1/*
   2 * Linux driver for System z and s390 unit record devices
   3 * (z/VM virtual punch, reader, printer)
   4 *
   5 * Copyright IBM Corp. 2001, 2009
   6 * Authors: Malcolm Beattie <beattiem@uk.ibm.com>
   7 *	    Michael Holzheu <holzheu@de.ibm.com>
   8 *	    Frank Munzert <munzert@de.ibm.com>
   9 */
  10
  11#define KMSG_COMPONENT "vmur"
  12#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  13
  14#include <linux/kernel_stat.h>
  15#include <linux/cdev.h>
  16#include <linux/slab.h>
 
  17
  18#include <asm/uaccess.h>
  19#include <asm/cio.h>
  20#include <asm/ccwdev.h>
  21#include <asm/debug.h>
  22#include <asm/diag.h>
  23
  24#include "vmur.h"
  25
  26/*
  27 * Driver overview
  28 *
  29 * Unit record device support is implemented as a character device driver.
  30 * We can fit at least 16 bits into a device minor number and use the
  31 * simple method of mapping a character device number with minor abcd
  32 * to the unit record device with devno abcd.
  33 * I/O to virtual unit record devices is handled as follows:
  34 * Reads: Diagnose code 0x14 (input spool file manipulation)
  35 * is used to read spool data page-wise.
  36 * Writes: The CCW used is WRITE_CCW_CMD (0x01). The device's record length
  37 * is available by reading sysfs attr reclen. Each write() to the device
  38 * must specify an integral multiple (maximal 511) of reclen.
  39 */
  40
  41static char ur_banner[] = "z/VM virtual unit record device driver";
  42
  43MODULE_AUTHOR("IBM Corporation");
  44MODULE_DESCRIPTION("s390 z/VM virtual unit record device driver");
  45MODULE_LICENSE("GPL");
  46
  47static dev_t ur_first_dev_maj_min;
  48static struct class *vmur_class;
  49static struct debug_info *vmur_dbf;
  50
  51/* We put the device's record length (for writes) in the driver_info field */
  52static struct ccw_device_id ur_ids[] = {
  53	{ CCWDEV_CU_DI(READER_PUNCH_DEVTYPE, 80) },
  54	{ CCWDEV_CU_DI(PRINTER_DEVTYPE, 132) },
  55	{ /* end of list */ }
  56};
  57
  58MODULE_DEVICE_TABLE(ccw, ur_ids);
  59
  60static int ur_probe(struct ccw_device *cdev);
  61static void ur_remove(struct ccw_device *cdev);
  62static int ur_set_online(struct ccw_device *cdev);
  63static int ur_set_offline(struct ccw_device *cdev);
  64static int ur_pm_suspend(struct ccw_device *cdev);
  65
  66static struct ccw_driver ur_driver = {
  67	.driver = {
  68		.name	= "vmur",
  69		.owner	= THIS_MODULE,
  70	},
  71	.ids		= ur_ids,
  72	.probe		= ur_probe,
  73	.remove		= ur_remove,
  74	.set_online	= ur_set_online,
  75	.set_offline	= ur_set_offline,
  76	.freeze		= ur_pm_suspend,
 
  77};
  78
  79static DEFINE_MUTEX(vmur_mutex);
  80
  81/*
  82 * Allocation, freeing, getting and putting of urdev structures
  83 *
  84 * Each ur device (urd) contains a reference to its corresponding ccw device
  85 * (cdev) using the urd->cdev pointer. Each ccw device has a reference to the
  86 * ur device using dev_get_drvdata(&cdev->dev) pointer.
  87 *
  88 * urd references:
  89 * - ur_probe gets a urd reference, ur_remove drops the reference
  90 *   dev_get_drvdata(&cdev->dev)
  91 * - ur_open gets a urd reference, ur_relase drops the reference
  92 *   (urf->urd)
  93 *
  94 * cdev references:
  95 * - urdev_alloc get a cdev reference (urd->cdev)
  96 * - urdev_free drops the cdev reference (urd->cdev)
  97 *
  98 * Setting and clearing of dev_get_drvdata(&cdev->dev) is protected by the ccwdev lock
  99 */
 100static struct urdev *urdev_alloc(struct ccw_device *cdev)
 101{
 102	struct urdev *urd;
 103
 104	urd = kzalloc(sizeof(struct urdev), GFP_KERNEL);
 105	if (!urd)
 106		return NULL;
 107	urd->reclen = cdev->id.driver_info;
 108	ccw_device_get_id(cdev, &urd->dev_id);
 109	mutex_init(&urd->io_mutex);
 110	init_waitqueue_head(&urd->wait);
 111	spin_lock_init(&urd->open_lock);
 112	atomic_set(&urd->ref_count,  1);
 113	urd->cdev = cdev;
 114	get_device(&cdev->dev);
 115	return urd;
 116}
 117
 118static void urdev_free(struct urdev *urd)
 119{
 120	TRACE("urdev_free: %p\n", urd);
 121	if (urd->cdev)
 122		put_device(&urd->cdev->dev);
 123	kfree(urd);
 124}
 125
 126static void urdev_get(struct urdev *urd)
 127{
 128	atomic_inc(&urd->ref_count);
 129}
 130
 131static struct urdev *urdev_get_from_cdev(struct ccw_device *cdev)
 132{
 133	struct urdev *urd;
 134	unsigned long flags;
 135
 136	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
 137	urd = dev_get_drvdata(&cdev->dev);
 138	if (urd)
 139		urdev_get(urd);
 140	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
 141	return urd;
 142}
 143
 144static struct urdev *urdev_get_from_devno(u16 devno)
 145{
 146	char bus_id[16];
 147	struct ccw_device *cdev;
 148	struct urdev *urd;
 149
 150	sprintf(bus_id, "0.0.%04x", devno);
 151	cdev = get_ccwdev_by_busid(&ur_driver, bus_id);
 152	if (!cdev)
 153		return NULL;
 154	urd = urdev_get_from_cdev(cdev);
 155	put_device(&cdev->dev);
 156	return urd;
 157}
 158
 159static void urdev_put(struct urdev *urd)
 160{
 161	if (atomic_dec_and_test(&urd->ref_count))
 162		urdev_free(urd);
 163}
 164
 165/*
 166 * State and contents of ur devices can be changed by class D users issuing
 167 * CP commands such as PURGE or TRANSFER, while the Linux guest is suspended.
 168 * Also the Linux guest might be logged off, which causes all active spool
 169 * files to be closed.
 170 * So we cannot guarantee that spool files are still the same when the Linux
 171 * guest is resumed. In order to avoid unpredictable results at resume time
 172 * we simply refuse to suspend if a ur device node is open.
 173 */
 174static int ur_pm_suspend(struct ccw_device *cdev)
 175{
 176	struct urdev *urd = dev_get_drvdata(&cdev->dev);
 177
 178	TRACE("ur_pm_suspend: cdev=%p\n", cdev);
 179	if (urd->open_flag) {
 180		pr_err("Unit record device %s is busy, %s refusing to "
 181		       "suspend.\n", dev_name(&cdev->dev), ur_banner);
 182		return -EBUSY;
 183	}
 184	return 0;
 185}
 186
 187/*
 188 * Low-level functions to do I/O to a ur device.
 189 *     alloc_chan_prog
 190 *     free_chan_prog
 191 *     do_ur_io
 192 *     ur_int_handler
 193 *
 194 * alloc_chan_prog allocates and builds the channel program
 195 * free_chan_prog frees memory of the channel program
 196 *
 197 * do_ur_io issues the channel program to the device and blocks waiting
 198 * on a completion event it publishes at urd->io_done. The function
 199 * serialises itself on the device's mutex so that only one I/O
 200 * is issued at a time (and that I/O is synchronous).
 201 *
 202 * ur_int_handler catches the "I/O done" interrupt, writes the
 203 * subchannel status word into the scsw member of the urdev structure
 204 * and complete()s the io_done to wake the waiting do_ur_io.
 205 *
 206 * The caller of do_ur_io is responsible for kfree()ing the channel program
 207 * address pointer that alloc_chan_prog returned.
 208 */
 209
 210static void free_chan_prog(struct ccw1 *cpa)
 211{
 212	struct ccw1 *ptr = cpa;
 213
 214	while (ptr->cda) {
 215		kfree((void *)(addr_t) ptr->cda);
 216		ptr++;
 217	}
 218	kfree(cpa);
 219}
 220
 221/*
 222 * alloc_chan_prog
 223 * The channel program we use is write commands chained together
 224 * with a final NOP CCW command-chained on (which ensures that CE and DE
 225 * are presented together in a single interrupt instead of as separate
 226 * interrupts unless an incorrect length indication kicks in first). The
 227 * data length in each CCW is reclen.
 228 */
 229static struct ccw1 *alloc_chan_prog(const char __user *ubuf, int rec_count,
 230				    int reclen)
 231{
 232	struct ccw1 *cpa;
 233	void *kbuf;
 234	int i;
 235
 236	TRACE("alloc_chan_prog(%p, %i, %i)\n", ubuf, rec_count, reclen);
 237
 238	/*
 239	 * We chain a NOP onto the writes to force CE+DE together.
 240	 * That means we allocate room for CCWs to cover count/reclen
 241	 * records plus a NOP.
 242	 */
 243	cpa = kzalloc((rec_count + 1) * sizeof(struct ccw1),
 244		      GFP_KERNEL | GFP_DMA);
 245	if (!cpa)
 246		return ERR_PTR(-ENOMEM);
 247
 248	for (i = 0; i < rec_count; i++) {
 249		cpa[i].cmd_code = WRITE_CCW_CMD;
 250		cpa[i].flags = CCW_FLAG_CC | CCW_FLAG_SLI;
 251		cpa[i].count = reclen;
 252		kbuf = kmalloc(reclen, GFP_KERNEL | GFP_DMA);
 253		if (!kbuf) {
 254			free_chan_prog(cpa);
 255			return ERR_PTR(-ENOMEM);
 256		}
 257		cpa[i].cda = (u32)(addr_t) kbuf;
 258		if (copy_from_user(kbuf, ubuf, reclen)) {
 259			free_chan_prog(cpa);
 260			return ERR_PTR(-EFAULT);
 261		}
 262		ubuf += reclen;
 263	}
 264	/* The following NOP CCW forces CE+DE to be presented together */
 265	cpa[i].cmd_code = CCW_CMD_NOOP;
 266	return cpa;
 267}
 268
 269static int do_ur_io(struct urdev *urd, struct ccw1 *cpa)
 270{
 271	int rc;
 272	struct ccw_device *cdev = urd->cdev;
 273	DECLARE_COMPLETION_ONSTACK(event);
 274
 275	TRACE("do_ur_io: cpa=%p\n", cpa);
 276
 277	rc = mutex_lock_interruptible(&urd->io_mutex);
 278	if (rc)
 279		return rc;
 280
 281	urd->io_done = &event;
 282
 283	spin_lock_irq(get_ccwdev_lock(cdev));
 284	rc = ccw_device_start(cdev, cpa, 1, 0, 0);
 285	spin_unlock_irq(get_ccwdev_lock(cdev));
 286
 287	TRACE("do_ur_io: ccw_device_start returned %d\n", rc);
 288	if (rc)
 289		goto out;
 290
 291	wait_for_completion(&event);
 292	TRACE("do_ur_io: I/O complete\n");
 293	rc = 0;
 294
 295out:
 296	mutex_unlock(&urd->io_mutex);
 297	return rc;
 298}
 299
 300/*
 301 * ur interrupt handler, called from the ccw_device layer
 302 */
 303static void ur_int_handler(struct ccw_device *cdev, unsigned long intparm,
 304			   struct irb *irb)
 305{
 306	struct urdev *urd;
 307
 308	kstat_cpu(smp_processor_id()).irqs[IOINT_VMR]++;
 309	TRACE("ur_int_handler: intparm=0x%lx cstat=%02x dstat=%02x res=%u\n",
 310	      intparm, irb->scsw.cmd.cstat, irb->scsw.cmd.dstat,
 311	      irb->scsw.cmd.count);
 312
 313	if (!intparm) {
 314		TRACE("ur_int_handler: unsolicited interrupt\n");
 315		return;
 316	}
 317	urd = dev_get_drvdata(&cdev->dev);
 318	BUG_ON(!urd);
 319	/* On special conditions irb is an error pointer */
 320	if (IS_ERR(irb))
 321		urd->io_request_rc = PTR_ERR(irb);
 322	else if (irb->scsw.cmd.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END))
 323		urd->io_request_rc = 0;
 324	else
 325		urd->io_request_rc = -EIO;
 326
 327	complete(urd->io_done);
 328}
 329
 330/*
 331 * reclen sysfs attribute - The record length to be used for write CCWs
 332 */
 333static ssize_t ur_attr_reclen_show(struct device *dev,
 334				   struct device_attribute *attr, char *buf)
 335{
 336	struct urdev *urd;
 337	int rc;
 338
 339	urd = urdev_get_from_cdev(to_ccwdev(dev));
 340	if (!urd)
 341		return -ENODEV;
 342	rc = sprintf(buf, "%zu\n", urd->reclen);
 343	urdev_put(urd);
 344	return rc;
 345}
 346
 347static DEVICE_ATTR(reclen, 0444, ur_attr_reclen_show, NULL);
 348
 349static int ur_create_attributes(struct device *dev)
 350{
 351	return device_create_file(dev, &dev_attr_reclen);
 352}
 353
 354static void ur_remove_attributes(struct device *dev)
 355{
 356	device_remove_file(dev, &dev_attr_reclen);
 357}
 358
 359/*
 360 * diagnose code 0x210 - retrieve device information
 361 * cc=0  normal completion, we have a real device
 362 * cc=1  CP paging error
 363 * cc=2  The virtual device exists, but is not associated with a real device
 364 * cc=3  Invalid device address, or the virtual device does not exist
 365 */
 366static int get_urd_class(struct urdev *urd)
 367{
 368	static struct diag210 ur_diag210;
 369	int cc;
 370
 371	ur_diag210.vrdcdvno = urd->dev_id.devno;
 372	ur_diag210.vrdclen = sizeof(struct diag210);
 373
 374	cc = diag210(&ur_diag210);
 375	switch (cc) {
 376	case 0:
 377		return -EOPNOTSUPP;
 378	case 2:
 379		return ur_diag210.vrdcvcla; /* virtual device class */
 380	case 3:
 381		return -ENODEV;
 382	default:
 383		return -EIO;
 384	}
 385}
 386
 387/*
 388 * Allocation and freeing of urfile structures
 389 */
 390static struct urfile *urfile_alloc(struct urdev *urd)
 391{
 392	struct urfile *urf;
 393
 394	urf = kzalloc(sizeof(struct urfile), GFP_KERNEL);
 395	if (!urf)
 396		return NULL;
 397	urf->urd = urd;
 398
 399	TRACE("urfile_alloc: urd=%p urf=%p rl=%zu\n", urd, urf,
 400	      urf->dev_reclen);
 401
 402	return urf;
 403}
 404
 405static void urfile_free(struct urfile *urf)
 406{
 407	TRACE("urfile_free: urf=%p urd=%p\n", urf, urf->urd);
 408	kfree(urf);
 409}
 410
 411/*
 412 * The fops implementation of the character device driver
 413 */
 414static ssize_t do_write(struct urdev *urd, const char __user *udata,
 415			size_t count, size_t reclen, loff_t *ppos)
 416{
 417	struct ccw1 *cpa;
 418	int rc;
 419
 420	cpa = alloc_chan_prog(udata, count / reclen, reclen);
 421	if (IS_ERR(cpa))
 422		return PTR_ERR(cpa);
 423
 424	rc = do_ur_io(urd, cpa);
 425	if (rc)
 426		goto fail_kfree_cpa;
 427
 428	if (urd->io_request_rc) {
 429		rc = urd->io_request_rc;
 430		goto fail_kfree_cpa;
 431	}
 432	*ppos += count;
 433	rc = count;
 434
 435fail_kfree_cpa:
 436	free_chan_prog(cpa);
 437	return rc;
 438}
 439
 440static ssize_t ur_write(struct file *file, const char __user *udata,
 441			size_t count, loff_t *ppos)
 442{
 443	struct urfile *urf = file->private_data;
 444
 445	TRACE("ur_write: count=%zu\n", count);
 446
 447	if (count == 0)
 448		return 0;
 449
 450	if (count % urf->dev_reclen)
 451		return -EINVAL;	/* count must be a multiple of reclen */
 452
 453	if (count > urf->dev_reclen * MAX_RECS_PER_IO)
 454		count = urf->dev_reclen * MAX_RECS_PER_IO;
 455
 456	return do_write(urf->urd, udata, count, urf->dev_reclen, ppos);
 457}
 458
 459/*
 460 * diagnose code 0x14 subcode 0x0028 - position spool file to designated
 461 *				       record
 462 * cc=0  normal completion
 463 * cc=2  no file active on the virtual reader or device not ready
 464 * cc=3  record specified is beyond EOF
 465 */
 466static int diag_position_to_record(int devno, int record)
 467{
 468	int cc;
 469
 470	cc = diag14(record, devno, 0x28);
 471	switch (cc) {
 472	case 0:
 473		return 0;
 474	case 2:
 475		return -ENOMEDIUM;
 476	case 3:
 477		return -ENODATA; /* position beyond end of file */
 478	default:
 479		return -EIO;
 480	}
 481}
 482
 483/*
 484 * diagnose code 0x14 subcode 0x0000 - read next spool file buffer
 485 * cc=0  normal completion
 486 * cc=1  EOF reached
 487 * cc=2  no file active on the virtual reader, and no file eligible
 488 * cc=3  file already active on the virtual reader or specified virtual
 489 *	 reader does not exist or is not a reader
 490 */
 491static int diag_read_file(int devno, char *buf)
 492{
 493	int cc;
 494
 495	cc = diag14((unsigned long) buf, devno, 0x00);
 496	switch (cc) {
 497	case 0:
 498		return 0;
 499	case 1:
 500		return -ENODATA;
 501	case 2:
 502		return -ENOMEDIUM;
 503	default:
 504		return -EIO;
 505	}
 506}
 507
 508static ssize_t diag14_read(struct file *file, char __user *ubuf, size_t count,
 509			   loff_t *offs)
 510{
 511	size_t len, copied, res;
 512	char *buf;
 513	int rc;
 514	u16 reclen;
 515	struct urdev *urd;
 516
 517	urd = ((struct urfile *) file->private_data)->urd;
 518	reclen = ((struct urfile *) file->private_data)->file_reclen;
 519
 520	rc = diag_position_to_record(urd->dev_id.devno, *offs / PAGE_SIZE + 1);
 521	if (rc == -ENODATA)
 522		return 0;
 523	if (rc)
 524		return rc;
 525
 526	len = min((size_t) PAGE_SIZE, count);
 527	buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
 528	if (!buf)
 529		return -ENOMEM;
 530
 531	copied = 0;
 532	res = (size_t) (*offs % PAGE_SIZE);
 533	do {
 534		rc = diag_read_file(urd->dev_id.devno, buf);
 535		if (rc == -ENODATA) {
 536			break;
 537		}
 538		if (rc)
 539			goto fail;
 540		if (reclen && (copied == 0) && (*offs < PAGE_SIZE))
 541			*((u16 *) &buf[FILE_RECLEN_OFFSET]) = reclen;
 542		len = min(count - copied, PAGE_SIZE - res);
 543		if (copy_to_user(ubuf + copied, buf + res, len)) {
 544			rc = -EFAULT;
 545			goto fail;
 546		}
 547		res = 0;
 548		copied += len;
 549	} while (copied != count);
 550
 551	*offs += copied;
 552	rc = copied;
 553fail:
 554	free_page((unsigned long) buf);
 555	return rc;
 556}
 557
 558static ssize_t ur_read(struct file *file, char __user *ubuf, size_t count,
 559		       loff_t *offs)
 560{
 561	struct urdev *urd;
 562	int rc;
 563
 564	TRACE("ur_read: count=%zu ppos=%li\n", count, (unsigned long) *offs);
 565
 566	if (count == 0)
 567		return 0;
 568
 569	urd = ((struct urfile *) file->private_data)->urd;
 570	rc = mutex_lock_interruptible(&urd->io_mutex);
 571	if (rc)
 572		return rc;
 573	rc = diag14_read(file, ubuf, count, offs);
 574	mutex_unlock(&urd->io_mutex);
 575	return rc;
 576}
 577
 578/*
 579 * diagnose code 0x14 subcode 0x0fff - retrieve next file descriptor
 580 * cc=0  normal completion
 581 * cc=1  no files on reader queue or no subsequent file
 582 * cc=2  spid specified is invalid
 583 */
 584static int diag_read_next_file_info(struct file_control_block *buf, int spid)
 585{
 586	int cc;
 587
 588	cc = diag14((unsigned long) buf, spid, 0xfff);
 589	switch (cc) {
 590	case 0:
 591		return 0;
 592	default:
 593		return -ENODATA;
 594	}
 595}
 596
 597static int verify_uri_device(struct urdev *urd)
 598{
 599	struct file_control_block *fcb;
 600	char *buf;
 601	int rc;
 602
 603	fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
 604	if (!fcb)
 605		return -ENOMEM;
 606
 607	/* check for empty reader device (beginning of chain) */
 608	rc = diag_read_next_file_info(fcb, 0);
 609	if (rc)
 610		goto fail_free_fcb;
 611
 612	/* if file is in hold status, we do not read it */
 613	if (fcb->file_stat & (FLG_SYSTEM_HOLD | FLG_USER_HOLD)) {
 614		rc = -EPERM;
 615		goto fail_free_fcb;
 616	}
 617
 618	/* open file on virtual reader	*/
 619	buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
 620	if (!buf) {
 621		rc = -ENOMEM;
 622		goto fail_free_fcb;
 623	}
 624	rc = diag_read_file(urd->dev_id.devno, buf);
 625	if ((rc != 0) && (rc != -ENODATA)) /* EOF does not hurt */
 626		goto fail_free_buf;
 627
 628	/* check if the file on top of the queue is open now */
 629	rc = diag_read_next_file_info(fcb, 0);
 630	if (rc)
 631		goto fail_free_buf;
 632	if (!(fcb->file_stat & FLG_IN_USE)) {
 633		rc = -EMFILE;
 634		goto fail_free_buf;
 635	}
 636	rc = 0;
 637
 638fail_free_buf:
 639	free_page((unsigned long) buf);
 640fail_free_fcb:
 641	kfree(fcb);
 642	return rc;
 643}
 644
 645static int verify_device(struct urdev *urd)
 646{
 647	switch (urd->class) {
 648	case DEV_CLASS_UR_O:
 649		return 0; /* no check needed here */
 650	case DEV_CLASS_UR_I:
 651		return verify_uri_device(urd);
 652	default:
 653		return -EOPNOTSUPP;
 654	}
 655}
 656
 657static int get_uri_file_reclen(struct urdev *urd)
 658{
 659	struct file_control_block *fcb;
 660	int rc;
 661
 662	fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
 663	if (!fcb)
 664		return -ENOMEM;
 665	rc = diag_read_next_file_info(fcb, 0);
 666	if (rc)
 667		goto fail_free;
 668	if (fcb->file_stat & FLG_CP_DUMP)
 669		rc = 0;
 670	else
 671		rc = fcb->rec_len;
 672
 673fail_free:
 674	kfree(fcb);
 675	return rc;
 676}
 677
 678static int get_file_reclen(struct urdev *urd)
 679{
 680	switch (urd->class) {
 681	case DEV_CLASS_UR_O:
 682		return 0;
 683	case DEV_CLASS_UR_I:
 684		return get_uri_file_reclen(urd);
 685	default:
 686		return -EOPNOTSUPP;
 687	}
 688}
 689
 690static int ur_open(struct inode *inode, struct file *file)
 691{
 692	u16 devno;
 693	struct urdev *urd;
 694	struct urfile *urf;
 695	unsigned short accmode;
 696	int rc;
 697
 698	accmode = file->f_flags & O_ACCMODE;
 699
 700	if (accmode == O_RDWR)
 701		return -EACCES;
 702	/*
 703	 * We treat the minor number as the devno of the ur device
 704	 * to find in the driver tree.
 705	 */
 706	devno = MINOR(file->f_dentry->d_inode->i_rdev);
 707
 708	urd = urdev_get_from_devno(devno);
 709	if (!urd) {
 710		rc = -ENXIO;
 711		goto out;
 712	}
 713
 714	spin_lock(&urd->open_lock);
 715	while (urd->open_flag) {
 716		spin_unlock(&urd->open_lock);
 717		if (file->f_flags & O_NONBLOCK) {
 718			rc = -EBUSY;
 719			goto fail_put;
 720		}
 721		if (wait_event_interruptible(urd->wait, urd->open_flag == 0)) {
 722			rc = -ERESTARTSYS;
 723			goto fail_put;
 724		}
 725		spin_lock(&urd->open_lock);
 726	}
 727	urd->open_flag++;
 728	spin_unlock(&urd->open_lock);
 729
 730	TRACE("ur_open\n");
 731
 732	if (((accmode == O_RDONLY) && (urd->class != DEV_CLASS_UR_I)) ||
 733	    ((accmode == O_WRONLY) && (urd->class != DEV_CLASS_UR_O))) {
 734		TRACE("ur_open: unsupported dev class (%d)\n", urd->class);
 735		rc = -EACCES;
 736		goto fail_unlock;
 737	}
 738
 739	rc = verify_device(urd);
 740	if (rc)
 741		goto fail_unlock;
 742
 743	urf = urfile_alloc(urd);
 744	if (!urf) {
 745		rc = -ENOMEM;
 746		goto fail_unlock;
 747	}
 748
 749	urf->dev_reclen = urd->reclen;
 750	rc = get_file_reclen(urd);
 751	if (rc < 0)
 752		goto fail_urfile_free;
 753	urf->file_reclen = rc;
 754	file->private_data = urf;
 755	return 0;
 756
 757fail_urfile_free:
 758	urfile_free(urf);
 759fail_unlock:
 760	spin_lock(&urd->open_lock);
 761	urd->open_flag--;
 762	spin_unlock(&urd->open_lock);
 763fail_put:
 764	urdev_put(urd);
 765out:
 766	return rc;
 767}
 768
 769static int ur_release(struct inode *inode, struct file *file)
 770{
 771	struct urfile *urf = file->private_data;
 772
 773	TRACE("ur_release\n");
 774	spin_lock(&urf->urd->open_lock);
 775	urf->urd->open_flag--;
 776	spin_unlock(&urf->urd->open_lock);
 777	wake_up_interruptible(&urf->urd->wait);
 778	urdev_put(urf->urd);
 779	urfile_free(urf);
 780	return 0;
 781}
 782
 783static loff_t ur_llseek(struct file *file, loff_t offset, int whence)
 784{
 785	loff_t newpos;
 786
 787	if ((file->f_flags & O_ACCMODE) != O_RDONLY)
 788		return -ESPIPE; /* seek allowed only for reader */
 789	if (offset % PAGE_SIZE)
 790		return -ESPIPE; /* only multiples of 4K allowed */
 791	switch (whence) {
 792	case 0: /* SEEK_SET */
 793		newpos = offset;
 794		break;
 795	case 1: /* SEEK_CUR */
 796		newpos = file->f_pos + offset;
 797		break;
 798	default:
 799		return -EINVAL;
 800	}
 801	file->f_pos = newpos;
 802	return newpos;
 803}
 804
 805static const struct file_operations ur_fops = {
 806	.owner	 = THIS_MODULE,
 807	.open	 = ur_open,
 808	.release = ur_release,
 809	.read	 = ur_read,
 810	.write	 = ur_write,
 811	.llseek  = ur_llseek,
 812};
 813
 814/*
 815 * ccw_device infrastructure:
 816 *     ur_probe creates the struct urdev (with refcount = 1), the device
 817 *     attributes, sets up the interrupt handler and validates the virtual
 818 *     unit record device.
 819 *     ur_remove removes the device attributes and drops the reference to
 820 *     struct urdev.
 821 *
 822 *     ur_probe, ur_remove, ur_set_online and ur_set_offline are serialized
 823 *     by the vmur_mutex lock.
 824 *
 825 *     urd->char_device is used as indication that the online function has
 826 *     been completed successfully.
 827 */
 828static int ur_probe(struct ccw_device *cdev)
 829{
 830	struct urdev *urd;
 831	int rc;
 832
 833	TRACE("ur_probe: cdev=%p\n", cdev);
 834
 835	mutex_lock(&vmur_mutex);
 836	urd = urdev_alloc(cdev);
 837	if (!urd) {
 838		rc = -ENOMEM;
 839		goto fail_unlock;
 840	}
 841
 842	rc = ur_create_attributes(&cdev->dev);
 843	if (rc) {
 844		rc = -ENOMEM;
 845		goto fail_urdev_put;
 846	}
 847	cdev->handler = ur_int_handler;
 848
 849	/* validate virtual unit record device */
 850	urd->class = get_urd_class(urd);
 851	if (urd->class < 0) {
 852		rc = urd->class;
 853		goto fail_remove_attr;
 854	}
 855	if ((urd->class != DEV_CLASS_UR_I) && (urd->class != DEV_CLASS_UR_O)) {
 856		rc = -EOPNOTSUPP;
 857		goto fail_remove_attr;
 858	}
 859	spin_lock_irq(get_ccwdev_lock(cdev));
 860	dev_set_drvdata(&cdev->dev, urd);
 861	spin_unlock_irq(get_ccwdev_lock(cdev));
 862
 863	mutex_unlock(&vmur_mutex);
 864	return 0;
 865
 866fail_remove_attr:
 867	ur_remove_attributes(&cdev->dev);
 868fail_urdev_put:
 869	urdev_put(urd);
 870fail_unlock:
 871	mutex_unlock(&vmur_mutex);
 872	return rc;
 873}
 874
 875static int ur_set_online(struct ccw_device *cdev)
 876{
 877	struct urdev *urd;
 878	int minor, major, rc;
 879	char node_id[16];
 880
 881	TRACE("ur_set_online: cdev=%p\n", cdev);
 882
 883	mutex_lock(&vmur_mutex);
 884	urd = urdev_get_from_cdev(cdev);
 885	if (!urd) {
 886		/* ur_remove already deleted our urd */
 887		rc = -ENODEV;
 888		goto fail_unlock;
 889	}
 890
 891	if (urd->char_device) {
 892		/* Another ur_set_online was faster */
 893		rc = -EBUSY;
 894		goto fail_urdev_put;
 895	}
 896
 897	minor = urd->dev_id.devno;
 898	major = MAJOR(ur_first_dev_maj_min);
 899
 900	urd->char_device = cdev_alloc();
 901	if (!urd->char_device) {
 902		rc = -ENOMEM;
 903		goto fail_urdev_put;
 904	}
 905
 906	cdev_init(urd->char_device, &ur_fops);
 907	urd->char_device->dev = MKDEV(major, minor);
 908	urd->char_device->owner = ur_fops.owner;
 909
 910	rc = cdev_add(urd->char_device, urd->char_device->dev, 1);
 911	if (rc)
 912		goto fail_free_cdev;
 913	if (urd->cdev->id.cu_type == READER_PUNCH_DEVTYPE) {
 914		if (urd->class == DEV_CLASS_UR_I)
 915			sprintf(node_id, "vmrdr-%s", dev_name(&cdev->dev));
 916		if (urd->class == DEV_CLASS_UR_O)
 917			sprintf(node_id, "vmpun-%s", dev_name(&cdev->dev));
 918	} else if (urd->cdev->id.cu_type == PRINTER_DEVTYPE) {
 919		sprintf(node_id, "vmprt-%s", dev_name(&cdev->dev));
 920	} else {
 921		rc = -EOPNOTSUPP;
 922		goto fail_free_cdev;
 923	}
 924
 925	urd->device = device_create(vmur_class, NULL, urd->char_device->dev,
 926				    NULL, "%s", node_id);
 927	if (IS_ERR(urd->device)) {
 928		rc = PTR_ERR(urd->device);
 929		TRACE("ur_set_online: device_create rc=%d\n", rc);
 930		goto fail_free_cdev;
 931	}
 932	urdev_put(urd);
 933	mutex_unlock(&vmur_mutex);
 934	return 0;
 935
 936fail_free_cdev:
 937	cdev_del(urd->char_device);
 938	urd->char_device = NULL;
 939fail_urdev_put:
 940	urdev_put(urd);
 941fail_unlock:
 942	mutex_unlock(&vmur_mutex);
 943	return rc;
 944}
 945
 946static int ur_set_offline_force(struct ccw_device *cdev, int force)
 947{
 948	struct urdev *urd;
 949	int rc;
 950
 951	TRACE("ur_set_offline: cdev=%p\n", cdev);
 952	urd = urdev_get_from_cdev(cdev);
 953	if (!urd)
 954		/* ur_remove already deleted our urd */
 955		return -ENODEV;
 956	if (!urd->char_device) {
 957		/* Another ur_set_offline was faster */
 958		rc = -EBUSY;
 959		goto fail_urdev_put;
 960	}
 961	if (!force && (atomic_read(&urd->ref_count) > 2)) {
 962		/* There is still a user of urd (e.g. ur_open) */
 963		TRACE("ur_set_offline: BUSY\n");
 964		rc = -EBUSY;
 965		goto fail_urdev_put;
 966	}
 967	device_destroy(vmur_class, urd->char_device->dev);
 968	cdev_del(urd->char_device);
 969	urd->char_device = NULL;
 970	rc = 0;
 971
 972fail_urdev_put:
 973	urdev_put(urd);
 974	return rc;
 975}
 976
 977static int ur_set_offline(struct ccw_device *cdev)
 978{
 979	int rc;
 980
 981	mutex_lock(&vmur_mutex);
 982	rc = ur_set_offline_force(cdev, 0);
 983	mutex_unlock(&vmur_mutex);
 984	return rc;
 985}
 986
 987static void ur_remove(struct ccw_device *cdev)
 988{
 989	unsigned long flags;
 990
 991	TRACE("ur_remove\n");
 992
 993	mutex_lock(&vmur_mutex);
 994
 995	if (cdev->online)
 996		ur_set_offline_force(cdev, 1);
 997	ur_remove_attributes(&cdev->dev);
 998
 999	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
1000	urdev_put(dev_get_drvdata(&cdev->dev));
1001	dev_set_drvdata(&cdev->dev, NULL);
1002	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
1003
1004	mutex_unlock(&vmur_mutex);
1005}
1006
1007/*
1008 * Module initialisation and cleanup
1009 */
1010static int __init ur_init(void)
1011{
1012	int rc;
1013	dev_t dev;
1014
1015	if (!MACHINE_IS_VM) {
1016		pr_err("The %s cannot be loaded without z/VM\n",
1017		       ur_banner);
1018		return -ENODEV;
1019	}
1020
1021	vmur_dbf = debug_register("vmur", 4, 1, 4 * sizeof(long));
1022	if (!vmur_dbf)
1023		return -ENOMEM;
1024	rc = debug_register_view(vmur_dbf, &debug_sprintf_view);
1025	if (rc)
1026		goto fail_free_dbf;
1027
1028	debug_set_level(vmur_dbf, 6);
1029
1030	vmur_class = class_create(THIS_MODULE, "vmur");
1031	if (IS_ERR(vmur_class)) {
1032		rc = PTR_ERR(vmur_class);
1033		goto fail_free_dbf;
1034	}
1035
1036	rc = ccw_driver_register(&ur_driver);
1037	if (rc)
1038		goto fail_class_destroy;
1039
1040	rc = alloc_chrdev_region(&dev, 0, NUM_MINORS, "vmur");
1041	if (rc) {
1042		pr_err("Kernel function alloc_chrdev_region failed with "
1043		       "error code %d\n", rc);
1044		goto fail_unregister_driver;
1045	}
1046	ur_first_dev_maj_min = MKDEV(MAJOR(dev), 0);
1047
1048	pr_info("%s loaded.\n", ur_banner);
1049	return 0;
1050
1051fail_unregister_driver:
1052	ccw_driver_unregister(&ur_driver);
1053fail_class_destroy:
1054	class_destroy(vmur_class);
1055fail_free_dbf:
1056	debug_unregister(vmur_dbf);
1057	return rc;
1058}
1059
1060static void __exit ur_exit(void)
1061{
1062	unregister_chrdev_region(ur_first_dev_maj_min, NUM_MINORS);
1063	ccw_driver_unregister(&ur_driver);
1064	class_destroy(vmur_class);
1065	debug_unregister(vmur_dbf);
1066	pr_info("%s unloaded.\n", ur_banner);
1067}
1068
1069module_init(ur_init);
1070module_exit(ur_exit);