = 3;
2852		DEBC_printk(STp, "Retensioning tape.\n");
2853		fileno = blkno = at_sm = 0;
2854		break;
2855	case MTEOM:
2856		if (!STp->fast_mteom) {
2857			/* space to the end of tape */
2858			ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2859			fileno = STps->drv_file;
2860			if (STps->eof >= ST_EOD_1)
2861				return 0;
2862			/* The next lines would hide the number of spaced FileMarks
2863			   That's why I inserted the previous lines. I had no luck
2864			   with detecting EOM with FSF, so we go now to EOM.
2865			   Joerg Weule */
2866		} else
2867			fileno = (-1);
2868		cmd[0] = SPACE;
2869		cmd[1] = 3;
2870		DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2871		blkno = -1;
2872		at_sm = 0;
2873		break;
2874	case MTERASE:
2875		if (STp->write_prot)
2876			return (-EACCES);
2877		cmd[0] = ERASE;
2878		cmd[1] = (arg ? 1 : 0);	/* Long erase with non-zero argument */
2879		if (STp->immediate) {
2880			cmd[1] |= 2;	/* Don't wait for completion */
2881			timeout = STp->device->request_queue->rq_timeout;
2882		}
2883		else
2884			timeout = STp->long_timeout * 8;
2885
2886		DEBC_printk(STp, "Erasing tape.\n");
2887		fileno = blkno = at_sm = 0;
2888		break;
2889	case MTSETBLK:		/* Set block length */
2890	case MTSETDENSITY:	/* Set tape density */
2891	case MTSETDRVBUFFER:	/* Set drive buffering */
2892	case SET_DENS_AND_BLK:	/* Set density and block size */
2893		chg_eof = 0;
2894		if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2895			return (-EIO);	/* Not allowed if data in buffer */
2896		if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2897		    (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2898		    STp->max_block > 0 &&
2899		    ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2900		     (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2901			st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2902			return (-EINVAL);
2903		}
2904		cmd[0] = MODE_SELECT;
2905		if ((STp->use_pf & USE_PF))
2906			cmd[1] = MODE_SELECT_PAGE_FORMAT;
2907		cmd[4] = datalen = 12;
2908		direction = DMA_TO_DEVICE;
2909
2910		memset((STp->buffer)->b_data, 0, 12);
2911		if (cmd_in == MTSETDRVBUFFER)
2912			(STp->buffer)->b_data[2] = (arg & 7) << 4;
2913		else
2914			(STp->buffer)->b_data[2] =
2915			    STp->drv_buffer << 4;
2916		(STp->buffer)->b_data[3] = 8;	/* block descriptor length */
2917		if (cmd_in == MTSETDENSITY) {
2918			(STp->buffer)->b_data[4] = arg;
2919			STp->density_changed = 1;	/* At least we tried ;-) */
2920		} else if (cmd_in == SET_DENS_AND_BLK)
2921			(STp->buffer)->b_data[4] = arg >> 24;
2922		else
2923			(STp->buffer)->b_data[4] = STp->density;
2924		if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2925			ltmp = arg & MT_ST_BLKSIZE_MASK;
2926			if (cmd_in == MTSETBLK)
2927				STp->blksize_changed = 1; /* At least we tried ;-) */
2928		} else
2929			ltmp = STp->block_size;
2930		(STp->buffer)->b_data[9] = (ltmp >> 16);
2931		(STp->buffer)->b_data[10] = (ltmp >> 8);
2932		(STp->buffer)->b_data[11] = ltmp;
2933		timeout = STp->device->request_queue->rq_timeout;
2934		DEBC(
2935			if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2936				st_printk(ST_DEB_MSG, STp,
2937					  "Setting block size to %d bytes.\n",
2938					  (STp->buffer)->b_data[9] * 65536 +
2939					  (STp->buffer)->b_data[10] * 256 +
2940					  (STp->buffer)->b_data[11]);
2941			if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2942				st_printk(ST_DEB_MSG, STp,
2943					  "Setting density code to %x.\n",
2944					  (STp->buffer)->b_data[4]);
2945			if (cmd_in == MTSETDRVBUFFER)
2946				st_printk(ST_DEB_MSG, STp,
2947					  "Setting drive buffer code to %d.\n",
2948					  ((STp->buffer)->b_data[2] >> 4) & 7);
2949		)
2950		break;
2951	default:
2952		return (-ENOSYS);
2953	}
2954
2955	SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2956			   timeout, MAX_RETRIES, 1);
2957	if (!SRpnt)
2958		return (STp->buffer)->syscall_result;
2959
2960	ioctl_result = (STp->buffer)->syscall_result;
2961
2962	if (!ioctl_result) {	/* SCSI command successful */
2963		st_release_request(SRpnt);
2964		SRpnt = NULL;
2965		STps->drv_block = blkno;
2966		STps->drv_file = fileno;
2967		STps->at_sm = at_sm;
2968
2969		if (cmd_in == MTBSFM)
2970			ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2971		else if (cmd_in == MTFSFM)
2972			ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2973
2974		if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2975			STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2976			if (STp->block_size != 0) {
2977				(STp->buffer)->buffer_blocks =
2978				    (STp->buffer)->buffer_size / STp->block_size;
2979			}
2980			(STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2981			if (cmd_in == SET_DENS_AND_BLK)
2982				STp->density = arg >> MT_ST_DENSITY_SHIFT;
2983		} else if (cmd_in == MTSETDRVBUFFER)
2984			STp->drv_buffer = (arg & 7);
2985		else if (cmd_in == MTSETDENSITY)
2986			STp->density = arg;
2987
2988		if (cmd_in == MTEOM)
2989			STps->eof = ST_EOD;
2990		else if (cmd_in == MTFSF)
2991			STps->eof = ST_FM;
2992		else if (chg_eof)
2993			STps->eof = ST_NOEOF;
2994
2995		if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
2996			STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
2997	} else { /* SCSI command was not completely successful. Don't return
2998                    from this block without releasing the SCSI command block! */
2999		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3000
3001		if (cmdstatp->flags & SENSE_EOM) {
3002			if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3003			    cmd_in != MTBSR && cmd_in != MTBSS)
3004				STps->eof = ST_EOM_OK;
3005			STps->drv_block = 0;
3006		}
3007
3008		if (cmdstatp->remainder_valid)
3009			undone = (int)cmdstatp->uremainder64;
3010		else
3011			undone = 0;
3012
3013		if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3014		    cmdstatp->have_sense &&
3015		    (cmdstatp->flags & SENSE_EOM)) {
3016			if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3017			    cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3018				ioctl_result = 0;	/* EOF(s) written successfully at EOM */
3019				STps->eof = ST_NOEOF;
3020			} else {  /* Writing EOF(s) failed */
3021				if (fileno >= 0)
3022					fileno -= undone;
3023				if (undone < arg)
3024					STps->eof = ST_NOEOF;
3025			}
3026			STps->drv_file = fileno;
3027		} else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3028			if (fileno >= 0)
3029				STps->drv_file = fileno - undone;
3030			else
3031				STps->drv_file = fileno;
3032			STps->drv_block = -1;
3033			STps->eof = ST_NOEOF;
3034		} else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3035			if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3036				undone = (-undone);
3037			if (STps->drv_file >= 0)
3038				STps->drv_file = fileno + undone;
3039			STps->drv_block = 0;
3040			STps->eof = ST_NOEOF;
3041		} else if (cmd_in == MTFSR) {
3042			if (cmdstatp->flags & SENSE_FMK) {	/* Hit filemark */
3043				if (STps->drv_file >= 0)
3044					STps->drv_file++;
3045				STps->drv_block = 0;
3046				STps->eof = ST_FM;
3047			} else {
3048				if (blkno >= undone)
3049					STps->drv_block = blkno - undone;
3050				else
3051					STps->drv_block = (-1);
3052				STps->eof = ST_NOEOF;
3053			}
3054		} else if (cmd_in == MTBSR) {
3055			if (cmdstatp->flags & SENSE_FMK) {	/* Hit filemark */
3056				STps->drv_file--;
3057				STps->drv_block = (-1);
3058			} else {
3059				if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3060					undone = (-undone);
3061				if (STps->drv_block >= 0)
3062					STps->drv_block = blkno + undone;
3063			}
3064			STps->eof = ST_NOEOF;
3065		} else if (cmd_in == MTEOM) {
3066			STps->drv_file = (-1);
3067			STps->drv_block = (-1);
3068			STps->eof = ST_EOD;
3069		} else if (cmd_in == MTSETBLK ||
3070			   cmd_in == MTSETDENSITY ||
3071			   cmd_in == MTSETDRVBUFFER ||
3072			   cmd_in == SET_DENS_AND_BLK) {
3073			if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3074			    !(STp->use_pf & PF_TESTED)) {
3075				/* Try the other possible state of Page Format if not
3076				   already tried */
3077				STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3078				st_release_request(SRpnt);
3079				SRpnt = NULL;
3080				return st_int_ioctl(STp, cmd_in, arg);
3081			}
3082		} else if (chg_eof)
3083			STps->eof = ST_NOEOF;
3084
3085		if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3086			STps->eof = ST_EOD;
3087
3088		st_release_request(SRpnt);
3089		SRpnt = NULL;
3090	}
3091
3092	return ioctl_result;
3093}
3094
3095
3096/* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3097   structure. */
3098
3099static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3100			int logical)
3101{
3102	int result;
3103	unsigned char scmd[MAX_COMMAND_SIZE];
3104	struct st_request *SRpnt;
3105
3106	if (STp->ready != ST_READY)
3107		return (-EIO);
3108
3109	memset(scmd, 0, MAX_COMMAND_SIZE);
3110	if ((STp->device)->scsi_level < SCSI_2) {
3111		scmd[0] = QFA_REQUEST_BLOCK;
3112		scmd[4] = 3;
3113	} else {
3114		scmd[0] = READ_POSITION;
3115		if (!logical && !STp->scsi2_logical)
3116			scmd[1] = 1;
3117	}
3118	SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3119			   STp->device->request_queue->rq_timeout,
3120			   MAX_READY_RETRIES, 1);
3121	if (!SRpnt)
3122		return (STp->buffer)->syscall_result;
3123
3124	if ((STp->buffer)->syscall_result != 0 ||
3125	    (STp->device->scsi_level >= SCSI_2 &&
3126	     ((STp->buffer)->b_data[0] & 4) != 0)) {
3127		*block = *partition = 0;
3128		DEBC_printk(STp, " Can't read tape position.\n");
3129		result = (-EIO);
3130	} else {
3131		result = 0;
3132		if ((STp->device)->scsi_level < SCSI_2) {
3133			*block = ((STp->buffer)->b_data[0] << 16)
3134			    + ((STp->buffer)->b_data[1] << 8)
3135			    + (STp->buffer)->b_data[2];
3136			*partition = 0;
3137		} else {
3138			*block = ((STp->buffer)->b_data[4] << 24)
3139			    + ((STp->buffer)->b_data[5] << 16)
3140			    + ((STp->buffer)->b_data[6] << 8)
3141			    + (STp->buffer)->b_data[7];
3142			*partition = (STp->buffer)->b_data[1];
3143			if (((STp->buffer)->b_data[0] & 0x80) &&
3144			    (STp->buffer)->b_data[1] == 0)	/* BOP of partition 0 */
3145				STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3146		}
3147		DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3148			    *block, *partition);
3149	}
3150	st_release_request(SRpnt);
3151	SRpnt = NULL;
3152
3153	return result;
3154}
3155
3156
3157/* Set the tape block and partition. Negative partition means that only the
3158   block should be set in vendor specific way. */
3159static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3160			int logical)
3161{
3162	struct st_partstat *STps;
3163	int result, p;
3164	unsigned int blk;
3165	int timeout;
3166	unsigned char scmd[MAX_COMMAND_SIZE];
3167	struct st_request *SRpnt;
3168
3169	if (STp->ready != ST_READY)
3170		return (-EIO);
3171	timeout = STp->long_timeout;
3172	STps = &(STp->ps[STp->partition]);
3173
3174	DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3175		    block, partition);
3176	DEB(if (partition < 0)
3177		return (-EIO); )
3178
3179	/* Update the location at the partition we are leaving */
3180	if ((!STp->can_partitions && partition != 0) ||
3181	    partition >= ST_NBR_PARTITIONS)
3182		return (-EINVAL);
3183	if (partition != STp->partition) {
3184		if (get_location(STp, &blk, &p, 1))
3185			STps->last_block_valid = 0;
3186		else {
3187			STps->last_block_valid = 1;
3188			STps->last_block_visited = blk;
3189			DEBC_printk(STp, "Visited block %d for "
3190				    "partition %d saved.\n",
3191				    blk, STp->partition);
3192		}
3193	}
3194
3195	memset(scmd, 0, MAX_COMMAND_SIZE);
3196	if ((STp->device)->scsi_level < SCSI_2) {
3197		scmd[0] = QFA_SEEK_BLOCK;
3198		scmd[2] = (block >> 16);
3199		scmd[3] = (block >> 8);
3200		scmd[4] = block;
3201		scmd[5] = 0;
3202	} else {
3203		scmd[0] = SEEK_10;
3204		scmd[3] = (block >> 24);
3205		scmd[4] = (block >> 16);
3206		scmd[5] = (block >> 8);
3207		scmd[6] = block;
3208		if (!logical && !STp->scsi2_logical)
3209			scmd[1] = 4;
3210		if (STp->partition != partition) {
3211			scmd[1] |= 2;
3212			scmd[8] = partition;
3213			DEBC_printk(STp, "Trying to change partition "
3214				    "from %d to %d\n", STp->partition,
3215				    partition);
3216		}
3217	}
3218	if (STp->immediate) {
3219		scmd[1] |= 1;		/* Don't wait for completion */
3220		timeout = STp->device->request_queue->rq_timeout;
3221	}
3222
3223	SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3224			   timeout, MAX_READY_RETRIES, 1);
3225	if (!SRpnt)
3226		return (STp->buffer)->syscall_result;
3227
3228	STps->drv_block = STps->drv_file = (-1);
3229	STps->eof = ST_NOEOF;
3230	if ((STp->buffer)->syscall_result != 0) {
3231		result = (-EIO);
3232		if (STp->can_partitions &&
3233		    (STp->device)->scsi_level >= SCSI_2 &&
3234		    (p = find_partition(STp)) >= 0)
3235			STp->partition = p;
3236	} else {
3237		if (STp->can_partitions) {
3238			STp->partition = partition;
3239			STps = &(STp->ps[partition]);
3240			if (!STps->last_block_valid ||
3241			    STps->last_block_visited != block) {
3242				STps->at_sm = 0;
3243				STps->rw = ST_IDLE;
3244			}
3245		} else
3246			STps->at_sm = 0;
3247		if (block == 0)
3248			STps->drv_block = STps->drv_file = 0;
3249		result = 0;
3250	}
3251
3252	st_release_request(SRpnt);
3253	SRpnt = NULL;
3254
3255	return result;
3256}
3257
3258
3259/* Find the current partition number for the drive status. Called from open and
3260   returns either partition number of negative error code. */
3261static int find_partition(struct scsi_tape *STp)
3262{
3263	int i, partition;
3264	unsigned int block;
3265
3266	if ((i = get_location(STp, &block, &partition, 1)) < 0)
3267		return i;
3268	if (partition >= ST_NBR_PARTITIONS)
3269		return (-EIO);
3270	return partition;
3271}
3272
3273
3274/* Change the partition if necessary */
3275static int switch_partition(struct scsi_tape *STp)
3276{
3277	struct st_partstat *STps;
3278
3279	if (STp->partition == STp->new_partition)
3280		return 0;
3281	STps = &(STp->ps[STp->new_partition]);
3282	if (!STps->last_block_valid)
3283		STps->last_block_visited = 0;
3284	return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3285}
3286
3287/* Functions for reading and writing the medium partition mode page. */
3288
3289#define PART_PAGE   0x11
3290#define PART_PAGE_FIXED_LENGTH 8
3291
3292#define PP_OFF_MAX_ADD_PARTS   2
3293#define PP_OFF_NBR_ADD_PARTS   3
3294#define PP_OFF_FLAGS           4
3295#define PP_OFF_PART_UNITS      6
3296#define PP_OFF_RESERVED        7
3297
3298#define PP_BIT_IDP             0x20
3299#define PP_BIT_FDP             0x80
3300#define PP_MSK_PSUM_MB         0x10
3301#define PP_MSK_PSUM_UNITS      0x18
3302#define PP_MSK_POFM            0x04
3303
3304/* Get the number of partitions on the tape. As a side effect reads the
3305   mode page into the tape buffer. */
3306static int nbr_partitions(struct scsi_tape *STp)
3307{
3308	int result;
3309
3310	if (STp->ready != ST_READY)
3311		return (-EIO);
3312
3313	result = read_mode_page(STp, PART_PAGE, 1);
3314
3315	if (result) {
3316		DEBC_printk(STp, "Can't read medium partition page.\n");
3317		result = (-EIO);
3318	} else {
3319		result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3320					      PP_OFF_NBR_ADD_PARTS] + 1;
3321		DEBC_printk(STp, "Number of partitions %d.\n", result);
3322	}
3323
3324	return result;
3325}
3326
3327
3328static int format_medium(struct scsi_tape *STp, int format)
3329{
3330	int result = 0;
3331	int timeout = STp->long_timeout;
3332	unsigned char scmd[MAX_COMMAND_SIZE];
3333	struct st_request *SRpnt;
3334
3335	memset(scmd, 0, MAX_COMMAND_SIZE);
3336	scmd[0] = FORMAT_UNIT;
3337	scmd[2] = format;
3338	if (STp->immediate) {
3339		scmd[1] |= 1;		/* Don't wait for completion */
3340		timeout = STp->device->request_queue->rq_timeout;
3341	}
3342	DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
3343	SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3344			   timeout, MAX_RETRIES, 1);
3345	if (!SRpnt)
3346		result = STp->buffer->syscall_result;
3347	return result;
3348}
3349
3350
3351/* Partition the tape into two partitions if size > 0 or one partition if
3352   size == 0.
3353
3354   The block descriptors are read and written because Sony SDT-7000 does not
3355   work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3356
3357   My HP C1533A drive returns only one partition size field. This is used to
3358   set the size of partition 1. There is no size field for the default partition.
3359   Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3360   used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3361   The following algorithm is used to accommodate both drives: if the number of
3362   partition size fields is greater than the maximum number of additional partitions
3363   in the mode page, the second field is used. Otherwise the first field is used.
3364
3365   For Seagate DDS drives the page length must be 8 when no partitions is defined
3366   and 10 when 1 partition is defined (information from Eric Lee Green). This is
3367   is acceptable also to some other old drives and enforced if the first partition
3368   size field is used for the first additional partition size.
3369
3370   For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
3371 */
3372static int partition_tape(struct scsi_tape *STp, int size)
3373{
3374	int result;
3375	int target_partition;
3376	bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
3377	int pgo, psd_cnt, psdo;
3378	int psum = PP_MSK_PSUM_MB, units = 0;
3379	unsigned char *bp;
3380
3381	result = read_mode_page(STp, PART_PAGE, 0);
3382	if (result) {
3383		DEBC_printk(STp, "Can't read partition mode page.\n");
3384		return result;
3385	}
3386	target_partition = 1;
3387	if (size < 0) {
3388		target_partition = 0;
3389		size = -size;
3390	}
3391
3392	/* The mode page is in the buffer. Let's modify it and write it. */
3393	bp = (STp->buffer)->b_data;
3394	pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3395	DEBC_printk(STp, "Partition page length is %d bytes.\n",
3396		    bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3397
3398	psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3399
3400	if (scsi3) {
3401		needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
3402		if (needs_format && size == 0) {
3403			/* No need to write the mode page when clearing
3404			 *  partitioning
3405			 */
3406			DEBC_printk(STp, "Formatting tape with one partition.\n");
3407			result = format_medium(STp, 0);
3408			goto out;
3409		}
3410		if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
3411			psd_cnt = 2;
3412		if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
3413			/* Use units scaling for large partitions if the device
3414			 * suggests it and no precision lost. Required for IBM
3415			 * TS1140/50 drives that don't support MB units.
3416			 */
3417			if (size >= 1000 && (size % 1000) == 0) {
3418				size /= 1000;
3419				psum = PP_MSK_PSUM_UNITS;
3420				units = 9; /* GB */
3421			}
3422		}
3423		/* Try it anyway if too large to specify in MB */
3424		if (psum == PP_MSK_PSUM_MB && size >= 65534) {
3425			size /= 1000;
3426			psum = PP_MSK_PSUM_UNITS;
3427			units = 9;  /* GB */
3428		}
3429	}
3430
3431	if (size >= 65535 ||  /* Does not fit into two bytes */
3432	    (target_partition == 0 && psd_cnt < 2)) {
3433		result = -EINVAL;
3434		goto out;
3435	}
3436
3437	psdo = pgo + PART_PAGE_FIXED_LENGTH;
3438	/* The second condition is for HP DDS which use only one partition size
3439	 * descriptor
3440	 */
3441	if (target_partition > 0 &&
3442	    (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
3443	     bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
3444		bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
3445		psdo += 2;
3446	}
3447	memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3448
3449	DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3450		    psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3451		    bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3452
3453	if (size == 0) {
3454		bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3455		if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3456		    bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3457		DEBC_printk(STp, "Formatting tape with one partition.\n");
3458	} else {
3459		bp[psdo] = (size >> 8) & 0xff;
3460		bp[psdo + 1] = size & 0xff;
3461		if (target_partition == 0)
3462			bp[psdo + 2] = bp[psdo + 3] = 0xff;
3463		bp[pgo + 3] = 1;
3464		if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3465		    bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3466		DEBC_printk(STp,
3467			    "Formatting tape with two partitions (%i = %d MB).\n",
3468			    target_partition, units > 0 ? size * 1000 : size);
3469	}
3470	bp[pgo + PP_OFF_PART_UNITS] = 0;
3471	bp[pgo + PP_OFF_RESERVED] = 0;
3472	if (size != 1 || units != 0) {
3473		bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
3474			(bp[pgo + PP_OFF_FLAGS] & 0x07);
3475		bp[pgo + PP_OFF_PART_UNITS] = units;
3476	} else
3477		bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
3478			(bp[pgo + PP_OFF_FLAGS] & 0x1f);
3479	bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
3480
3481	result = write_mode_page(STp, PART_PAGE, 1);
3482
3483	if (!result && needs_format)
3484		result = format_medium(STp, 1);
3485
3486	if (result) {
3487		st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3488		result = (-EIO);
3489	}
3490
3491out:
3492	return result;
3493}
3494
3495
3496
3497/* The ioctl command */
3498static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3499{
3500	int i, cmd_nr, cmd_type, bt;
3501	int retval = 0;
3502	unsigned int blk;
3503	struct scsi_tape *STp = file->private_data;
3504	struct st_modedef *STm;
3505	struct st_partstat *STps;
3506	void __user *p = (void __user *)arg;
3507
3508	if (mutex_lock_interruptible(&STp->lock))
3509		return -ERESTARTSYS;
3510
3511	DEB(
3512	if (debugging && !STp->in_use) {
3513		st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3514		retval = (-EIO);
3515		goto out;
3516	} ) /* end DEB */
3517
3518	STm = &(STp->modes[STp->current_mode]);
3519	STps = &(STp->ps[STp->partition]);
3520
3521	/*
3522	 * If we are in the middle of error recovery, don't let anyone
3523	 * else try and use this device.  Also, if error recovery fails, it
3524	 * may try and take the device offline, in which case all further
3525	 * access to the device is prohibited.
3526	 */
3527	retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3528			file->f_flags & O_NDELAY);
3529	if (retval)
3530		goto out;
3531
3532	cmd_type = _IOC_TYPE(cmd_in);
3533	cmd_nr = _IOC_NR(cmd_in);
3534
3535	if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3536		struct mtop mtc;
3537
3538		if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3539			retval = (-EINVAL);
3540			goto out;
3541		}
3542
3543		i = copy_from_user(&mtc, p, sizeof(struct mtop));
3544		if (i) {
3545			retval = (-EFAULT);
3546			goto out;
3547		}
3548
3549		if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3550			st_printk(KERN_WARNING, STp,
3551				  "MTSETDRVBUFFER only allowed for root.\n");
3552			retval = (-EPERM);
3553			goto out;
3554		}
3555		if (!STm->defined &&
3556		    (mtc.mt_op != MTSETDRVBUFFER &&
3557		     (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3558			retval = (-ENXIO);
3559			goto out;
3560		}
3561
3562		if (!STp->pos_unknown) {
3563
3564			if (STps->eof == ST_FM_HIT) {
3565				if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3566                                    mtc.mt_op == MTEOM) {
3567					mtc.mt_count -= 1;
3568					if (STps->drv_file >= 0)
3569						STps->drv_file += 1;
3570				} else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3571					mtc.mt_count += 1;
3572					if (STps->drv_file >= 0)
3573						STps->drv_file += 1;
3574				}
3575			}
3576
3577			if (mtc.mt_op == MTSEEK) {
3578				/* Old position must be restored if partition will be
3579                                   changed */
3580				i = !STp->can_partitions ||
3581				    (STp->new_partition != STp->partition);
3582			} else {
3583				i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3584				    mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3585				    mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3586				    mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3587				    mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3588				    mtc.mt_op == MTCOMPRESSION;
3589			}
3590			i = flush_buffer(STp, i);
3591			if (i < 0) {
3592				retval = i;
3593				goto out;
3594			}
3595			if (STps->rw == ST_WRITING &&
3596			    (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3597			     mtc.mt_op == MTSEEK ||
3598			     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3599				i = st_int_ioctl(STp, MTWEOF, 1);
3600				if (i < 0) {
3601					retval = i;
3602					goto out;
3603				}
3604				if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3605					mtc.mt_count++;
3606				STps->rw = ST_IDLE;
3607			     }
3608
3609		} else {
3610			/*
3611			 * If there was a bus reset, block further access
3612			 * to this device.  If the user wants to rewind the tape,
3613			 * then reset the flag and allow access again.
3614			 */
3615			if (mtc.mt_op != MTREW &&
3616			    mtc.mt_op != MTOFFL &&
3617			    mtc.mt_op != MTRETEN &&
3618			    mtc.mt_op != MTERASE &&
3619			    mtc.mt_op != MTSEEK &&
3620			    mtc.mt_op != MTEOM) {
3621				retval = (-EIO);
3622				goto out;
3623			}
3624			reset_state(STp);
3625			/* remove this when the midlevel properly clears was_reset */
3626			STp->device->was_reset = 0;
3627		}
3628
3629		if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3630		    mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3631		    mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3632			STps->rw = ST_IDLE;	/* Prevent automatic WEOF and fsf */
3633
3634		if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3635			do_door_lock(STp, 0);	/* Ignore result! */
3636
3637		if (mtc.mt_op == MTSETDRVBUFFER &&
3638		    (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3639			retval = st_set_options(STp, mtc.mt_count);
3640			goto out;
3641		}
3642
3643		if (mtc.mt_op == MTSETPART) {
3644			if (!STp->can_partitions ||
3645			    mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3646				retval = (-EINVAL);
3647				goto out;
3648			}
3649			if (mtc.mt_count >= STp->nbr_partitions &&
3650			    (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3651				retval = (-EIO);
3652				goto out;
3653			}
3654			if (mtc.mt_count >= STp->nbr_partitions) {
3655				retval = (-EINVAL);
3656				goto out;
3657			}
3658			STp->new_partition = mtc.mt_count;
3659			retval = 0;
3660			goto out;
3661		}
3662
3663		if (mtc.mt_op == MTMKPART) {
3664			if (!STp->can_partitions) {
3665				retval = (-EINVAL);
3666				goto out;
3667			}
3668			i = do_load_unload(STp, file, 1);
3669			if (i < 0) {
3670				retval = i;
3671				goto out;
3672			}
3673			i = partition_tape(STp, mtc.mt_count);
3674			if (i < 0) {
3675				retval = i;
3676				goto out;
3677			}
3678			for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3679				STp->ps[i].rw = ST_IDLE;
3680				STp->ps[i].at_sm = 0;
3681				STp->ps[i].last_block_valid = 0;
3682			}
3683			STp->partition = STp->new_partition = 0;
3684			STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3685			STps->drv_block = STps->drv_file = 0;
3686			retval = 0;
3687			goto out;
3688		}
3689
3690		if (mtc.mt_op == MTSEEK) {
3691			i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3692			if (!STp->can_partitions)
3693				STp->ps[0].rw = ST_IDLE;
3694			retval = i;
3695			goto out;
3696		}
3697
3698		if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3699			retval = do_load_unload(STp, file, 0);
3700			goto out;
3701		}
3702
3703		if (mtc.mt_op == MTLOAD) {
3704			retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3705			goto out;
3706		}
3707
3708		if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3709			retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3710			goto out;
3711		}
3712
3713		if (STp->can_partitions && STp->ready == ST_READY &&
3714		    (i = switch_partition(STp)) < 0) {
3715			retval = i;
3716			goto out;
3717		}
3718
3719		if (mtc.mt_op == MTCOMPRESSION)
3720			retval = st_compression(STp, (mtc.mt_count & 1));
3721		else
3722			retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3723		goto out;
3724	}
3725	if (!STm->defined) {
3726		retval = (-ENXIO);
3727		goto out;
3728	}
3729
3730	if ((i = flush_buffer(STp, 0)) < 0) {
3731		retval = i;
3732		goto out;
3733	}
3734	if (STp->can_partitions &&
3735	    (i = switch_partition(STp)) < 0) {
3736		retval = i;
3737		goto out;
3738	}
3739
3740	if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3741		struct mtget mt_status;
3742
3743		if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3744			 retval = (-EINVAL);
3745			 goto out;
3746		}
3747
3748		mt_status.mt_type = STp->tape_type;
3749		mt_status.mt_dsreg =
3750		    ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3751		    ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3752		mt_status.mt_blkno = STps->drv_block;
3753		mt_status.mt_fileno = STps->drv_file;
3754		if (STp->block_size != 0) {
3755			if (STps->rw == ST_WRITING)
3756				mt_status.mt_blkno +=
3757				    (STp->buffer)->buffer_bytes / STp->block_size;
3758			else if (STps->rw == ST_READING)
3759				mt_status.mt_blkno -=
3760                                        ((STp->buffer)->buffer_bytes +
3761                                         STp->block_size - 1) / STp->block_size;
3762		}
3763
3764		mt_status.mt_gstat = 0;
3765		if (STp->drv_write_prot)
3766			mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3767		if (mt_status.mt_blkno == 0) {
3768			if (mt_status.mt_fileno == 0)
3769				mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3770			else
3771				mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3772		}
3773		mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3774		mt_status.mt_resid = STp->partition;
3775		if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3776			mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3777		else if (STps->eof >= ST_EOM_OK)
3778			mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3779		if (STp->density == 1)
3780			mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3781		else if (STp->density == 2)
3782			mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3783		else if (STp->density == 3)
3784			mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3785		if (STp->ready == ST_READY)
3786			mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3787		if (STp->ready == ST_NO_TAPE)
3788			mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3789		if (STps->at_sm)
3790			mt_status.mt_gstat |= GMT_SM(0xffffffff);
3791		if (STm->do_async_writes ||
3792                    (STm->do_buffer_writes && STp->block_size != 0) ||
3793		    STp->drv_buffer != 0)
3794			mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3795		if (STp->cleaning_req)
3796			mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3797
3798		i = copy_to_user(p, &mt_status, sizeof(struct mtget));
3799		if (i) {
3800			retval = (-EFAULT);
3801			goto out;
3802		}
3803
3804		STp->recover_reg = 0;		/* Clear after read */
3805		retval = 0;
3806		goto out;
3807	}			/* End of MTIOCGET */
3808	if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3809		struct mtpos mt_pos;
3810		if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3811			 retval = (-EINVAL);
3812			 goto out;
3813		}
3814		if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3815			retval = i;
3816			goto out;
3817		}
3818		mt_pos.mt_blkno = blk;
3819		i = copy_to_user(p, &mt_pos, sizeof(struct mtpos));
3820		if (i)
3821			retval = (-EFAULT);
3822		goto out;
3823	}
3824	mutex_unlock(&STp->lock);
3825	switch (cmd_in) {
3826		case SCSI_IOCTL_GET_IDLUN:
3827		case SCSI_IOCTL_GET_BUS_NUMBER:
3828			break;
3829		default:
3830			if ((cmd_in == SG_IO ||
3831			     cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3832			     cmd_in == CDROM_SEND_PACKET) &&
3833			    !capable(CAP_SYS_RAWIO))
3834				i = -EPERM;
3835			else
3836				i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3837						   file->f_mode, cmd_in, p);
3838			if (i != -ENOTTY)
3839				return i;
3840			break;
3841	}
3842	retval = scsi_ioctl(STp->device, cmd_in, p);
3843	if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) { /* unload */
3844		STp->rew_at_close = 0;
3845		STp->ready = ST_NO_TAPE;
3846	}
3847	return retval;
3848
3849 out:
3850	mutex_unlock(&STp->lock);
3851	return retval;
3852}
3853
3854#ifdef CONFIG_COMPAT
3855static long st_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3856{
3857	struct scsi_tape *STp = file->private_data;
3858	struct scsi_device *sdev = STp->device;
3859	int ret = -ENOIOCTLCMD;
3860	if (sdev->host->hostt->compat_ioctl) { 
3861
3862		ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
3863
3864	}
3865	return ret;
3866}
3867#endif
3868
3869
3870
3871/* Try to allocate a new tape buffer. Calling function must not hold
3872   dev_arr_lock. */
3873static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
3874{
3875	struct st_buffer *tb;
3876
3877	tb = kzalloc(sizeof(struct st_buffer), GFP_ATOMIC);
3878	if (!tb) {
3879		printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3880		return NULL;
3881	}
3882	tb->frp_segs = 0;
3883	tb->use_sg = max_sg;
3884	tb->dma = need_dma;
3885	tb->buffer_size = 0;
3886
3887	tb->reserved_pages = kzalloc(max_sg * sizeof(struct page *),
3888				     GFP_ATOMIC);
3889	if (!tb->reserved_pages) {
3890		kfree(tb);
3891		return NULL;
3892	}
3893
3894	return tb;
3895}
3896
3897
3898/* Try to allocate enough space in the tape buffer */
3899#define ST_MAX_ORDER 6
3900
3901static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3902{
3903	int segs, max_segs, b_size, order, got;
3904	gfp_t priority;
3905
3906	if (new_size <= STbuffer->buffer_size)
3907		return 1;
3908
3909	if (STbuffer->buffer_size <= PAGE_SIZE)
3910		normalize_buffer(STbuffer);  /* Avoid extra segment */
3911
3912	max_segs = STbuffer->use_sg;
3913
3914	priority = GFP_KERNEL | __GFP_NOWARN;
3915	if (need_dma)
3916		priority |= GFP_DMA;
3917
3918	if (STbuffer->cleared)
3919		priority |= __GFP_ZERO;
3920
3921	if (STbuffer->frp_segs) {
3922		order = STbuffer->reserved_page_order;
3923		b_size = PAGE_SIZE << order;
3924	} else {
3925		for (b_size = PAGE_SIZE, order = 0;
3926		     order < ST_MAX_ORDER &&
3927			     max_segs * (PAGE_SIZE << order) < new_size;
3928		     order++, b_size *= 2)
3929			;  /* empty */
3930		STbuffer->reserved_page_order = order;
3931	}
3932	if (max_segs * (PAGE_SIZE << order) < new_size) {
3933		if (order == ST_MAX_ORDER)
3934			return 0;
3935		normalize_buffer(STbuffer);
3936		return enlarge_buffer(STbuffer, new_size, need_dma);
3937	}
3938
3939	for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3940	     segs < max_segs && got < new_size;) {
3941		struct page *page;
3942
3943		page = alloc_pages(priority, order);
3944		if (!page) {
3945			DEB(STbuffer->buffer_size = got);
3946			normalize_buffer(STbuffer);
3947			return 0;
3948		}
3949
3950		STbuffer->frp_segs += 1;
3951		got += b_size;
3952		STbuffer->buffer_size = got;
3953		STbuffer->reserved_pages[segs] = page;
3954		segs++;
3955	}
3956	STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3957
3958	return 1;
3959}
3960
3961
3962/* Make sure that no data from previous user is in the internal buffer */
3963static void clear_buffer(struct st_buffer * st_bp)
3964{
3965	int i;
3966
3967	for (i=0; i < st_bp->frp_segs; i++)
3968		memset(page_address(st_bp->reserved_pages[i]), 0,
3969		       PAGE_SIZE << st_bp->reserved_page_order);
3970	st_bp->cleared = 1;
3971}
3972
3973
3974/* Release the extra buffer */
3975static void normalize_buffer(struct st_buffer * STbuffer)
3976{
3977	int i, order = STbuffer->reserved_page_order;
3978
3979	for (i = 0; i < STbuffer->frp_segs; i++) {
3980		__free_pages(STbuffer->reserved_pages[i], order);
3981		STbuffer->buffer_size -= (PAGE_SIZE << order);
3982	}
3983	STbuffer->frp_segs = 0;
3984	STbuffer->sg_segs = 0;
3985	STbuffer->reserved_page_order = 0;
3986	STbuffer->map_data.offset = 0;
3987}
3988
3989
3990/* Move data from the user buffer to the tape buffer. Returns zero (success) or
3991   negative error code. */
3992static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3993{
3994	int i, cnt, res, offset;
3995	int length = PAGE_SIZE << st_bp->reserved_page_order;
3996
3997	for (i = 0, offset = st_bp->buffer_bytes;
3998	     i < st_bp->frp_segs && offset >= length; i++)
3999		offset -= length;
4000	if (i == st_bp->frp_segs) {	/* Should never happen */
4001		printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
4002		return (-EIO);
4003	}
4004	for (; i < st_bp->frp_segs && do_count > 0; i++) {
4005		struct page *page = st_bp->reserved_pages[i];
4006		cnt = length - offset < do_count ? length - offset : do_count;
4007		res = copy_from_user(page_address(page) + offset, ubp, cnt);
4008		if (res)
4009			return (-EFAULT);
4010		do_count -= cnt;
4011		st_bp->buffer_bytes += cnt;
4012		ubp += cnt;
4013		offset = 0;
4014	}
4015	if (do_count) /* Should never happen */
4016		return (-EIO);
4017
4018	return 0;
4019}
4020
4021
4022/* Move data from the tape buffer to the user buffer. Returns zero (success) or
4023   negative error code. */
4024static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4025{
4026	int i, cnt, res, offset;
4027	int length = PAGE_SIZE << st_bp->reserved_page_order;
4028
4029	for (i = 0, offset = st_bp->read_pointer;
4030	     i < st_bp->frp_segs && offset >= length; i++)
4031		offset -= length;
4032	if (i == st_bp->frp_segs) {	/* Should never happen */
4033		printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4034		return (-EIO);
4035	}
4036	for (; i < st_bp->frp_segs && do_count > 0; i++) {
4037		struct page *page = st_bp->reserved_pages[i];
4038		cnt = length - offset < do_count ? length - offset : do_count;
4039		res = copy_to_user(ubp, page_address(page) + offset, cnt);
4040		if (res)
4041			return (-EFAULT);
4042		do_count -= cnt;
4043		st_bp->buffer_bytes -= cnt;
4044		st_bp->read_pointer += cnt;
4045		ubp += cnt;
4046		offset = 0;
4047	}
4048	if (do_count) /* Should never happen */
4049		return (-EIO);
4050
4051	return 0;
4052}
4053
4054
4055/* Move data towards start of buffer */
4056static void move_buffer_data(struct st_buffer * st_bp, int offset)
4057{
4058	int src_seg, dst_seg, src_offset = 0, dst_offset;
4059	int count, total;
4060	int length = PAGE_SIZE << st_bp->reserved_page_order;
4061
4062	if (offset == 0)
4063		return;
4064
4065	total=st_bp->buffer_bytes - offset;
4066	for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4067		src_offset = offset;
4068		if (src_offset < length)
4069			break;
4070		offset -= length;
4071	}
4072
4073	st_bp->buffer_bytes = st_bp->read_pointer = total;
4074	for (dst_seg=dst_offset=0; total > 0; ) {
4075		struct page *dpage = st_bp->reserved_pages[dst_seg];
4076		struct page *spage = st_bp->reserved_pages[src_seg];
4077
4078		count = min(length - dst_offset, length - src_offset);
4079		memmove(page_address(dpage) + dst_offset,
4080			page_address(spage) + src_offset, count);
4081		src_offset += count;
4082		if (src_offset >= length) {
4083			src_seg++;
4084			src_offset = 0;
4085		}
4086		dst_offset += count;
4087		if (dst_offset >= length) {
4088			dst_seg++;
4089			dst_offset = 0;
4090		}
4091		total -= count;
4092	}
4093}
4094
4095/* Validate the options from command line or module parameters */
4096static void validate_options(void)
4097{
4098	if (buffer_kbs > 0)
4099		st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4100	if (max_sg_segs >= ST_FIRST_SG)
4101		st_max_sg_segs = max_sg_segs;
4102}
4103
4104#ifndef MODULE
4105/* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4106 */
4107static int __init st_setup(char *str)
4108{
4109	int i, len, ints[5];
4110	char *stp;
4111
4112	stp = get_options(str, ARRAY_SIZE(ints), ints);
4113
4114	if (ints[0] > 0) {
4115		for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4116			if (parms[i].val)
4117				*parms[i].val = ints[i + 1];
4118	} else {
4119		while (stp != NULL) {
4120			for (i = 0; i < ARRAY_SIZE(parms); i++) {
4121				len = strlen(parms[i].name);
4122				if (!strncmp(stp, parms[i].name, len) &&
4123				    (*(stp + len) == ':' || *(stp + len) == '=')) {
4124					if (parms[i].val)
4125						*parms[i].val =
4126							simple_strtoul(stp + len + 1, NULL, 0);
4127					else
4128						printk(KERN_WARNING "st: Obsolete parameter %s\n",
4129						       parms[i].name);
4130					break;
4131				}
4132			}
4133			if (i >= ARRAY_SIZE(parms))
4134				 printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4135					stp);
4136			stp = strchr(stp, ',');
4137			if (stp)
4138				stp++;
4139		}
4140	}
4141
4142	validate_options();
4143
4144	return 1;
4145}
4146
4147__setup("st=", st_setup);
4148
4149#endif
4150
4151static const struct file_operations st_fops =
4152{
4153	.owner =	THIS_MODULE,
4154	.read =		st_read,
4155	.write =	st_write,
4156	.unlocked_ioctl = st_ioctl,
4157#ifdef CONFIG_COMPAT
4158	.compat_ioctl = st_compat_ioctl,
4159#endif
4160	.open =		st_open,
4161	.flush =	st_flush,
4162	.release =	st_release,
4163	.llseek =	noop_llseek,
4164};
4165
4166static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4167{
4168	int i, error;
4169	dev_t cdev_devno;
4170	struct cdev *cdev;
4171	struct device *dev;
4172	struct st_modedef *STm = &(tape->modes[mode]);
4173	char name[10];
4174	int dev_num = tape->index;
4175
4176	cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4177
4178	cdev = cdev_alloc();
4179	if (!cdev) {
4180		pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4181		error = -ENOMEM;
4182		goto out;
4183	}
4184	cdev->owner = THIS_MODULE;
4185	cdev->ops = &st_fops;
4186	STm->cdevs[rew] = cdev;
4187
4188	error = cdev_add(cdev, cdev_devno, 1);
4189	if (error) {
4190		pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4191		       rew ? "non" : "auto", mode);
4192		pr_err("st%d: Device not attached.\n", dev_num);
4193		goto out_free;
4194	}
4195
4196	i = mode << (4 - ST_NBR_MODE_BITS);
4197	snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4198		 tape->disk->disk_name, st_formats[i]);
4199
4200	dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4201			    cdev_devno, &tape->modes[mode], "%s", name);
4202	if (IS_ERR(dev)) {
4203		pr_err("st%d: device_create failed\n", dev_num);
4204		error = PTR_ERR(dev);
4205		goto out_free;
4206	}
4207
4208	STm->devs[rew] = dev;
4209
4210	return 0;
4211out_free:
4212	cdev_del(STm->cdevs[rew]);
4213out:
4214	STm->cdevs[rew] = NULL;
4215	STm->devs[rew] = NULL;
4216	return error;
4217}
4218
4219static int create_cdevs(struct scsi_tape *tape)
4220{
4221	int mode, error;
4222	for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4223		error = create_one_cdev(tape, mode, 0);
4224		if (error)
4225			return error;
4226		error = create_one_cdev(tape, mode, 1);
4227		if (error)
4228			return error;
4229	}
4230
4231	return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4232				 &tape->modes[0].devs[0]->kobj, "tape");
4233}
4234
4235static void remove_cdevs(struct scsi_tape *tape)
4236{
4237	int mode, rew;
4238	sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4239	for (mode = 0; mode < ST_NBR_MODES; mode++) {
4240		struct st_modedef *STm = &(tape->modes[mode]);
4241		for (rew = 0; rew < 2; rew++) {
4242			if (STm->cdevs[rew])
4243				cdev_del(STm->cdevs[rew]);
4244			if (STm->devs[rew])
4245				device_unregister(STm->devs[rew]);
4246		}
4247	}
4248}
4249
4250static int st_probe(struct device *dev)
4251{
4252	struct scsi_device *SDp = to_scsi_device(dev);
4253	struct gendisk *disk = NULL;
4254	struct scsi_tape *tpnt = NULL;
4255	struct st_modedef *STm;
4256	struct st_partstat *STps;
4257	struct st_buffer *buffer;
4258	int i, error;
4259	char *stp;
4260
4261	if (SDp->type != TYPE_TAPE)
4262		return -ENODEV;
4263	if ((stp = st_incompatible(SDp))) {
4264		sdev_printk(KERN_INFO, SDp, "Found incompatible tape\n");
4265		sdev_printk(KERN_INFO, SDp,
4266			    "st: The suggested driver is %s.\n", stp);
4267		return -ENODEV;
4268	}
4269
4270	scsi_autopm_get_device(SDp);
4271	i = queue_max_segments(SDp->request_queue);
4272	if (st_max_sg_segs < i)
4273		i = st_max_sg_segs;
4274	buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);
4275	if (buffer == NULL) {
4276		sdev_printk(KERN_ERR, SDp,
4277			    "st: Can't allocate new tape buffer. "
4278			    "Device not attached.\n");
4279		goto out;
4280	}
4281
4282	disk = alloc_disk(1);
4283	if (!disk) {
4284		sdev_printk(KERN_ERR, SDp,
4285			    "st: out of memory. Device not attached.\n");
4286		goto out_buffer_free;
4287	}
4288
4289	tpnt = kzalloc(sizeof(struct scsi_tape), GFP_ATOMIC);
4290	if (tpnt == NULL) {
4291		sdev_printk(KERN_ERR, SDp,
4292			    "st: Can't allocate device descriptor.\n");
4293		goto out_put_disk;
4294	}
4295	kref_init(&tpnt->kref);
4296	tpnt->disk = disk;
4297	disk->private_data = &tpnt->driver;
4298	disk->queue = SDp->request_queue;
4299	/* SCSI tape doesn't register this gendisk via add_disk().  Manually
4300	 * take queue reference that release_disk() expects. */
4301	if (!blk_get_queue(disk->queue))
4302		goto out_put_disk;
 
4303	tpnt->driver = &st_template;
4304
4305	tpnt->device = SDp;
4306	if (SDp->scsi_level <= 2)
4307		tpnt->tape_type = MT_ISSCSI1;
4308	else
4309		tpnt->tape_type = MT_ISSCSI2;
4310
4311	tpnt->buffer = buffer;
4312	tpnt->buffer->last_SRpnt = NULL;
4313
4314	tpnt->inited = 0;
4315	tpnt->dirty = 0;
4316	tpnt->in_use = 0;
4317	tpnt->drv_buffer = 1;	/* Try buffering if no mode sense */
4318	tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
4319	tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4320	tpnt->density = 0;
4321	tpnt->do_auto_lock = ST_AUTO_LOCK;
4322	tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4323	tpnt->can_partitions = 0;
4324	tpnt->two_fm = ST_TWO_FM;
4325	tpnt->fast_mteom = ST_FAST_MTEOM;
4326	tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4327	tpnt->sili = ST_SILI;
4328	tpnt->immediate = ST_NOWAIT;
4329	tpnt->immediate_filemark = 0;
4330	tpnt->default_drvbuffer = 0xff;		/* No forced buffering */
4331	tpnt->partition = 0;
4332	tpnt->new_partition = 0;
4333	tpnt->nbr_partitions = 0;
4334	blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4335	tpnt->long_timeout = ST_LONG_TIMEOUT;
4336	tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4337
4338	for (i = 0; i < ST_NBR_MODES; i++) {
4339		STm = &(tpnt->modes[i]);
4340		STm->defined = 0;
4341		STm->sysv = ST_SYSV;
4342		STm->defaults_for_writes = 0;
4343		STm->do_async_writes = ST_ASYNC_WRITES;
4344		STm->do_buffer_writes = ST_BUFFER_WRITES;
4345		STm->do_read_ahead = ST_READ_AHEAD;
4346		STm->default_compression = ST_DONT_TOUCH;
4347		STm->default_blksize = (-1);	/* No forced size */
4348		STm->default_density = (-1);	/* No forced density */
4349		STm->tape = tpnt;
4350	}
4351
4352	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4353		STps = &(tpnt->ps[i]);
4354		STps->rw = ST_IDLE;
4355		STps->eof = ST_NOEOF;
4356		STps->at_sm = 0;
4357		STps->last_block_valid = 0;
4358		STps->drv_block = (-1);
4359		STps->drv_file = (-1);
4360	}
4361
4362	tpnt->current_mode = 0;
4363	tpnt->modes[0].defined = 1;
4364
4365	tpnt->density_changed = tpnt->compression_changed =
4366	    tpnt->blksize_changed = 0;
4367	mutex_init(&tpnt->lock);
4368
4369	idr_preload(GFP_KERNEL);
4370	spin_lock(&st_index_lock);
4371	error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4372	spin_unlock(&st_index_lock);
4373	idr_preload_end();
4374	if (error < 0) {
4375		pr_warn("st: idr allocation failed: %d\n", error);
4376		goto out_put_queue;
4377	}
4378	tpnt->index = error;
4379	sprintf(disk->disk_name, "st%d", tpnt->index);
4380	tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4381	if (tpnt->stats == NULL) {
4382		sdev_printk(KERN_ERR, SDp,
4383			    "st: Can't allocate statistics.\n");
4384		goto out_idr_remove;
4385	}
4386
4387	dev_set_drvdata(dev, tpnt);
4388
4389
4390	error = create_cdevs(tpnt);
4391	if (error)
4392		goto out_remove_devs;
4393	scsi_autopm_put_device(SDp);
4394
4395	sdev_printk(KERN_NOTICE, SDp,
4396		    "Attached scsi tape %s\n", tape_name(tpnt));
4397	sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4398		    tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4399		    queue_dma_alignment(SDp->request_queue) + 1);
4400
4401	return 0;
4402
4403out_remove_devs:
4404	remove_cdevs(tpnt);
4405	kfree(tpnt->stats);
4406out_idr_remove:
4407	spin_lock(&st_index_lock);
4408	idr_remove(&st_index_idr, tpnt->index);
4409	spin_unlock(&st_index_lock);
4410out_put_queue:
4411	blk_put_queue(disk->queue);
4412out_put_disk:
4413	put_disk(disk);
4414	kfree(tpnt);
4415out_buffer_free:
4416	kfree(buffer);
4417out:
4418	scsi_autopm_put_device(SDp);
4419	return -ENODEV;
4420};
4421
4422
4423static int st_remove(struct device *dev)
4424{
4425	struct scsi_tape *tpnt = dev_get_drvdata(dev);
4426	int index = tpnt->index;
4427
4428	scsi_autopm_get_device(to_scsi_device(dev));
4429	remove_cdevs(tpnt);
4430
4431	mutex_lock(&st_ref_mutex);
4432	kref_put(&tpnt->kref, scsi_tape_release);
4433	mutex_unlock(&st_ref_mutex);
4434	spin_lock(&st_index_lock);
4435	idr_remove(&st_index_idr, index);
4436	spin_unlock(&st_index_lock);
4437	return 0;
4438}
4439
4440/**
4441 *      scsi_tape_release - Called to free the Scsi_Tape structure
4442 *      @kref: pointer to embedded kref
4443 *
4444 *      st_ref_mutex must be held entering this routine.  Because it is
4445 *      called on last put, you should always use the scsi_tape_get()
4446 *      scsi_tape_put() helpers which manipulate the semaphore directly
4447 *      and never do a direct kref_put().
4448 **/
4449static void scsi_tape_release(struct kref *kref)
4450{
4451	struct scsi_tape *tpnt = to_scsi_tape(kref);
4452	struct gendisk *disk = tpnt->disk;
4453
4454	tpnt->device = NULL;
4455
4456	if (tpnt->buffer) {
4457		normalize_buffer(tpnt->buffer);
4458		kfree(tpnt->buffer->reserved_pages);
4459		kfree(tpnt->buffer);
4460	}
4461
4462	disk->private_data = NULL;
4463	put_disk(disk);
4464	kfree(tpnt->stats);
4465	kfree(tpnt);
4466	return;
4467}
4468
4469static struct class st_sysfs_class = {
4470	.name = "scsi_tape",
4471	.dev_groups = st_dev_groups,
4472};
4473
4474static int __init init_st(void)
4475{
4476	int err;
4477
4478	validate_options();
4479
4480	printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4481		verstr, st_fixed_buffer_size, st_max_sg_segs);
4482
4483	debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4484	if (debugging) {
4485		printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4486			debugging);
4487	}
4488
4489	err = class_register(&st_sysfs_class);
4490	if (err) {
4491		pr_err("Unable register sysfs class for SCSI tapes\n");
4492		return err;
4493	}
4494
4495	err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4496				     ST_MAX_TAPE_ENTRIES, "st");
4497	if (err) {
4498		printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4499		       SCSI_TAPE_MAJOR);
4500		goto err_class;
4501	}
4502
4503	err = scsi_register_driver(&st_template.gendrv);
4504	if (err)
4505		goto err_chrdev;
4506
4507	return 0;
4508
4509err_chrdev:
4510	unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4511				 ST_MAX_TAPE_ENTRIES);
4512err_class:
4513	class_unregister(&st_sysfs_class);
4514	return err;
4515}
4516
4517static void __exit exit_st(void)
4518{
4519	scsi_unregister_driver(&st_template.gendrv);
4520	unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4521				 ST_MAX_TAPE_ENTRIES);
4522	class_unregister(&st_sysfs_class);
4523	idr_destroy(&st_index_idr);
4524	printk(KERN_INFO "st: Unloaded.\n");
4525}
4526
4527module_init(init_st);
4528module_exit(exit_st);
4529
4530
4531/* The sysfs driver interface. Read-only at the moment */
4532static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4533{
4534	return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4535}
4536static DRIVER_ATTR_RO(try_direct_io);
4537
4538static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4539{
4540	return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4541}
4542static DRIVER_ATTR_RO(fixed_buffer_size);
4543
4544static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4545{
4546	return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4547}
4548static DRIVER_ATTR_RO(max_sg_segs);
4549
4550static ssize_t version_show(struct device_driver *ddd, char *buf)
4551{
4552	return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4553}
4554static DRIVER_ATTR_RO(version);
4555
4556#if DEBUG
4557static ssize_t debug_flag_store(struct device_driver *ddp,
4558	const char *buf, size_t count)
4559{
4560/* We only care what the first byte of the data is the rest is unused.
4561 * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4562 * other values have -EINVAL returned if they are passed in.
4563 */
4564	if (count > 0) {
4565		if (buf[0] == '0') {
4566			debugging = NO_DEBUG;
4567			return count;
4568		} else if (buf[0] == '1') {
4569			debugging = 1;
4570			return count;
4571		}
4572	}
4573	return -EINVAL;
4574}
4575
4576static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4577{
4578	return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4579}
4580static DRIVER_ATTR_RW(debug_flag);
4581#endif
4582
4583static struct attribute *st_drv_attrs[] = {
4584	&driver_attr_try_direct_io.attr,
4585	&driver_attr_fixed_buffer_size.attr,
4586	&driver_attr_max_sg_segs.attr,
4587	&driver_attr_version.attr,
4588#if DEBUG
4589	&driver_attr_debug_flag.attr,
4590#endif
4591	NULL,
4592};
4593ATTRIBUTE_GROUPS(st_drv);
4594
4595/* The sysfs simple class interface */
4596static ssize_t
4597defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4598{
4599	struct st_modedef *STm = dev_get_drvdata(dev);
4600	ssize_t l = 0;
4601
4602	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4603	return l;
4604}
4605static DEVICE_ATTR_RO(defined);
4606
4607static ssize_t
4608default_blksize_show(struct device *dev, struct device_attribute *attr,
4609		     char *buf)
4610{
4611	struct st_modedef *STm = dev_get_drvdata(dev);
4612	ssize_t l = 0;
4613
4614	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4615	return l;
4616}
4617static DEVICE_ATTR_RO(default_blksize);
4618
4619static ssize_t
4620default_density_show(struct device *dev, struct device_attribute *attr,
4621		     char *buf)
4622{
4623	struct st_modedef *STm = dev_get_drvdata(dev);
4624	ssize_t l = 0;
4625	char *fmt;
4626
4627	fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4628	l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4629	return l;
4630}
4631static DEVICE_ATTR_RO(default_density);
4632
4633static ssize_t
4634default_compression_show(struct device *dev, struct device_attribute *attr,
4635			 char *buf)
4636{
4637	struct st_modedef *STm = dev_get_drvdata(dev);
4638	ssize_t l = 0;
4639
4640	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4641	return l;
4642}
4643static DEVICE_ATTR_RO(default_compression);
4644
4645static ssize_t
4646options_show(struct device *dev, struct device_attribute *attr, char *buf)
4647{
4648	struct st_modedef *STm = dev_get_drvdata(dev);
4649	struct scsi_tape *STp = STm->tape;
4650	int options;
4651	ssize_t l = 0;
4652
4653	options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4654	options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4655	options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4656	DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4657	options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4658	options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4659	options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4660	options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4661	options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4662	options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4663	options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4664	options |= STm->sysv ? MT_ST_SYSV : 0;
4665	options |= STp->immediate ? MT_ST_NOWAIT : 0;
4666	options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4667	options |= STp->sili ? MT_ST_SILI : 0;
4668
4669	l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4670	return l;
4671}
4672static DEVICE_ATTR_RO(options);
4673
4674/* Support for tape stats */
4675
4676/**
4677 * read_cnt_show - return read count - count of reads made from tape drive
4678 * @dev: struct device
4679 * @attr: attribute structure
4680 * @buf: buffer to return formatted data in
4681 */
4682static ssize_t read_cnt_show(struct device *dev,
4683	struct device_attribute *attr, char *buf)
4684{
4685	struct st_modedef *STm = dev_get_drvdata(dev);
4686
4687	return sprintf(buf, "%lld",
4688		       (long long)atomic64_read(&STm->tape->stats->read_cnt));
4689}
4690static DEVICE_ATTR_RO(read_cnt);
4691
4692/**
4693 * read_byte_cnt_show - return read byte count - tape drives
4694 * may use blocks less than 512 bytes this gives the raw byte count of
4695 * of data read from the tape drive.
4696 * @dev: struct device
4697 * @attr: attribute structure
4698 * @buf: buffer to return formatted data in
4699 */
4700static ssize_t read_byte_cnt_show(struct device *dev,
4701	struct device_attribute *attr, char *buf)
4702{
4703	struct st_modedef *STm = dev_get_drvdata(dev);
4704
4705	return sprintf(buf, "%lld",
4706		       (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4707}
4708static DEVICE_ATTR_RO(read_byte_cnt);
4709
4710/**
4711 * read_us_show - return read us - overall time spent waiting on reads in ns.
4712 * @dev: struct device
4713 * @attr: attribute structure
4714 * @buf: buffer to return formatted data in
4715 */
4716static ssize_t read_ns_show(struct device *dev,
4717	struct device_attribute *attr, char *buf)
4718{
4719	struct st_modedef *STm = dev_get_drvdata(dev);
4720
4721	return sprintf(buf, "%lld",
4722		       (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4723}
4724static DEVICE_ATTR_RO(read_ns);
4725
4726/**
4727 * write_cnt_show - write count - number of user calls
4728 * to write(2) that have written data to tape.
4729 * @dev: struct device
4730 * @attr: attribute structure
4731 * @buf: buffer to return formatted data in
4732 */
4733static ssize_t write_cnt_show(struct device *dev,
4734	struct device_attribute *attr, char *buf)
4735{
4736	struct st_modedef *STm = dev_get_drvdata(dev);
4737
4738	return sprintf(buf, "%lld",
4739		       (long long)atomic64_read(&STm->tape->stats->write_cnt));
4740}
4741static DEVICE_ATTR_RO(write_cnt);
4742
4743/**
4744 * write_byte_cnt_show - write byte count - raw count of
4745 * bytes written to tape.
4746 * @dev: struct device
4747 * @attr: attribute structure
4748 * @buf: buffer to return formatted data in
4749 */
4750static ssize_t write_byte_cnt_show(struct device *dev,
4751	struct device_attribute *attr, char *buf)
4752{
4753	struct st_modedef *STm = dev_get_drvdata(dev);
4754
4755	return sprintf(buf, "%lld",
4756		       (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4757}
4758static DEVICE_ATTR_RO(write_byte_cnt);
4759
4760/**
4761 * write_ns_show - write ns - number of nanoseconds waiting on write
4762 * requests to complete.
4763 * @dev: struct device
4764 * @attr: attribute structure
4765 * @buf: buffer to return formatted data in
4766 */
4767static ssize_t write_ns_show(struct device *dev,
4768	struct device_attribute *attr, char *buf)
4769{
4770	struct st_modedef *STm = dev_get_drvdata(dev);
4771
4772	return sprintf(buf, "%lld",
4773		       (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4774}
4775static DEVICE_ATTR_RO(write_ns);
4776
4777/**
4778 * in_flight_show - number of I/Os currently in flight -
4779 * in most cases this will be either 0 or 1. It may be higher if someone
4780 * has also issued other SCSI commands such as via an ioctl.
4781 * @dev: struct device
4782 * @attr: attribute structure
4783 * @buf: buffer to return formatted data in
4784 */
4785static ssize_t in_flight_show(struct device *dev,
4786	struct device_attribute *attr, char *buf)
4787{
4788	struct st_modedef *STm = dev_get_drvdata(dev);
4789
4790	return sprintf(buf, "%lld",
4791		       (long long)atomic64_read(&STm->tape->stats->in_flight));
4792}
4793static DEVICE_ATTR_RO(in_flight);
4794
4795/**
4796 * io_ns_show - io wait ns - this is the number of ns spent
4797 * waiting on all I/O to complete. This includes tape movement commands
4798 * such as rewinding, seeking to end of file or tape, it also includes
4799 * read and write. To determine the time spent on tape movement
4800 * subtract the read and write ns from this value.
4801 * @dev: struct device
4802 * @attr: attribute structure
4803 * @buf: buffer to return formatted data in
4804 */
4805static ssize_t io_ns_show(struct device *dev,
4806	struct device_attribute *attr, char *buf)
4807{
4808	struct st_modedef *STm = dev_get_drvdata(dev);
4809
4810	return sprintf(buf, "%lld",
4811		       (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4812}
4813static DEVICE_ATTR_RO(io_ns);
4814
4815/**
4816 * other_cnt_show - other io count - this is the number of
4817 * I/O requests other than read and write requests.
4818 * Typically these are tape movement requests but will include driver
4819 * tape movement. This includes only requests issued by the st driver.
4820 * @dev: struct device
4821 * @attr: attribute structure
4822 * @buf: buffer to return formatted data in
4823 */
4824static ssize_t other_cnt_show(struct device *dev,
4825	struct device_attribute *attr, char *buf)
4826{
4827	struct st_modedef *STm = dev_get_drvdata(dev);
4828
4829	return sprintf(buf, "%lld",
4830		       (long long)atomic64_read(&STm->tape->stats->other_cnt));
4831}
4832static DEVICE_ATTR_RO(other_cnt);
4833
4834/**
4835 * resid_cnt_show - A count of the number of times we get a residual
4836 * count - this should indicate someone issuing reads larger than the
4837 * block size on tape.
4838 * @dev: struct device
4839 * @attr: attribute structure
4840 * @buf: buffer to return formatted data in
4841 */
4842static ssize_t resid_cnt_show(struct device *dev,
4843	struct device_attribute *attr, char *buf)
4844{
4845	struct st_modedef *STm = dev_get_drvdata(dev);
4846
4847	return sprintf(buf, "%lld",
4848		       (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4849}
4850static DEVICE_ATTR_RO(resid_cnt);
4851
4852static struct attribute *st_dev_attrs[] = {
4853	&dev_attr_defined.attr,
4854	&dev_attr_default_blksize.attr,
4855	&dev_attr_default_density.attr,
4856	&dev_attr_default_compression.attr,
4857	&dev_attr_options.attr,
4858	NULL,
4859};
4860
4861static struct attribute *st_stats_attrs[] = {
4862	&dev_attr_read_cnt.attr,
4863	&dev_attr_read_byte_cnt.attr,
4864	&dev_attr_read_ns.attr,
4865	&dev_attr_write_cnt.attr,
4866	&dev_attr_write_byte_cnt.attr,
4867	&dev_attr_write_ns.attr,
4868	&dev_attr_in_flight.attr,
4869	&dev_attr_io_ns.attr,
4870	&dev_attr_other_cnt.attr,
4871	&dev_attr_resid_cnt.attr,
4872	NULL,
4873};
4874
4875static struct attribute_group stats_group = {
4876	.name = "stats",
4877	.attrs = st_stats_attrs,
4878};
4879
4880static struct attribute_group st_group = {
4881	.attrs = st_dev_attrs,
4882};
4883
4884static const struct attribute_group *st_dev_groups[] = {
4885	&st_group,
4886	&stats_group,
4887	NULL,
4888};
4889
4890/* The following functions may be useful for a larger audience. */
4891static int sgl_map_user_pages(struct st_buffer *STbp,
4892			      const unsigned int max_pages, unsigned long uaddr,
4893			      size_t count, int rw)
4894{
4895	unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4896	unsigned long start = uaddr >> PAGE_SHIFT;
4897	const int nr_pages = end - start;
4898	int res, i, j;
4899	struct page **pages;
4900	struct rq_map_data *mdata = &STbp->map_data;
4901
4902	/* User attempted Overflow! */
4903	if ((uaddr + count) < uaddr)
4904		return -EINVAL;
4905
4906	/* Too big */
4907        if (nr_pages > max_pages)
4908		return -ENOMEM;
4909
4910	/* Hmm? */
4911	if (count == 0)
4912		return 0;
4913
4914	if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_KERNEL)) == NULL)
4915		return -ENOMEM;
4916
4917        /* Try to fault in all of the necessary pages */
4918        /* rw==READ means read from drive, write into memory area */
4919	res = get_user_pages_unlocked(
4920		uaddr,
4921		nr_pages,
4922		rw == READ,
4923		0, /* don't force */
4924		pages);
4925
4926	/* Errors and no page mapped should return here */
4927	if (res < nr_pages)
4928		goto out_unmap;
4929
4930        for (i=0; i < nr_pages; i++) {
4931                /* FIXME: flush superflous for rw==READ,
4932                 * probably wrong function for rw==WRITE
4933                 */
4934		flush_dcache_page(pages[i]);
4935        }
4936
4937	mdata->offset = uaddr & ~PAGE_MASK;
4938	STbp->mapped_pages = pages;
4939
4940	return nr_pages;
4941 out_unmap:
4942	if (res > 0) {
4943		for (j=0; j < res; j++)
4944			put_page(pages[j]);
4945		res = 0;
4946	}
4947	kfree(pages);
4948	return res;
4949}
4950
4951
4952/* And unmap them... */
4953static int sgl_unmap_user_pages(struct st_buffer *STbp,
4954				const unsigned int nr_pages, int dirtied)
4955{
4956	int i;
4957
4958	for (i=0; i < nr_pages; i++) {
4959		struct page *page = STbp->mapped_pages[i];
4960
4961		if (dirtied)
4962			SetPageDirty(page);
4963		/* FIXME: cache flush missing for rw==READ
4964		 * FIXME: call the correct reference counting function
4965		 */
4966		put_page(page);
4967	}
4968	kfree(STbp->mapped_pages);
4969	STbp->mapped_pages = NULL;
4970
4971	return 0;
4972}