1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *    basic function of the tape device driver
4  *
5  *  S390 and zSeries version
6  *    Copyright IBM Corp. 2001, 2009
7  *    Author(s): Carsten Otte <cotte@de.ibm.com>
8  *		 Michael Holzheu <holzheu@de.ibm.com>
9  *		 Tuan Ngo-Anh <ngoanh@de.ibm.com>
10  *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
11  *		 Stefan Bader <shbader@de.ibm.com>
12  */
13 
14 #define KMSG_COMPONENT "tape"
15 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
16 
17 #include <linux/module.h>
18 #include <linux/init.h>	     // for kernel parameters
19 #include <linux/kmod.h>	     // for requesting modules
20 #include <linux/spinlock.h>  // for locks
21 #include <linux/vmalloc.h>
22 #include <linux/list.h>
23 #include <linux/slab.h>
24 
25 #include <asm/types.h>	     // for variable types
26 
27 #define TAPE_DBF_AREA	tape_core_dbf
28 
29 #include "tape.h"
30 #include "tape_std.h"
31 
32 #define LONG_BUSY_TIMEOUT 180 /* seconds */
33 
34 static void __tape_do_irq (struct ccw_device *, unsigned long, struct irb *);
35 static void tape_delayed_next_request(struct work_struct *);
36 static void tape_long_busy_timeout(struct timer_list *t);
37 
38 /*
39  * One list to contain all tape devices of all disciplines, so
40  * we can assign the devices to minor numbers of the same major
41  * The list is protected by the rwlock
42  */
43 static LIST_HEAD(tape_device_list);
44 static DEFINE_RWLOCK(tape_device_lock);
45 
46 /*
47  * Pointer to debug area.
48  */
49 debug_info_t *TAPE_DBF_AREA = NULL;
50 EXPORT_SYMBOL(TAPE_DBF_AREA);
51 
52 /*
53  * Printable strings for tape enumerations.
54  */
55 const char *tape_state_verbose[TS_SIZE] =
56 {
57 	[TS_UNUSED]   = "UNUSED",
58 	[TS_IN_USE]   = "IN_USE",
59 	[TS_BLKUSE]   = "BLKUSE",
60 	[TS_INIT]     = "INIT  ",
61 	[TS_NOT_OPER] = "NOT_OP"
62 };
63 
64 const char *tape_op_verbose[TO_SIZE] =
65 {
66 	[TO_BLOCK] = "BLK",	[TO_BSB] = "BSB",
67 	[TO_BSF] = "BSF",	[TO_DSE] = "DSE",
68 	[TO_FSB] = "FSB",	[TO_FSF] = "FSF",
69 	[TO_LBL] = "LBL",	[TO_NOP] = "NOP",
70 	[TO_RBA] = "RBA",	[TO_RBI] = "RBI",
71 	[TO_RFO] = "RFO",	[TO_REW] = "REW",
72 	[TO_RUN] = "RUN",	[TO_WRI] = "WRI",
73 	[TO_WTM] = "WTM",	[TO_MSEN] = "MSN",
74 	[TO_LOAD] = "LOA",	[TO_READ_CONFIG] = "RCF",
75 	[TO_READ_ATTMSG] = "RAT",
76 	[TO_DIS] = "DIS",	[TO_ASSIGN] = "ASS",
77 	[TO_UNASSIGN] = "UAS",  [TO_CRYPT_ON] = "CON",
78 	[TO_CRYPT_OFF] = "COF",	[TO_KEKL_SET] = "KLS",
79 	[TO_KEKL_QUERY] = "KLQ",[TO_RDC] = "RDC",
80 };
81 
devid_to_int(struct ccw_dev_id * dev_id)82 static int devid_to_int(struct ccw_dev_id *dev_id)
83 {
84 	return dev_id->devno + (dev_id->ssid << 16);
85 }
86 
87 /*
88  * Some channel attached tape specific attributes.
89  *
90  * FIXME: In the future the first_minor and blocksize attribute should be
91  *        replaced by a link to the cdev tree.
92  */
93 static ssize_t
tape_medium_state_show(struct device * dev,struct device_attribute * attr,char * buf)94 tape_medium_state_show(struct device *dev, struct device_attribute *attr, char *buf)
95 {
96 	struct tape_device *tdev;
97 
98 	tdev = dev_get_drvdata(dev);
99 	return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->medium_state);
100 }
101 
102 static
103 DEVICE_ATTR(medium_state, 0444, tape_medium_state_show, NULL);
104 
105 static ssize_t
tape_first_minor_show(struct device * dev,struct device_attribute * attr,char * buf)106 tape_first_minor_show(struct device *dev, struct device_attribute *attr, char *buf)
107 {
108 	struct tape_device *tdev;
109 
110 	tdev = dev_get_drvdata(dev);
111 	return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->first_minor);
112 }
113 
114 static
115 DEVICE_ATTR(first_minor, 0444, tape_first_minor_show, NULL);
116 
117 static ssize_t
tape_state_show(struct device * dev,struct device_attribute * attr,char * buf)118 tape_state_show(struct device *dev, struct device_attribute *attr, char *buf)
119 {
120 	struct tape_device *tdev;
121 
122 	tdev = dev_get_drvdata(dev);
123 	return scnprintf(buf, PAGE_SIZE, "%s\n", (tdev->first_minor < 0) ?
124 		"OFFLINE" : tape_state_verbose[tdev->tape_state]);
125 }
126 
127 static
128 DEVICE_ATTR(state, 0444, tape_state_show, NULL);
129 
130 static ssize_t
tape_operation_show(struct device * dev,struct device_attribute * attr,char * buf)131 tape_operation_show(struct device *dev, struct device_attribute *attr, char *buf)
132 {
133 	struct tape_device *tdev;
134 	ssize_t rc;
135 
136 	tdev = dev_get_drvdata(dev);
137 	if (tdev->first_minor < 0)
138 		return scnprintf(buf, PAGE_SIZE, "N/A\n");
139 
140 	spin_lock_irq(get_ccwdev_lock(tdev->cdev));
141 	if (list_empty(&tdev->req_queue))
142 		rc = scnprintf(buf, PAGE_SIZE, "---\n");
143 	else {
144 		struct tape_request *req;
145 
146 		req = list_entry(tdev->req_queue.next, struct tape_request,
147 			list);
148 		rc = scnprintf(buf,PAGE_SIZE, "%s\n", tape_op_verbose[req->op]);
149 	}
150 	spin_unlock_irq(get_ccwdev_lock(tdev->cdev));
151 	return rc;
152 }
153 
154 static
155 DEVICE_ATTR(operation, 0444, tape_operation_show, NULL);
156 
157 static ssize_t
tape_blocksize_show(struct device * dev,struct device_attribute * attr,char * buf)158 tape_blocksize_show(struct device *dev, struct device_attribute *attr, char *buf)
159 {
160 	struct tape_device *tdev;
161 
162 	tdev = dev_get_drvdata(dev);
163 
164 	return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->char_data.block_size);
165 }
166 
167 static
168 DEVICE_ATTR(blocksize, 0444, tape_blocksize_show, NULL);
169 
170 static struct attribute *tape_attrs[] = {
171 	&dev_attr_medium_state.attr,
172 	&dev_attr_first_minor.attr,
173 	&dev_attr_state.attr,
174 	&dev_attr_operation.attr,
175 	&dev_attr_blocksize.attr,
176 	NULL
177 };
178 
179 static const struct attribute_group tape_attr_group = {
180 	.attrs = tape_attrs,
181 };
182 
183 /*
184  * Tape state functions
185  */
186 void
tape_state_set(struct tape_device * device,enum tape_state newstate)187 tape_state_set(struct tape_device *device, enum tape_state newstate)
188 {
189 	const char *str;
190 
191 	if (device->tape_state == TS_NOT_OPER) {
192 		DBF_EVENT(3, "ts_set err: not oper\n");
193 		return;
194 	}
195 	DBF_EVENT(4, "ts. dev:	%x\n", device->first_minor);
196 	DBF_EVENT(4, "old ts:\t\n");
197 	if (device->tape_state < TS_SIZE && device->tape_state >=0 )
198 		str = tape_state_verbose[device->tape_state];
199 	else
200 		str = "UNKNOWN TS";
201 	DBF_EVENT(4, "%s\n", str);
202 	DBF_EVENT(4, "new ts:\t\n");
203 	if (newstate < TS_SIZE && newstate >= 0)
204 		str = tape_state_verbose[newstate];
205 	else
206 		str = "UNKNOWN TS";
207 	DBF_EVENT(4, "%s\n", str);
208 	device->tape_state = newstate;
209 	wake_up(&device->state_change_wq);
210 }
211 
212 struct tape_med_state_work_data {
213 	struct tape_device *device;
214 	enum tape_medium_state state;
215 	struct work_struct  work;
216 };
217 
218 static void
tape_med_state_work_handler(struct work_struct * work)219 tape_med_state_work_handler(struct work_struct *work)
220 {
221 	static char env_state_loaded[] = "MEDIUM_STATE=LOADED";
222 	static char env_state_unloaded[] = "MEDIUM_STATE=UNLOADED";
223 	struct tape_med_state_work_data *p =
224 		container_of(work, struct tape_med_state_work_data, work);
225 	struct tape_device *device = p->device;
226 	char *envp[] = { NULL, NULL };
227 
228 	switch (p->state) {
229 	case MS_UNLOADED:
230 		pr_info("%s: The tape cartridge has been successfully "
231 			"unloaded\n", dev_name(&device->cdev->dev));
232 		envp[0] = env_state_unloaded;
233 		kobject_uevent_env(&device->cdev->dev.kobj, KOBJ_CHANGE, envp);
234 		break;
235 	case MS_LOADED:
236 		pr_info("%s: A tape cartridge has been mounted\n",
237 			dev_name(&device->cdev->dev));
238 		envp[0] = env_state_loaded;
239 		kobject_uevent_env(&device->cdev->dev.kobj, KOBJ_CHANGE, envp);
240 		break;
241 	default:
242 		break;
243 	}
244 	tape_put_device(device);
245 	kfree(p);
246 }
247 
248 static void
tape_med_state_work(struct tape_device * device,enum tape_medium_state state)249 tape_med_state_work(struct tape_device *device, enum tape_medium_state state)
250 {
251 	struct tape_med_state_work_data *p;
252 
253 	p = kzalloc(sizeof(*p), GFP_ATOMIC);
254 	if (p) {
255 		INIT_WORK(&p->work, tape_med_state_work_handler);
256 		p->device = tape_get_device(device);
257 		p->state = state;
258 		schedule_work(&p->work);
259 	}
260 }
261 
262 void
tape_med_state_set(struct tape_device * device,enum tape_medium_state newstate)263 tape_med_state_set(struct tape_device *device, enum tape_medium_state newstate)
264 {
265 	enum tape_medium_state oldstate;
266 
267 	oldstate = device->medium_state;
268 	if (oldstate == newstate)
269 		return;
270 	device->medium_state = newstate;
271 	switch(newstate){
272 	case MS_UNLOADED:
273 		device->tape_generic_status |= GMT_DR_OPEN(~0);
274 		if (oldstate == MS_LOADED)
275 			tape_med_state_work(device, MS_UNLOADED);
276 		break;
277 	case MS_LOADED:
278 		device->tape_generic_status &= ~GMT_DR_OPEN(~0);
279 		if (oldstate == MS_UNLOADED)
280 			tape_med_state_work(device, MS_LOADED);
281 		break;
282 	default:
283 		break;
284 	}
285 	wake_up(&device->state_change_wq);
286 }
287 
288 /*
289  * Stop running ccw. Has to be called with the device lock held.
290  */
291 static int
__tape_cancel_io(struct tape_device * device,struct tape_request * request)292 __tape_cancel_io(struct tape_device *device, struct tape_request *request)
293 {
294 	int retries;
295 	int rc;
296 
297 	/* Check if interrupt has already been processed */
298 	if (request->callback == NULL)
299 		return 0;
300 
301 	rc = 0;
302 	for (retries = 0; retries < 5; retries++) {
303 		rc = ccw_device_clear(device->cdev, (long) request);
304 
305 		switch (rc) {
306 			case 0:
307 				request->status	= TAPE_REQUEST_DONE;
308 				return 0;
309 			case -EBUSY:
310 				request->status	= TAPE_REQUEST_CANCEL;
311 				schedule_delayed_work(&device->tape_dnr, 0);
312 				return 0;
313 			case -ENODEV:
314 				DBF_EXCEPTION(2, "device gone, retry\n");
315 				break;
316 			case -EIO:
317 				DBF_EXCEPTION(2, "I/O error, retry\n");
318 				break;
319 			default:
320 				BUG();
321 		}
322 	}
323 
324 	return rc;
325 }
326 
327 /*
328  * Add device into the sorted list, giving it the first
329  * available minor number.
330  */
331 static int
tape_assign_minor(struct tape_device * device)332 tape_assign_minor(struct tape_device *device)
333 {
334 	struct tape_device *tmp;
335 	int minor;
336 
337 	minor = 0;
338 	write_lock(&tape_device_lock);
339 	list_for_each_entry(tmp, &tape_device_list, node) {
340 		if (minor < tmp->first_minor)
341 			break;
342 		minor += TAPE_MINORS_PER_DEV;
343 	}
344 	if (minor >= 256) {
345 		write_unlock(&tape_device_lock);
346 		return -ENODEV;
347 	}
348 	device->first_minor = minor;
349 	list_add_tail(&device->node, &tmp->node);
350 	write_unlock(&tape_device_lock);
351 	return 0;
352 }
353 
354 /* remove device from the list */
355 static void
tape_remove_minor(struct tape_device * device)356 tape_remove_minor(struct tape_device *device)
357 {
358 	write_lock(&tape_device_lock);
359 	list_del_init(&device->node);
360 	device->first_minor = -1;
361 	write_unlock(&tape_device_lock);
362 }
363 
364 /*
365  * Set a device online.
366  *
367  * This function is called by the common I/O layer to move a device from the
368  * detected but offline into the online state.
369  * If we return an error (RC < 0) the device remains in the offline state. This
370  * can happen if the device is assigned somewhere else, for example.
371  */
372 int
tape_generic_online(struct tape_device * device,struct tape_discipline * discipline)373 tape_generic_online(struct tape_device *device,
374 		   struct tape_discipline *discipline)
375 {
376 	int rc;
377 
378 	DBF_LH(6, "tape_enable_device(%p, %p)\n", device, discipline);
379 
380 	if (device->tape_state != TS_INIT) {
381 		DBF_LH(3, "Tapestate not INIT (%d)\n", device->tape_state);
382 		return -EINVAL;
383 	}
384 
385 	timer_setup(&device->lb_timeout, tape_long_busy_timeout, 0);
386 
387 	/* Let the discipline have a go at the device. */
388 	device->discipline = discipline;
389 	if (!try_module_get(discipline->owner)) {
390 		return -EINVAL;
391 	}
392 
393 	rc = discipline->setup_device(device);
394 	if (rc)
395 		goto out;
396 	rc = tape_assign_minor(device);
397 	if (rc)
398 		goto out_discipline;
399 
400 	rc = tapechar_setup_device(device);
401 	if (rc)
402 		goto out_minor;
403 
404 	tape_state_set(device, TS_UNUSED);
405 
406 	DBF_LH(3, "(%08x): Drive set online\n", device->cdev_id);
407 
408 	return 0;
409 
410 out_minor:
411 	tape_remove_minor(device);
412 out_discipline:
413 	device->discipline->cleanup_device(device);
414 	device->discipline = NULL;
415 out:
416 	module_put(discipline->owner);
417 	return rc;
418 }
419 
420 static void
tape_cleanup_device(struct tape_device * device)421 tape_cleanup_device(struct tape_device *device)
422 {
423 	tapechar_cleanup_device(device);
424 	device->discipline->cleanup_device(device);
425 	module_put(device->discipline->owner);
426 	tape_remove_minor(device);
427 	tape_med_state_set(device, MS_UNKNOWN);
428 }
429 
430 /*
431  * Suspend device.
432  *
433  * Called by the common I/O layer if the drive should be suspended on user
434  * request. We refuse to suspend if the device is loaded or in use for the
435  * following reason:
436  * While the Linux guest is suspended, it might be logged off which causes
437  * devices to be detached. Tape devices are automatically rewound and unloaded
438  * during DETACH processing (unless the tape device was attached with the
439  * NOASSIGN or MULTIUSER option). After rewind/unload, there is no way to
440  * resume the original state of the tape device, since we would need to
441  * manually re-load the cartridge which was active at suspend time.
442  */
tape_generic_pm_suspend(struct ccw_device * cdev)443 int tape_generic_pm_suspend(struct ccw_device *cdev)
444 {
445 	struct tape_device *device;
446 
447 	device = dev_get_drvdata(&cdev->dev);
448 	if (!device) {
449 		return -ENODEV;
450 	}
451 
452 	DBF_LH(3, "(%08x): tape_generic_pm_suspend(%p)\n",
453 		device->cdev_id, device);
454 
455 	if (device->medium_state != MS_UNLOADED) {
456 		pr_err("A cartridge is loaded in tape device %s, "
457 		       "refusing to suspend\n", dev_name(&cdev->dev));
458 		return -EBUSY;
459 	}
460 
461 	spin_lock_irq(get_ccwdev_lock(device->cdev));
462 	switch (device->tape_state) {
463 		case TS_INIT:
464 		case TS_NOT_OPER:
465 		case TS_UNUSED:
466 			spin_unlock_irq(get_ccwdev_lock(device->cdev));
467 			break;
468 		default:
469 			pr_err("Tape device %s is busy, refusing to "
470 			       "suspend\n", dev_name(&cdev->dev));
471 			spin_unlock_irq(get_ccwdev_lock(device->cdev));
472 			return -EBUSY;
473 	}
474 
475 	DBF_LH(3, "(%08x): Drive suspended.\n", device->cdev_id);
476 	return 0;
477 }
478 
479 /*
480  * Set device offline.
481  *
482  * Called by the common I/O layer if the drive should set offline on user
483  * request. We may prevent this by returning an error.
484  * Manual offline is only allowed while the drive is not in use.
485  */
486 int
tape_generic_offline(struct ccw_device * cdev)487 tape_generic_offline(struct ccw_device *cdev)
488 {
489 	struct tape_device *device;
490 
491 	device = dev_get_drvdata(&cdev->dev);
492 	if (!device) {
493 		return -ENODEV;
494 	}
495 
496 	DBF_LH(3, "(%08x): tape_generic_offline(%p)\n",
497 		device->cdev_id, device);
498 
499 	spin_lock_irq(get_ccwdev_lock(device->cdev));
500 	switch (device->tape_state) {
501 		case TS_INIT:
502 		case TS_NOT_OPER:
503 			spin_unlock_irq(get_ccwdev_lock(device->cdev));
504 			break;
505 		case TS_UNUSED:
506 			tape_state_set(device, TS_INIT);
507 			spin_unlock_irq(get_ccwdev_lock(device->cdev));
508 			tape_cleanup_device(device);
509 			break;
510 		default:
511 			DBF_EVENT(3, "(%08x): Set offline failed "
512 				"- drive in use.\n",
513 				device->cdev_id);
514 			spin_unlock_irq(get_ccwdev_lock(device->cdev));
515 			return -EBUSY;
516 	}
517 
518 	DBF_LH(3, "(%08x): Drive set offline.\n", device->cdev_id);
519 	return 0;
520 }
521 
522 /*
523  * Allocate memory for a new device structure.
524  */
525 static struct tape_device *
tape_alloc_device(void)526 tape_alloc_device(void)
527 {
528 	struct tape_device *device;
529 
530 	device = kzalloc(sizeof(struct tape_device), GFP_KERNEL);
531 	if (device == NULL) {
532 		DBF_EXCEPTION(2, "ti:no mem\n");
533 		return ERR_PTR(-ENOMEM);
534 	}
535 	device->modeset_byte = kmalloc(1, GFP_KERNEL | GFP_DMA);
536 	if (device->modeset_byte == NULL) {
537 		DBF_EXCEPTION(2, "ti:no mem\n");
538 		kfree(device);
539 		return ERR_PTR(-ENOMEM);
540 	}
541 	mutex_init(&device->mutex);
542 	INIT_LIST_HEAD(&device->req_queue);
543 	INIT_LIST_HEAD(&device->node);
544 	init_waitqueue_head(&device->state_change_wq);
545 	init_waitqueue_head(&device->wait_queue);
546 	device->tape_state = TS_INIT;
547 	device->medium_state = MS_UNKNOWN;
548 	*device->modeset_byte = 0;
549 	device->first_minor = -1;
550 	atomic_set(&device->ref_count, 1);
551 	INIT_DELAYED_WORK(&device->tape_dnr, tape_delayed_next_request);
552 
553 	return device;
554 }
555 
556 /*
557  * Get a reference to an existing device structure. This will automatically
558  * increment the reference count.
559  */
560 struct tape_device *
tape_get_device(struct tape_device * device)561 tape_get_device(struct tape_device *device)
562 {
563 	int count;
564 
565 	count = atomic_inc_return(&device->ref_count);
566 	DBF_EVENT(4, "tape_get_device(%p) = %i\n", device, count);
567 	return device;
568 }
569 
570 /*
571  * Decrease the reference counter of a devices structure. If the
572  * reference counter reaches zero free the device structure.
573  * The function returns a NULL pointer to be used by the caller
574  * for clearing reference pointers.
575  */
576 void
tape_put_device(struct tape_device * device)577 tape_put_device(struct tape_device *device)
578 {
579 	int count;
580 
581 	count = atomic_dec_return(&device->ref_count);
582 	DBF_EVENT(4, "tape_put_device(%p) -> %i\n", device, count);
583 	BUG_ON(count < 0);
584 	if (count == 0) {
585 		kfree(device->modeset_byte);
586 		kfree(device);
587 	}
588 }
589 
590 /*
591  * Find tape device by a device index.
592  */
593 struct tape_device *
tape_find_device(int devindex)594 tape_find_device(int devindex)
595 {
596 	struct tape_device *device, *tmp;
597 
598 	device = ERR_PTR(-ENODEV);
599 	read_lock(&tape_device_lock);
600 	list_for_each_entry(tmp, &tape_device_list, node) {
601 		if (tmp->first_minor / TAPE_MINORS_PER_DEV == devindex) {
602 			device = tape_get_device(tmp);
603 			break;
604 		}
605 	}
606 	read_unlock(&tape_device_lock);
607 	return device;
608 }
609 
610 /*
611  * Driverfs tape probe function.
612  */
613 int
tape_generic_probe(struct ccw_device * cdev)614 tape_generic_probe(struct ccw_device *cdev)
615 {
616 	struct tape_device *device;
617 	int ret;
618 	struct ccw_dev_id dev_id;
619 
620 	device = tape_alloc_device();
621 	if (IS_ERR(device))
622 		return -ENODEV;
623 	ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP |
624 				     CCWDEV_DO_MULTIPATH);
625 	ret = sysfs_create_group(&cdev->dev.kobj, &tape_attr_group);
626 	if (ret) {
627 		tape_put_device(device);
628 		return ret;
629 	}
630 	dev_set_drvdata(&cdev->dev, device);
631 	cdev->handler = __tape_do_irq;
632 	device->cdev = cdev;
633 	ccw_device_get_id(cdev, &dev_id);
634 	device->cdev_id = devid_to_int(&dev_id);
635 	return ret;
636 }
637 
638 static void
__tape_discard_requests(struct tape_device * device)639 __tape_discard_requests(struct tape_device *device)
640 {
641 	struct tape_request *	request;
642 	struct list_head *	l, *n;
643 
644 	list_for_each_safe(l, n, &device->req_queue) {
645 		request = list_entry(l, struct tape_request, list);
646 		if (request->status == TAPE_REQUEST_IN_IO)
647 			request->status = TAPE_REQUEST_DONE;
648 		list_del(&request->list);
649 
650 		/* Decrease ref_count for removed request. */
651 		request->device = NULL;
652 		tape_put_device(device);
653 		request->rc = -EIO;
654 		if (request->callback != NULL)
655 			request->callback(request, request->callback_data);
656 	}
657 }
658 
659 /*
660  * Driverfs tape remove function.
661  *
662  * This function is called whenever the common I/O layer detects the device
663  * gone. This can happen at any time and we cannot refuse.
664  */
665 void
tape_generic_remove(struct ccw_device * cdev)666 tape_generic_remove(struct ccw_device *cdev)
667 {
668 	struct tape_device *	device;
669 
670 	device = dev_get_drvdata(&cdev->dev);
671 	if (!device) {
672 		return;
673 	}
674 	DBF_LH(3, "(%08x): tape_generic_remove(%p)\n", device->cdev_id, cdev);
675 
676 	spin_lock_irq(get_ccwdev_lock(device->cdev));
677 	switch (device->tape_state) {
678 		case TS_INIT:
679 			tape_state_set(device, TS_NOT_OPER);
680 		case TS_NOT_OPER:
681 			/*
682 			 * Nothing to do.
683 			 */
684 			spin_unlock_irq(get_ccwdev_lock(device->cdev));
685 			break;
686 		case TS_UNUSED:
687 			/*
688 			 * Need only to release the device.
689 			 */
690 			tape_state_set(device, TS_NOT_OPER);
691 			spin_unlock_irq(get_ccwdev_lock(device->cdev));
692 			tape_cleanup_device(device);
693 			break;
694 		default:
695 			/*
696 			 * There may be requests on the queue. We will not get
697 			 * an interrupt for a request that was running. So we
698 			 * just post them all as I/O errors.
699 			 */
700 			DBF_EVENT(3, "(%08x): Drive in use vanished!\n",
701 				device->cdev_id);
702 			pr_warn("%s: A tape unit was detached while in use\n",
703 				dev_name(&device->cdev->dev));
704 			tape_state_set(device, TS_NOT_OPER);
705 			__tape_discard_requests(device);
706 			spin_unlock_irq(get_ccwdev_lock(device->cdev));
707 			tape_cleanup_device(device);
708 	}
709 
710 	device = dev_get_drvdata(&cdev->dev);
711 	if (device) {
712 		sysfs_remove_group(&cdev->dev.kobj, &tape_attr_group);
713 		dev_set_drvdata(&cdev->dev, NULL);
714 		tape_put_device(device);
715 	}
716 }
717 
718 /*
719  * Allocate a new tape ccw request
720  */
721 struct tape_request *
tape_alloc_request(int cplength,int datasize)722 tape_alloc_request(int cplength, int datasize)
723 {
724 	struct tape_request *request;
725 
726 	BUG_ON(datasize > PAGE_SIZE || (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
727 
728 	DBF_LH(6, "tape_alloc_request(%d, %d)\n", cplength, datasize);
729 
730 	request = kzalloc(sizeof(struct tape_request), GFP_KERNEL);
731 	if (request == NULL) {
732 		DBF_EXCEPTION(1, "cqra nomem\n");
733 		return ERR_PTR(-ENOMEM);
734 	}
735 	/* allocate channel program */
736 	if (cplength > 0) {
737 		request->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
738 					  GFP_ATOMIC | GFP_DMA);
739 		if (request->cpaddr == NULL) {
740 			DBF_EXCEPTION(1, "cqra nomem\n");
741 			kfree(request);
742 			return ERR_PTR(-ENOMEM);
743 		}
744 	}
745 	/* alloc small kernel buffer */
746 	if (datasize > 0) {
747 		request->cpdata = kzalloc(datasize, GFP_KERNEL | GFP_DMA);
748 		if (request->cpdata == NULL) {
749 			DBF_EXCEPTION(1, "cqra nomem\n");
750 			kfree(request->cpaddr);
751 			kfree(request);
752 			return ERR_PTR(-ENOMEM);
753 		}
754 	}
755 	DBF_LH(6, "New request %p(%p/%p)\n", request, request->cpaddr,
756 		request->cpdata);
757 
758 	return request;
759 }
760 
761 /*
762  * Free tape ccw request
763  */
764 void
tape_free_request(struct tape_request * request)765 tape_free_request (struct tape_request * request)
766 {
767 	DBF_LH(6, "Free request %p\n", request);
768 
769 	if (request->device)
770 		tape_put_device(request->device);
771 	kfree(request->cpdata);
772 	kfree(request->cpaddr);
773 	kfree(request);
774 }
775 
776 static int
__tape_start_io(struct tape_device * device,struct tape_request * request)777 __tape_start_io(struct tape_device *device, struct tape_request *request)
778 {
779 	int rc;
780 
781 	rc = ccw_device_start(
782 		device->cdev,
783 		request->cpaddr,
784 		(unsigned long) request,
785 		0x00,
786 		request->options
787 	);
788 	if (rc == 0) {
789 		request->status = TAPE_REQUEST_IN_IO;
790 	} else if (rc == -EBUSY) {
791 		/* The common I/O subsystem is currently busy. Retry later. */
792 		request->status = TAPE_REQUEST_QUEUED;
793 		schedule_delayed_work(&device->tape_dnr, 0);
794 		rc = 0;
795 	} else {
796 		/* Start failed. Remove request and indicate failure. */
797 		DBF_EVENT(1, "tape: start request failed with RC = %i\n", rc);
798 	}
799 	return rc;
800 }
801 
802 static void
__tape_start_next_request(struct tape_device * device)803 __tape_start_next_request(struct tape_device *device)
804 {
805 	struct list_head *l, *n;
806 	struct tape_request *request;
807 	int rc;
808 
809 	DBF_LH(6, "__tape_start_next_request(%p)\n", device);
810 	/*
811 	 * Try to start each request on request queue until one is
812 	 * started successful.
813 	 */
814 	list_for_each_safe(l, n, &device->req_queue) {
815 		request = list_entry(l, struct tape_request, list);
816 
817 		/*
818 		 * Avoid race condition if bottom-half was triggered more than
819 		 * once.
820 		 */
821 		if (request->status == TAPE_REQUEST_IN_IO)
822 			return;
823 		/*
824 		 * Request has already been stopped. We have to wait until
825 		 * the request is removed from the queue in the interrupt
826 		 * handling.
827 		 */
828 		if (request->status == TAPE_REQUEST_DONE)
829 			return;
830 
831 		/*
832 		 * We wanted to cancel the request but the common I/O layer
833 		 * was busy at that time. This can only happen if this
834 		 * function is called by delayed_next_request.
835 		 * Otherwise we start the next request on the queue.
836 		 */
837 		if (request->status == TAPE_REQUEST_CANCEL) {
838 			rc = __tape_cancel_io(device, request);
839 		} else {
840 			rc = __tape_start_io(device, request);
841 		}
842 		if (rc == 0)
843 			return;
844 
845 		/* Set ending status. */
846 		request->rc = rc;
847 		request->status = TAPE_REQUEST_DONE;
848 
849 		/* Remove from request queue. */
850 		list_del(&request->list);
851 
852 		/* Do callback. */
853 		if (request->callback != NULL)
854 			request->callback(request, request->callback_data);
855 	}
856 }
857 
858 static void
tape_delayed_next_request(struct work_struct * work)859 tape_delayed_next_request(struct work_struct *work)
860 {
861 	struct tape_device *device =
862 		container_of(work, struct tape_device, tape_dnr.work);
863 
864 	DBF_LH(6, "tape_delayed_next_request(%p)\n", device);
865 	spin_lock_irq(get_ccwdev_lock(device->cdev));
866 	__tape_start_next_request(device);
867 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
868 }
869 
tape_long_busy_timeout(struct timer_list * t)870 static void tape_long_busy_timeout(struct timer_list *t)
871 {
872 	struct tape_device *device = from_timer(device, t, lb_timeout);
873 	struct tape_request *request;
874 
875 	spin_lock_irq(get_ccwdev_lock(device->cdev));
876 	request = list_entry(device->req_queue.next, struct tape_request, list);
877 	BUG_ON(request->status != TAPE_REQUEST_LONG_BUSY);
878 	DBF_LH(6, "%08x: Long busy timeout.\n", device->cdev_id);
879 	__tape_start_next_request(device);
880 	tape_put_device(device);
881 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
882 }
883 
884 static void
__tape_end_request(struct tape_device * device,struct tape_request * request,int rc)885 __tape_end_request(
886 	struct tape_device *	device,
887 	struct tape_request *	request,
888 	int			rc)
889 {
890 	DBF_LH(6, "__tape_end_request(%p, %p, %i)\n", device, request, rc);
891 	if (request) {
892 		request->rc = rc;
893 		request->status = TAPE_REQUEST_DONE;
894 
895 		/* Remove from request queue. */
896 		list_del(&request->list);
897 
898 		/* Do callback. */
899 		if (request->callback != NULL)
900 			request->callback(request, request->callback_data);
901 	}
902 
903 	/* Start next request. */
904 	if (!list_empty(&device->req_queue))
905 		__tape_start_next_request(device);
906 }
907 
908 /*
909  * Write sense data to dbf
910  */
911 void
tape_dump_sense_dbf(struct tape_device * device,struct tape_request * request,struct irb * irb)912 tape_dump_sense_dbf(struct tape_device *device, struct tape_request *request,
913 		    struct irb *irb)
914 {
915 	unsigned int *sptr;
916 	const char* op;
917 
918 	if (request != NULL)
919 		op = tape_op_verbose[request->op];
920 	else
921 		op = "---";
922 	DBF_EVENT(3, "DSTAT : %02x   CSTAT: %02x\n",
923 		  irb->scsw.cmd.dstat, irb->scsw.cmd.cstat);
924 	DBF_EVENT(3, "DEVICE: %08x OP\t: %s\n", device->cdev_id, op);
925 	sptr = (unsigned int *) irb->ecw;
926 	DBF_EVENT(3, "%08x %08x\n", sptr[0], sptr[1]);
927 	DBF_EVENT(3, "%08x %08x\n", sptr[2], sptr[3]);
928 	DBF_EVENT(3, "%08x %08x\n", sptr[4], sptr[5]);
929 	DBF_EVENT(3, "%08x %08x\n", sptr[6], sptr[7]);
930 }
931 
932 /*
933  * I/O helper function. Adds the request to the request queue
934  * and starts it if the tape is idle. Has to be called with
935  * the device lock held.
936  */
937 static int
__tape_start_request(struct tape_device * device,struct tape_request * request)938 __tape_start_request(struct tape_device *device, struct tape_request *request)
939 {
940 	int rc;
941 
942 	switch (request->op) {
943 		case TO_MSEN:
944 		case TO_ASSIGN:
945 		case TO_UNASSIGN:
946 		case TO_READ_ATTMSG:
947 		case TO_RDC:
948 			if (device->tape_state == TS_INIT)
949 				break;
950 			if (device->tape_state == TS_UNUSED)
951 				break;
952 		default:
953 			if (device->tape_state == TS_BLKUSE)
954 				break;
955 			if (device->tape_state != TS_IN_USE)
956 				return -ENODEV;
957 	}
958 
959 	/* Increase use count of device for the added request. */
960 	request->device = tape_get_device(device);
961 
962 	if (list_empty(&device->req_queue)) {
963 		/* No other requests are on the queue. Start this one. */
964 		rc = __tape_start_io(device, request);
965 		if (rc)
966 			return rc;
967 
968 		DBF_LH(5, "Request %p added for execution.\n", request);
969 		list_add(&request->list, &device->req_queue);
970 	} else {
971 		DBF_LH(5, "Request %p add to queue.\n", request);
972 		request->status = TAPE_REQUEST_QUEUED;
973 		list_add_tail(&request->list, &device->req_queue);
974 	}
975 	return 0;
976 }
977 
978 /*
979  * Add the request to the request queue, try to start it if the
980  * tape is idle. Return without waiting for end of i/o.
981  */
982 int
tape_do_io_async(struct tape_device * device,struct tape_request * request)983 tape_do_io_async(struct tape_device *device, struct tape_request *request)
984 {
985 	int rc;
986 
987 	DBF_LH(6, "tape_do_io_async(%p, %p)\n", device, request);
988 
989 	spin_lock_irq(get_ccwdev_lock(device->cdev));
990 	/* Add request to request queue and try to start it. */
991 	rc = __tape_start_request(device, request);
992 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
993 	return rc;
994 }
995 
996 /*
997  * tape_do_io/__tape_wake_up
998  * Add the request to the request queue, try to start it if the
999  * tape is idle and wait uninterruptible for its completion.
1000  */
1001 static void
__tape_wake_up(struct tape_request * request,void * data)1002 __tape_wake_up(struct tape_request *request, void *data)
1003 {
1004 	request->callback = NULL;
1005 	wake_up((wait_queue_head_t *) data);
1006 }
1007 
1008 int
tape_do_io(struct tape_device * device,struct tape_request * request)1009 tape_do_io(struct tape_device *device, struct tape_request *request)
1010 {
1011 	int rc;
1012 
1013 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1014 	/* Setup callback */
1015 	request->callback = __tape_wake_up;
1016 	request->callback_data = &device->wait_queue;
1017 	/* Add request to request queue and try to start it. */
1018 	rc = __tape_start_request(device, request);
1019 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1020 	if (rc)
1021 		return rc;
1022 	/* Request added to the queue. Wait for its completion. */
1023 	wait_event(device->wait_queue, (request->callback == NULL));
1024 	/* Get rc from request */
1025 	return request->rc;
1026 }
1027 
1028 /*
1029  * tape_do_io_interruptible/__tape_wake_up_interruptible
1030  * Add the request to the request queue, try to start it if the
1031  * tape is idle and wait uninterruptible for its completion.
1032  */
1033 static void
__tape_wake_up_interruptible(struct tape_request * request,void * data)1034 __tape_wake_up_interruptible(struct tape_request *request, void *data)
1035 {
1036 	request->callback = NULL;
1037 	wake_up_interruptible((wait_queue_head_t *) data);
1038 }
1039 
1040 int
tape_do_io_interruptible(struct tape_device * device,struct tape_request * request)1041 tape_do_io_interruptible(struct tape_device *device,
1042 			 struct tape_request *request)
1043 {
1044 	int rc;
1045 
1046 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1047 	/* Setup callback */
1048 	request->callback = __tape_wake_up_interruptible;
1049 	request->callback_data = &device->wait_queue;
1050 	rc = __tape_start_request(device, request);
1051 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1052 	if (rc)
1053 		return rc;
1054 	/* Request added to the queue. Wait for its completion. */
1055 	rc = wait_event_interruptible(device->wait_queue,
1056 				      (request->callback == NULL));
1057 	if (rc != -ERESTARTSYS)
1058 		/* Request finished normally. */
1059 		return request->rc;
1060 
1061 	/* Interrupted by a signal. We have to stop the current request. */
1062 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1063 	rc = __tape_cancel_io(device, request);
1064 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1065 	if (rc == 0) {
1066 		/* Wait for the interrupt that acknowledges the halt. */
1067 		do {
1068 			rc = wait_event_interruptible(
1069 				device->wait_queue,
1070 				(request->callback == NULL)
1071 			);
1072 		} while (rc == -ERESTARTSYS);
1073 
1074 		DBF_EVENT(3, "IO stopped on %08x\n", device->cdev_id);
1075 		rc = -ERESTARTSYS;
1076 	}
1077 	return rc;
1078 }
1079 
1080 /*
1081  * Stop running ccw.
1082  */
1083 int
tape_cancel_io(struct tape_device * device,struct tape_request * request)1084 tape_cancel_io(struct tape_device *device, struct tape_request *request)
1085 {
1086 	int rc;
1087 
1088 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1089 	rc = __tape_cancel_io(device, request);
1090 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1091 	return rc;
1092 }
1093 
1094 /*
1095  * Tape interrupt routine, called from the ccw_device layer
1096  */
1097 static void
__tape_do_irq(struct ccw_device * cdev,unsigned long intparm,struct irb * irb)1098 __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
1099 {
1100 	struct tape_device *device;
1101 	struct tape_request *request;
1102 	int rc;
1103 
1104 	device = dev_get_drvdata(&cdev->dev);
1105 	if (device == NULL) {
1106 		return;
1107 	}
1108 	request = (struct tape_request *) intparm;
1109 
1110 	DBF_LH(6, "__tape_do_irq(device=%p, request=%p)\n", device, request);
1111 
1112 	/* On special conditions irb is an error pointer */
1113 	if (IS_ERR(irb)) {
1114 		/* FIXME: What to do with the request? */
1115 		switch (PTR_ERR(irb)) {
1116 			case -ETIMEDOUT:
1117 				DBF_LH(1, "(%08x): Request timed out\n",
1118 				       device->cdev_id);
1119 			case -EIO:
1120 				__tape_end_request(device, request, -EIO);
1121 				break;
1122 			default:
1123 				DBF_LH(1, "(%08x): Unexpected i/o error %li\n",
1124 				       device->cdev_id,	PTR_ERR(irb));
1125 		}
1126 		return;
1127 	}
1128 
1129 	/*
1130 	 * If the condition code is not zero and the start function bit is
1131 	 * still set, this is an deferred error and the last start I/O did
1132 	 * not succeed. At this point the condition that caused the deferred
1133 	 * error might still apply. So we just schedule the request to be
1134 	 * started later.
1135 	 */
1136 	if (irb->scsw.cmd.cc != 0 &&
1137 	    (irb->scsw.cmd.fctl & SCSW_FCTL_START_FUNC) &&
1138 	    (request->status == TAPE_REQUEST_IN_IO)) {
1139 		DBF_EVENT(3,"(%08x): deferred cc=%i, fctl=%i. restarting\n",
1140 			device->cdev_id, irb->scsw.cmd.cc, irb->scsw.cmd.fctl);
1141 		request->status = TAPE_REQUEST_QUEUED;
1142 		schedule_delayed_work(&device->tape_dnr, HZ);
1143 		return;
1144 	}
1145 
1146 	/* May be an unsolicited irq */
1147 	if(request != NULL)
1148 		request->rescnt = irb->scsw.cmd.count;
1149 	else if ((irb->scsw.cmd.dstat == 0x85 || irb->scsw.cmd.dstat == 0x80) &&
1150 		 !list_empty(&device->req_queue)) {
1151 		/* Not Ready to Ready after long busy ? */
1152 		struct tape_request *req;
1153 		req = list_entry(device->req_queue.next,
1154 				 struct tape_request, list);
1155 		if (req->status == TAPE_REQUEST_LONG_BUSY) {
1156 			DBF_EVENT(3, "(%08x): del timer\n", device->cdev_id);
1157 			if (del_timer(&device->lb_timeout)) {
1158 				tape_put_device(device);
1159 				__tape_start_next_request(device);
1160 			}
1161 			return;
1162 		}
1163 	}
1164 	if (irb->scsw.cmd.dstat != 0x0c) {
1165 		/* Set the 'ONLINE' flag depending on sense byte 1 */
1166 		if(*(((__u8 *) irb->ecw) + 1) & SENSE_DRIVE_ONLINE)
1167 			device->tape_generic_status |= GMT_ONLINE(~0);
1168 		else
1169 			device->tape_generic_status &= ~GMT_ONLINE(~0);
1170 
1171 		/*
1172 		 * Any request that does not come back with channel end
1173 		 * and device end is unusual. Log the sense data.
1174 		 */
1175 		DBF_EVENT(3,"-- Tape Interrupthandler --\n");
1176 		tape_dump_sense_dbf(device, request, irb);
1177 	} else {
1178 		/* Upon normal completion the device _is_ online */
1179 		device->tape_generic_status |= GMT_ONLINE(~0);
1180 	}
1181 	if (device->tape_state == TS_NOT_OPER) {
1182 		DBF_EVENT(6, "tape:device is not operational\n");
1183 		return;
1184 	}
1185 
1186 	/*
1187 	 * Request that were canceled still come back with an interrupt.
1188 	 * To detect these request the state will be set to TAPE_REQUEST_DONE.
1189 	 */
1190 	if(request != NULL && request->status == TAPE_REQUEST_DONE) {
1191 		__tape_end_request(device, request, -EIO);
1192 		return;
1193 	}
1194 
1195 	rc = device->discipline->irq(device, request, irb);
1196 	/*
1197 	 * rc < 0 : request finished unsuccessfully.
1198 	 * rc == TAPE_IO_SUCCESS: request finished successfully.
1199 	 * rc == TAPE_IO_PENDING: request is still running. Ignore rc.
1200 	 * rc == TAPE_IO_RETRY: request finished but needs another go.
1201 	 * rc == TAPE_IO_STOP: request needs to get terminated.
1202 	 */
1203 	switch (rc) {
1204 		case TAPE_IO_SUCCESS:
1205 			/* Upon normal completion the device _is_ online */
1206 			device->tape_generic_status |= GMT_ONLINE(~0);
1207 			__tape_end_request(device, request, rc);
1208 			break;
1209 		case TAPE_IO_PENDING:
1210 			break;
1211 		case TAPE_IO_LONG_BUSY:
1212 			device->lb_timeout.expires = jiffies +
1213 				LONG_BUSY_TIMEOUT * HZ;
1214 			DBF_EVENT(3, "(%08x): add timer\n", device->cdev_id);
1215 			add_timer(&device->lb_timeout);
1216 			request->status = TAPE_REQUEST_LONG_BUSY;
1217 			break;
1218 		case TAPE_IO_RETRY:
1219 			rc = __tape_start_io(device, request);
1220 			if (rc)
1221 				__tape_end_request(device, request, rc);
1222 			break;
1223 		case TAPE_IO_STOP:
1224 			rc = __tape_cancel_io(device, request);
1225 			if (rc)
1226 				__tape_end_request(device, request, rc);
1227 			break;
1228 		default:
1229 			if (rc > 0) {
1230 				DBF_EVENT(6, "xunknownrc\n");
1231 				__tape_end_request(device, request, -EIO);
1232 			} else {
1233 				__tape_end_request(device, request, rc);
1234 			}
1235 			break;
1236 	}
1237 }
1238 
1239 /*
1240  * Tape device open function used by tape_char frontend.
1241  */
1242 int
tape_open(struct tape_device * device)1243 tape_open(struct tape_device *device)
1244 {
1245 	int rc;
1246 
1247 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1248 	if (device->tape_state == TS_NOT_OPER) {
1249 		DBF_EVENT(6, "TAPE:nodev\n");
1250 		rc = -ENODEV;
1251 	} else if (device->tape_state == TS_IN_USE) {
1252 		DBF_EVENT(6, "TAPE:dbusy\n");
1253 		rc = -EBUSY;
1254 	} else if (device->tape_state == TS_BLKUSE) {
1255 		DBF_EVENT(6, "TAPE:dbusy\n");
1256 		rc = -EBUSY;
1257 	} else if (device->discipline != NULL &&
1258 		   !try_module_get(device->discipline->owner)) {
1259 		DBF_EVENT(6, "TAPE:nodisc\n");
1260 		rc = -ENODEV;
1261 	} else {
1262 		tape_state_set(device, TS_IN_USE);
1263 		rc = 0;
1264 	}
1265 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1266 	return rc;
1267 }
1268 
1269 /*
1270  * Tape device release function used by tape_char frontend.
1271  */
1272 int
tape_release(struct tape_device * device)1273 tape_release(struct tape_device *device)
1274 {
1275 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1276 	if (device->tape_state == TS_IN_USE)
1277 		tape_state_set(device, TS_UNUSED);
1278 	module_put(device->discipline->owner);
1279 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1280 	return 0;
1281 }
1282 
1283 /*
1284  * Execute a magnetic tape command a number of times.
1285  */
1286 int
tape_mtop(struct tape_device * device,int mt_op,int mt_count)1287 tape_mtop(struct tape_device *device, int mt_op, int mt_count)
1288 {
1289 	tape_mtop_fn fn;
1290 	int rc;
1291 
1292 	DBF_EVENT(6, "TAPE:mtio\n");
1293 	DBF_EVENT(6, "TAPE:ioop: %x\n", mt_op);
1294 	DBF_EVENT(6, "TAPE:arg:	 %x\n", mt_count);
1295 
1296 	if (mt_op < 0 || mt_op >= TAPE_NR_MTOPS)
1297 		return -EINVAL;
1298 	fn = device->discipline->mtop_array[mt_op];
1299 	if (fn == NULL)
1300 		return -EINVAL;
1301 
1302 	/* We assume that the backends can handle count up to 500. */
1303 	if (mt_op == MTBSR  || mt_op == MTFSR  || mt_op == MTFSF  ||
1304 	    mt_op == MTBSF  || mt_op == MTFSFM || mt_op == MTBSFM) {
1305 		rc = 0;
1306 		for (; mt_count > 500; mt_count -= 500)
1307 			if ((rc = fn(device, 500)) != 0)
1308 				break;
1309 		if (rc == 0)
1310 			rc = fn(device, mt_count);
1311 	} else
1312 		rc = fn(device, mt_count);
1313 	return rc;
1314 
1315 }
1316 
1317 /*
1318  * Tape init function.
1319  */
1320 static int
tape_init(void)1321 tape_init (void)
1322 {
1323 	TAPE_DBF_AREA = debug_register ( "tape", 2, 2, 4*sizeof(long));
1324 	debug_register_view(TAPE_DBF_AREA, &debug_sprintf_view);
1325 #ifdef DBF_LIKE_HELL
1326 	debug_set_level(TAPE_DBF_AREA, 6);
1327 #endif
1328 	DBF_EVENT(3, "tape init\n");
1329 	tape_proc_init();
1330 	tapechar_init ();
1331 	return 0;
1332 }
1333 
1334 /*
1335  * Tape exit function.
1336  */
1337 static void
tape_exit(void)1338 tape_exit(void)
1339 {
1340 	DBF_EVENT(6, "tape exit\n");
1341 
1342 	/* Get rid of the frontends */
1343 	tapechar_exit();
1344 	tape_proc_cleanup();
1345 	debug_unregister (TAPE_DBF_AREA);
1346 }
1347 
1348 MODULE_AUTHOR("(C) 2001 IBM Deutschland Entwicklung GmbH by Carsten Otte and "
1349 	      "Michael Holzheu (cotte@de.ibm.com,holzheu@de.ibm.com)");
1350 MODULE_DESCRIPTION("Linux on zSeries channel attached tape device driver");
1351 MODULE_LICENSE("GPL");
1352 
1353 module_init(tape_init);
1354 module_exit(tape_exit);
1355 
1356 EXPORT_SYMBOL(tape_generic_remove);
1357 EXPORT_SYMBOL(tape_generic_probe);
1358 EXPORT_SYMBOL(tape_generic_online);
1359 EXPORT_SYMBOL(tape_generic_offline);
1360 EXPORT_SYMBOL(tape_generic_pm_suspend);
1361 EXPORT_SYMBOL(tape_put_device);
1362 EXPORT_SYMBOL(tape_get_device);
1363 EXPORT_SYMBOL(tape_state_verbose);
1364 EXPORT_SYMBOL(tape_op_verbose);
1365 EXPORT_SYMBOL(tape_state_set);
1366 EXPORT_SYMBOL(tape_med_state_set);
1367 EXPORT_SYMBOL(tape_alloc_request);
1368 EXPORT_SYMBOL(tape_free_request);
1369 EXPORT_SYMBOL(tape_dump_sense_dbf);
1370 EXPORT_SYMBOL(tape_do_io);
1371 EXPORT_SYMBOL(tape_do_io_async);
1372 EXPORT_SYMBOL(tape_do_io_interruptible);
1373 EXPORT_SYMBOL(tape_cancel_io);
1374 EXPORT_SYMBOL(tape_mtop);
1375