xref: /openbmc/linux/drivers/s390/char/vmur.c (revision 1aaba11d)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Linux driver for System z and s390 unit record devices
4  * (z/VM virtual punch, reader, printer)
5  *
6  * Copyright IBM Corp. 2001, 2009
7  * Authors: Malcolm Beattie <beattiem@uk.ibm.com>
8  *	    Michael Holzheu <holzheu@de.ibm.com>
9  *	    Frank Munzert <munzert@de.ibm.com>
10  */
11 
12 #define KMSG_COMPONENT "vmur"
13 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
14 
15 #include <linux/cdev.h>
16 #include <linux/slab.h>
17 #include <linux/module.h>
18 #include <linux/kobject.h>
19 
20 #include <linux/uaccess.h>
21 #include <asm/cio.h>
22 #include <asm/ccwdev.h>
23 #include <asm/debug.h>
24 #include <asm/diag.h>
25 #include <asm/scsw.h>
26 
27 #include "vmur.h"
28 
29 /*
30  * Driver overview
31  *
32  * Unit record device support is implemented as a character device driver.
33  * We can fit at least 16 bits into a device minor number and use the
34  * simple method of mapping a character device number with minor abcd
35  * to the unit record device with devno abcd.
36  * I/O to virtual unit record devices is handled as follows:
37  * Reads: Diagnose code 0x14 (input spool file manipulation)
38  * is used to read spool data page-wise.
39  * Writes: The CCW used is WRITE_CCW_CMD (0x01). The device's record length
40  * is available by reading sysfs attr reclen. Each write() to the device
41  * must specify an integral multiple (maximal 511) of reclen.
42  */
43 
44 static char ur_banner[] = "z/VM virtual unit record device driver";
45 
46 MODULE_AUTHOR("IBM Corporation");
47 MODULE_DESCRIPTION("s390 z/VM virtual unit record device driver");
48 MODULE_LICENSE("GPL");
49 
50 static dev_t ur_first_dev_maj_min;
51 static struct class *vmur_class;
52 static struct debug_info *vmur_dbf;
53 
54 /* We put the device's record length (for writes) in the driver_info field */
55 static struct ccw_device_id ur_ids[] = {
56 	{ CCWDEV_CU_DI(READER_PUNCH_DEVTYPE, 80) },
57 	{ CCWDEV_CU_DI(PRINTER_DEVTYPE, 132) },
58 	{ /* end of list */ }
59 };
60 
61 MODULE_DEVICE_TABLE(ccw, ur_ids);
62 
63 static int ur_probe(struct ccw_device *cdev);
64 static void ur_remove(struct ccw_device *cdev);
65 static int ur_set_online(struct ccw_device *cdev);
66 static int ur_set_offline(struct ccw_device *cdev);
67 
68 static struct ccw_driver ur_driver = {
69 	.driver = {
70 		.name	= "vmur",
71 		.owner	= THIS_MODULE,
72 	},
73 	.ids		= ur_ids,
74 	.probe		= ur_probe,
75 	.remove		= ur_remove,
76 	.set_online	= ur_set_online,
77 	.set_offline	= ur_set_offline,
78 	.int_class	= IRQIO_VMR,
79 };
80 
81 static DEFINE_MUTEX(vmur_mutex);
82 
83 static void ur_uevent(struct work_struct *ws);
84 
85 /*
86  * Allocation, freeing, getting and putting of urdev structures
87  *
88  * Each ur device (urd) contains a reference to its corresponding ccw device
89  * (cdev) using the urd->cdev pointer. Each ccw device has a reference to the
90  * ur device using dev_get_drvdata(&cdev->dev) pointer.
91  *
92  * urd references:
93  * - ur_probe gets a urd reference, ur_remove drops the reference
94  *   dev_get_drvdata(&cdev->dev)
95  * - ur_open gets a urd reference, ur_release drops the reference
96  *   (urf->urd)
97  *
98  * cdev references:
99  * - urdev_alloc get a cdev reference (urd->cdev)
100  * - urdev_free drops the cdev reference (urd->cdev)
101  *
102  * Setting and clearing of dev_get_drvdata(&cdev->dev) is protected by the ccwdev lock
103  */
urdev_alloc(struct ccw_device * cdev)104 static struct urdev *urdev_alloc(struct ccw_device *cdev)
105 {
106 	struct urdev *urd;
107 
108 	urd = kzalloc(sizeof(struct urdev), GFP_KERNEL);
109 	if (!urd)
110 		return NULL;
111 	urd->reclen = cdev->id.driver_info;
112 	ccw_device_get_id(cdev, &urd->dev_id);
113 	mutex_init(&urd->io_mutex);
114 	init_waitqueue_head(&urd->wait);
115 	INIT_WORK(&urd->uevent_work, ur_uevent);
116 	spin_lock_init(&urd->open_lock);
117 	refcount_set(&urd->ref_count,  1);
118 	urd->cdev = cdev;
119 	get_device(&cdev->dev);
120 	return urd;
121 }
122 
urdev_free(struct urdev * urd)123 static void urdev_free(struct urdev *urd)
124 {
125 	TRACE("urdev_free: %p\n", urd);
126 	if (urd->cdev)
127 		put_device(&urd->cdev->dev);
128 	kfree(urd);
129 }
130 
urdev_get(struct urdev * urd)131 static void urdev_get(struct urdev *urd)
132 {
133 	refcount_inc(&urd->ref_count);
134 }
135 
urdev_get_from_cdev(struct ccw_device * cdev)136 static struct urdev *urdev_get_from_cdev(struct ccw_device *cdev)
137 {
138 	struct urdev *urd;
139 	unsigned long flags;
140 
141 	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
142 	urd = dev_get_drvdata(&cdev->dev);
143 	if (urd)
144 		urdev_get(urd);
145 	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
146 	return urd;
147 }
148 
urdev_get_from_devno(u16 devno)149 static struct urdev *urdev_get_from_devno(u16 devno)
150 {
151 	char bus_id[16];
152 	struct ccw_device *cdev;
153 	struct urdev *urd;
154 
155 	sprintf(bus_id, "0.0.%04x", devno);
156 	cdev = get_ccwdev_by_busid(&ur_driver, bus_id);
157 	if (!cdev)
158 		return NULL;
159 	urd = urdev_get_from_cdev(cdev);
160 	put_device(&cdev->dev);
161 	return urd;
162 }
163 
urdev_put(struct urdev * urd)164 static void urdev_put(struct urdev *urd)
165 {
166 	if (refcount_dec_and_test(&urd->ref_count))
167 		urdev_free(urd);
168 }
169 
170 /*
171  * Low-level functions to do I/O to a ur device.
172  *     alloc_chan_prog
173  *     free_chan_prog
174  *     do_ur_io
175  *     ur_int_handler
176  *
177  * alloc_chan_prog allocates and builds the channel program
178  * free_chan_prog frees memory of the channel program
179  *
180  * do_ur_io issues the channel program to the device and blocks waiting
181  * on a completion event it publishes at urd->io_done. The function
182  * serialises itself on the device's mutex so that only one I/O
183  * is issued at a time (and that I/O is synchronous).
184  *
185  * ur_int_handler catches the "I/O done" interrupt, writes the
186  * subchannel status word into the scsw member of the urdev structure
187  * and complete()s the io_done to wake the waiting do_ur_io.
188  *
189  * The caller of do_ur_io is responsible for kfree()ing the channel program
190  * address pointer that alloc_chan_prog returned.
191  */
192 
free_chan_prog(struct ccw1 * cpa)193 static void free_chan_prog(struct ccw1 *cpa)
194 {
195 	struct ccw1 *ptr = cpa;
196 
197 	while (ptr->cda) {
198 		kfree((void *)(addr_t) ptr->cda);
199 		ptr++;
200 	}
201 	kfree(cpa);
202 }
203 
204 /*
205  * alloc_chan_prog
206  * The channel program we use is write commands chained together
207  * with a final NOP CCW command-chained on (which ensures that CE and DE
208  * are presented together in a single interrupt instead of as separate
209  * interrupts unless an incorrect length indication kicks in first). The
210  * data length in each CCW is reclen.
211  */
alloc_chan_prog(const char __user * ubuf,int rec_count,int reclen)212 static struct ccw1 *alloc_chan_prog(const char __user *ubuf, int rec_count,
213 				    int reclen)
214 {
215 	struct ccw1 *cpa;
216 	void *kbuf;
217 	int i;
218 
219 	TRACE("alloc_chan_prog(%p, %i, %i)\n", ubuf, rec_count, reclen);
220 
221 	/*
222 	 * We chain a NOP onto the writes to force CE+DE together.
223 	 * That means we allocate room for CCWs to cover count/reclen
224 	 * records plus a NOP.
225 	 */
226 	cpa = kcalloc(rec_count + 1, sizeof(struct ccw1),
227 		      GFP_KERNEL | GFP_DMA);
228 	if (!cpa)
229 		return ERR_PTR(-ENOMEM);
230 
231 	for (i = 0; i < rec_count; i++) {
232 		cpa[i].cmd_code = WRITE_CCW_CMD;
233 		cpa[i].flags = CCW_FLAG_CC | CCW_FLAG_SLI;
234 		cpa[i].count = reclen;
235 		kbuf = kmalloc(reclen, GFP_KERNEL | GFP_DMA);
236 		if (!kbuf) {
237 			free_chan_prog(cpa);
238 			return ERR_PTR(-ENOMEM);
239 		}
240 		cpa[i].cda = (u32)(addr_t) kbuf;
241 		if (copy_from_user(kbuf, ubuf, reclen)) {
242 			free_chan_prog(cpa);
243 			return ERR_PTR(-EFAULT);
244 		}
245 		ubuf += reclen;
246 	}
247 	/* The following NOP CCW forces CE+DE to be presented together */
248 	cpa[i].cmd_code = CCW_CMD_NOOP;
249 	return cpa;
250 }
251 
do_ur_io(struct urdev * urd,struct ccw1 * cpa)252 static int do_ur_io(struct urdev *urd, struct ccw1 *cpa)
253 {
254 	int rc;
255 	struct ccw_device *cdev = urd->cdev;
256 	DECLARE_COMPLETION_ONSTACK(event);
257 
258 	TRACE("do_ur_io: cpa=%p\n", cpa);
259 
260 	rc = mutex_lock_interruptible(&urd->io_mutex);
261 	if (rc)
262 		return rc;
263 
264 	urd->io_done = &event;
265 
266 	spin_lock_irq(get_ccwdev_lock(cdev));
267 	rc = ccw_device_start(cdev, cpa, 1, 0, 0);
268 	spin_unlock_irq(get_ccwdev_lock(cdev));
269 
270 	TRACE("do_ur_io: ccw_device_start returned %d\n", rc);
271 	if (rc)
272 		goto out;
273 
274 	wait_for_completion(&event);
275 	TRACE("do_ur_io: I/O complete\n");
276 	rc = 0;
277 
278 out:
279 	mutex_unlock(&urd->io_mutex);
280 	return rc;
281 }
282 
ur_uevent(struct work_struct * ws)283 static void ur_uevent(struct work_struct *ws)
284 {
285 	struct urdev *urd = container_of(ws, struct urdev, uevent_work);
286 	char *envp[] = {
287 		"EVENT=unsol_de",	/* Unsolicited device-end interrupt */
288 		NULL
289 	};
290 
291 	kobject_uevent_env(&urd->cdev->dev.kobj, KOBJ_CHANGE, envp);
292 	urdev_put(urd);
293 }
294 
295 /*
296  * ur interrupt handler, called from the ccw_device layer
297  */
ur_int_handler(struct ccw_device * cdev,unsigned long intparm,struct irb * irb)298 static void ur_int_handler(struct ccw_device *cdev, unsigned long intparm,
299 			   struct irb *irb)
300 {
301 	struct urdev *urd;
302 
303 	if (!IS_ERR(irb)) {
304 		TRACE("ur_int_handler: intparm=0x%lx cstat=%02x dstat=%02x res=%u\n",
305 		      intparm, irb->scsw.cmd.cstat, irb->scsw.cmd.dstat,
306 		      irb->scsw.cmd.count);
307 	}
308 	urd = dev_get_drvdata(&cdev->dev);
309 	if (!intparm) {
310 		TRACE("ur_int_handler: unsolicited interrupt\n");
311 
312 		if (scsw_dstat(&irb->scsw) & DEV_STAT_DEV_END) {
313 			/*
314 			 * Userspace might be interested in a transition to
315 			 * device-ready state.
316 			 */
317 			urdev_get(urd);
318 			schedule_work(&urd->uevent_work);
319 		}
320 
321 		return;
322 	}
323 	/* On special conditions irb is an error pointer */
324 	if (IS_ERR(irb))
325 		urd->io_request_rc = PTR_ERR(irb);
326 	else if (irb->scsw.cmd.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END))
327 		urd->io_request_rc = 0;
328 	else
329 		urd->io_request_rc = -EIO;
330 
331 	complete(urd->io_done);
332 }
333 
334 /*
335  * reclen sysfs attribute - The record length to be used for write CCWs
336  */
ur_attr_reclen_show(struct device * dev,struct device_attribute * attr,char * buf)337 static ssize_t ur_attr_reclen_show(struct device *dev,
338 				   struct device_attribute *attr, char *buf)
339 {
340 	struct urdev *urd;
341 	int rc;
342 
343 	urd = urdev_get_from_cdev(to_ccwdev(dev));
344 	if (!urd)
345 		return -ENODEV;
346 	rc = sprintf(buf, "%zu\n", urd->reclen);
347 	urdev_put(urd);
348 	return rc;
349 }
350 
351 static DEVICE_ATTR(reclen, 0444, ur_attr_reclen_show, NULL);
352 
ur_create_attributes(struct device * dev)353 static int ur_create_attributes(struct device *dev)
354 {
355 	return device_create_file(dev, &dev_attr_reclen);
356 }
357 
ur_remove_attributes(struct device * dev)358 static void ur_remove_attributes(struct device *dev)
359 {
360 	device_remove_file(dev, &dev_attr_reclen);
361 }
362 
363 /*
364  * diagnose code 0x210 - retrieve device information
365  * cc=0  normal completion, we have a real device
366  * cc=1  CP paging error
367  * cc=2  The virtual device exists, but is not associated with a real device
368  * cc=3  Invalid device address, or the virtual device does not exist
369  */
get_urd_class(struct urdev * urd)370 static int get_urd_class(struct urdev *urd)
371 {
372 	static struct diag210 ur_diag210;
373 	int cc;
374 
375 	ur_diag210.vrdcdvno = urd->dev_id.devno;
376 	ur_diag210.vrdclen = sizeof(struct diag210);
377 
378 	cc = diag210(&ur_diag210);
379 	switch (cc) {
380 	case 0:
381 		return -EOPNOTSUPP;
382 	case 2:
383 		return ur_diag210.vrdcvcla; /* virtual device class */
384 	case 3:
385 		return -ENODEV;
386 	default:
387 		return -EIO;
388 	}
389 }
390 
391 /*
392  * Allocation and freeing of urfile structures
393  */
urfile_alloc(struct urdev * urd)394 static struct urfile *urfile_alloc(struct urdev *urd)
395 {
396 	struct urfile *urf;
397 
398 	urf = kzalloc(sizeof(struct urfile), GFP_KERNEL);
399 	if (!urf)
400 		return NULL;
401 	urf->urd = urd;
402 
403 	TRACE("urfile_alloc: urd=%p urf=%p rl=%zu\n", urd, urf,
404 	      urf->dev_reclen);
405 
406 	return urf;
407 }
408 
urfile_free(struct urfile * urf)409 static void urfile_free(struct urfile *urf)
410 {
411 	TRACE("urfile_free: urf=%p urd=%p\n", urf, urf->urd);
412 	kfree(urf);
413 }
414 
415 /*
416  * The fops implementation of the character device driver
417  */
do_write(struct urdev * urd,const char __user * udata,size_t count,size_t reclen,loff_t * ppos)418 static ssize_t do_write(struct urdev *urd, const char __user *udata,
419 			size_t count, size_t reclen, loff_t *ppos)
420 {
421 	struct ccw1 *cpa;
422 	int rc;
423 
424 	cpa = alloc_chan_prog(udata, count / reclen, reclen);
425 	if (IS_ERR(cpa))
426 		return PTR_ERR(cpa);
427 
428 	rc = do_ur_io(urd, cpa);
429 	if (rc)
430 		goto fail_kfree_cpa;
431 
432 	if (urd->io_request_rc) {
433 		rc = urd->io_request_rc;
434 		goto fail_kfree_cpa;
435 	}
436 	*ppos += count;
437 	rc = count;
438 
439 fail_kfree_cpa:
440 	free_chan_prog(cpa);
441 	return rc;
442 }
443 
ur_write(struct file * file,const char __user * udata,size_t count,loff_t * ppos)444 static ssize_t ur_write(struct file *file, const char __user *udata,
445 			size_t count, loff_t *ppos)
446 {
447 	struct urfile *urf = file->private_data;
448 
449 	TRACE("ur_write: count=%zu\n", count);
450 
451 	if (count == 0)
452 		return 0;
453 
454 	if (count % urf->dev_reclen)
455 		return -EINVAL;	/* count must be a multiple of reclen */
456 
457 	if (count > urf->dev_reclen * MAX_RECS_PER_IO)
458 		count = urf->dev_reclen * MAX_RECS_PER_IO;
459 
460 	return do_write(urf->urd, udata, count, urf->dev_reclen, ppos);
461 }
462 
463 /*
464  * diagnose code 0x14 subcode 0x0028 - position spool file to designated
465  *				       record
466  * cc=0  normal completion
467  * cc=2  no file active on the virtual reader or device not ready
468  * cc=3  record specified is beyond EOF
469  */
diag_position_to_record(int devno,int record)470 static int diag_position_to_record(int devno, int record)
471 {
472 	int cc;
473 
474 	cc = diag14(record, devno, 0x28);
475 	switch (cc) {
476 	case 0:
477 		return 0;
478 	case 2:
479 		return -ENOMEDIUM;
480 	case 3:
481 		return -ENODATA; /* position beyond end of file */
482 	default:
483 		return -EIO;
484 	}
485 }
486 
487 /*
488  * diagnose code 0x14 subcode 0x0000 - read next spool file buffer
489  * cc=0  normal completion
490  * cc=1  EOF reached
491  * cc=2  no file active on the virtual reader, and no file eligible
492  * cc=3  file already active on the virtual reader or specified virtual
493  *	 reader does not exist or is not a reader
494  */
diag_read_file(int devno,char * buf)495 static int diag_read_file(int devno, char *buf)
496 {
497 	int cc;
498 
499 	cc = diag14((unsigned long) buf, devno, 0x00);
500 	switch (cc) {
501 	case 0:
502 		return 0;
503 	case 1:
504 		return -ENODATA;
505 	case 2:
506 		return -ENOMEDIUM;
507 	default:
508 		return -EIO;
509 	}
510 }
511 
diag14_read(struct file * file,char __user * ubuf,size_t count,loff_t * offs)512 static ssize_t diag14_read(struct file *file, char __user *ubuf, size_t count,
513 			   loff_t *offs)
514 {
515 	size_t len, copied, res;
516 	char *buf;
517 	int rc;
518 	u16 reclen;
519 	struct urdev *urd;
520 
521 	urd = ((struct urfile *) file->private_data)->urd;
522 	reclen = ((struct urfile *) file->private_data)->file_reclen;
523 
524 	rc = diag_position_to_record(urd->dev_id.devno, *offs / PAGE_SIZE + 1);
525 	if (rc == -ENODATA)
526 		return 0;
527 	if (rc)
528 		return rc;
529 
530 	len = min((size_t) PAGE_SIZE, count);
531 	buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
532 	if (!buf)
533 		return -ENOMEM;
534 
535 	copied = 0;
536 	res = (size_t) (*offs % PAGE_SIZE);
537 	do {
538 		rc = diag_read_file(urd->dev_id.devno, buf);
539 		if (rc == -ENODATA) {
540 			break;
541 		}
542 		if (rc)
543 			goto fail;
544 		if (reclen && (copied == 0) && (*offs < PAGE_SIZE))
545 			*((u16 *) &buf[FILE_RECLEN_OFFSET]) = reclen;
546 		len = min(count - copied, PAGE_SIZE - res);
547 		if (copy_to_user(ubuf + copied, buf + res, len)) {
548 			rc = -EFAULT;
549 			goto fail;
550 		}
551 		res = 0;
552 		copied += len;
553 	} while (copied != count);
554 
555 	*offs += copied;
556 	rc = copied;
557 fail:
558 	free_page((unsigned long) buf);
559 	return rc;
560 }
561 
ur_read(struct file * file,char __user * ubuf,size_t count,loff_t * offs)562 static ssize_t ur_read(struct file *file, char __user *ubuf, size_t count,
563 		       loff_t *offs)
564 {
565 	struct urdev *urd;
566 	int rc;
567 
568 	TRACE("ur_read: count=%zu ppos=%li\n", count, (unsigned long) *offs);
569 
570 	if (count == 0)
571 		return 0;
572 
573 	urd = ((struct urfile *) file->private_data)->urd;
574 	rc = mutex_lock_interruptible(&urd->io_mutex);
575 	if (rc)
576 		return rc;
577 	rc = diag14_read(file, ubuf, count, offs);
578 	mutex_unlock(&urd->io_mutex);
579 	return rc;
580 }
581 
582 /*
583  * diagnose code 0x14 subcode 0x0fff - retrieve next file descriptor
584  * cc=0  normal completion
585  * cc=1  no files on reader queue or no subsequent file
586  * cc=2  spid specified is invalid
587  */
diag_read_next_file_info(struct file_control_block * buf,int spid)588 static int diag_read_next_file_info(struct file_control_block *buf, int spid)
589 {
590 	int cc;
591 
592 	cc = diag14((unsigned long) buf, spid, 0xfff);
593 	switch (cc) {
594 	case 0:
595 		return 0;
596 	default:
597 		return -ENODATA;
598 	}
599 }
600 
verify_uri_device(struct urdev * urd)601 static int verify_uri_device(struct urdev *urd)
602 {
603 	struct file_control_block *fcb;
604 	char *buf;
605 	int rc;
606 
607 	fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
608 	if (!fcb)
609 		return -ENOMEM;
610 
611 	/* check for empty reader device (beginning of chain) */
612 	rc = diag_read_next_file_info(fcb, 0);
613 	if (rc)
614 		goto fail_free_fcb;
615 
616 	/* if file is in hold status, we do not read it */
617 	if (fcb->file_stat & (FLG_SYSTEM_HOLD | FLG_USER_HOLD)) {
618 		rc = -EPERM;
619 		goto fail_free_fcb;
620 	}
621 
622 	/* open file on virtual reader	*/
623 	buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
624 	if (!buf) {
625 		rc = -ENOMEM;
626 		goto fail_free_fcb;
627 	}
628 	rc = diag_read_file(urd->dev_id.devno, buf);
629 	if ((rc != 0) && (rc != -ENODATA)) /* EOF does not hurt */
630 		goto fail_free_buf;
631 
632 	/* check if the file on top of the queue is open now */
633 	rc = diag_read_next_file_info(fcb, 0);
634 	if (rc)
635 		goto fail_free_buf;
636 	if (!(fcb->file_stat & FLG_IN_USE)) {
637 		rc = -EMFILE;
638 		goto fail_free_buf;
639 	}
640 	rc = 0;
641 
642 fail_free_buf:
643 	free_page((unsigned long) buf);
644 fail_free_fcb:
645 	kfree(fcb);
646 	return rc;
647 }
648 
verify_device(struct urdev * urd)649 static int verify_device(struct urdev *urd)
650 {
651 	switch (urd->class) {
652 	case DEV_CLASS_UR_O:
653 		return 0; /* no check needed here */
654 	case DEV_CLASS_UR_I:
655 		return verify_uri_device(urd);
656 	default:
657 		return -EOPNOTSUPP;
658 	}
659 }
660 
get_uri_file_reclen(struct urdev * urd)661 static int get_uri_file_reclen(struct urdev *urd)
662 {
663 	struct file_control_block *fcb;
664 	int rc;
665 
666 	fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
667 	if (!fcb)
668 		return -ENOMEM;
669 	rc = diag_read_next_file_info(fcb, 0);
670 	if (rc)
671 		goto fail_free;
672 	if (fcb->file_stat & FLG_CP_DUMP)
673 		rc = 0;
674 	else
675 		rc = fcb->rec_len;
676 
677 fail_free:
678 	kfree(fcb);
679 	return rc;
680 }
681 
get_file_reclen(struct urdev * urd)682 static int get_file_reclen(struct urdev *urd)
683 {
684 	switch (urd->class) {
685 	case DEV_CLASS_UR_O:
686 		return 0;
687 	case DEV_CLASS_UR_I:
688 		return get_uri_file_reclen(urd);
689 	default:
690 		return -EOPNOTSUPP;
691 	}
692 }
693 
ur_open(struct inode * inode,struct file * file)694 static int ur_open(struct inode *inode, struct file *file)
695 {
696 	u16 devno;
697 	struct urdev *urd;
698 	struct urfile *urf;
699 	unsigned short accmode;
700 	int rc;
701 
702 	accmode = file->f_flags & O_ACCMODE;
703 
704 	if (accmode == O_RDWR)
705 		return -EACCES;
706 	/*
707 	 * We treat the minor number as the devno of the ur device
708 	 * to find in the driver tree.
709 	 */
710 	devno = iminor(file_inode(file));
711 
712 	urd = urdev_get_from_devno(devno);
713 	if (!urd) {
714 		rc = -ENXIO;
715 		goto out;
716 	}
717 
718 	spin_lock(&urd->open_lock);
719 	while (urd->open_flag) {
720 		spin_unlock(&urd->open_lock);
721 		if (file->f_flags & O_NONBLOCK) {
722 			rc = -EBUSY;
723 			goto fail_put;
724 		}
725 		if (wait_event_interruptible(urd->wait, urd->open_flag == 0)) {
726 			rc = -ERESTARTSYS;
727 			goto fail_put;
728 		}
729 		spin_lock(&urd->open_lock);
730 	}
731 	urd->open_flag++;
732 	spin_unlock(&urd->open_lock);
733 
734 	TRACE("ur_open\n");
735 
736 	if (((accmode == O_RDONLY) && (urd->class != DEV_CLASS_UR_I)) ||
737 	    ((accmode == O_WRONLY) && (urd->class != DEV_CLASS_UR_O))) {
738 		TRACE("ur_open: unsupported dev class (%d)\n", urd->class);
739 		rc = -EACCES;
740 		goto fail_unlock;
741 	}
742 
743 	rc = verify_device(urd);
744 	if (rc)
745 		goto fail_unlock;
746 
747 	urf = urfile_alloc(urd);
748 	if (!urf) {
749 		rc = -ENOMEM;
750 		goto fail_unlock;
751 	}
752 
753 	urf->dev_reclen = urd->reclen;
754 	rc = get_file_reclen(urd);
755 	if (rc < 0)
756 		goto fail_urfile_free;
757 	urf->file_reclen = rc;
758 	file->private_data = urf;
759 	return 0;
760 
761 fail_urfile_free:
762 	urfile_free(urf);
763 fail_unlock:
764 	spin_lock(&urd->open_lock);
765 	urd->open_flag--;
766 	spin_unlock(&urd->open_lock);
767 fail_put:
768 	urdev_put(urd);
769 out:
770 	return rc;
771 }
772 
ur_release(struct inode * inode,struct file * file)773 static int ur_release(struct inode *inode, struct file *file)
774 {
775 	struct urfile *urf = file->private_data;
776 
777 	TRACE("ur_release\n");
778 	spin_lock(&urf->urd->open_lock);
779 	urf->urd->open_flag--;
780 	spin_unlock(&urf->urd->open_lock);
781 	wake_up_interruptible(&urf->urd->wait);
782 	urdev_put(urf->urd);
783 	urfile_free(urf);
784 	return 0;
785 }
786 
ur_llseek(struct file * file,loff_t offset,int whence)787 static loff_t ur_llseek(struct file *file, loff_t offset, int whence)
788 {
789 	if ((file->f_flags & O_ACCMODE) != O_RDONLY)
790 		return -ESPIPE; /* seek allowed only for reader */
791 	if (offset % PAGE_SIZE)
792 		return -ESPIPE; /* only multiples of 4K allowed */
793 	return no_seek_end_llseek(file, offset, whence);
794 }
795 
796 static const struct file_operations ur_fops = {
797 	.owner	 = THIS_MODULE,
798 	.open	 = ur_open,
799 	.release = ur_release,
800 	.read	 = ur_read,
801 	.write	 = ur_write,
802 	.llseek  = ur_llseek,
803 };
804 
805 /*
806  * ccw_device infrastructure:
807  *     ur_probe creates the struct urdev (with refcount = 1), the device
808  *     attributes, sets up the interrupt handler and validates the virtual
809  *     unit record device.
810  *     ur_remove removes the device attributes and drops the reference to
811  *     struct urdev.
812  *
813  *     ur_probe, ur_remove, ur_set_online and ur_set_offline are serialized
814  *     by the vmur_mutex lock.
815  *
816  *     urd->char_device is used as indication that the online function has
817  *     been completed successfully.
818  */
ur_probe(struct ccw_device * cdev)819 static int ur_probe(struct ccw_device *cdev)
820 {
821 	struct urdev *urd;
822 	int rc;
823 
824 	TRACE("ur_probe: cdev=%p\n", cdev);
825 
826 	mutex_lock(&vmur_mutex);
827 	urd = urdev_alloc(cdev);
828 	if (!urd) {
829 		rc = -ENOMEM;
830 		goto fail_unlock;
831 	}
832 
833 	rc = ur_create_attributes(&cdev->dev);
834 	if (rc) {
835 		rc = -ENOMEM;
836 		goto fail_urdev_put;
837 	}
838 
839 	/* validate virtual unit record device */
840 	urd->class = get_urd_class(urd);
841 	if (urd->class < 0) {
842 		rc = urd->class;
843 		goto fail_remove_attr;
844 	}
845 	if ((urd->class != DEV_CLASS_UR_I) && (urd->class != DEV_CLASS_UR_O)) {
846 		rc = -EOPNOTSUPP;
847 		goto fail_remove_attr;
848 	}
849 	spin_lock_irq(get_ccwdev_lock(cdev));
850 	dev_set_drvdata(&cdev->dev, urd);
851 	cdev->handler = ur_int_handler;
852 	spin_unlock_irq(get_ccwdev_lock(cdev));
853 
854 	mutex_unlock(&vmur_mutex);
855 	return 0;
856 
857 fail_remove_attr:
858 	ur_remove_attributes(&cdev->dev);
859 fail_urdev_put:
860 	urdev_put(urd);
861 fail_unlock:
862 	mutex_unlock(&vmur_mutex);
863 	return rc;
864 }
865 
ur_set_online(struct ccw_device * cdev)866 static int ur_set_online(struct ccw_device *cdev)
867 {
868 	struct urdev *urd;
869 	int minor, major, rc;
870 	char node_id[16];
871 
872 	TRACE("ur_set_online: cdev=%p\n", cdev);
873 
874 	mutex_lock(&vmur_mutex);
875 	urd = urdev_get_from_cdev(cdev);
876 	if (!urd) {
877 		/* ur_remove already deleted our urd */
878 		rc = -ENODEV;
879 		goto fail_unlock;
880 	}
881 
882 	if (urd->char_device) {
883 		/* Another ur_set_online was faster */
884 		rc = -EBUSY;
885 		goto fail_urdev_put;
886 	}
887 
888 	minor = urd->dev_id.devno;
889 	major = MAJOR(ur_first_dev_maj_min);
890 
891 	urd->char_device = cdev_alloc();
892 	if (!urd->char_device) {
893 		rc = -ENOMEM;
894 		goto fail_urdev_put;
895 	}
896 
897 	urd->char_device->ops = &ur_fops;
898 	urd->char_device->owner = ur_fops.owner;
899 
900 	rc = cdev_add(urd->char_device, MKDEV(major, minor), 1);
901 	if (rc)
902 		goto fail_free_cdev;
903 	if (urd->cdev->id.cu_type == READER_PUNCH_DEVTYPE) {
904 		if (urd->class == DEV_CLASS_UR_I)
905 			sprintf(node_id, "vmrdr-%s", dev_name(&cdev->dev));
906 		if (urd->class == DEV_CLASS_UR_O)
907 			sprintf(node_id, "vmpun-%s", dev_name(&cdev->dev));
908 	} else if (urd->cdev->id.cu_type == PRINTER_DEVTYPE) {
909 		sprintf(node_id, "vmprt-%s", dev_name(&cdev->dev));
910 	} else {
911 		rc = -EOPNOTSUPP;
912 		goto fail_free_cdev;
913 	}
914 
915 	urd->device = device_create(vmur_class, &cdev->dev,
916 				    urd->char_device->dev, NULL, "%s", node_id);
917 	if (IS_ERR(urd->device)) {
918 		rc = PTR_ERR(urd->device);
919 		TRACE("ur_set_online: device_create rc=%d\n", rc);
920 		goto fail_free_cdev;
921 	}
922 	urdev_put(urd);
923 	mutex_unlock(&vmur_mutex);
924 	return 0;
925 
926 fail_free_cdev:
927 	cdev_del(urd->char_device);
928 	urd->char_device = NULL;
929 fail_urdev_put:
930 	urdev_put(urd);
931 fail_unlock:
932 	mutex_unlock(&vmur_mutex);
933 	return rc;
934 }
935 
ur_set_offline_force(struct ccw_device * cdev,int force)936 static int ur_set_offline_force(struct ccw_device *cdev, int force)
937 {
938 	struct urdev *urd;
939 	int rc;
940 
941 	TRACE("ur_set_offline: cdev=%p\n", cdev);
942 	urd = urdev_get_from_cdev(cdev);
943 	if (!urd)
944 		/* ur_remove already deleted our urd */
945 		return -ENODEV;
946 	if (!urd->char_device) {
947 		/* Another ur_set_offline was faster */
948 		rc = -EBUSY;
949 		goto fail_urdev_put;
950 	}
951 	if (!force && (refcount_read(&urd->ref_count) > 2)) {
952 		/* There is still a user of urd (e.g. ur_open) */
953 		TRACE("ur_set_offline: BUSY\n");
954 		rc = -EBUSY;
955 		goto fail_urdev_put;
956 	}
957 	if (cancel_work_sync(&urd->uevent_work)) {
958 		/* Work not run yet - need to release reference here */
959 		urdev_put(urd);
960 	}
961 	device_destroy(vmur_class, urd->char_device->dev);
962 	cdev_del(urd->char_device);
963 	urd->char_device = NULL;
964 	rc = 0;
965 
966 fail_urdev_put:
967 	urdev_put(urd);
968 	return rc;
969 }
970 
ur_set_offline(struct ccw_device * cdev)971 static int ur_set_offline(struct ccw_device *cdev)
972 {
973 	int rc;
974 
975 	mutex_lock(&vmur_mutex);
976 	rc = ur_set_offline_force(cdev, 0);
977 	mutex_unlock(&vmur_mutex);
978 	return rc;
979 }
980 
ur_remove(struct ccw_device * cdev)981 static void ur_remove(struct ccw_device *cdev)
982 {
983 	unsigned long flags;
984 
985 	TRACE("ur_remove\n");
986 
987 	mutex_lock(&vmur_mutex);
988 
989 	if (cdev->online)
990 		ur_set_offline_force(cdev, 1);
991 	ur_remove_attributes(&cdev->dev);
992 
993 	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
994 	urdev_put(dev_get_drvdata(&cdev->dev));
995 	dev_set_drvdata(&cdev->dev, NULL);
996 	cdev->handler = NULL;
997 	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
998 
999 	mutex_unlock(&vmur_mutex);
1000 }
1001 
1002 /*
1003  * Module initialisation and cleanup
1004  */
ur_init(void)1005 static int __init ur_init(void)
1006 {
1007 	int rc;
1008 	dev_t dev;
1009 
1010 	if (!MACHINE_IS_VM) {
1011 		pr_err("The %s cannot be loaded without z/VM\n",
1012 		       ur_banner);
1013 		return -ENODEV;
1014 	}
1015 
1016 	vmur_dbf = debug_register("vmur", 4, 1, 4 * sizeof(long));
1017 	if (!vmur_dbf)
1018 		return -ENOMEM;
1019 	rc = debug_register_view(vmur_dbf, &debug_sprintf_view);
1020 	if (rc)
1021 		goto fail_free_dbf;
1022 
1023 	debug_set_level(vmur_dbf, 6);
1024 
1025 	vmur_class = class_create("vmur");
1026 	if (IS_ERR(vmur_class)) {
1027 		rc = PTR_ERR(vmur_class);
1028 		goto fail_free_dbf;
1029 	}
1030 
1031 	rc = ccw_driver_register(&ur_driver);
1032 	if (rc)
1033 		goto fail_class_destroy;
1034 
1035 	rc = alloc_chrdev_region(&dev, 0, NUM_MINORS, "vmur");
1036 	if (rc) {
1037 		pr_err("Kernel function alloc_chrdev_region failed with "
1038 		       "error code %d\n", rc);
1039 		goto fail_unregister_driver;
1040 	}
1041 	ur_first_dev_maj_min = MKDEV(MAJOR(dev), 0);
1042 
1043 	pr_info("%s loaded.\n", ur_banner);
1044 	return 0;
1045 
1046 fail_unregister_driver:
1047 	ccw_driver_unregister(&ur_driver);
1048 fail_class_destroy:
1049 	class_destroy(vmur_class);
1050 fail_free_dbf:
1051 	debug_unregister(vmur_dbf);
1052 	return rc;
1053 }
1054 
ur_exit(void)1055 static void __exit ur_exit(void)
1056 {
1057 	unregister_chrdev_region(ur_first_dev_maj_min, NUM_MINORS);
1058 	ccw_driver_unregister(&ur_driver);
1059 	class_destroy(vmur_class);
1060 	debug_unregister(vmur_dbf);
1061 	pr_info("%s unloaded.\n", ur_banner);
1062 }
1063 
1064 module_init(ur_init);
1065 module_exit(ur_exit);
1066