1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  scsi.c Copyright (C) 1992 Drew Eckhardt
   4 *         Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
   5 *         Copyright (C) 2002, 2003 Christoph Hellwig
   6 *
   7 *  generic mid-level SCSI driver
   8 *      Initial versions: Drew Eckhardt
   9 *      Subsequent revisions: Eric Youngdale
  10 *
  11 *  <drew@colorado.edu>
  12 *
  13 *  Bug correction thanks go to :
  14 *      Rik Faith <faith@cs.unc.edu>
  15 *      Tommy Thorn <tthorn>
  16 *      Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de>
  17 *
  18 *  Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
  19 *  add scatter-gather, multiple outstanding request, and other
  20 *  enhancements.
  21 *
  22 *  Native multichannel, wide scsi, /proc/scsi and hot plugging
  23 *  support added by Michael Neuffer <mike@i-connect.net>
  24 *
  25 *  Added request_module("scsi_hostadapter") for kerneld:
  26 *  (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf)
  27 *  Bjorn Ekwall  <bj0rn@blox.se>
  28 *  (changed to kmod)
  29 *
  30 *  Major improvements to the timeout, abort, and reset processing,
  31 *  as well as performance modifications for large queue depths by
  32 *  Leonard N. Zubkoff <lnz@dandelion.com>
  33 *
  34 *  Converted cli() code to spinlocks, Ingo Molnar
  35 *
  36 *  Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
  37 *
  38 *  out_of_space hacks, D. Gilbert (dpg) 990608
  39 */
  40
  41#include <linux/module.h>
  42#include <linux/moduleparam.h>
  43#include <linux/kernel.h>
  44#include <linux/timer.h>
  45#include <linux/string.h>
  46#include <linux/slab.h>
  47#include <linux/blkdev.h>
  48#include <linux/delay.h>
  49#include <linux/init.h>
  50#include <linux/completion.h>
  51#include <linux/unistd.h>
  52#include <linux/spinlock.h>
  53#include <linux/kmod.h>
  54#include <linux/interrupt.h>
  55#include <linux/notifier.h>
  56#include <linux/cpu.h>
  57#include <linux/mutex.h>
  58#include <asm/unaligned.h>
  59
  60#include <scsi/scsi.h>
  61#include <scsi/scsi_cmnd.h>
  62#include <scsi/scsi_dbg.h>
  63#include <scsi/scsi_device.h>
  64#include <scsi/scsi_driver.h>
  65#include <scsi/scsi_eh.h>
  66#include <scsi/scsi_host.h>
  67#include <scsi/scsi_tcq.h>
  68
  69#include "scsi_priv.h"
  70#include "scsi_logging.h"
  71
  72#define CREATE_TRACE_POINTS
  73#include <trace/events/scsi.h>
  74
  75/*
  76 * Definitions and constants.
  77 */
  78
  79/*
  80 * Note - the initial logging level can be set here to log events at boot time.
  81 * After the system is up, you may enable logging via the /proc interface.
  82 */
  83unsigned int scsi_logging_level;
  84#if defined(CONFIG_SCSI_LOGGING)
  85EXPORT_SYMBOL(scsi_logging_level);
  86#endif
  87
  88#ifdef CONFIG_SCSI_LOGGING
  89void scsi_log_send(struct scsi_cmnd *cmd)
  90{
  91	unsigned int level;
  92
  93	/*
  94	 * If ML QUEUE log level is greater than or equal to:
  95	 *
  96	 * 1: nothing (match completion)
  97	 *
  98	 * 2: log opcode + command of all commands + cmd address
  99	 *
 100	 * 3: same as 2
 101	 *
 102	 * 4: same as 3
 103	 */
 104	if (unlikely(scsi_logging_level)) {
 105		level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
 106				       SCSI_LOG_MLQUEUE_BITS);
 107		if (level > 1) {
 108			scmd_printk(KERN_INFO, cmd,
 109				    "Send: scmd 0x%p\n", cmd);
 110			scsi_print_command(cmd);
 111		}
 112	}
 113}
 114
 115void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
 116{
 117	unsigned int level;
 118
 119	/*
 120	 * If ML COMPLETE log level is greater than or equal to:
 121	 *
 122	 * 1: log disposition, result, opcode + command, and conditionally
 123	 * sense data for failures or non SUCCESS dispositions.
 124	 *
 125	 * 2: same as 1 but for all command completions.
 126	 *
 127	 * 3: same as 2
 128	 *
 129	 * 4: same as 3 plus dump extra junk
 130	 */
 131	if (unlikely(scsi_logging_level)) {
 132		level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
 133				       SCSI_LOG_MLCOMPLETE_BITS);
 134		if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
 135		    (level > 1)) {
 136			scsi_print_result(cmd, "Done", disposition);
 137			scsi_print_command(cmd);
 138			if (scsi_status_is_check_condition(cmd->result))
 139				scsi_print_sense(cmd);
 140			if (level > 3)
 141				scmd_printk(KERN_INFO, cmd,
 142					    "scsi host busy %d failed %d\n",
 143					    scsi_host_busy(cmd->device->host),
 144					    cmd->device->host->host_failed);
 145		}
 146	}
 147}
 148#endif
 149
 150/**
 151 * scsi_finish_command - cleanup and pass command back to upper layer
 152 * @cmd: the command
 153 *
 154 * Description: Pass command off to upper layer for finishing of I/O
 155 *              request, waking processes that are waiting on results,
 156 *              etc.
 157 */
 158void scsi_finish_command(struct scsi_cmnd *cmd)
 159{
 160	struct scsi_device *sdev = cmd->device;
 161	struct scsi_target *starget = scsi_target(sdev);
 162	struct Scsi_Host *shost = sdev->host;
 163	struct scsi_driver *drv;
 164	unsigned int good_bytes;
 165
 166	scsi_device_unbusy(sdev, cmd);
 167
 168	/*
 169	 * Clear the flags that say that the device/target/host is no longer
 170	 * capable of accepting new commands.
 171	 */
 172	if (atomic_read(&shost->host_blocked))
 173		atomic_set(&shost->host_blocked, 0);
 174	if (atomic_read(&starget->target_blocked))
 175		atomic_set(&starget->target_blocked, 0);
 176	if (atomic_read(&sdev->device_blocked))
 177		atomic_set(&sdev->device_blocked, 0);
 178
 179	SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
 180				"Notifying upper driver of completion "
 181				"(result %x)\n", cmd->result));
 182
 183	good_bytes = scsi_bufflen(cmd);
 184	if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
 185		int old_good_bytes = good_bytes;
 186		drv = scsi_cmd_to_driver(cmd);
 187		if (drv->done)
 188			good_bytes = drv->done(cmd);
 189		/*
 190		 * USB may not give sense identifying bad sector and
 191		 * simply return a residue instead, so subtract off the
 192		 * residue if drv->done() error processing indicates no
 193		 * change to the completion length.
 194		 */
 195		if (good_bytes == old_good_bytes)
 196			good_bytes -= scsi_get_resid(cmd);
 197	}
 198	scsi_io_completion(cmd, good_bytes);
 199}
 200
 201
 202/*
 203 * 4096 is big enough for saturating fast SCSI LUNs.
 204 */
 205int scsi_device_max_queue_depth(struct scsi_device *sdev)
 206{
 207	return min_t(int, sdev->host->can_queue, 4096);
 208}
 209
 210/**
 211 * scsi_change_queue_depth - change a device's queue depth
 212 * @sdev: SCSI Device in question
 213 * @depth: number of commands allowed to be queued to the driver
 214 *
 215 * Sets the device queue depth and returns the new value.
 216 */
 217int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
 218{
 219	depth = min_t(int, depth, scsi_device_max_queue_depth(sdev));
 220
 221	if (depth > 0) {
 222		sdev->queue_depth = depth;
 223		wmb();
 224	}
 225
 226	if (sdev->request_queue)
 227		blk_set_queue_depth(sdev->request_queue, depth);
 228
 229	sbitmap_resize(&sdev->budget_map, sdev->queue_depth);
 230
 231	return sdev->queue_depth;
 232}
 233EXPORT_SYMBOL(scsi_change_queue_depth);
 234
 235/**
 236 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
 237 * @sdev: SCSI Device in question
 238 * @depth: Current number of outstanding SCSI commands on this device,
 239 *         not counting the one returned as QUEUE_FULL.
 240 *
 241 * Description:	This function will track successive QUEUE_FULL events on a
 242 * 		specific SCSI device to determine if and when there is a
 243 * 		need to adjust the queue depth on the device.
 244 *
 245 * Returns:	0 - No change needed, >0 - Adjust queue depth to this new depth,
 246 * 		-1 - Drop back to untagged operation using host->cmd_per_lun
 247 * 			as the untagged command depth
 248 *
 249 * Lock Status:	None held on entry
 250 *
 251 * Notes:	Low level drivers may call this at any time and we will do
 252 * 		"The Right Thing."  We are interrupt context safe.
 253 */
 254int scsi_track_queue_full(struct scsi_device *sdev, int depth)
 255{
 256
 257	/*
 258	 * Don't let QUEUE_FULLs on the same
 259	 * jiffies count, they could all be from
 260	 * same event.
 261	 */
 262	if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
 263		return 0;
 264
 265	sdev->last_queue_full_time = jiffies;
 266	if (sdev->last_queue_full_depth != depth) {
 267		sdev->last_queue_full_count = 1;
 268		sdev->last_queue_full_depth = depth;
 269	} else {
 270		sdev->last_queue_full_count++;
 271	}
 272
 273	if (sdev->last_queue_full_count <= 10)
 274		return 0;
 275
 276	return scsi_change_queue_depth(sdev, depth);
 277}
 278EXPORT_SYMBOL(scsi_track_queue_full);
 279
 280/**
 281 * scsi_vpd_inquiry - Request a device provide us with a VPD page
 282 * @sdev: The device to ask
 283 * @buffer: Where to put the result
 284 * @page: Which Vital Product Data to return
 285 * @len: The length of the buffer
 286 *
 287 * This is an internal helper function.  You probably want to use
 288 * scsi_get_vpd_page instead.
 289 *
 290 * Returns size of the vpd page on success or a negative error number.
 291 */
 292static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
 293							u8 page, unsigned len)
 294{
 295	int result;
 296	unsigned char cmd[16];
 297
 298	if (len < 4)
 299		return -EINVAL;
 300
 301	cmd[0] = INQUIRY;
 302	cmd[1] = 1;		/* EVPD */
 303	cmd[2] = page;
 304	cmd[3] = len >> 8;
 305	cmd[4] = len & 0xff;
 306	cmd[5] = 0;		/* Control byte */
 307
 308	/*
 309	 * I'm not convinced we need to try quite this hard to get VPD, but
 310	 * all the existing users tried this hard.
 311	 */
 312	result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, len,
 313				  30 * HZ, 3, NULL);
 314	if (result)
 315		return -EIO;
 316
 317	/*
 318	 * Sanity check that we got the page back that we asked for and that
 319	 * the page size is not 0.
 320	 */
 321	if (buffer[1] != page)
 322		return -EIO;
 323
 324	result = get_unaligned_be16(&buffer[2]);
 325	if (!result)
 326		return -EIO;
 327
 328	return result + 4;
 329}
 330
 331enum scsi_vpd_parameters {
 332	SCSI_VPD_HEADER_SIZE = 4,
 333	SCSI_VPD_LIST_SIZE = 36,
 334};
 335
 336static int scsi_get_vpd_size(struct scsi_device *sdev, u8 page)
 337{
 338	unsigned char vpd[SCSI_VPD_LIST_SIZE] __aligned(4);
 339	int result;
 340
 341	if (sdev->no_vpd_size)
 342		return SCSI_DEFAULT_VPD_LEN;
 343
 344	/*
 345	 * Fetch the supported pages VPD and validate that the requested page
 346	 * number is present.
 347	 */
 348	if (page != 0) {
 349		result = scsi_vpd_inquiry(sdev, vpd, 0, sizeof(vpd));
 350		if (result < SCSI_VPD_HEADER_SIZE)
 351			return 0;
 352
 353		result -= SCSI_VPD_HEADER_SIZE;
 354		if (!memchr(&vpd[SCSI_VPD_HEADER_SIZE], page, result))
 355			return 0;
 356	}
 357	/*
 358	 * Fetch the VPD page header to find out how big the page
 359	 * is. This is done to prevent problems on legacy devices
 360	 * which can not handle allocation lengths as large as
 361	 * potentially requested by the caller.
 362	 */
 363	result = scsi_vpd_inquiry(sdev, vpd, page, SCSI_VPD_HEADER_SIZE);
 364	if (result < 0)
 365		return 0;
 366
 367	if (result < SCSI_VPD_HEADER_SIZE) {
 368		dev_warn_once(&sdev->sdev_gendev,
 369			      "%s: short VPD page 0x%02x length: %d bytes\n",
 370			      __func__, page, result);
 371		return 0;
 372	}
 373
 374	return result;
 375}
 376
 377/**
 378 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
 379 * @sdev: The device to ask
 380 * @page: Which Vital Product Data to return
 381 * @buf: where to store the VPD
 382 * @buf_len: number of bytes in the VPD buffer area
 383 *
 384 * SCSI devices may optionally supply Vital Product Data.  Each 'page'
 385 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
 386 * If the device supports this VPD page, this routine fills @buf
 387 * with the data from that page and return 0. If the VPD page is not
 388 * supported or its content cannot be retrieved, -EINVAL is returned.
 389 */
 390int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
 391		      int buf_len)
 392{
 393	int result, vpd_len;
 394
 395	if (!scsi_device_supports_vpd(sdev))
 396		return -EINVAL;
 397
 398	vpd_len = scsi_get_vpd_size(sdev, page);
 399	if (vpd_len <= 0)
 400		return -EINVAL;
 401
 402	vpd_len = min(vpd_len, buf_len);
 403
 404	/*
 405	 * Fetch the actual page. Since the appropriate size was reported
 406	 * by the device it is now safe to ask for something bigger.
 407	 */
 408	memset(buf, 0, buf_len);
 409	result = scsi_vpd_inquiry(sdev, buf, page, vpd_len);
 410	if (result < 0)
 411		return -EINVAL;
 412	else if (result > vpd_len)
 413		dev_warn_once(&sdev->sdev_gendev,
 414			      "%s: VPD page 0x%02x result %d > %d bytes\n",
 415			      __func__, page, result, vpd_len);
 416
 417	return 0;
 418}
 419EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
 420
 421/**
 422 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
 423 * @sdev: The device to ask
 424 * @page: Which Vital Product Data to return
 425 *
 426 * Returns %NULL upon failure.
 427 */
 428static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
 429{
 430	struct scsi_vpd *vpd_buf;
 431	int vpd_len, result;
 432
 433	vpd_len = scsi_get_vpd_size(sdev, page);
 434	if (vpd_len <= 0)
 435		return NULL;
 436
 437retry_pg:
 438	/*
 439	 * Fetch the actual page. Since the appropriate size was reported
 440	 * by the device it is now safe to ask for something bigger.
 441	 */
 442	vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
 443	if (!vpd_buf)
 444		return NULL;
 445
 446	result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
 447	if (result < 0) {
 448		kfree(vpd_buf);
 449		return NULL;
 450	}
 451	if (result > vpd_len) {
 452		dev_warn_once(&sdev->sdev_gendev,
 453			      "%s: VPD page 0x%02x result %d > %d bytes\n",
 454			      __func__, page, result, vpd_len);
 455		vpd_len = result;
 456		kfree(vpd_buf);
 457		goto retry_pg;
 458	}
 459
 460	vpd_buf->len = result;
 461
 462	return vpd_buf;
 463}
 464
 465static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
 466				 struct scsi_vpd __rcu **sdev_vpd_buf)
 467{
 468	struct scsi_vpd *vpd_buf;
 469
 470	vpd_buf = scsi_get_vpd_buf(sdev, page);
 471	if (!vpd_buf)
 472		return;
 473
 474	mutex_lock(&sdev->inquiry_mutex);
 475	vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf,
 476				      lockdep_is_held(&sdev->inquiry_mutex));
 477	mutex_unlock(&sdev->inquiry_mutex);
 478
 479	if (vpd_buf)
 480		kfree_rcu(vpd_buf, rcu);
 481}
 482
 483/**
 484 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
 485 * @sdev: The device to ask
 486 *
 487 * Attach the 'Device Identification' VPD page (0x83) and the
 488 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
 489 * structure. This information can be used to identify the device
 490 * uniquely.
 491 */
 492void scsi_attach_vpd(struct scsi_device *sdev)
 493{
 494	int i;
 495	struct scsi_vpd *vpd_buf;
 496
 497	if (!scsi_device_supports_vpd(sdev))
 498		return;
 499
 500	/* Ask for all the pages supported by this device */
 501	vpd_buf = scsi_get_vpd_buf(sdev, 0);
 502	if (!vpd_buf)
 503		return;
 504
 505	for (i = 4; i < vpd_buf->len; i++) {
 506		if (vpd_buf->data[i] == 0x0)
 507			scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0);
 508		if (vpd_buf->data[i] == 0x80)
 509			scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
 510		if (vpd_buf->data[i] == 0x83)
 511			scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
 512		if (vpd_buf->data[i] == 0x89)
 513			scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89);
 514		if (vpd_buf->data[i] == 0xb0)
 515			scsi_update_vpd_page(sdev, 0xb0, &sdev->vpd_pgb0);
 516		if (vpd_buf->data[i] == 0xb1)
 517			scsi_update_vpd_page(sdev, 0xb1, &sdev->vpd_pgb1);
 518		if (vpd_buf->data[i] == 0xb2)
 519			scsi_update_vpd_page(sdev, 0xb2, &sdev->vpd_pgb2);
 520	}
 521	kfree(vpd_buf);
 522}
 523
 524/**
 525 * scsi_report_opcode - Find out if a given command is supported
 526 * @sdev:	scsi device to query
 527 * @buffer:	scratch buffer (must be at least 20 bytes long)
 528 * @len:	length of buffer
 529 * @opcode:	opcode for the command to look up
 530 * @sa:		service action for the command to look up
 531 *
 532 * Uses the REPORT SUPPORTED OPERATION CODES to check support for the
 533 * command identified with @opcode and @sa. If the command does not
 534 * have a service action, @sa must be 0. Returns -EINVAL if RSOC fails,
 535 * 0 if the command is not supported and 1 if the device claims to
 536 * support the command.
 537 */
 538int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
 539		       unsigned int len, unsigned char opcode,
 540		       unsigned short sa)
 541{
 542	unsigned char cmd[16];
 543	struct scsi_sense_hdr sshdr;
 544	int result, request_len;
 545	const struct scsi_exec_args exec_args = {
 546		.sshdr = &sshdr,
 547	};
 548
 549	if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
 550		return -EINVAL;
 551
 552	/* RSOC header + size of command we are asking about */
 553	request_len = 4 + COMMAND_SIZE(opcode);
 554	if (request_len > len) {
 555		dev_warn_once(&sdev->sdev_gendev,
 556			      "%s: len %u bytes, opcode 0x%02x needs %u\n",
 557			      __func__, len, opcode, request_len);
 558		return -EINVAL;
 559	}
 560
 561	memset(cmd, 0, 16);
 562	cmd[0] = MAINTENANCE_IN;
 563	cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
 564	if (!sa) {
 565		cmd[2] = 1;	/* One command format */
 566		cmd[3] = opcode;
 567	} else {
 568		cmd[2] = 3;	/* One command format with service action */
 569		cmd[3] = opcode;
 570		put_unaligned_be16(sa, &cmd[4]);
 571	}
 572	put_unaligned_be32(request_len, &cmd[6]);
 573	memset(buffer, 0, len);
 574
 575	result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer,
 576				  request_len, 30 * HZ, 3, &exec_args);
 
 577	if (result < 0)
 578		return result;
 579	if (result && scsi_sense_valid(&sshdr) &&
 580	    sshdr.sense_key == ILLEGAL_REQUEST &&
 581	    (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
 582		return -EINVAL;
 583
 584	if ((buffer[1] & 3) == 3) /* Command supported */
 585		return 1;
 586
 587	return 0;
 588}
 589EXPORT_SYMBOL(scsi_report_opcode);
 590
 591#define SCSI_CDL_CHECK_BUF_LEN	64
 592
 593static bool scsi_cdl_check_cmd(struct scsi_device *sdev, u8 opcode, u16 sa,
 594			       unsigned char *buf)
 595{
 596	int ret;
 597	u8 cdlp;
 598
 599	/* Check operation code */
 600	ret = scsi_report_opcode(sdev, buf, SCSI_CDL_CHECK_BUF_LEN, opcode, sa);
 601	if (ret <= 0)
 602		return false;
 603
 604	if ((buf[1] & 0x03) != 0x03)
 605		return false;
 606
 607	/*
 608	 * See SPC-6, One_command parameter data format for
 609	 * REPORT SUPPORTED OPERATION CODES. We have the following cases
 610	 * depending on rwcdlp (buf[0] & 0x01) value:
 611	 *  - rwcdlp == 0: then cdlp indicates support for the A mode page when
 612	 *		   it is equal to 1 and for the B mode page when it is
 613	 *		   equal to 2.
 614	 *  - rwcdlp == 1: then cdlp indicates support for the T2A mode page
 615	 *		   when it is equal to 1 and for the T2B mode page when
 616	 *		   it is equal to 2.
 617	 * Overall, to detect support for command duration limits, we only need
 618	 * to check that cdlp is 1 or 2.
 619	 */
 620	cdlp = (buf[1] & 0x18) >> 3;
 621
 622	return cdlp == 0x01 || cdlp == 0x02;
 623}
 624
 625/**
 626 * scsi_cdl_check - Check if a SCSI device supports Command Duration Limits
 627 * @sdev: The device to check
 628 */
 629void scsi_cdl_check(struct scsi_device *sdev)
 630{
 631	bool cdl_supported;
 632	unsigned char *buf;
 633
 634	/*
 635	 * Support for CDL was defined in SPC-5. Ignore devices reporting an
 636	 * lower SPC version. This also avoids problems with old drives choking
 637	 * on MAINTENANCE_IN / MI_REPORT_SUPPORTED_OPERATION_CODES with a
 638	 * service action specified, as done in scsi_cdl_check_cmd().
 639	 */
 640	if (sdev->scsi_level < SCSI_SPC_5) {
 641		sdev->cdl_supported = 0;
 642		return;
 643	}
 644
 645	buf = kmalloc(SCSI_CDL_CHECK_BUF_LEN, GFP_KERNEL);
 646	if (!buf) {
 647		sdev->cdl_supported = 0;
 648		return;
 649	}
 650
 651	/* Check support for READ_16, WRITE_16, READ_32 and WRITE_32 commands */
 652	cdl_supported =
 653		scsi_cdl_check_cmd(sdev, READ_16, 0, buf) ||
 654		scsi_cdl_check_cmd(sdev, WRITE_16, 0, buf) ||
 655		scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, READ_32, buf) ||
 656		scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, WRITE_32, buf);
 657	if (cdl_supported) {
 658		/*
 659		 * We have CDL support: force the use of READ16/WRITE16.
 660		 * READ32 and WRITE32 will be used for devices that support
 661		 * the T10_PI_TYPE2_PROTECTION protection type.
 662		 */
 663		sdev->use_16_for_rw = 1;
 664		sdev->use_10_for_rw = 0;
 665
 666		sdev->cdl_supported = 1;
 667	} else {
 668		sdev->cdl_supported = 0;
 669	}
 670
 671	kfree(buf);
 672}
 673
 674/**
 675 * scsi_cdl_enable - Enable or disable a SCSI device supports for Command
 676 *                   Duration Limits
 677 * @sdev: The target device
 678 * @enable: the target state
 679 */
 680int scsi_cdl_enable(struct scsi_device *sdev, bool enable)
 681{
 682	struct scsi_mode_data data;
 683	struct scsi_sense_hdr sshdr;
 684	struct scsi_vpd *vpd;
 685	bool is_ata = false;
 686	char buf[64];
 687	int ret;
 688
 689	if (!sdev->cdl_supported)
 690		return -EOPNOTSUPP;
 691
 692	rcu_read_lock();
 693	vpd = rcu_dereference(sdev->vpd_pg89);
 694	if (vpd)
 695		is_ata = true;
 696	rcu_read_unlock();
 697
 698	/*
 699	 * For ATA devices, CDL needs to be enabled with a SET FEATURES command.
 700	 */
 701	if (is_ata) {
 702		char *buf_data;
 703		int len;
 704
 705		ret = scsi_mode_sense(sdev, 0x08, 0x0a, 0xf2, buf, sizeof(buf),
 706				      5 * HZ, 3, &data, NULL);
 707		if (ret)
 708			return -EINVAL;
 709
 710		/* Enable CDL using the ATA feature page */
 711		len = min_t(size_t, sizeof(buf),
 712			    data.length - data.header_length -
 713			    data.block_descriptor_length);
 714		buf_data = buf + data.header_length +
 715			data.block_descriptor_length;
 716		if (enable)
 717			buf_data[4] = 0x02;
 718		else
 719			buf_data[4] = 0;
 720
 721		ret = scsi_mode_select(sdev, 1, 0, buf_data, len, 5 * HZ, 3,
 722				       &data, &sshdr);
 723		if (ret) {
 724			if (ret > 0 && scsi_sense_valid(&sshdr))
 725				scsi_print_sense_hdr(sdev,
 726					dev_name(&sdev->sdev_gendev), &sshdr);
 727			return ret;
 728		}
 729	}
 730
 731	sdev->cdl_enable = enable;
 732
 733	return 0;
 734}
 735
 736/**
 737 * scsi_device_get  -  get an additional reference to a scsi_device
 738 * @sdev:	device to get a reference to
 739 *
 740 * Description: Gets a reference to the scsi_device and increments the use count
 741 * of the underlying LLDD module.  You must hold host_lock of the
 742 * parent Scsi_Host or already have a reference when calling this.
 743 *
 744 * This will fail if a device is deleted or cancelled, or when the LLD module
 745 * is in the process of being unloaded.
 746 */
 747int scsi_device_get(struct scsi_device *sdev)
 748{
 749	if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
 750		goto fail;
 751	if (!try_module_get(sdev->host->hostt->module))
 752		goto fail;
 753	if (!get_device(&sdev->sdev_gendev))
 754		goto fail_put_module;
 755	return 0;
 756
 757fail_put_module:
 758	module_put(sdev->host->hostt->module);
 759fail:
 760	return -ENXIO;
 761}
 762EXPORT_SYMBOL(scsi_device_get);
 763
 764/**
 765 * scsi_device_put  -  release a reference to a scsi_device
 766 * @sdev:	device to release a reference on.
 767 *
 768 * Description: Release a reference to the scsi_device and decrements the use
 769 * count of the underlying LLDD module.  The device is freed once the last
 770 * user vanishes.
 771 */
 772void scsi_device_put(struct scsi_device *sdev)
 773{
 774	struct module *mod = sdev->host->hostt->module;
 775
 776	put_device(&sdev->sdev_gendev);
 777	module_put(mod);
 778}
 779EXPORT_SYMBOL(scsi_device_put);
 780
 781/* helper for shost_for_each_device, see that for documentation */
 782struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
 783					   struct scsi_device *prev)
 784{
 785	struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
 786	struct scsi_device *next = NULL;
 787	unsigned long flags;
 788
 789	spin_lock_irqsave(shost->host_lock, flags);
 790	while (list->next != &shost->__devices) {
 791		next = list_entry(list->next, struct scsi_device, siblings);
 792		/* skip devices that we can't get a reference to */
 793		if (!scsi_device_get(next))
 794			break;
 795		next = NULL;
 796		list = list->next;
 797	}
 798	spin_unlock_irqrestore(shost->host_lock, flags);
 799
 800	if (prev)
 801		scsi_device_put(prev);
 802	return next;
 803}
 804EXPORT_SYMBOL(__scsi_iterate_devices);
 805
 806/**
 807 * starget_for_each_device  -  helper to walk all devices of a target
 808 * @starget:	target whose devices we want to iterate over.
 809 * @data:	Opaque passed to each function call.
 810 * @fn:		Function to call on each device
 811 *
 812 * This traverses over each device of @starget.  The devices have
 813 * a reference that must be released by scsi_host_put when breaking
 814 * out of the loop.
 815 */
 816void starget_for_each_device(struct scsi_target *starget, void *data,
 817		     void (*fn)(struct scsi_device *, void *))
 818{
 819	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
 820	struct scsi_device *sdev;
 821
 822	shost_for_each_device(sdev, shost) {
 823		if ((sdev->channel == starget->channel) &&
 824		    (sdev->id == starget->id))
 825			fn(sdev, data);
 826	}
 827}
 828EXPORT_SYMBOL(starget_for_each_device);
 829
 830/**
 831 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
 832 * @starget:	target whose devices we want to iterate over.
 833 * @data:	parameter for callback @fn()
 834 * @fn:		callback function that is invoked for each device
 835 *
 836 * This traverses over each device of @starget.  It does _not_
 837 * take a reference on the scsi_device, so the whole loop must be
 838 * protected by shost->host_lock.
 839 *
 840 * Note:  The only reason why drivers would want to use this is because
 841 * they need to access the device list in irq context.  Otherwise you
 842 * really want to use starget_for_each_device instead.
 843 **/
 844void __starget_for_each_device(struct scsi_target *starget, void *data,
 845			       void (*fn)(struct scsi_device *, void *))
 846{
 847	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
 848	struct scsi_device *sdev;
 849
 850	__shost_for_each_device(sdev, shost) {
 851		if ((sdev->channel == starget->channel) &&
 852		    (sdev->id == starget->id))
 853			fn(sdev, data);
 854	}
 855}
 856EXPORT_SYMBOL(__starget_for_each_device);
 857
 858/**
 859 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
 860 * @starget:	SCSI target pointer
 861 * @lun:	SCSI Logical Unit Number
 862 *
 863 * Description: Looks up the scsi_device with the specified @lun for a given
 864 * @starget.  The returned scsi_device does not have an additional
 865 * reference.  You must hold the host's host_lock over this call and
 866 * any access to the returned scsi_device. A scsi_device in state
 867 * SDEV_DEL is skipped.
 868 *
 869 * Note:  The only reason why drivers should use this is because
 870 * they need to access the device list in irq context.  Otherwise you
 871 * really want to use scsi_device_lookup_by_target instead.
 872 **/
 873struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
 874						   u64 lun)
 875{
 876	struct scsi_device *sdev;
 877
 878	list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
 879		if (sdev->sdev_state == SDEV_DEL)
 880			continue;
 881		if (sdev->lun ==lun)
 882			return sdev;
 883	}
 884
 885	return NULL;
 886}
 887EXPORT_SYMBOL(__scsi_device_lookup_by_target);
 888
 889/**
 890 * scsi_device_lookup_by_target - find a device given the target
 891 * @starget:	SCSI target pointer
 892 * @lun:	SCSI Logical Unit Number
 893 *
 894 * Description: Looks up the scsi_device with the specified @lun for a given
 895 * @starget.  The returned scsi_device has an additional reference that
 896 * needs to be released with scsi_device_put once you're done with it.
 897 **/
 898struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
 899						 u64 lun)
 900{
 901	struct scsi_device *sdev;
 902	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
 903	unsigned long flags;
 904
 905	spin_lock_irqsave(shost->host_lock, flags);
 906	sdev = __scsi_device_lookup_by_target(starget, lun);
 907	if (sdev && scsi_device_get(sdev))
 908		sdev = NULL;
 909	spin_unlock_irqrestore(shost->host_lock, flags);
 910
 911	return sdev;
 912}
 913EXPORT_SYMBOL(scsi_device_lookup_by_target);
 914
 915/**
 916 * __scsi_device_lookup - find a device given the host (UNLOCKED)
 917 * @shost:	SCSI host pointer
 918 * @channel:	SCSI channel (zero if only one channel)
 919 * @id:		SCSI target number (physical unit number)
 920 * @lun:	SCSI Logical Unit Number
 921 *
 922 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
 923 * for a given host. The returned scsi_device does not have an additional
 924 * reference.  You must hold the host's host_lock over this call and any access
 925 * to the returned scsi_device.
 926 *
 927 * Note:  The only reason why drivers would want to use this is because
 928 * they need to access the device list in irq context.  Otherwise you
 929 * really want to use scsi_device_lookup instead.
 930 **/
 931struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
 932		uint channel, uint id, u64 lun)
 933{
 934	struct scsi_device *sdev;
 935
 936	list_for_each_entry(sdev, &shost->__devices, siblings) {
 937		if (sdev->sdev_state == SDEV_DEL)
 938			continue;
 939		if (sdev->channel == channel && sdev->id == id &&
 940				sdev->lun ==lun)
 941			return sdev;
 942	}
 943
 944	return NULL;
 945}
 946EXPORT_SYMBOL(__scsi_device_lookup);
 947
 948/**
 949 * scsi_device_lookup - find a device given the host
 950 * @shost:	SCSI host pointer
 951 * @channel:	SCSI channel (zero if only one channel)
 952 * @id:		SCSI target number (physical unit number)
 953 * @lun:	SCSI Logical Unit Number
 954 *
 955 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
 956 * for a given host.  The returned scsi_device has an additional reference that
 957 * needs to be released with scsi_device_put once you're done with it.
 958 **/
 959struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
 960		uint channel, uint id, u64 lun)
 961{
 962	struct scsi_device *sdev;
 963	unsigned long flags;
 964
 965	spin_lock_irqsave(shost->host_lock, flags);
 966	sdev = __scsi_device_lookup(shost, channel, id, lun);
 967	if (sdev && scsi_device_get(sdev))
 968		sdev = NULL;
 969	spin_unlock_irqrestore(shost->host_lock, flags);
 970
 971	return sdev;
 972}
 973EXPORT_SYMBOL(scsi_device_lookup);
 974
 975MODULE_DESCRIPTION("SCSI core");
 976MODULE_LICENSE("GPL");
 977
 978module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
 979MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
 980
 981static int __init init_scsi(void)
 982{
 983	int error;
 984
 985	error = scsi_init_procfs();
 986	if (error)
 987		goto cleanup_queue;
 988	error = scsi_init_devinfo();
 989	if (error)
 990		goto cleanup_procfs;
 991	error = scsi_init_hosts();
 992	if (error)
 993		goto cleanup_devlist;
 994	error = scsi_init_sysctl();
 995	if (error)
 996		goto cleanup_hosts;
 997	error = scsi_sysfs_register();
 998	if (error)
 999		goto cleanup_sysctl;
1000
1001	scsi_netlink_init();
1002
1003	printk(KERN_NOTICE "SCSI subsystem initialized\n");
1004	return 0;
1005
1006cleanup_sysctl:
1007	scsi_exit_sysctl();
1008cleanup_hosts:
1009	scsi_exit_hosts();
1010cleanup_devlist:
1011	scsi_exit_devinfo();
1012cleanup_procfs:
1013	scsi_exit_procfs();
1014cleanup_queue:
1015	scsi_exit_queue();
1016	printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1017	       -error);
1018	return error;
1019}
1020
1021static void __exit exit_scsi(void)
1022{
1023	scsi_netlink_exit();
1024	scsi_sysfs_unregister();
1025	scsi_exit_sysctl();
1026	scsi_exit_hosts();
1027	scsi_exit_devinfo();
1028	scsi_exit_procfs();
1029	scsi_exit_queue();
1030}
1031
1032subsys_initcall(init_scsi);
1033module_exit(exit_scsi);