xref: /openbmc/linux/drivers/s390/char/vmur.c (revision 4800cd83)
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 
41 static char ur_banner[] = "z/VM virtual unit record device driver";
42 
43 MODULE_AUTHOR("IBM Corporation");
44 MODULE_DESCRIPTION("s390 z/VM virtual unit record device driver");
45 MODULE_LICENSE("GPL");
46 
47 static dev_t ur_first_dev_maj_min;
48 static struct class *vmur_class;
49 static struct debug_info *vmur_dbf;
50 
51 /* We put the device's record length (for writes) in the driver_info field */
52 static 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 
58 MODULE_DEVICE_TABLE(ccw, ur_ids);
59 
60 static int ur_probe(struct ccw_device *cdev);
61 static void ur_remove(struct ccw_device *cdev);
62 static int ur_set_online(struct ccw_device *cdev);
63 static int ur_set_offline(struct ccw_device *cdev);
64 static int ur_pm_suspend(struct ccw_device *cdev);
65 
66 static struct ccw_driver ur_driver = {
67 	.name		= "vmur",
68 	.owner		= THIS_MODULE,
69 	.ids		= ur_ids,
70 	.probe		= ur_probe,
71 	.remove		= ur_remove,
72 	.set_online	= ur_set_online,
73 	.set_offline	= ur_set_offline,
74 	.freeze		= ur_pm_suspend,
75 };
76 
77 static DEFINE_MUTEX(vmur_mutex);
78 
79 /*
80  * Allocation, freeing, getting and putting of urdev structures
81  *
82  * Each ur device (urd) contains a reference to its corresponding ccw device
83  * (cdev) using the urd->cdev pointer. Each ccw device has a reference to the
84  * ur device using dev_get_drvdata(&cdev->dev) pointer.
85  *
86  * urd references:
87  * - ur_probe gets a urd reference, ur_remove drops the reference
88  *   dev_get_drvdata(&cdev->dev)
89  * - ur_open gets a urd reference, ur_relase drops the reference
90  *   (urf->urd)
91  *
92  * cdev references:
93  * - urdev_alloc get a cdev reference (urd->cdev)
94  * - urdev_free drops the cdev reference (urd->cdev)
95  *
96  * Setting and clearing of dev_get_drvdata(&cdev->dev) is protected by the ccwdev lock
97  */
98 static struct urdev *urdev_alloc(struct ccw_device *cdev)
99 {
100 	struct urdev *urd;
101 
102 	urd = kzalloc(sizeof(struct urdev), GFP_KERNEL);
103 	if (!urd)
104 		return NULL;
105 	urd->reclen = cdev->id.driver_info;
106 	ccw_device_get_id(cdev, &urd->dev_id);
107 	mutex_init(&urd->io_mutex);
108 	init_waitqueue_head(&urd->wait);
109 	spin_lock_init(&urd->open_lock);
110 	atomic_set(&urd->ref_count,  1);
111 	urd->cdev = cdev;
112 	get_device(&cdev->dev);
113 	return urd;
114 }
115 
116 static void urdev_free(struct urdev *urd)
117 {
118 	TRACE("urdev_free: %p\n", urd);
119 	if (urd->cdev)
120 		put_device(&urd->cdev->dev);
121 	kfree(urd);
122 }
123 
124 static void urdev_get(struct urdev *urd)
125 {
126 	atomic_inc(&urd->ref_count);
127 }
128 
129 static struct urdev *urdev_get_from_cdev(struct ccw_device *cdev)
130 {
131 	struct urdev *urd;
132 	unsigned long flags;
133 
134 	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
135 	urd = dev_get_drvdata(&cdev->dev);
136 	if (urd)
137 		urdev_get(urd);
138 	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
139 	return urd;
140 }
141 
142 static struct urdev *urdev_get_from_devno(u16 devno)
143 {
144 	char bus_id[16];
145 	struct ccw_device *cdev;
146 	struct urdev *urd;
147 
148 	sprintf(bus_id, "0.0.%04x", devno);
149 	cdev = get_ccwdev_by_busid(&ur_driver, bus_id);
150 	if (!cdev)
151 		return NULL;
152 	urd = urdev_get_from_cdev(cdev);
153 	put_device(&cdev->dev);
154 	return urd;
155 }
156 
157 static void urdev_put(struct urdev *urd)
158 {
159 	if (atomic_dec_and_test(&urd->ref_count))
160 		urdev_free(urd);
161 }
162 
163 /*
164  * State and contents of ur devices can be changed by class D users issuing
165  * CP commands such as PURGE or TRANSFER, while the Linux guest is suspended.
166  * Also the Linux guest might be logged off, which causes all active spool
167  * files to be closed.
168  * So we cannot guarantee that spool files are still the same when the Linux
169  * guest is resumed. In order to avoid unpredictable results at resume time
170  * we simply refuse to suspend if a ur device node is open.
171  */
172 static int ur_pm_suspend(struct ccw_device *cdev)
173 {
174 	struct urdev *urd = dev_get_drvdata(&cdev->dev);
175 
176 	TRACE("ur_pm_suspend: cdev=%p\n", cdev);
177 	if (urd->open_flag) {
178 		pr_err("Unit record device %s is busy, %s refusing to "
179 		       "suspend.\n", dev_name(&cdev->dev), ur_banner);
180 		return -EBUSY;
181 	}
182 	return 0;
183 }
184 
185 /*
186  * Low-level functions to do I/O to a ur device.
187  *     alloc_chan_prog
188  *     free_chan_prog
189  *     do_ur_io
190  *     ur_int_handler
191  *
192  * alloc_chan_prog allocates and builds the channel program
193  * free_chan_prog frees memory of the channel program
194  *
195  * do_ur_io issues the channel program to the device and blocks waiting
196  * on a completion event it publishes at urd->io_done. The function
197  * serialises itself on the device's mutex so that only one I/O
198  * is issued at a time (and that I/O is synchronous).
199  *
200  * ur_int_handler catches the "I/O done" interrupt, writes the
201  * subchannel status word into the scsw member of the urdev structure
202  * and complete()s the io_done to wake the waiting do_ur_io.
203  *
204  * The caller of do_ur_io is responsible for kfree()ing the channel program
205  * address pointer that alloc_chan_prog returned.
206  */
207 
208 static void free_chan_prog(struct ccw1 *cpa)
209 {
210 	struct ccw1 *ptr = cpa;
211 
212 	while (ptr->cda) {
213 		kfree((void *)(addr_t) ptr->cda);
214 		ptr++;
215 	}
216 	kfree(cpa);
217 }
218 
219 /*
220  * alloc_chan_prog
221  * The channel program we use is write commands chained together
222  * with a final NOP CCW command-chained on (which ensures that CE and DE
223  * are presented together in a single interrupt instead of as separate
224  * interrupts unless an incorrect length indication kicks in first). The
225  * data length in each CCW is reclen.
226  */
227 static struct ccw1 *alloc_chan_prog(const char __user *ubuf, int rec_count,
228 				    int reclen)
229 {
230 	struct ccw1 *cpa;
231 	void *kbuf;
232 	int i;
233 
234 	TRACE("alloc_chan_prog(%p, %i, %i)\n", ubuf, rec_count, reclen);
235 
236 	/*
237 	 * We chain a NOP onto the writes to force CE+DE together.
238 	 * That means we allocate room for CCWs to cover count/reclen
239 	 * records plus a NOP.
240 	 */
241 	cpa = kzalloc((rec_count + 1) * sizeof(struct ccw1),
242 		      GFP_KERNEL | GFP_DMA);
243 	if (!cpa)
244 		return ERR_PTR(-ENOMEM);
245 
246 	for (i = 0; i < rec_count; i++) {
247 		cpa[i].cmd_code = WRITE_CCW_CMD;
248 		cpa[i].flags = CCW_FLAG_CC | CCW_FLAG_SLI;
249 		cpa[i].count = reclen;
250 		kbuf = kmalloc(reclen, GFP_KERNEL | GFP_DMA);
251 		if (!kbuf) {
252 			free_chan_prog(cpa);
253 			return ERR_PTR(-ENOMEM);
254 		}
255 		cpa[i].cda = (u32)(addr_t) kbuf;
256 		if (copy_from_user(kbuf, ubuf, reclen)) {
257 			free_chan_prog(cpa);
258 			return ERR_PTR(-EFAULT);
259 		}
260 		ubuf += reclen;
261 	}
262 	/* The following NOP CCW forces CE+DE to be presented together */
263 	cpa[i].cmd_code = CCW_CMD_NOOP;
264 	return cpa;
265 }
266 
267 static int do_ur_io(struct urdev *urd, struct ccw1 *cpa)
268 {
269 	int rc;
270 	struct ccw_device *cdev = urd->cdev;
271 	DECLARE_COMPLETION_ONSTACK(event);
272 
273 	TRACE("do_ur_io: cpa=%p\n", cpa);
274 
275 	rc = mutex_lock_interruptible(&urd->io_mutex);
276 	if (rc)
277 		return rc;
278 
279 	urd->io_done = &event;
280 
281 	spin_lock_irq(get_ccwdev_lock(cdev));
282 	rc = ccw_device_start(cdev, cpa, 1, 0, 0);
283 	spin_unlock_irq(get_ccwdev_lock(cdev));
284 
285 	TRACE("do_ur_io: ccw_device_start returned %d\n", rc);
286 	if (rc)
287 		goto out;
288 
289 	wait_for_completion(&event);
290 	TRACE("do_ur_io: I/O complete\n");
291 	rc = 0;
292 
293 out:
294 	mutex_unlock(&urd->io_mutex);
295 	return rc;
296 }
297 
298 /*
299  * ur interrupt handler, called from the ccw_device layer
300  */
301 static void ur_int_handler(struct ccw_device *cdev, unsigned long intparm,
302 			   struct irb *irb)
303 {
304 	struct urdev *urd;
305 
306 	kstat_cpu(smp_processor_id()).irqs[IOINT_VMR]++;
307 	TRACE("ur_int_handler: intparm=0x%lx cstat=%02x dstat=%02x res=%u\n",
308 	      intparm, irb->scsw.cmd.cstat, irb->scsw.cmd.dstat,
309 	      irb->scsw.cmd.count);
310 
311 	if (!intparm) {
312 		TRACE("ur_int_handler: unsolicited interrupt\n");
313 		return;
314 	}
315 	urd = dev_get_drvdata(&cdev->dev);
316 	BUG_ON(!urd);
317 	/* On special conditions irb is an error pointer */
318 	if (IS_ERR(irb))
319 		urd->io_request_rc = PTR_ERR(irb);
320 	else if (irb->scsw.cmd.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END))
321 		urd->io_request_rc = 0;
322 	else
323 		urd->io_request_rc = -EIO;
324 
325 	complete(urd->io_done);
326 }
327 
328 /*
329  * reclen sysfs attribute - The record length to be used for write CCWs
330  */
331 static ssize_t ur_attr_reclen_show(struct device *dev,
332 				   struct device_attribute *attr, char *buf)
333 {
334 	struct urdev *urd;
335 	int rc;
336 
337 	urd = urdev_get_from_cdev(to_ccwdev(dev));
338 	if (!urd)
339 		return -ENODEV;
340 	rc = sprintf(buf, "%zu\n", urd->reclen);
341 	urdev_put(urd);
342 	return rc;
343 }
344 
345 static DEVICE_ATTR(reclen, 0444, ur_attr_reclen_show, NULL);
346 
347 static int ur_create_attributes(struct device *dev)
348 {
349 	return device_create_file(dev, &dev_attr_reclen);
350 }
351 
352 static void ur_remove_attributes(struct device *dev)
353 {
354 	device_remove_file(dev, &dev_attr_reclen);
355 }
356 
357 /*
358  * diagnose code 0x210 - retrieve device information
359  * cc=0  normal completion, we have a real device
360  * cc=1  CP paging error
361  * cc=2  The virtual device exists, but is not associated with a real device
362  * cc=3  Invalid device address, or the virtual device does not exist
363  */
364 static int get_urd_class(struct urdev *urd)
365 {
366 	static struct diag210 ur_diag210;
367 	int cc;
368 
369 	ur_diag210.vrdcdvno = urd->dev_id.devno;
370 	ur_diag210.vrdclen = sizeof(struct diag210);
371 
372 	cc = diag210(&ur_diag210);
373 	switch (cc) {
374 	case 0:
375 		return -EOPNOTSUPP;
376 	case 2:
377 		return ur_diag210.vrdcvcla; /* virtual device class */
378 	case 3:
379 		return -ENODEV;
380 	default:
381 		return -EIO;
382 	}
383 }
384 
385 /*
386  * Allocation and freeing of urfile structures
387  */
388 static struct urfile *urfile_alloc(struct urdev *urd)
389 {
390 	struct urfile *urf;
391 
392 	urf = kzalloc(sizeof(struct urfile), GFP_KERNEL);
393 	if (!urf)
394 		return NULL;
395 	urf->urd = urd;
396 
397 	TRACE("urfile_alloc: urd=%p urf=%p rl=%zu\n", urd, urf,
398 	      urf->dev_reclen);
399 
400 	return urf;
401 }
402 
403 static void urfile_free(struct urfile *urf)
404 {
405 	TRACE("urfile_free: urf=%p urd=%p\n", urf, urf->urd);
406 	kfree(urf);
407 }
408 
409 /*
410  * The fops implementation of the character device driver
411  */
412 static ssize_t do_write(struct urdev *urd, const char __user *udata,
413 			size_t count, size_t reclen, loff_t *ppos)
414 {
415 	struct ccw1 *cpa;
416 	int rc;
417 
418 	cpa = alloc_chan_prog(udata, count / reclen, reclen);
419 	if (IS_ERR(cpa))
420 		return PTR_ERR(cpa);
421 
422 	rc = do_ur_io(urd, cpa);
423 	if (rc)
424 		goto fail_kfree_cpa;
425 
426 	if (urd->io_request_rc) {
427 		rc = urd->io_request_rc;
428 		goto fail_kfree_cpa;
429 	}
430 	*ppos += count;
431 	rc = count;
432 
433 fail_kfree_cpa:
434 	free_chan_prog(cpa);
435 	return rc;
436 }
437 
438 static ssize_t ur_write(struct file *file, const char __user *udata,
439 			size_t count, loff_t *ppos)
440 {
441 	struct urfile *urf = file->private_data;
442 
443 	TRACE("ur_write: count=%zu\n", count);
444 
445 	if (count == 0)
446 		return 0;
447 
448 	if (count % urf->dev_reclen)
449 		return -EINVAL;	/* count must be a multiple of reclen */
450 
451 	if (count > urf->dev_reclen * MAX_RECS_PER_IO)
452 		count = urf->dev_reclen * MAX_RECS_PER_IO;
453 
454 	return do_write(urf->urd, udata, count, urf->dev_reclen, ppos);
455 }
456 
457 /*
458  * diagnose code 0x14 subcode 0x0028 - position spool file to designated
459  *				       record
460  * cc=0  normal completion
461  * cc=2  no file active on the virtual reader or device not ready
462  * cc=3  record specified is beyond EOF
463  */
464 static int diag_position_to_record(int devno, int record)
465 {
466 	int cc;
467 
468 	cc = diag14(record, devno, 0x28);
469 	switch (cc) {
470 	case 0:
471 		return 0;
472 	case 2:
473 		return -ENOMEDIUM;
474 	case 3:
475 		return -ENODATA; /* position beyond end of file */
476 	default:
477 		return -EIO;
478 	}
479 }
480 
481 /*
482  * diagnose code 0x14 subcode 0x0000 - read next spool file buffer
483  * cc=0  normal completion
484  * cc=1  EOF reached
485  * cc=2  no file active on the virtual reader, and no file eligible
486  * cc=3  file already active on the virtual reader or specified virtual
487  *	 reader does not exist or is not a reader
488  */
489 static int diag_read_file(int devno, char *buf)
490 {
491 	int cc;
492 
493 	cc = diag14((unsigned long) buf, devno, 0x00);
494 	switch (cc) {
495 	case 0:
496 		return 0;
497 	case 1:
498 		return -ENODATA;
499 	case 2:
500 		return -ENOMEDIUM;
501 	default:
502 		return -EIO;
503 	}
504 }
505 
506 static ssize_t diag14_read(struct file *file, char __user *ubuf, size_t count,
507 			   loff_t *offs)
508 {
509 	size_t len, copied, res;
510 	char *buf;
511 	int rc;
512 	u16 reclen;
513 	struct urdev *urd;
514 
515 	urd = ((struct urfile *) file->private_data)->urd;
516 	reclen = ((struct urfile *) file->private_data)->file_reclen;
517 
518 	rc = diag_position_to_record(urd->dev_id.devno, *offs / PAGE_SIZE + 1);
519 	if (rc == -ENODATA)
520 		return 0;
521 	if (rc)
522 		return rc;
523 
524 	len = min((size_t) PAGE_SIZE, count);
525 	buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
526 	if (!buf)
527 		return -ENOMEM;
528 
529 	copied = 0;
530 	res = (size_t) (*offs % PAGE_SIZE);
531 	do {
532 		rc = diag_read_file(urd->dev_id.devno, buf);
533 		if (rc == -ENODATA) {
534 			break;
535 		}
536 		if (rc)
537 			goto fail;
538 		if (reclen && (copied == 0) && (*offs < PAGE_SIZE))
539 			*((u16 *) &buf[FILE_RECLEN_OFFSET]) = reclen;
540 		len = min(count - copied, PAGE_SIZE - res);
541 		if (copy_to_user(ubuf + copied, buf + res, len)) {
542 			rc = -EFAULT;
543 			goto fail;
544 		}
545 		res = 0;
546 		copied += len;
547 	} while (copied != count);
548 
549 	*offs += copied;
550 	rc = copied;
551 fail:
552 	free_page((unsigned long) buf);
553 	return rc;
554 }
555 
556 static ssize_t ur_read(struct file *file, char __user *ubuf, size_t count,
557 		       loff_t *offs)
558 {
559 	struct urdev *urd;
560 	int rc;
561 
562 	TRACE("ur_read: count=%zu ppos=%li\n", count, (unsigned long) *offs);
563 
564 	if (count == 0)
565 		return 0;
566 
567 	urd = ((struct urfile *) file->private_data)->urd;
568 	rc = mutex_lock_interruptible(&urd->io_mutex);
569 	if (rc)
570 		return rc;
571 	rc = diag14_read(file, ubuf, count, offs);
572 	mutex_unlock(&urd->io_mutex);
573 	return rc;
574 }
575 
576 /*
577  * diagnose code 0x14 subcode 0x0fff - retrieve next file descriptor
578  * cc=0  normal completion
579  * cc=1  no files on reader queue or no subsequent file
580  * cc=2  spid specified is invalid
581  */
582 static int diag_read_next_file_info(struct file_control_block *buf, int spid)
583 {
584 	int cc;
585 
586 	cc = diag14((unsigned long) buf, spid, 0xfff);
587 	switch (cc) {
588 	case 0:
589 		return 0;
590 	default:
591 		return -ENODATA;
592 	}
593 }
594 
595 static int verify_uri_device(struct urdev *urd)
596 {
597 	struct file_control_block *fcb;
598 	char *buf;
599 	int rc;
600 
601 	fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
602 	if (!fcb)
603 		return -ENOMEM;
604 
605 	/* check for empty reader device (beginning of chain) */
606 	rc = diag_read_next_file_info(fcb, 0);
607 	if (rc)
608 		goto fail_free_fcb;
609 
610 	/* if file is in hold status, we do not read it */
611 	if (fcb->file_stat & (FLG_SYSTEM_HOLD | FLG_USER_HOLD)) {
612 		rc = -EPERM;
613 		goto fail_free_fcb;
614 	}
615 
616 	/* open file on virtual reader	*/
617 	buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
618 	if (!buf) {
619 		rc = -ENOMEM;
620 		goto fail_free_fcb;
621 	}
622 	rc = diag_read_file(urd->dev_id.devno, buf);
623 	if ((rc != 0) && (rc != -ENODATA)) /* EOF does not hurt */
624 		goto fail_free_buf;
625 
626 	/* check if the file on top of the queue is open now */
627 	rc = diag_read_next_file_info(fcb, 0);
628 	if (rc)
629 		goto fail_free_buf;
630 	if (!(fcb->file_stat & FLG_IN_USE)) {
631 		rc = -EMFILE;
632 		goto fail_free_buf;
633 	}
634 	rc = 0;
635 
636 fail_free_buf:
637 	free_page((unsigned long) buf);
638 fail_free_fcb:
639 	kfree(fcb);
640 	return rc;
641 }
642 
643 static int verify_device(struct urdev *urd)
644 {
645 	switch (urd->class) {
646 	case DEV_CLASS_UR_O:
647 		return 0; /* no check needed here */
648 	case DEV_CLASS_UR_I:
649 		return verify_uri_device(urd);
650 	default:
651 		return -EOPNOTSUPP;
652 	}
653 }
654 
655 static int get_uri_file_reclen(struct urdev *urd)
656 {
657 	struct file_control_block *fcb;
658 	int rc;
659 
660 	fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
661 	if (!fcb)
662 		return -ENOMEM;
663 	rc = diag_read_next_file_info(fcb, 0);
664 	if (rc)
665 		goto fail_free;
666 	if (fcb->file_stat & FLG_CP_DUMP)
667 		rc = 0;
668 	else
669 		rc = fcb->rec_len;
670 
671 fail_free:
672 	kfree(fcb);
673 	return rc;
674 }
675 
676 static int get_file_reclen(struct urdev *urd)
677 {
678 	switch (urd->class) {
679 	case DEV_CLASS_UR_O:
680 		return 0;
681 	case DEV_CLASS_UR_I:
682 		return get_uri_file_reclen(urd);
683 	default:
684 		return -EOPNOTSUPP;
685 	}
686 }
687 
688 static int ur_open(struct inode *inode, struct file *file)
689 {
690 	u16 devno;
691 	struct urdev *urd;
692 	struct urfile *urf;
693 	unsigned short accmode;
694 	int rc;
695 
696 	accmode = file->f_flags & O_ACCMODE;
697 
698 	if (accmode == O_RDWR)
699 		return -EACCES;
700 	/*
701 	 * We treat the minor number as the devno of the ur device
702 	 * to find in the driver tree.
703 	 */
704 	devno = MINOR(file->f_dentry->d_inode->i_rdev);
705 
706 	urd = urdev_get_from_devno(devno);
707 	if (!urd) {
708 		rc = -ENXIO;
709 		goto out;
710 	}
711 
712 	spin_lock(&urd->open_lock);
713 	while (urd->open_flag) {
714 		spin_unlock(&urd->open_lock);
715 		if (file->f_flags & O_NONBLOCK) {
716 			rc = -EBUSY;
717 			goto fail_put;
718 		}
719 		if (wait_event_interruptible(urd->wait, urd->open_flag == 0)) {
720 			rc = -ERESTARTSYS;
721 			goto fail_put;
722 		}
723 		spin_lock(&urd->open_lock);
724 	}
725 	urd->open_flag++;
726 	spin_unlock(&urd->open_lock);
727 
728 	TRACE("ur_open\n");
729 
730 	if (((accmode == O_RDONLY) && (urd->class != DEV_CLASS_UR_I)) ||
731 	    ((accmode == O_WRONLY) && (urd->class != DEV_CLASS_UR_O))) {
732 		TRACE("ur_open: unsupported dev class (%d)\n", urd->class);
733 		rc = -EACCES;
734 		goto fail_unlock;
735 	}
736 
737 	rc = verify_device(urd);
738 	if (rc)
739 		goto fail_unlock;
740 
741 	urf = urfile_alloc(urd);
742 	if (!urf) {
743 		rc = -ENOMEM;
744 		goto fail_unlock;
745 	}
746 
747 	urf->dev_reclen = urd->reclen;
748 	rc = get_file_reclen(urd);
749 	if (rc < 0)
750 		goto fail_urfile_free;
751 	urf->file_reclen = rc;
752 	file->private_data = urf;
753 	return 0;
754 
755 fail_urfile_free:
756 	urfile_free(urf);
757 fail_unlock:
758 	spin_lock(&urd->open_lock);
759 	urd->open_flag--;
760 	spin_unlock(&urd->open_lock);
761 fail_put:
762 	urdev_put(urd);
763 out:
764 	return rc;
765 }
766 
767 static int ur_release(struct inode *inode, struct file *file)
768 {
769 	struct urfile *urf = file->private_data;
770 
771 	TRACE("ur_release\n");
772 	spin_lock(&urf->urd->open_lock);
773 	urf->urd->open_flag--;
774 	spin_unlock(&urf->urd->open_lock);
775 	wake_up_interruptible(&urf->urd->wait);
776 	urdev_put(urf->urd);
777 	urfile_free(urf);
778 	return 0;
779 }
780 
781 static loff_t ur_llseek(struct file *file, loff_t offset, int whence)
782 {
783 	loff_t newpos;
784 
785 	if ((file->f_flags & O_ACCMODE) != O_RDONLY)
786 		return -ESPIPE; /* seek allowed only for reader */
787 	if (offset % PAGE_SIZE)
788 		return -ESPIPE; /* only multiples of 4K allowed */
789 	switch (whence) {
790 	case 0: /* SEEK_SET */
791 		newpos = offset;
792 		break;
793 	case 1: /* SEEK_CUR */
794 		newpos = file->f_pos + offset;
795 		break;
796 	default:
797 		return -EINVAL;
798 	}
799 	file->f_pos = newpos;
800 	return newpos;
801 }
802 
803 static const struct file_operations ur_fops = {
804 	.owner	 = THIS_MODULE,
805 	.open	 = ur_open,
806 	.release = ur_release,
807 	.read	 = ur_read,
808 	.write	 = ur_write,
809 	.llseek  = ur_llseek,
810 };
811 
812 /*
813  * ccw_device infrastructure:
814  *     ur_probe creates the struct urdev (with refcount = 1), the device
815  *     attributes, sets up the interrupt handler and validates the virtual
816  *     unit record device.
817  *     ur_remove removes the device attributes and drops the reference to
818  *     struct urdev.
819  *
820  *     ur_probe, ur_remove, ur_set_online and ur_set_offline are serialized
821  *     by the vmur_mutex lock.
822  *
823  *     urd->char_device is used as indication that the online function has
824  *     been completed successfully.
825  */
826 static int ur_probe(struct ccw_device *cdev)
827 {
828 	struct urdev *urd;
829 	int rc;
830 
831 	TRACE("ur_probe: cdev=%p\n", cdev);
832 
833 	mutex_lock(&vmur_mutex);
834 	urd = urdev_alloc(cdev);
835 	if (!urd) {
836 		rc = -ENOMEM;
837 		goto fail_unlock;
838 	}
839 
840 	rc = ur_create_attributes(&cdev->dev);
841 	if (rc) {
842 		rc = -ENOMEM;
843 		goto fail_urdev_put;
844 	}
845 	cdev->handler = ur_int_handler;
846 
847 	/* validate virtual unit record device */
848 	urd->class = get_urd_class(urd);
849 	if (urd->class < 0) {
850 		rc = urd->class;
851 		goto fail_remove_attr;
852 	}
853 	if ((urd->class != DEV_CLASS_UR_I) && (urd->class != DEV_CLASS_UR_O)) {
854 		rc = -EOPNOTSUPP;
855 		goto fail_remove_attr;
856 	}
857 	spin_lock_irq(get_ccwdev_lock(cdev));
858 	dev_set_drvdata(&cdev->dev, urd);
859 	spin_unlock_irq(get_ccwdev_lock(cdev));
860 
861 	mutex_unlock(&vmur_mutex);
862 	return 0;
863 
864 fail_remove_attr:
865 	ur_remove_attributes(&cdev->dev);
866 fail_urdev_put:
867 	urdev_put(urd);
868 fail_unlock:
869 	mutex_unlock(&vmur_mutex);
870 	return rc;
871 }
872 
873 static int ur_set_online(struct ccw_device *cdev)
874 {
875 	struct urdev *urd;
876 	int minor, major, rc;
877 	char node_id[16];
878 
879 	TRACE("ur_set_online: cdev=%p\n", cdev);
880 
881 	mutex_lock(&vmur_mutex);
882 	urd = urdev_get_from_cdev(cdev);
883 	if (!urd) {
884 		/* ur_remove already deleted our urd */
885 		rc = -ENODEV;
886 		goto fail_unlock;
887 	}
888 
889 	if (urd->char_device) {
890 		/* Another ur_set_online was faster */
891 		rc = -EBUSY;
892 		goto fail_urdev_put;
893 	}
894 
895 	minor = urd->dev_id.devno;
896 	major = MAJOR(ur_first_dev_maj_min);
897 
898 	urd->char_device = cdev_alloc();
899 	if (!urd->char_device) {
900 		rc = -ENOMEM;
901 		goto fail_urdev_put;
902 	}
903 
904 	cdev_init(urd->char_device, &ur_fops);
905 	urd->char_device->dev = MKDEV(major, minor);
906 	urd->char_device->owner = ur_fops.owner;
907 
908 	rc = cdev_add(urd->char_device, urd->char_device->dev, 1);
909 	if (rc)
910 		goto fail_free_cdev;
911 	if (urd->cdev->id.cu_type == READER_PUNCH_DEVTYPE) {
912 		if (urd->class == DEV_CLASS_UR_I)
913 			sprintf(node_id, "vmrdr-%s", dev_name(&cdev->dev));
914 		if (urd->class == DEV_CLASS_UR_O)
915 			sprintf(node_id, "vmpun-%s", dev_name(&cdev->dev));
916 	} else if (urd->cdev->id.cu_type == PRINTER_DEVTYPE) {
917 		sprintf(node_id, "vmprt-%s", dev_name(&cdev->dev));
918 	} else {
919 		rc = -EOPNOTSUPP;
920 		goto fail_free_cdev;
921 	}
922 
923 	urd->device = device_create(vmur_class, NULL, urd->char_device->dev,
924 				    NULL, "%s", node_id);
925 	if (IS_ERR(urd->device)) {
926 		rc = PTR_ERR(urd->device);
927 		TRACE("ur_set_online: device_create rc=%d\n", rc);
928 		goto fail_free_cdev;
929 	}
930 	urdev_put(urd);
931 	mutex_unlock(&vmur_mutex);
932 	return 0;
933 
934 fail_free_cdev:
935 	cdev_del(urd->char_device);
936 	urd->char_device = NULL;
937 fail_urdev_put:
938 	urdev_put(urd);
939 fail_unlock:
940 	mutex_unlock(&vmur_mutex);
941 	return rc;
942 }
943 
944 static int ur_set_offline_force(struct ccw_device *cdev, int force)
945 {
946 	struct urdev *urd;
947 	int rc;
948 
949 	TRACE("ur_set_offline: cdev=%p\n", cdev);
950 	urd = urdev_get_from_cdev(cdev);
951 	if (!urd)
952 		/* ur_remove already deleted our urd */
953 		return -ENODEV;
954 	if (!urd->char_device) {
955 		/* Another ur_set_offline was faster */
956 		rc = -EBUSY;
957 		goto fail_urdev_put;
958 	}
959 	if (!force && (atomic_read(&urd->ref_count) > 2)) {
960 		/* There is still a user of urd (e.g. ur_open) */
961 		TRACE("ur_set_offline: BUSY\n");
962 		rc = -EBUSY;
963 		goto fail_urdev_put;
964 	}
965 	device_destroy(vmur_class, urd->char_device->dev);
966 	cdev_del(urd->char_device);
967 	urd->char_device = NULL;
968 	rc = 0;
969 
970 fail_urdev_put:
971 	urdev_put(urd);
972 	return rc;
973 }
974 
975 static int ur_set_offline(struct ccw_device *cdev)
976 {
977 	int rc;
978 
979 	mutex_lock(&vmur_mutex);
980 	rc = ur_set_offline_force(cdev, 0);
981 	mutex_unlock(&vmur_mutex);
982 	return rc;
983 }
984 
985 static void ur_remove(struct ccw_device *cdev)
986 {
987 	unsigned long flags;
988 
989 	TRACE("ur_remove\n");
990 
991 	mutex_lock(&vmur_mutex);
992 
993 	if (cdev->online)
994 		ur_set_offline_force(cdev, 1);
995 	ur_remove_attributes(&cdev->dev);
996 
997 	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
998 	urdev_put(dev_get_drvdata(&cdev->dev));
999 	dev_set_drvdata(&cdev->dev, NULL);
1000 	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
1001 
1002 	mutex_unlock(&vmur_mutex);
1003 }
1004 
1005 /*
1006  * Module initialisation and cleanup
1007  */
1008 static int __init ur_init(void)
1009 {
1010 	int rc;
1011 	dev_t dev;
1012 
1013 	if (!MACHINE_IS_VM) {
1014 		pr_err("The %s cannot be loaded without z/VM\n",
1015 		       ur_banner);
1016 		return -ENODEV;
1017 	}
1018 
1019 	vmur_dbf = debug_register("vmur", 4, 1, 4 * sizeof(long));
1020 	if (!vmur_dbf)
1021 		return -ENOMEM;
1022 	rc = debug_register_view(vmur_dbf, &debug_sprintf_view);
1023 	if (rc)
1024 		goto fail_free_dbf;
1025 
1026 	debug_set_level(vmur_dbf, 6);
1027 
1028 	vmur_class = class_create(THIS_MODULE, "vmur");
1029 	if (IS_ERR(vmur_class)) {
1030 		rc = PTR_ERR(vmur_class);
1031 		goto fail_free_dbf;
1032 	}
1033 
1034 	rc = ccw_driver_register(&ur_driver);
1035 	if (rc)
1036 		goto fail_class_destroy;
1037 
1038 	rc = alloc_chrdev_region(&dev, 0, NUM_MINORS, "vmur");
1039 	if (rc) {
1040 		pr_err("Kernel function alloc_chrdev_region failed with "
1041 		       "error code %d\n", rc);
1042 		goto fail_unregister_driver;
1043 	}
1044 	ur_first_dev_maj_min = MKDEV(MAJOR(dev), 0);
1045 
1046 	pr_info("%s loaded.\n", ur_banner);
1047 	return 0;
1048 
1049 fail_unregister_driver:
1050 	ccw_driver_unregister(&ur_driver);
1051 fail_class_destroy:
1052 	class_destroy(vmur_class);
1053 fail_free_dbf:
1054 	debug_unregister(vmur_dbf);
1055 	return rc;
1056 }
1057 
1058 static void __exit ur_exit(void)
1059 {
1060 	unregister_chrdev_region(ur_first_dev_maj_min, NUM_MINORS);
1061 	ccw_driver_unregister(&ur_driver);
1062 	class_destroy(vmur_class);
1063 	debug_unregister(vmur_dbf);
1064 	pr_info("%s unloaded.\n", ur_banner);
1065 }
1066 
1067 module_init(ur_init);
1068 module_exit(ur_exit);
1069