xref: /linux/drivers/s390/char/vmur.c (revision 79790b6818e96c58fe2bffee1b418c16e64e7b80)
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 const struct class vmur_class = {
52 	.name = "vmur",
53 };
54 static struct debug_info *vmur_dbf;
55 
56 /* We put the device's record length (for writes) in the driver_info field */
57 static struct ccw_device_id ur_ids[] = {
58 	{ CCWDEV_CU_DI(READER_PUNCH_DEVTYPE, 80) },
59 	{ CCWDEV_CU_DI(PRINTER_DEVTYPE, 132) },
60 	{ /* end of list */ }
61 };
62 
63 MODULE_DEVICE_TABLE(ccw, ur_ids);
64 
65 static int ur_probe(struct ccw_device *cdev);
66 static void ur_remove(struct ccw_device *cdev);
67 static int ur_set_online(struct ccw_device *cdev);
68 static int ur_set_offline(struct ccw_device *cdev);
69 
70 static struct ccw_driver ur_driver = {
71 	.driver = {
72 		.name	= "vmur",
73 		.owner	= THIS_MODULE,
74 	},
75 	.ids		= ur_ids,
76 	.probe		= ur_probe,
77 	.remove		= ur_remove,
78 	.set_online	= ur_set_online,
79 	.set_offline	= ur_set_offline,
80 	.int_class	= IRQIO_VMR,
81 };
82 
83 static DEFINE_MUTEX(vmur_mutex);
84 
85 static void ur_uevent(struct work_struct *ws);
86 
87 /*
88  * Allocation, freeing, getting and putting of urdev structures
89  *
90  * Each ur device (urd) contains a reference to its corresponding ccw device
91  * (cdev) using the urd->cdev pointer. Each ccw device has a reference to the
92  * ur device using dev_get_drvdata(&cdev->dev) pointer.
93  *
94  * urd references:
95  * - ur_probe gets a urd reference, ur_remove drops the reference
96  *   dev_get_drvdata(&cdev->dev)
97  * - ur_open gets a urd reference, ur_release drops the reference
98  *   (urf->urd)
99  *
100  * cdev references:
101  * - urdev_alloc get a cdev reference (urd->cdev)
102  * - urdev_free drops the cdev reference (urd->cdev)
103  *
104  * Setting and clearing of dev_get_drvdata(&cdev->dev) is protected by the ccwdev lock
105  */
urdev_alloc(struct ccw_device * cdev)106 static struct urdev *urdev_alloc(struct ccw_device *cdev)
107 {
108 	struct urdev *urd;
109 
110 	urd = kzalloc(sizeof(struct urdev), GFP_KERNEL);
111 	if (!urd)
112 		return NULL;
113 	urd->reclen = cdev->id.driver_info;
114 	ccw_device_get_id(cdev, &urd->dev_id);
115 	mutex_init(&urd->io_mutex);
116 	init_waitqueue_head(&urd->wait);
117 	INIT_WORK(&urd->uevent_work, ur_uevent);
118 	spin_lock_init(&urd->open_lock);
119 	refcount_set(&urd->ref_count,  1);
120 	urd->cdev = cdev;
121 	get_device(&cdev->dev);
122 	return urd;
123 }
124 
urdev_free(struct urdev * urd)125 static void urdev_free(struct urdev *urd)
126 {
127 	TRACE("urdev_free: %p\n", urd);
128 	if (urd->cdev)
129 		put_device(&urd->cdev->dev);
130 	kfree(urd);
131 }
132 
urdev_get(struct urdev * urd)133 static void urdev_get(struct urdev *urd)
134 {
135 	refcount_inc(&urd->ref_count);
136 }
137 
urdev_get_from_cdev(struct ccw_device * cdev)138 static struct urdev *urdev_get_from_cdev(struct ccw_device *cdev)
139 {
140 	struct urdev *urd;
141 	unsigned long flags;
142 
143 	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
144 	urd = dev_get_drvdata(&cdev->dev);
145 	if (urd)
146 		urdev_get(urd);
147 	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
148 	return urd;
149 }
150 
urdev_get_from_devno(u16 devno)151 static struct urdev *urdev_get_from_devno(u16 devno)
152 {
153 	char bus_id[16];
154 	struct ccw_device *cdev;
155 	struct urdev *urd;
156 
157 	sprintf(bus_id, "0.0.%04x", devno);
158 	cdev = get_ccwdev_by_busid(&ur_driver, bus_id);
159 	if (!cdev)
160 		return NULL;
161 	urd = urdev_get_from_cdev(cdev);
162 	put_device(&cdev->dev);
163 	return urd;
164 }
165 
urdev_put(struct urdev * urd)166 static void urdev_put(struct urdev *urd)
167 {
168 	if (refcount_dec_and_test(&urd->ref_count))
169 		urdev_free(urd);
170 }
171 
172 /*
173  * Low-level functions to do I/O to a ur device.
174  *     alloc_chan_prog
175  *     free_chan_prog
176  *     do_ur_io
177  *     ur_int_handler
178  *
179  * alloc_chan_prog allocates and builds the channel program
180  * free_chan_prog frees memory of the channel program
181  *
182  * do_ur_io issues the channel program to the device and blocks waiting
183  * on a completion event it publishes at urd->io_done. The function
184  * serialises itself on the device's mutex so that only one I/O
185  * is issued at a time (and that I/O is synchronous).
186  *
187  * ur_int_handler catches the "I/O done" interrupt, writes the
188  * subchannel status word into the scsw member of the urdev structure
189  * and complete()s the io_done to wake the waiting do_ur_io.
190  *
191  * The caller of do_ur_io is responsible for kfree()ing the channel program
192  * address pointer that alloc_chan_prog returned.
193  */
194 
free_chan_prog(struct ccw1 * cpa)195 static void free_chan_prog(struct ccw1 *cpa)
196 {
197 	struct ccw1 *ptr = cpa;
198 
199 	while (ptr->cda) {
200 		kfree(dma32_to_virt(ptr->cda));
201 		ptr++;
202 	}
203 	kfree(cpa);
204 }
205 
206 /*
207  * alloc_chan_prog
208  * The channel program we use is write commands chained together
209  * with a final NOP CCW command-chained on (which ensures that CE and DE
210  * are presented together in a single interrupt instead of as separate
211  * interrupts unless an incorrect length indication kicks in first). The
212  * data length in each CCW is reclen.
213  */
alloc_chan_prog(const char __user * ubuf,int rec_count,int reclen)214 static struct ccw1 *alloc_chan_prog(const char __user *ubuf, int rec_count,
215 				    int reclen)
216 {
217 	struct ccw1 *cpa;
218 	void *kbuf;
219 	int i;
220 
221 	TRACE("alloc_chan_prog(%p, %i, %i)\n", ubuf, rec_count, reclen);
222 
223 	/*
224 	 * We chain a NOP onto the writes to force CE+DE together.
225 	 * That means we allocate room for CCWs to cover count/reclen
226 	 * records plus a NOP.
227 	 */
228 	cpa = kcalloc(rec_count + 1, sizeof(struct ccw1),
229 		      GFP_KERNEL | GFP_DMA);
230 	if (!cpa)
231 		return ERR_PTR(-ENOMEM);
232 
233 	for (i = 0; i < rec_count; i++) {
234 		cpa[i].cmd_code = WRITE_CCW_CMD;
235 		cpa[i].flags = CCW_FLAG_CC | CCW_FLAG_SLI;
236 		cpa[i].count = reclen;
237 		kbuf = kmalloc(reclen, GFP_KERNEL | GFP_DMA);
238 		if (!kbuf) {
239 			free_chan_prog(cpa);
240 			return ERR_PTR(-ENOMEM);
241 		}
242 		cpa[i].cda = virt_to_dma32(kbuf);
243 		if (copy_from_user(kbuf, ubuf, reclen)) {
244 			free_chan_prog(cpa);
245 			return ERR_PTR(-EFAULT);
246 		}
247 		ubuf += reclen;
248 	}
249 	/* The following NOP CCW forces CE+DE to be presented together */
250 	cpa[i].cmd_code = CCW_CMD_NOOP;
251 	return cpa;
252 }
253 
do_ur_io(struct urdev * urd,struct ccw1 * cpa)254 static int do_ur_io(struct urdev *urd, struct ccw1 *cpa)
255 {
256 	int rc;
257 	struct ccw_device *cdev = urd->cdev;
258 	DECLARE_COMPLETION_ONSTACK(event);
259 
260 	TRACE("do_ur_io: cpa=%p\n", cpa);
261 
262 	rc = mutex_lock_interruptible(&urd->io_mutex);
263 	if (rc)
264 		return rc;
265 
266 	urd->io_done = &event;
267 
268 	spin_lock_irq(get_ccwdev_lock(cdev));
269 	rc = ccw_device_start(cdev, cpa, 1, 0, 0);
270 	spin_unlock_irq(get_ccwdev_lock(cdev));
271 
272 	TRACE("do_ur_io: ccw_device_start returned %d\n", rc);
273 	if (rc)
274 		goto out;
275 
276 	wait_for_completion(&event);
277 	TRACE("do_ur_io: I/O complete\n");
278 	rc = 0;
279 
280 out:
281 	mutex_unlock(&urd->io_mutex);
282 	return rc;
283 }
284 
ur_uevent(struct work_struct * ws)285 static void ur_uevent(struct work_struct *ws)
286 {
287 	struct urdev *urd = container_of(ws, struct urdev, uevent_work);
288 	char *envp[] = {
289 		"EVENT=unsol_de",	/* Unsolicited device-end interrupt */
290 		NULL
291 	};
292 
293 	kobject_uevent_env(&urd->cdev->dev.kobj, KOBJ_CHANGE, envp);
294 	urdev_put(urd);
295 }
296 
297 /*
298  * ur interrupt handler, called from the ccw_device layer
299  */
ur_int_handler(struct ccw_device * cdev,unsigned long intparm,struct irb * irb)300 static void ur_int_handler(struct ccw_device *cdev, unsigned long intparm,
301 			   struct irb *irb)
302 {
303 	struct urdev *urd;
304 
305 	if (!IS_ERR(irb)) {
306 		TRACE("ur_int_handler: intparm=0x%lx cstat=%02x dstat=%02x res=%u\n",
307 		      intparm, irb->scsw.cmd.cstat, irb->scsw.cmd.dstat,
308 		      irb->scsw.cmd.count);
309 	}
310 	urd = dev_get_drvdata(&cdev->dev);
311 	if (!intparm) {
312 		TRACE("ur_int_handler: unsolicited interrupt\n");
313 
314 		if (scsw_dstat(&irb->scsw) & DEV_STAT_DEV_END) {
315 			/*
316 			 * Userspace might be interested in a transition to
317 			 * device-ready state.
318 			 */
319 			urdev_get(urd);
320 			schedule_work(&urd->uevent_work);
321 		}
322 
323 		return;
324 	}
325 	/* On special conditions irb is an error pointer */
326 	if (IS_ERR(irb))
327 		urd->io_request_rc = PTR_ERR(irb);
328 	else if (irb->scsw.cmd.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END))
329 		urd->io_request_rc = 0;
330 	else
331 		urd->io_request_rc = -EIO;
332 
333 	complete(urd->io_done);
334 }
335 
336 /*
337  * reclen sysfs attribute - The record length to be used for write CCWs
338  */
ur_attr_reclen_show(struct device * dev,struct device_attribute * attr,char * buf)339 static ssize_t ur_attr_reclen_show(struct device *dev,
340 				   struct device_attribute *attr, char *buf)
341 {
342 	struct urdev *urd;
343 	int rc;
344 
345 	urd = urdev_get_from_cdev(to_ccwdev(dev));
346 	if (!urd)
347 		return -ENODEV;
348 	rc = sprintf(buf, "%zu\n", urd->reclen);
349 	urdev_put(urd);
350 	return rc;
351 }
352 
353 static DEVICE_ATTR(reclen, 0444, ur_attr_reclen_show, NULL);
354 
ur_create_attributes(struct device * dev)355 static int ur_create_attributes(struct device *dev)
356 {
357 	return device_create_file(dev, &dev_attr_reclen);
358 }
359 
ur_remove_attributes(struct device * dev)360 static void ur_remove_attributes(struct device *dev)
361 {
362 	device_remove_file(dev, &dev_attr_reclen);
363 }
364 
365 /*
366  * diagnose code 0x210 - retrieve device information
367  * cc=0  normal completion, we have a real device
368  * cc=1  CP paging error
369  * cc=2  The virtual device exists, but is not associated with a real device
370  * cc=3  Invalid device address, or the virtual device does not exist
371  */
get_urd_class(struct urdev * urd)372 static int get_urd_class(struct urdev *urd)
373 {
374 	static struct diag210 ur_diag210;
375 	int cc;
376 
377 	ur_diag210.vrdcdvno = urd->dev_id.devno;
378 	ur_diag210.vrdclen = sizeof(struct diag210);
379 
380 	cc = diag210(&ur_diag210);
381 	switch (cc) {
382 	case 0:
383 		return -EOPNOTSUPP;
384 	case 2:
385 		return ur_diag210.vrdcvcla; /* virtual device class */
386 	case 3:
387 		return -ENODEV;
388 	default:
389 		return -EIO;
390 	}
391 }
392 
393 /*
394  * Allocation and freeing of urfile structures
395  */
urfile_alloc(struct urdev * urd)396 static struct urfile *urfile_alloc(struct urdev *urd)
397 {
398 	struct urfile *urf;
399 
400 	urf = kzalloc(sizeof(struct urfile), GFP_KERNEL);
401 	if (!urf)
402 		return NULL;
403 	urf->urd = urd;
404 
405 	TRACE("urfile_alloc: urd=%p urf=%p rl=%zu\n", urd, urf,
406 	      urf->dev_reclen);
407 
408 	return urf;
409 }
410 
urfile_free(struct urfile * urf)411 static void urfile_free(struct urfile *urf)
412 {
413 	TRACE("urfile_free: urf=%p urd=%p\n", urf, urf->urd);
414 	kfree(urf);
415 }
416 
417 /*
418  * The fops implementation of the character device driver
419  */
do_write(struct urdev * urd,const char __user * udata,size_t count,size_t reclen,loff_t * ppos)420 static ssize_t do_write(struct urdev *urd, const char __user *udata,
421 			size_t count, size_t reclen, loff_t *ppos)
422 {
423 	struct ccw1 *cpa;
424 	int rc;
425 
426 	cpa = alloc_chan_prog(udata, count / reclen, reclen);
427 	if (IS_ERR(cpa))
428 		return PTR_ERR(cpa);
429 
430 	rc = do_ur_io(urd, cpa);
431 	if (rc)
432 		goto fail_kfree_cpa;
433 
434 	if (urd->io_request_rc) {
435 		rc = urd->io_request_rc;
436 		goto fail_kfree_cpa;
437 	}
438 	*ppos += count;
439 	rc = count;
440 
441 fail_kfree_cpa:
442 	free_chan_prog(cpa);
443 	return rc;
444 }
445 
ur_write(struct file * file,const char __user * udata,size_t count,loff_t * ppos)446 static ssize_t ur_write(struct file *file, const char __user *udata,
447 			size_t count, loff_t *ppos)
448 {
449 	struct urfile *urf = file->private_data;
450 
451 	TRACE("ur_write: count=%zu\n", count);
452 
453 	if (count == 0)
454 		return 0;
455 
456 	if (count % urf->dev_reclen)
457 		return -EINVAL;	/* count must be a multiple of reclen */
458 
459 	if (count > urf->dev_reclen * MAX_RECS_PER_IO)
460 		count = urf->dev_reclen * MAX_RECS_PER_IO;
461 
462 	return do_write(urf->urd, udata, count, urf->dev_reclen, ppos);
463 }
464 
465 /*
466  * diagnose code 0x14 subcode 0x0028 - position spool file to designated
467  *				       record
468  * cc=0  normal completion
469  * cc=2  no file active on the virtual reader or device not ready
470  * cc=3  record specified is beyond EOF
471  */
diag_position_to_record(int devno,int record)472 static int diag_position_to_record(int devno, int record)
473 {
474 	int cc;
475 
476 	cc = diag14(record, devno, 0x28);
477 	switch (cc) {
478 	case 0:
479 		return 0;
480 	case 2:
481 		return -ENOMEDIUM;
482 	case 3:
483 		return -ENODATA; /* position beyond end of file */
484 	default:
485 		return -EIO;
486 	}
487 }
488 
489 /*
490  * diagnose code 0x14 subcode 0x0000 - read next spool file buffer
491  * cc=0  normal completion
492  * cc=1  EOF reached
493  * cc=2  no file active on the virtual reader, and no file eligible
494  * cc=3  file already active on the virtual reader or specified virtual
495  *	 reader does not exist or is not a reader
496  */
diag_read_file(int devno,char * buf)497 static int diag_read_file(int devno, char *buf)
498 {
499 	int cc;
500 
501 	cc = diag14((unsigned long) buf, devno, 0x00);
502 	switch (cc) {
503 	case 0:
504 		return 0;
505 	case 1:
506 		return -ENODATA;
507 	case 2:
508 		return -ENOMEDIUM;
509 	default:
510 		return -EIO;
511 	}
512 }
513 
diag14_read(struct file * file,char __user * ubuf,size_t count,loff_t * offs)514 static ssize_t diag14_read(struct file *file, char __user *ubuf, size_t count,
515 			   loff_t *offs)
516 {
517 	size_t len, copied, res;
518 	char *buf;
519 	int rc;
520 	u16 reclen;
521 	struct urdev *urd;
522 
523 	urd = ((struct urfile *) file->private_data)->urd;
524 	reclen = ((struct urfile *) file->private_data)->file_reclen;
525 
526 	rc = diag_position_to_record(urd->dev_id.devno, *offs / PAGE_SIZE + 1);
527 	if (rc == -ENODATA)
528 		return 0;
529 	if (rc)
530 		return rc;
531 
532 	len = min((size_t) PAGE_SIZE, count);
533 	buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
534 	if (!buf)
535 		return -ENOMEM;
536 
537 	copied = 0;
538 	res = (size_t) (*offs % PAGE_SIZE);
539 	do {
540 		rc = diag_read_file(urd->dev_id.devno, buf);
541 		if (rc == -ENODATA) {
542 			break;
543 		}
544 		if (rc)
545 			goto fail;
546 		if (reclen && (copied == 0) && (*offs < PAGE_SIZE))
547 			*((u16 *) &buf[FILE_RECLEN_OFFSET]) = reclen;
548 		len = min(count - copied, PAGE_SIZE - res);
549 		if (copy_to_user(ubuf + copied, buf + res, len)) {
550 			rc = -EFAULT;
551 			goto fail;
552 		}
553 		res = 0;
554 		copied += len;
555 	} while (copied != count);
556 
557 	*offs += copied;
558 	rc = copied;
559 fail:
560 	free_page((unsigned long) buf);
561 	return rc;
562 }
563 
ur_read(struct file * file,char __user * ubuf,size_t count,loff_t * offs)564 static ssize_t ur_read(struct file *file, char __user *ubuf, size_t count,
565 		       loff_t *offs)
566 {
567 	struct urdev *urd;
568 	int rc;
569 
570 	TRACE("ur_read: count=%zu ppos=%li\n", count, (unsigned long) *offs);
571 
572 	if (count == 0)
573 		return 0;
574 
575 	urd = ((struct urfile *) file->private_data)->urd;
576 	rc = mutex_lock_interruptible(&urd->io_mutex);
577 	if (rc)
578 		return rc;
579 	rc = diag14_read(file, ubuf, count, offs);
580 	mutex_unlock(&urd->io_mutex);
581 	return rc;
582 }
583 
584 /*
585  * diagnose code 0x14 subcode 0x0fff - retrieve next file descriptor
586  * cc=0  normal completion
587  * cc=1  no files on reader queue or no subsequent file
588  * cc=2  spid specified is invalid
589  */
diag_read_next_file_info(struct file_control_block * buf,int spid)590 static int diag_read_next_file_info(struct file_control_block *buf, int spid)
591 {
592 	int cc;
593 
594 	cc = diag14((unsigned long) buf, spid, 0xfff);
595 	switch (cc) {
596 	case 0:
597 		return 0;
598 	default:
599 		return -ENODATA;
600 	}
601 }
602 
verify_uri_device(struct urdev * urd)603 static int verify_uri_device(struct urdev *urd)
604 {
605 	struct file_control_block *fcb;
606 	char *buf;
607 	int rc;
608 
609 	fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
610 	if (!fcb)
611 		return -ENOMEM;
612 
613 	/* check for empty reader device (beginning of chain) */
614 	rc = diag_read_next_file_info(fcb, 0);
615 	if (rc)
616 		goto fail_free_fcb;
617 
618 	/* if file is in hold status, we do not read it */
619 	if (fcb->file_stat & (FLG_SYSTEM_HOLD | FLG_USER_HOLD)) {
620 		rc = -EPERM;
621 		goto fail_free_fcb;
622 	}
623 
624 	/* open file on virtual reader	*/
625 	buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
626 	if (!buf) {
627 		rc = -ENOMEM;
628 		goto fail_free_fcb;
629 	}
630 	rc = diag_read_file(urd->dev_id.devno, buf);
631 	if ((rc != 0) && (rc != -ENODATA)) /* EOF does not hurt */
632 		goto fail_free_buf;
633 
634 	/* check if the file on top of the queue is open now */
635 	rc = diag_read_next_file_info(fcb, 0);
636 	if (rc)
637 		goto fail_free_buf;
638 	if (!(fcb->file_stat & FLG_IN_USE)) {
639 		rc = -EMFILE;
640 		goto fail_free_buf;
641 	}
642 	rc = 0;
643 
644 fail_free_buf:
645 	free_page((unsigned long) buf);
646 fail_free_fcb:
647 	kfree(fcb);
648 	return rc;
649 }
650 
verify_device(struct urdev * urd)651 static int verify_device(struct urdev *urd)
652 {
653 	switch (urd->class) {
654 	case DEV_CLASS_UR_O:
655 		return 0; /* no check needed here */
656 	case DEV_CLASS_UR_I:
657 		return verify_uri_device(urd);
658 	default:
659 		return -EOPNOTSUPP;
660 	}
661 }
662 
get_uri_file_reclen(struct urdev * urd)663 static int get_uri_file_reclen(struct urdev *urd)
664 {
665 	struct file_control_block *fcb;
666 	int rc;
667 
668 	fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
669 	if (!fcb)
670 		return -ENOMEM;
671 	rc = diag_read_next_file_info(fcb, 0);
672 	if (rc)
673 		goto fail_free;
674 	if (fcb->file_stat & FLG_CP_DUMP)
675 		rc = 0;
676 	else
677 		rc = fcb->rec_len;
678 
679 fail_free:
680 	kfree(fcb);
681 	return rc;
682 }
683 
get_file_reclen(struct urdev * urd)684 static int get_file_reclen(struct urdev *urd)
685 {
686 	switch (urd->class) {
687 	case DEV_CLASS_UR_O:
688 		return 0;
689 	case DEV_CLASS_UR_I:
690 		return get_uri_file_reclen(urd);
691 	default:
692 		return -EOPNOTSUPP;
693 	}
694 }
695 
ur_open(struct inode * inode,struct file * file)696 static int ur_open(struct inode *inode, struct file *file)
697 {
698 	u16 devno;
699 	struct urdev *urd;
700 	struct urfile *urf;
701 	unsigned short accmode;
702 	int rc;
703 
704 	accmode = file->f_flags & O_ACCMODE;
705 
706 	if (accmode == O_RDWR)
707 		return -EACCES;
708 	/*
709 	 * We treat the minor number as the devno of the ur device
710 	 * to find in the driver tree.
711 	 */
712 	devno = iminor(file_inode(file));
713 
714 	urd = urdev_get_from_devno(devno);
715 	if (!urd) {
716 		rc = -ENXIO;
717 		goto out;
718 	}
719 
720 	spin_lock(&urd->open_lock);
721 	while (urd->open_flag) {
722 		spin_unlock(&urd->open_lock);
723 		if (file->f_flags & O_NONBLOCK) {
724 			rc = -EBUSY;
725 			goto fail_put;
726 		}
727 		if (wait_event_interruptible(urd->wait, urd->open_flag == 0)) {
728 			rc = -ERESTARTSYS;
729 			goto fail_put;
730 		}
731 		spin_lock(&urd->open_lock);
732 	}
733 	urd->open_flag++;
734 	spin_unlock(&urd->open_lock);
735 
736 	TRACE("ur_open\n");
737 
738 	if (((accmode == O_RDONLY) && (urd->class != DEV_CLASS_UR_I)) ||
739 	    ((accmode == O_WRONLY) && (urd->class != DEV_CLASS_UR_O))) {
740 		TRACE("ur_open: unsupported dev class (%d)\n", urd->class);
741 		rc = -EACCES;
742 		goto fail_unlock;
743 	}
744 
745 	rc = verify_device(urd);
746 	if (rc)
747 		goto fail_unlock;
748 
749 	urf = urfile_alloc(urd);
750 	if (!urf) {
751 		rc = -ENOMEM;
752 		goto fail_unlock;
753 	}
754 
755 	urf->dev_reclen = urd->reclen;
756 	rc = get_file_reclen(urd);
757 	if (rc < 0)
758 		goto fail_urfile_free;
759 	urf->file_reclen = rc;
760 	file->private_data = urf;
761 	return 0;
762 
763 fail_urfile_free:
764 	urfile_free(urf);
765 fail_unlock:
766 	spin_lock(&urd->open_lock);
767 	urd->open_flag--;
768 	spin_unlock(&urd->open_lock);
769 fail_put:
770 	urdev_put(urd);
771 out:
772 	return rc;
773 }
774 
ur_release(struct inode * inode,struct file * file)775 static int ur_release(struct inode *inode, struct file *file)
776 {
777 	struct urfile *urf = file->private_data;
778 
779 	TRACE("ur_release\n");
780 	spin_lock(&urf->urd->open_lock);
781 	urf->urd->open_flag--;
782 	spin_unlock(&urf->urd->open_lock);
783 	wake_up_interruptible(&urf->urd->wait);
784 	urdev_put(urf->urd);
785 	urfile_free(urf);
786 	return 0;
787 }
788 
ur_llseek(struct file * file,loff_t offset,int whence)789 static loff_t ur_llseek(struct file *file, loff_t offset, int whence)
790 {
791 	if ((file->f_flags & O_ACCMODE) != O_RDONLY)
792 		return -ESPIPE; /* seek allowed only for reader */
793 	if (offset % PAGE_SIZE)
794 		return -ESPIPE; /* only multiples of 4K allowed */
795 	return no_seek_end_llseek(file, offset, whence);
796 }
797 
798 static const struct file_operations ur_fops = {
799 	.owner	 = THIS_MODULE,
800 	.open	 = ur_open,
801 	.release = ur_release,
802 	.read	 = ur_read,
803 	.write	 = ur_write,
804 	.llseek  = ur_llseek,
805 };
806 
807 /*
808  * ccw_device infrastructure:
809  *     ur_probe creates the struct urdev (with refcount = 1), the device
810  *     attributes, sets up the interrupt handler and validates the virtual
811  *     unit record device.
812  *     ur_remove removes the device attributes and drops the reference to
813  *     struct urdev.
814  *
815  *     ur_probe, ur_remove, ur_set_online and ur_set_offline are serialized
816  *     by the vmur_mutex lock.
817  *
818  *     urd->char_device is used as indication that the online function has
819  *     been completed successfully.
820  */
ur_probe(struct ccw_device * cdev)821 static int ur_probe(struct ccw_device *cdev)
822 {
823 	struct urdev *urd;
824 	int rc;
825 
826 	TRACE("ur_probe: cdev=%p\n", cdev);
827 
828 	mutex_lock(&vmur_mutex);
829 	urd = urdev_alloc(cdev);
830 	if (!urd) {
831 		rc = -ENOMEM;
832 		goto fail_unlock;
833 	}
834 
835 	rc = ur_create_attributes(&cdev->dev);
836 	if (rc) {
837 		rc = -ENOMEM;
838 		goto fail_urdev_put;
839 	}
840 
841 	/* validate virtual unit record device */
842 	urd->class = get_urd_class(urd);
843 	if (urd->class < 0) {
844 		rc = urd->class;
845 		goto fail_remove_attr;
846 	}
847 	if ((urd->class != DEV_CLASS_UR_I) && (urd->class != DEV_CLASS_UR_O)) {
848 		rc = -EOPNOTSUPP;
849 		goto fail_remove_attr;
850 	}
851 	spin_lock_irq(get_ccwdev_lock(cdev));
852 	dev_set_drvdata(&cdev->dev, urd);
853 	cdev->handler = ur_int_handler;
854 	spin_unlock_irq(get_ccwdev_lock(cdev));
855 
856 	mutex_unlock(&vmur_mutex);
857 	return 0;
858 
859 fail_remove_attr:
860 	ur_remove_attributes(&cdev->dev);
861 fail_urdev_put:
862 	urdev_put(urd);
863 fail_unlock:
864 	mutex_unlock(&vmur_mutex);
865 	return rc;
866 }
867 
ur_set_online(struct ccw_device * cdev)868 static int ur_set_online(struct ccw_device *cdev)
869 {
870 	struct urdev *urd;
871 	int minor, major, rc;
872 	char node_id[16];
873 
874 	TRACE("ur_set_online: cdev=%p\n", cdev);
875 
876 	mutex_lock(&vmur_mutex);
877 	urd = urdev_get_from_cdev(cdev);
878 	if (!urd) {
879 		/* ur_remove already deleted our urd */
880 		rc = -ENODEV;
881 		goto fail_unlock;
882 	}
883 
884 	if (urd->char_device) {
885 		/* Another ur_set_online was faster */
886 		rc = -EBUSY;
887 		goto fail_urdev_put;
888 	}
889 
890 	minor = urd->dev_id.devno;
891 	major = MAJOR(ur_first_dev_maj_min);
892 
893 	urd->char_device = cdev_alloc();
894 	if (!urd->char_device) {
895 		rc = -ENOMEM;
896 		goto fail_urdev_put;
897 	}
898 
899 	urd->char_device->ops = &ur_fops;
900 	urd->char_device->owner = ur_fops.owner;
901 
902 	rc = cdev_add(urd->char_device, MKDEV(major, minor), 1);
903 	if (rc)
904 		goto fail_free_cdev;
905 	if (urd->cdev->id.cu_type == READER_PUNCH_DEVTYPE) {
906 		if (urd->class == DEV_CLASS_UR_I)
907 			sprintf(node_id, "vmrdr-%s", dev_name(&cdev->dev));
908 		if (urd->class == DEV_CLASS_UR_O)
909 			sprintf(node_id, "vmpun-%s", dev_name(&cdev->dev));
910 	} else if (urd->cdev->id.cu_type == PRINTER_DEVTYPE) {
911 		sprintf(node_id, "vmprt-%s", dev_name(&cdev->dev));
912 	} else {
913 		rc = -EOPNOTSUPP;
914 		goto fail_free_cdev;
915 	}
916 
917 	urd->device = device_create(&vmur_class, &cdev->dev,
918 				    urd->char_device->dev, NULL, "%s", node_id);
919 	if (IS_ERR(urd->device)) {
920 		rc = PTR_ERR(urd->device);
921 		TRACE("ur_set_online: device_create rc=%d\n", rc);
922 		goto fail_free_cdev;
923 	}
924 	urdev_put(urd);
925 	mutex_unlock(&vmur_mutex);
926 	return 0;
927 
928 fail_free_cdev:
929 	cdev_del(urd->char_device);
930 	urd->char_device = NULL;
931 fail_urdev_put:
932 	urdev_put(urd);
933 fail_unlock:
934 	mutex_unlock(&vmur_mutex);
935 	return rc;
936 }
937 
ur_set_offline_force(struct ccw_device * cdev,int force)938 static int ur_set_offline_force(struct ccw_device *cdev, int force)
939 {
940 	struct urdev *urd;
941 	int rc;
942 
943 	TRACE("ur_set_offline: cdev=%p\n", cdev);
944 	urd = urdev_get_from_cdev(cdev);
945 	if (!urd)
946 		/* ur_remove already deleted our urd */
947 		return -ENODEV;
948 	if (!urd->char_device) {
949 		/* Another ur_set_offline was faster */
950 		rc = -EBUSY;
951 		goto fail_urdev_put;
952 	}
953 	if (!force && (refcount_read(&urd->ref_count) > 2)) {
954 		/* There is still a user of urd (e.g. ur_open) */
955 		TRACE("ur_set_offline: BUSY\n");
956 		rc = -EBUSY;
957 		goto fail_urdev_put;
958 	}
959 	if (cancel_work_sync(&urd->uevent_work)) {
960 		/* Work not run yet - need to release reference here */
961 		urdev_put(urd);
962 	}
963 	device_destroy(&vmur_class, urd->char_device->dev);
964 	cdev_del(urd->char_device);
965 	urd->char_device = NULL;
966 	rc = 0;
967 
968 fail_urdev_put:
969 	urdev_put(urd);
970 	return rc;
971 }
972 
ur_set_offline(struct ccw_device * cdev)973 static int ur_set_offline(struct ccw_device *cdev)
974 {
975 	int rc;
976 
977 	mutex_lock(&vmur_mutex);
978 	rc = ur_set_offline_force(cdev, 0);
979 	mutex_unlock(&vmur_mutex);
980 	return rc;
981 }
982 
ur_remove(struct ccw_device * cdev)983 static void ur_remove(struct ccw_device *cdev)
984 {
985 	unsigned long flags;
986 
987 	TRACE("ur_remove\n");
988 
989 	mutex_lock(&vmur_mutex);
990 
991 	if (cdev->online)
992 		ur_set_offline_force(cdev, 1);
993 	ur_remove_attributes(&cdev->dev);
994 
995 	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
996 	urdev_put(dev_get_drvdata(&cdev->dev));
997 	dev_set_drvdata(&cdev->dev, NULL);
998 	cdev->handler = NULL;
999 	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
1000 
1001 	mutex_unlock(&vmur_mutex);
1002 }
1003 
1004 /*
1005  * Module initialisation and cleanup
1006  */
ur_init(void)1007 static int __init ur_init(void)
1008 {
1009 	int rc;
1010 	dev_t dev;
1011 
1012 	if (!MACHINE_IS_VM) {
1013 		pr_err("The %s cannot be loaded without z/VM\n",
1014 		       ur_banner);
1015 		return -ENODEV;
1016 	}
1017 
1018 	vmur_dbf = debug_register("vmur", 4, 1, 4 * sizeof(long));
1019 	if (!vmur_dbf)
1020 		return -ENOMEM;
1021 	rc = debug_register_view(vmur_dbf, &debug_sprintf_view);
1022 	if (rc)
1023 		goto fail_free_dbf;
1024 
1025 	debug_set_level(vmur_dbf, 6);
1026 
1027 	rc = class_register(&vmur_class);
1028 	if (rc)
1029 		goto fail_free_dbf;
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_unregister(&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_unregister(&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