xref: /linux/drivers/s390/block/dasd.c (revision c0c914eca7f251c70facc37dfebeaf176601918d)
1 /*
2  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
3  *		    Horst Hummel <Horst.Hummel@de.ibm.com>
4  *		    Carsten Otte <Cotte@de.ibm.com>
5  *		    Martin Schwidefsky <schwidefsky@de.ibm.com>
6  * Bugreports.to..: <Linux390@de.ibm.com>
7  * Copyright IBM Corp. 1999, 2009
8  */
9 
10 #define KMSG_COMPONENT "dasd"
11 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
12 
13 #include <linux/kmod.h>
14 #include <linux/init.h>
15 #include <linux/interrupt.h>
16 #include <linux/ctype.h>
17 #include <linux/major.h>
18 #include <linux/slab.h>
19 #include <linux/hdreg.h>
20 #include <linux/async.h>
21 #include <linux/mutex.h>
22 #include <linux/debugfs.h>
23 #include <linux/seq_file.h>
24 #include <linux/vmalloc.h>
25 
26 #include <asm/ccwdev.h>
27 #include <asm/ebcdic.h>
28 #include <asm/idals.h>
29 #include <asm/itcw.h>
30 #include <asm/diag.h>
31 
32 /* This is ugly... */
33 #define PRINTK_HEADER "dasd:"
34 
35 #include "dasd_int.h"
36 /*
37  * SECTION: Constant definitions to be used within this file
38  */
39 #define DASD_CHANQ_MAX_SIZE 4
40 
41 #define DASD_DIAG_MOD		"dasd_diag_mod"
42 
43 /*
44  * SECTION: exported variables of dasd.c
45  */
46 debug_info_t *dasd_debug_area;
47 EXPORT_SYMBOL(dasd_debug_area);
48 static struct dentry *dasd_debugfs_root_entry;
49 struct dasd_discipline *dasd_diag_discipline_pointer;
50 EXPORT_SYMBOL(dasd_diag_discipline_pointer);
51 void dasd_int_handler(struct ccw_device *, unsigned long, struct irb *);
52 
53 MODULE_AUTHOR("Holger Smolinski <Holger.Smolinski@de.ibm.com>");
54 MODULE_DESCRIPTION("Linux on S/390 DASD device driver,"
55 		   " Copyright IBM Corp. 2000");
56 MODULE_SUPPORTED_DEVICE("dasd");
57 MODULE_LICENSE("GPL");
58 
59 /*
60  * SECTION: prototypes for static functions of dasd.c
61  */
62 static int  dasd_alloc_queue(struct dasd_block *);
63 static void dasd_setup_queue(struct dasd_block *);
64 static void dasd_free_queue(struct dasd_block *);
65 static void dasd_flush_request_queue(struct dasd_block *);
66 static int dasd_flush_block_queue(struct dasd_block *);
67 static void dasd_device_tasklet(struct dasd_device *);
68 static void dasd_block_tasklet(struct dasd_block *);
69 static void do_kick_device(struct work_struct *);
70 static void do_restore_device(struct work_struct *);
71 static void do_reload_device(struct work_struct *);
72 static void dasd_return_cqr_cb(struct dasd_ccw_req *, void *);
73 static void dasd_device_timeout(unsigned long);
74 static void dasd_block_timeout(unsigned long);
75 static void __dasd_process_erp(struct dasd_device *, struct dasd_ccw_req *);
76 static void dasd_profile_init(struct dasd_profile *, struct dentry *);
77 static void dasd_profile_exit(struct dasd_profile *);
78 
79 /*
80  * SECTION: Operations on the device structure.
81  */
82 static wait_queue_head_t dasd_init_waitq;
83 static wait_queue_head_t dasd_flush_wq;
84 static wait_queue_head_t generic_waitq;
85 static wait_queue_head_t shutdown_waitq;
86 
87 /*
88  * Allocate memory for a new device structure.
89  */
90 struct dasd_device *dasd_alloc_device(void)
91 {
92 	struct dasd_device *device;
93 
94 	device = kzalloc(sizeof(struct dasd_device), GFP_ATOMIC);
95 	if (!device)
96 		return ERR_PTR(-ENOMEM);
97 
98 	/* Get two pages for normal block device operations. */
99 	device->ccw_mem = (void *) __get_free_pages(GFP_ATOMIC | GFP_DMA, 1);
100 	if (!device->ccw_mem) {
101 		kfree(device);
102 		return ERR_PTR(-ENOMEM);
103 	}
104 	/* Get one page for error recovery. */
105 	device->erp_mem = (void *) get_zeroed_page(GFP_ATOMIC | GFP_DMA);
106 	if (!device->erp_mem) {
107 		free_pages((unsigned long) device->ccw_mem, 1);
108 		kfree(device);
109 		return ERR_PTR(-ENOMEM);
110 	}
111 
112 	dasd_init_chunklist(&device->ccw_chunks, device->ccw_mem, PAGE_SIZE*2);
113 	dasd_init_chunklist(&device->erp_chunks, device->erp_mem, PAGE_SIZE);
114 	spin_lock_init(&device->mem_lock);
115 	atomic_set(&device->tasklet_scheduled, 0);
116 	tasklet_init(&device->tasklet,
117 		     (void (*)(unsigned long)) dasd_device_tasklet,
118 		     (unsigned long) device);
119 	INIT_LIST_HEAD(&device->ccw_queue);
120 	init_timer(&device->timer);
121 	device->timer.function = dasd_device_timeout;
122 	device->timer.data = (unsigned long) device;
123 	INIT_WORK(&device->kick_work, do_kick_device);
124 	INIT_WORK(&device->restore_device, do_restore_device);
125 	INIT_WORK(&device->reload_device, do_reload_device);
126 	device->state = DASD_STATE_NEW;
127 	device->target = DASD_STATE_NEW;
128 	mutex_init(&device->state_mutex);
129 	spin_lock_init(&device->profile.lock);
130 	return device;
131 }
132 
133 /*
134  * Free memory of a device structure.
135  */
136 void dasd_free_device(struct dasd_device *device)
137 {
138 	kfree(device->private);
139 	free_page((unsigned long) device->erp_mem);
140 	free_pages((unsigned long) device->ccw_mem, 1);
141 	kfree(device);
142 }
143 
144 /*
145  * Allocate memory for a new device structure.
146  */
147 struct dasd_block *dasd_alloc_block(void)
148 {
149 	struct dasd_block *block;
150 
151 	block = kzalloc(sizeof(*block), GFP_ATOMIC);
152 	if (!block)
153 		return ERR_PTR(-ENOMEM);
154 	/* open_count = 0 means device online but not in use */
155 	atomic_set(&block->open_count, -1);
156 
157 	spin_lock_init(&block->request_queue_lock);
158 	atomic_set(&block->tasklet_scheduled, 0);
159 	tasklet_init(&block->tasklet,
160 		     (void (*)(unsigned long)) dasd_block_tasklet,
161 		     (unsigned long) block);
162 	INIT_LIST_HEAD(&block->ccw_queue);
163 	spin_lock_init(&block->queue_lock);
164 	init_timer(&block->timer);
165 	block->timer.function = dasd_block_timeout;
166 	block->timer.data = (unsigned long) block;
167 	spin_lock_init(&block->profile.lock);
168 
169 	return block;
170 }
171 EXPORT_SYMBOL_GPL(dasd_alloc_block);
172 
173 /*
174  * Free memory of a device structure.
175  */
176 void dasd_free_block(struct dasd_block *block)
177 {
178 	kfree(block);
179 }
180 EXPORT_SYMBOL_GPL(dasd_free_block);
181 
182 /*
183  * Make a new device known to the system.
184  */
185 static int dasd_state_new_to_known(struct dasd_device *device)
186 {
187 	int rc;
188 
189 	/*
190 	 * As long as the device is not in state DASD_STATE_NEW we want to
191 	 * keep the reference count > 0.
192 	 */
193 	dasd_get_device(device);
194 
195 	if (device->block) {
196 		rc = dasd_alloc_queue(device->block);
197 		if (rc) {
198 			dasd_put_device(device);
199 			return rc;
200 		}
201 	}
202 	device->state = DASD_STATE_KNOWN;
203 	return 0;
204 }
205 
206 /*
207  * Let the system forget about a device.
208  */
209 static int dasd_state_known_to_new(struct dasd_device *device)
210 {
211 	/* Disable extended error reporting for this device. */
212 	dasd_eer_disable(device);
213 	/* Forget the discipline information. */
214 	if (device->discipline) {
215 		if (device->discipline->uncheck_device)
216 			device->discipline->uncheck_device(device);
217 		module_put(device->discipline->owner);
218 	}
219 	device->discipline = NULL;
220 	if (device->base_discipline)
221 		module_put(device->base_discipline->owner);
222 	device->base_discipline = NULL;
223 	device->state = DASD_STATE_NEW;
224 
225 	if (device->block)
226 		dasd_free_queue(device->block);
227 
228 	/* Give up reference we took in dasd_state_new_to_known. */
229 	dasd_put_device(device);
230 	return 0;
231 }
232 
233 static struct dentry *dasd_debugfs_setup(const char *name,
234 					 struct dentry *base_dentry)
235 {
236 	struct dentry *pde;
237 
238 	if (!base_dentry)
239 		return NULL;
240 	pde = debugfs_create_dir(name, base_dentry);
241 	if (!pde || IS_ERR(pde))
242 		return NULL;
243 	return pde;
244 }
245 
246 /*
247  * Request the irq line for the device.
248  */
249 static int dasd_state_known_to_basic(struct dasd_device *device)
250 {
251 	struct dasd_block *block = device->block;
252 	int rc = 0;
253 
254 	/* Allocate and register gendisk structure. */
255 	if (block) {
256 		rc = dasd_gendisk_alloc(block);
257 		if (rc)
258 			return rc;
259 		block->debugfs_dentry =
260 			dasd_debugfs_setup(block->gdp->disk_name,
261 					   dasd_debugfs_root_entry);
262 		dasd_profile_init(&block->profile, block->debugfs_dentry);
263 		if (dasd_global_profile_level == DASD_PROFILE_ON)
264 			dasd_profile_on(&device->block->profile);
265 	}
266 	device->debugfs_dentry =
267 		dasd_debugfs_setup(dev_name(&device->cdev->dev),
268 				   dasd_debugfs_root_entry);
269 	dasd_profile_init(&device->profile, device->debugfs_dentry);
270 
271 	/* register 'device' debug area, used for all DBF_DEV_XXX calls */
272 	device->debug_area = debug_register(dev_name(&device->cdev->dev), 4, 1,
273 					    8 * sizeof(long));
274 	debug_register_view(device->debug_area, &debug_sprintf_view);
275 	debug_set_level(device->debug_area, DBF_WARNING);
276 	DBF_DEV_EVENT(DBF_EMERG, device, "%s", "debug area created");
277 
278 	device->state = DASD_STATE_BASIC;
279 
280 	return rc;
281 }
282 
283 /*
284  * Release the irq line for the device. Terminate any running i/o.
285  */
286 static int dasd_state_basic_to_known(struct dasd_device *device)
287 {
288 	int rc;
289 
290 	if (device->discipline->basic_to_known) {
291 		rc = device->discipline->basic_to_known(device);
292 		if (rc)
293 			return rc;
294 	}
295 
296 	if (device->block) {
297 		dasd_profile_exit(&device->block->profile);
298 		debugfs_remove(device->block->debugfs_dentry);
299 		dasd_gendisk_free(device->block);
300 		dasd_block_clear_timer(device->block);
301 	}
302 	rc = dasd_flush_device_queue(device);
303 	if (rc)
304 		return rc;
305 	dasd_device_clear_timer(device);
306 	dasd_profile_exit(&device->profile);
307 	debugfs_remove(device->debugfs_dentry);
308 	DBF_DEV_EVENT(DBF_EMERG, device, "%p debug area deleted", device);
309 	if (device->debug_area != NULL) {
310 		debug_unregister(device->debug_area);
311 		device->debug_area = NULL;
312 	}
313 	device->state = DASD_STATE_KNOWN;
314 	return 0;
315 }
316 
317 /*
318  * Do the initial analysis. The do_analysis function may return
319  * -EAGAIN in which case the device keeps the state DASD_STATE_BASIC
320  * until the discipline decides to continue the startup sequence
321  * by calling the function dasd_change_state. The eckd disciplines
322  * uses this to start a ccw that detects the format. The completion
323  * interrupt for this detection ccw uses the kernel event daemon to
324  * trigger the call to dasd_change_state. All this is done in the
325  * discipline code, see dasd_eckd.c.
326  * After the analysis ccw is done (do_analysis returned 0) the block
327  * device is setup.
328  * In case the analysis returns an error, the device setup is stopped
329  * (a fake disk was already added to allow formatting).
330  */
331 static int dasd_state_basic_to_ready(struct dasd_device *device)
332 {
333 	int rc;
334 	struct dasd_block *block;
335 
336 	rc = 0;
337 	block = device->block;
338 	/* make disk known with correct capacity */
339 	if (block) {
340 		if (block->base->discipline->do_analysis != NULL)
341 			rc = block->base->discipline->do_analysis(block);
342 		if (rc) {
343 			if (rc != -EAGAIN) {
344 				device->state = DASD_STATE_UNFMT;
345 				goto out;
346 			}
347 			return rc;
348 		}
349 		dasd_setup_queue(block);
350 		set_capacity(block->gdp,
351 			     block->blocks << block->s2b_shift);
352 		device->state = DASD_STATE_READY;
353 		rc = dasd_scan_partitions(block);
354 		if (rc) {
355 			device->state = DASD_STATE_BASIC;
356 			return rc;
357 		}
358 	} else {
359 		device->state = DASD_STATE_READY;
360 	}
361 out:
362 	if (device->discipline->basic_to_ready)
363 		rc = device->discipline->basic_to_ready(device);
364 	return rc;
365 }
366 
367 static inline
368 int _wait_for_empty_queues(struct dasd_device *device)
369 {
370 	if (device->block)
371 		return list_empty(&device->ccw_queue) &&
372 			list_empty(&device->block->ccw_queue);
373 	else
374 		return list_empty(&device->ccw_queue);
375 }
376 
377 /*
378  * Remove device from block device layer. Destroy dirty buffers.
379  * Forget format information. Check if the target level is basic
380  * and if it is create fake disk for formatting.
381  */
382 static int dasd_state_ready_to_basic(struct dasd_device *device)
383 {
384 	int rc;
385 
386 	device->state = DASD_STATE_BASIC;
387 	if (device->block) {
388 		struct dasd_block *block = device->block;
389 		rc = dasd_flush_block_queue(block);
390 		if (rc) {
391 			device->state = DASD_STATE_READY;
392 			return rc;
393 		}
394 		dasd_flush_request_queue(block);
395 		dasd_destroy_partitions(block);
396 		block->blocks = 0;
397 		block->bp_block = 0;
398 		block->s2b_shift = 0;
399 	}
400 	return 0;
401 }
402 
403 /*
404  * Back to basic.
405  */
406 static int dasd_state_unfmt_to_basic(struct dasd_device *device)
407 {
408 	device->state = DASD_STATE_BASIC;
409 	return 0;
410 }
411 
412 /*
413  * Make the device online and schedule the bottom half to start
414  * the requeueing of requests from the linux request queue to the
415  * ccw queue.
416  */
417 static int
418 dasd_state_ready_to_online(struct dasd_device * device)
419 {
420 	struct gendisk *disk;
421 	struct disk_part_iter piter;
422 	struct hd_struct *part;
423 
424 	device->state = DASD_STATE_ONLINE;
425 	if (device->block) {
426 		dasd_schedule_block_bh(device->block);
427 		if ((device->features & DASD_FEATURE_USERAW)) {
428 			disk = device->block->gdp;
429 			kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
430 			return 0;
431 		}
432 		disk = device->block->bdev->bd_disk;
433 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
434 		while ((part = disk_part_iter_next(&piter)))
435 			kobject_uevent(&part_to_dev(part)->kobj, KOBJ_CHANGE);
436 		disk_part_iter_exit(&piter);
437 	}
438 	return 0;
439 }
440 
441 /*
442  * Stop the requeueing of requests again.
443  */
444 static int dasd_state_online_to_ready(struct dasd_device *device)
445 {
446 	int rc;
447 	struct gendisk *disk;
448 	struct disk_part_iter piter;
449 	struct hd_struct *part;
450 
451 	if (device->discipline->online_to_ready) {
452 		rc = device->discipline->online_to_ready(device);
453 		if (rc)
454 			return rc;
455 	}
456 
457 	device->state = DASD_STATE_READY;
458 	if (device->block && !(device->features & DASD_FEATURE_USERAW)) {
459 		disk = device->block->bdev->bd_disk;
460 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
461 		while ((part = disk_part_iter_next(&piter)))
462 			kobject_uevent(&part_to_dev(part)->kobj, KOBJ_CHANGE);
463 		disk_part_iter_exit(&piter);
464 	}
465 	return 0;
466 }
467 
468 /*
469  * Device startup state changes.
470  */
471 static int dasd_increase_state(struct dasd_device *device)
472 {
473 	int rc;
474 
475 	rc = 0;
476 	if (device->state == DASD_STATE_NEW &&
477 	    device->target >= DASD_STATE_KNOWN)
478 		rc = dasd_state_new_to_known(device);
479 
480 	if (!rc &&
481 	    device->state == DASD_STATE_KNOWN &&
482 	    device->target >= DASD_STATE_BASIC)
483 		rc = dasd_state_known_to_basic(device);
484 
485 	if (!rc &&
486 	    device->state == DASD_STATE_BASIC &&
487 	    device->target >= DASD_STATE_READY)
488 		rc = dasd_state_basic_to_ready(device);
489 
490 	if (!rc &&
491 	    device->state == DASD_STATE_UNFMT &&
492 	    device->target > DASD_STATE_UNFMT)
493 		rc = -EPERM;
494 
495 	if (!rc &&
496 	    device->state == DASD_STATE_READY &&
497 	    device->target >= DASD_STATE_ONLINE)
498 		rc = dasd_state_ready_to_online(device);
499 
500 	return rc;
501 }
502 
503 /*
504  * Device shutdown state changes.
505  */
506 static int dasd_decrease_state(struct dasd_device *device)
507 {
508 	int rc;
509 
510 	rc = 0;
511 	if (device->state == DASD_STATE_ONLINE &&
512 	    device->target <= DASD_STATE_READY)
513 		rc = dasd_state_online_to_ready(device);
514 
515 	if (!rc &&
516 	    device->state == DASD_STATE_READY &&
517 	    device->target <= DASD_STATE_BASIC)
518 		rc = dasd_state_ready_to_basic(device);
519 
520 	if (!rc &&
521 	    device->state == DASD_STATE_UNFMT &&
522 	    device->target <= DASD_STATE_BASIC)
523 		rc = dasd_state_unfmt_to_basic(device);
524 
525 	if (!rc &&
526 	    device->state == DASD_STATE_BASIC &&
527 	    device->target <= DASD_STATE_KNOWN)
528 		rc = dasd_state_basic_to_known(device);
529 
530 	if (!rc &&
531 	    device->state == DASD_STATE_KNOWN &&
532 	    device->target <= DASD_STATE_NEW)
533 		rc = dasd_state_known_to_new(device);
534 
535 	return rc;
536 }
537 
538 /*
539  * This is the main startup/shutdown routine.
540  */
541 static void dasd_change_state(struct dasd_device *device)
542 {
543 	int rc;
544 
545 	if (device->state == device->target)
546 		/* Already where we want to go today... */
547 		return;
548 	if (device->state < device->target)
549 		rc = dasd_increase_state(device);
550 	else
551 		rc = dasd_decrease_state(device);
552 	if (rc == -EAGAIN)
553 		return;
554 	if (rc)
555 		device->target = device->state;
556 
557 	/* let user-space know that the device status changed */
558 	kobject_uevent(&device->cdev->dev.kobj, KOBJ_CHANGE);
559 
560 	if (device->state == device->target)
561 		wake_up(&dasd_init_waitq);
562 }
563 
564 /*
565  * Kick starter for devices that did not complete the startup/shutdown
566  * procedure or were sleeping because of a pending state.
567  * dasd_kick_device will schedule a call do do_kick_device to the kernel
568  * event daemon.
569  */
570 static void do_kick_device(struct work_struct *work)
571 {
572 	struct dasd_device *device = container_of(work, struct dasd_device, kick_work);
573 	mutex_lock(&device->state_mutex);
574 	dasd_change_state(device);
575 	mutex_unlock(&device->state_mutex);
576 	dasd_schedule_device_bh(device);
577 	dasd_put_device(device);
578 }
579 
580 void dasd_kick_device(struct dasd_device *device)
581 {
582 	dasd_get_device(device);
583 	/* queue call to dasd_kick_device to the kernel event daemon. */
584 	if (!schedule_work(&device->kick_work))
585 		dasd_put_device(device);
586 }
587 EXPORT_SYMBOL(dasd_kick_device);
588 
589 /*
590  * dasd_reload_device will schedule a call do do_reload_device to the kernel
591  * event daemon.
592  */
593 static void do_reload_device(struct work_struct *work)
594 {
595 	struct dasd_device *device = container_of(work, struct dasd_device,
596 						  reload_device);
597 	device->discipline->reload(device);
598 	dasd_put_device(device);
599 }
600 
601 void dasd_reload_device(struct dasd_device *device)
602 {
603 	dasd_get_device(device);
604 	/* queue call to dasd_reload_device to the kernel event daemon. */
605 	if (!schedule_work(&device->reload_device))
606 		dasd_put_device(device);
607 }
608 EXPORT_SYMBOL(dasd_reload_device);
609 
610 /*
611  * dasd_restore_device will schedule a call do do_restore_device to the kernel
612  * event daemon.
613  */
614 static void do_restore_device(struct work_struct *work)
615 {
616 	struct dasd_device *device = container_of(work, struct dasd_device,
617 						  restore_device);
618 	device->cdev->drv->restore(device->cdev);
619 	dasd_put_device(device);
620 }
621 
622 void dasd_restore_device(struct dasd_device *device)
623 {
624 	dasd_get_device(device);
625 	/* queue call to dasd_restore_device to the kernel event daemon. */
626 	if (!schedule_work(&device->restore_device))
627 		dasd_put_device(device);
628 }
629 
630 /*
631  * Set the target state for a device and starts the state change.
632  */
633 void dasd_set_target_state(struct dasd_device *device, int target)
634 {
635 	dasd_get_device(device);
636 	mutex_lock(&device->state_mutex);
637 	/* If we are in probeonly mode stop at DASD_STATE_READY. */
638 	if (dasd_probeonly && target > DASD_STATE_READY)
639 		target = DASD_STATE_READY;
640 	if (device->target != target) {
641 		if (device->state == target)
642 			wake_up(&dasd_init_waitq);
643 		device->target = target;
644 	}
645 	if (device->state != device->target)
646 		dasd_change_state(device);
647 	mutex_unlock(&device->state_mutex);
648 	dasd_put_device(device);
649 }
650 EXPORT_SYMBOL(dasd_set_target_state);
651 
652 /*
653  * Enable devices with device numbers in [from..to].
654  */
655 static inline int _wait_for_device(struct dasd_device *device)
656 {
657 	return (device->state == device->target);
658 }
659 
660 void dasd_enable_device(struct dasd_device *device)
661 {
662 	dasd_set_target_state(device, DASD_STATE_ONLINE);
663 	if (device->state <= DASD_STATE_KNOWN)
664 		/* No discipline for device found. */
665 		dasd_set_target_state(device, DASD_STATE_NEW);
666 	/* Now wait for the devices to come up. */
667 	wait_event(dasd_init_waitq, _wait_for_device(device));
668 
669 	dasd_reload_device(device);
670 	if (device->discipline->kick_validate)
671 		device->discipline->kick_validate(device);
672 }
673 EXPORT_SYMBOL(dasd_enable_device);
674 
675 /*
676  * SECTION: device operation (interrupt handler, start i/o, term i/o ...)
677  */
678 
679 unsigned int dasd_global_profile_level = DASD_PROFILE_OFF;
680 
681 #ifdef CONFIG_DASD_PROFILE
682 struct dasd_profile dasd_global_profile = {
683 	.lock = __SPIN_LOCK_UNLOCKED(dasd_global_profile.lock),
684 };
685 static struct dentry *dasd_debugfs_global_entry;
686 
687 /*
688  * Add profiling information for cqr before execution.
689  */
690 static void dasd_profile_start(struct dasd_block *block,
691 			       struct dasd_ccw_req *cqr,
692 			       struct request *req)
693 {
694 	struct list_head *l;
695 	unsigned int counter;
696 	struct dasd_device *device;
697 
698 	/* count the length of the chanq for statistics */
699 	counter = 0;
700 	if (dasd_global_profile_level || block->profile.data)
701 		list_for_each(l, &block->ccw_queue)
702 			if (++counter >= 31)
703 				break;
704 
705 	spin_lock(&dasd_global_profile.lock);
706 	if (dasd_global_profile.data) {
707 		dasd_global_profile.data->dasd_io_nr_req[counter]++;
708 		if (rq_data_dir(req) == READ)
709 			dasd_global_profile.data->dasd_read_nr_req[counter]++;
710 	}
711 	spin_unlock(&dasd_global_profile.lock);
712 
713 	spin_lock(&block->profile.lock);
714 	if (block->profile.data) {
715 		block->profile.data->dasd_io_nr_req[counter]++;
716 		if (rq_data_dir(req) == READ)
717 			block->profile.data->dasd_read_nr_req[counter]++;
718 	}
719 	spin_unlock(&block->profile.lock);
720 
721 	/*
722 	 * We count the request for the start device, even though it may run on
723 	 * some other device due to error recovery. This way we make sure that
724 	 * we count each request only once.
725 	 */
726 	device = cqr->startdev;
727 	if (device->profile.data) {
728 		counter = 1; /* request is not yet queued on the start device */
729 		list_for_each(l, &device->ccw_queue)
730 			if (++counter >= 31)
731 				break;
732 	}
733 	spin_lock(&device->profile.lock);
734 	if (device->profile.data) {
735 		device->profile.data->dasd_io_nr_req[counter]++;
736 		if (rq_data_dir(req) == READ)
737 			device->profile.data->dasd_read_nr_req[counter]++;
738 	}
739 	spin_unlock(&device->profile.lock);
740 }
741 
742 /*
743  * Add profiling information for cqr after execution.
744  */
745 
746 #define dasd_profile_counter(value, index)			   \
747 {								   \
748 	for (index = 0; index < 31 && value >> (2+index); index++) \
749 		;						   \
750 }
751 
752 static void dasd_profile_end_add_data(struct dasd_profile_info *data,
753 				      int is_alias,
754 				      int is_tpm,
755 				      int is_read,
756 				      long sectors,
757 				      int sectors_ind,
758 				      int tottime_ind,
759 				      int tottimeps_ind,
760 				      int strtime_ind,
761 				      int irqtime_ind,
762 				      int irqtimeps_ind,
763 				      int endtime_ind)
764 {
765 	/* in case of an overflow, reset the whole profile */
766 	if (data->dasd_io_reqs == UINT_MAX) {
767 			memset(data, 0, sizeof(*data));
768 			getnstimeofday(&data->starttod);
769 	}
770 	data->dasd_io_reqs++;
771 	data->dasd_io_sects += sectors;
772 	if (is_alias)
773 		data->dasd_io_alias++;
774 	if (is_tpm)
775 		data->dasd_io_tpm++;
776 
777 	data->dasd_io_secs[sectors_ind]++;
778 	data->dasd_io_times[tottime_ind]++;
779 	data->dasd_io_timps[tottimeps_ind]++;
780 	data->dasd_io_time1[strtime_ind]++;
781 	data->dasd_io_time2[irqtime_ind]++;
782 	data->dasd_io_time2ps[irqtimeps_ind]++;
783 	data->dasd_io_time3[endtime_ind]++;
784 
785 	if (is_read) {
786 		data->dasd_read_reqs++;
787 		data->dasd_read_sects += sectors;
788 		if (is_alias)
789 			data->dasd_read_alias++;
790 		if (is_tpm)
791 			data->dasd_read_tpm++;
792 		data->dasd_read_secs[sectors_ind]++;
793 		data->dasd_read_times[tottime_ind]++;
794 		data->dasd_read_time1[strtime_ind]++;
795 		data->dasd_read_time2[irqtime_ind]++;
796 		data->dasd_read_time3[endtime_ind]++;
797 	}
798 }
799 
800 static void dasd_profile_end(struct dasd_block *block,
801 			     struct dasd_ccw_req *cqr,
802 			     struct request *req)
803 {
804 	long strtime, irqtime, endtime, tottime;	/* in microseconds */
805 	long tottimeps, sectors;
806 	struct dasd_device *device;
807 	int sectors_ind, tottime_ind, tottimeps_ind, strtime_ind;
808 	int irqtime_ind, irqtimeps_ind, endtime_ind;
809 
810 	device = cqr->startdev;
811 	if (!(dasd_global_profile_level ||
812 	      block->profile.data ||
813 	      device->profile.data))
814 		return;
815 
816 	sectors = blk_rq_sectors(req);
817 	if (!cqr->buildclk || !cqr->startclk ||
818 	    !cqr->stopclk || !cqr->endclk ||
819 	    !sectors)
820 		return;
821 
822 	strtime = ((cqr->startclk - cqr->buildclk) >> 12);
823 	irqtime = ((cqr->stopclk - cqr->startclk) >> 12);
824 	endtime = ((cqr->endclk - cqr->stopclk) >> 12);
825 	tottime = ((cqr->endclk - cqr->buildclk) >> 12);
826 	tottimeps = tottime / sectors;
827 
828 	dasd_profile_counter(sectors, sectors_ind);
829 	dasd_profile_counter(tottime, tottime_ind);
830 	dasd_profile_counter(tottimeps, tottimeps_ind);
831 	dasd_profile_counter(strtime, strtime_ind);
832 	dasd_profile_counter(irqtime, irqtime_ind);
833 	dasd_profile_counter(irqtime / sectors, irqtimeps_ind);
834 	dasd_profile_counter(endtime, endtime_ind);
835 
836 	spin_lock(&dasd_global_profile.lock);
837 	if (dasd_global_profile.data) {
838 		dasd_profile_end_add_data(dasd_global_profile.data,
839 					  cqr->startdev != block->base,
840 					  cqr->cpmode == 1,
841 					  rq_data_dir(req) == READ,
842 					  sectors, sectors_ind, tottime_ind,
843 					  tottimeps_ind, strtime_ind,
844 					  irqtime_ind, irqtimeps_ind,
845 					  endtime_ind);
846 	}
847 	spin_unlock(&dasd_global_profile.lock);
848 
849 	spin_lock(&block->profile.lock);
850 	if (block->profile.data)
851 		dasd_profile_end_add_data(block->profile.data,
852 					  cqr->startdev != block->base,
853 					  cqr->cpmode == 1,
854 					  rq_data_dir(req) == READ,
855 					  sectors, sectors_ind, tottime_ind,
856 					  tottimeps_ind, strtime_ind,
857 					  irqtime_ind, irqtimeps_ind,
858 					  endtime_ind);
859 	spin_unlock(&block->profile.lock);
860 
861 	spin_lock(&device->profile.lock);
862 	if (device->profile.data)
863 		dasd_profile_end_add_data(device->profile.data,
864 					  cqr->startdev != block->base,
865 					  cqr->cpmode == 1,
866 					  rq_data_dir(req) == READ,
867 					  sectors, sectors_ind, tottime_ind,
868 					  tottimeps_ind, strtime_ind,
869 					  irqtime_ind, irqtimeps_ind,
870 					  endtime_ind);
871 	spin_unlock(&device->profile.lock);
872 }
873 
874 void dasd_profile_reset(struct dasd_profile *profile)
875 {
876 	struct dasd_profile_info *data;
877 
878 	spin_lock_bh(&profile->lock);
879 	data = profile->data;
880 	if (!data) {
881 		spin_unlock_bh(&profile->lock);
882 		return;
883 	}
884 	memset(data, 0, sizeof(*data));
885 	getnstimeofday(&data->starttod);
886 	spin_unlock_bh(&profile->lock);
887 }
888 
889 int dasd_profile_on(struct dasd_profile *profile)
890 {
891 	struct dasd_profile_info *data;
892 
893 	data = kzalloc(sizeof(*data), GFP_KERNEL);
894 	if (!data)
895 		return -ENOMEM;
896 	spin_lock_bh(&profile->lock);
897 	if (profile->data) {
898 		spin_unlock_bh(&profile->lock);
899 		kfree(data);
900 		return 0;
901 	}
902 	getnstimeofday(&data->starttod);
903 	profile->data = data;
904 	spin_unlock_bh(&profile->lock);
905 	return 0;
906 }
907 
908 void dasd_profile_off(struct dasd_profile *profile)
909 {
910 	spin_lock_bh(&profile->lock);
911 	kfree(profile->data);
912 	profile->data = NULL;
913 	spin_unlock_bh(&profile->lock);
914 }
915 
916 char *dasd_get_user_string(const char __user *user_buf, size_t user_len)
917 {
918 	char *buffer;
919 
920 	buffer = vmalloc(user_len + 1);
921 	if (buffer == NULL)
922 		return ERR_PTR(-ENOMEM);
923 	if (copy_from_user(buffer, user_buf, user_len) != 0) {
924 		vfree(buffer);
925 		return ERR_PTR(-EFAULT);
926 	}
927 	/* got the string, now strip linefeed. */
928 	if (buffer[user_len - 1] == '\n')
929 		buffer[user_len - 1] = 0;
930 	else
931 		buffer[user_len] = 0;
932 	return buffer;
933 }
934 
935 static ssize_t dasd_stats_write(struct file *file,
936 				const char __user *user_buf,
937 				size_t user_len, loff_t *pos)
938 {
939 	char *buffer, *str;
940 	int rc;
941 	struct seq_file *m = (struct seq_file *)file->private_data;
942 	struct dasd_profile *prof = m->private;
943 
944 	if (user_len > 65536)
945 		user_len = 65536;
946 	buffer = dasd_get_user_string(user_buf, user_len);
947 	if (IS_ERR(buffer))
948 		return PTR_ERR(buffer);
949 
950 	str = skip_spaces(buffer);
951 	rc = user_len;
952 	if (strncmp(str, "reset", 5) == 0) {
953 		dasd_profile_reset(prof);
954 	} else if (strncmp(str, "on", 2) == 0) {
955 		rc = dasd_profile_on(prof);
956 		if (rc)
957 			goto out;
958 		rc = user_len;
959 		if (prof == &dasd_global_profile) {
960 			dasd_profile_reset(prof);
961 			dasd_global_profile_level = DASD_PROFILE_GLOBAL_ONLY;
962 		}
963 	} else if (strncmp(str, "off", 3) == 0) {
964 		if (prof == &dasd_global_profile)
965 			dasd_global_profile_level = DASD_PROFILE_OFF;
966 		dasd_profile_off(prof);
967 	} else
968 		rc = -EINVAL;
969 out:
970 	vfree(buffer);
971 	return rc;
972 }
973 
974 static void dasd_stats_array(struct seq_file *m, unsigned int *array)
975 {
976 	int i;
977 
978 	for (i = 0; i < 32; i++)
979 		seq_printf(m, "%u ", array[i]);
980 	seq_putc(m, '\n');
981 }
982 
983 static void dasd_stats_seq_print(struct seq_file *m,
984 				 struct dasd_profile_info *data)
985 {
986 	seq_printf(m, "start_time %ld.%09ld\n",
987 		   data->starttod.tv_sec, data->starttod.tv_nsec);
988 	seq_printf(m, "total_requests %u\n", data->dasd_io_reqs);
989 	seq_printf(m, "total_sectors %u\n", data->dasd_io_sects);
990 	seq_printf(m, "total_pav %u\n", data->dasd_io_alias);
991 	seq_printf(m, "total_hpf %u\n", data->dasd_io_tpm);
992 	seq_puts(m, "histogram_sectors ");
993 	dasd_stats_array(m, data->dasd_io_secs);
994 	seq_puts(m, "histogram_io_times ");
995 	dasd_stats_array(m, data->dasd_io_times);
996 	seq_puts(m, "histogram_io_times_weighted ");
997 	dasd_stats_array(m, data->dasd_io_timps);
998 	seq_puts(m, "histogram_time_build_to_ssch ");
999 	dasd_stats_array(m, data->dasd_io_time1);
1000 	seq_puts(m, "histogram_time_ssch_to_irq ");
1001 	dasd_stats_array(m, data->dasd_io_time2);
1002 	seq_puts(m, "histogram_time_ssch_to_irq_weighted ");
1003 	dasd_stats_array(m, data->dasd_io_time2ps);
1004 	seq_puts(m, "histogram_time_irq_to_end ");
1005 	dasd_stats_array(m, data->dasd_io_time3);
1006 	seq_puts(m, "histogram_ccw_queue_length ");
1007 	dasd_stats_array(m, data->dasd_io_nr_req);
1008 	seq_printf(m, "total_read_requests %u\n", data->dasd_read_reqs);
1009 	seq_printf(m, "total_read_sectors %u\n", data->dasd_read_sects);
1010 	seq_printf(m, "total_read_pav %u\n", data->dasd_read_alias);
1011 	seq_printf(m, "total_read_hpf %u\n", data->dasd_read_tpm);
1012 	seq_puts(m, "histogram_read_sectors ");
1013 	dasd_stats_array(m, data->dasd_read_secs);
1014 	seq_puts(m, "histogram_read_times ");
1015 	dasd_stats_array(m, data->dasd_read_times);
1016 	seq_puts(m, "histogram_read_time_build_to_ssch ");
1017 	dasd_stats_array(m, data->dasd_read_time1);
1018 	seq_puts(m, "histogram_read_time_ssch_to_irq ");
1019 	dasd_stats_array(m, data->dasd_read_time2);
1020 	seq_puts(m, "histogram_read_time_irq_to_end ");
1021 	dasd_stats_array(m, data->dasd_read_time3);
1022 	seq_puts(m, "histogram_read_ccw_queue_length ");
1023 	dasd_stats_array(m, data->dasd_read_nr_req);
1024 }
1025 
1026 static int dasd_stats_show(struct seq_file *m, void *v)
1027 {
1028 	struct dasd_profile *profile;
1029 	struct dasd_profile_info *data;
1030 
1031 	profile = m->private;
1032 	spin_lock_bh(&profile->lock);
1033 	data = profile->data;
1034 	if (!data) {
1035 		spin_unlock_bh(&profile->lock);
1036 		seq_puts(m, "disabled\n");
1037 		return 0;
1038 	}
1039 	dasd_stats_seq_print(m, data);
1040 	spin_unlock_bh(&profile->lock);
1041 	return 0;
1042 }
1043 
1044 static int dasd_stats_open(struct inode *inode, struct file *file)
1045 {
1046 	struct dasd_profile *profile = inode->i_private;
1047 	return single_open(file, dasd_stats_show, profile);
1048 }
1049 
1050 static const struct file_operations dasd_stats_raw_fops = {
1051 	.owner		= THIS_MODULE,
1052 	.open		= dasd_stats_open,
1053 	.read		= seq_read,
1054 	.llseek		= seq_lseek,
1055 	.release	= single_release,
1056 	.write		= dasd_stats_write,
1057 };
1058 
1059 static void dasd_profile_init(struct dasd_profile *profile,
1060 			      struct dentry *base_dentry)
1061 {
1062 	umode_t mode;
1063 	struct dentry *pde;
1064 
1065 	if (!base_dentry)
1066 		return;
1067 	profile->dentry = NULL;
1068 	profile->data = NULL;
1069 	mode = (S_IRUSR | S_IWUSR | S_IFREG);
1070 	pde = debugfs_create_file("statistics", mode, base_dentry,
1071 				  profile, &dasd_stats_raw_fops);
1072 	if (pde && !IS_ERR(pde))
1073 		profile->dentry = pde;
1074 	return;
1075 }
1076 
1077 static void dasd_profile_exit(struct dasd_profile *profile)
1078 {
1079 	dasd_profile_off(profile);
1080 	debugfs_remove(profile->dentry);
1081 	profile->dentry = NULL;
1082 }
1083 
1084 static void dasd_statistics_removeroot(void)
1085 {
1086 	dasd_global_profile_level = DASD_PROFILE_OFF;
1087 	dasd_profile_exit(&dasd_global_profile);
1088 	debugfs_remove(dasd_debugfs_global_entry);
1089 	debugfs_remove(dasd_debugfs_root_entry);
1090 }
1091 
1092 static void dasd_statistics_createroot(void)
1093 {
1094 	struct dentry *pde;
1095 
1096 	dasd_debugfs_root_entry = NULL;
1097 	pde = debugfs_create_dir("dasd", NULL);
1098 	if (!pde || IS_ERR(pde))
1099 		goto error;
1100 	dasd_debugfs_root_entry = pde;
1101 	pde = debugfs_create_dir("global", dasd_debugfs_root_entry);
1102 	if (!pde || IS_ERR(pde))
1103 		goto error;
1104 	dasd_debugfs_global_entry = pde;
1105 	dasd_profile_init(&dasd_global_profile, dasd_debugfs_global_entry);
1106 	return;
1107 
1108 error:
1109 	DBF_EVENT(DBF_ERR, "%s",
1110 		  "Creation of the dasd debugfs interface failed");
1111 	dasd_statistics_removeroot();
1112 	return;
1113 }
1114 
1115 #else
1116 #define dasd_profile_start(block, cqr, req) do {} while (0)
1117 #define dasd_profile_end(block, cqr, req) do {} while (0)
1118 
1119 static void dasd_statistics_createroot(void)
1120 {
1121 	return;
1122 }
1123 
1124 static void dasd_statistics_removeroot(void)
1125 {
1126 	return;
1127 }
1128 
1129 int dasd_stats_generic_show(struct seq_file *m, void *v)
1130 {
1131 	seq_puts(m, "Statistics are not activated in this kernel\n");
1132 	return 0;
1133 }
1134 
1135 static void dasd_profile_init(struct dasd_profile *profile,
1136 			      struct dentry *base_dentry)
1137 {
1138 	return;
1139 }
1140 
1141 static void dasd_profile_exit(struct dasd_profile *profile)
1142 {
1143 	return;
1144 }
1145 
1146 int dasd_profile_on(struct dasd_profile *profile)
1147 {
1148 	return 0;
1149 }
1150 
1151 #endif				/* CONFIG_DASD_PROFILE */
1152 
1153 /*
1154  * Allocate memory for a channel program with 'cplength' channel
1155  * command words and 'datasize' additional space. There are two
1156  * variantes: 1) dasd_kmalloc_request uses kmalloc to get the needed
1157  * memory and 2) dasd_smalloc_request uses the static ccw memory
1158  * that gets allocated for each device.
1159  */
1160 struct dasd_ccw_req *dasd_kmalloc_request(int magic, int cplength,
1161 					  int datasize,
1162 					  struct dasd_device *device)
1163 {
1164 	struct dasd_ccw_req *cqr;
1165 
1166 	/* Sanity checks */
1167 	BUG_ON(datasize > PAGE_SIZE ||
1168 	     (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
1169 
1170 	cqr = kzalloc(sizeof(struct dasd_ccw_req), GFP_ATOMIC);
1171 	if (cqr == NULL)
1172 		return ERR_PTR(-ENOMEM);
1173 	cqr->cpaddr = NULL;
1174 	if (cplength > 0) {
1175 		cqr->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
1176 				      GFP_ATOMIC | GFP_DMA);
1177 		if (cqr->cpaddr == NULL) {
1178 			kfree(cqr);
1179 			return ERR_PTR(-ENOMEM);
1180 		}
1181 	}
1182 	cqr->data = NULL;
1183 	if (datasize > 0) {
1184 		cqr->data = kzalloc(datasize, GFP_ATOMIC | GFP_DMA);
1185 		if (cqr->data == NULL) {
1186 			kfree(cqr->cpaddr);
1187 			kfree(cqr);
1188 			return ERR_PTR(-ENOMEM);
1189 		}
1190 	}
1191 	cqr->magic =  magic;
1192 	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
1193 	dasd_get_device(device);
1194 	return cqr;
1195 }
1196 EXPORT_SYMBOL(dasd_kmalloc_request);
1197 
1198 struct dasd_ccw_req *dasd_smalloc_request(int magic, int cplength,
1199 					  int datasize,
1200 					  struct dasd_device *device)
1201 {
1202 	unsigned long flags;
1203 	struct dasd_ccw_req *cqr;
1204 	char *data;
1205 	int size;
1206 
1207 	size = (sizeof(struct dasd_ccw_req) + 7L) & -8L;
1208 	if (cplength > 0)
1209 		size += cplength * sizeof(struct ccw1);
1210 	if (datasize > 0)
1211 		size += datasize;
1212 	spin_lock_irqsave(&device->mem_lock, flags);
1213 	cqr = (struct dasd_ccw_req *)
1214 		dasd_alloc_chunk(&device->ccw_chunks, size);
1215 	spin_unlock_irqrestore(&device->mem_lock, flags);
1216 	if (cqr == NULL)
1217 		return ERR_PTR(-ENOMEM);
1218 	memset(cqr, 0, sizeof(struct dasd_ccw_req));
1219 	data = (char *) cqr + ((sizeof(struct dasd_ccw_req) + 7L) & -8L);
1220 	cqr->cpaddr = NULL;
1221 	if (cplength > 0) {
1222 		cqr->cpaddr = (struct ccw1 *) data;
1223 		data += cplength*sizeof(struct ccw1);
1224 		memset(cqr->cpaddr, 0, cplength*sizeof(struct ccw1));
1225 	}
1226 	cqr->data = NULL;
1227 	if (datasize > 0) {
1228 		cqr->data = data;
1229  		memset(cqr->data, 0, datasize);
1230 	}
1231 	cqr->magic = magic;
1232 	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
1233 	dasd_get_device(device);
1234 	return cqr;
1235 }
1236 EXPORT_SYMBOL(dasd_smalloc_request);
1237 
1238 /*
1239  * Free memory of a channel program. This function needs to free all the
1240  * idal lists that might have been created by dasd_set_cda and the
1241  * struct dasd_ccw_req itself.
1242  */
1243 void dasd_kfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
1244 {
1245 	struct ccw1 *ccw;
1246 
1247 	/* Clear any idals used for the request. */
1248 	ccw = cqr->cpaddr;
1249 	do {
1250 		clear_normalized_cda(ccw);
1251 	} while (ccw++->flags & (CCW_FLAG_CC | CCW_FLAG_DC));
1252 	kfree(cqr->cpaddr);
1253 	kfree(cqr->data);
1254 	kfree(cqr);
1255 	dasd_put_device(device);
1256 }
1257 EXPORT_SYMBOL(dasd_kfree_request);
1258 
1259 void dasd_sfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
1260 {
1261 	unsigned long flags;
1262 
1263 	spin_lock_irqsave(&device->mem_lock, flags);
1264 	dasd_free_chunk(&device->ccw_chunks, cqr);
1265 	spin_unlock_irqrestore(&device->mem_lock, flags);
1266 	dasd_put_device(device);
1267 }
1268 EXPORT_SYMBOL(dasd_sfree_request);
1269 
1270 /*
1271  * Check discipline magic in cqr.
1272  */
1273 static inline int dasd_check_cqr(struct dasd_ccw_req *cqr)
1274 {
1275 	struct dasd_device *device;
1276 
1277 	if (cqr == NULL)
1278 		return -EINVAL;
1279 	device = cqr->startdev;
1280 	if (strncmp((char *) &cqr->magic, device->discipline->ebcname, 4)) {
1281 		DBF_DEV_EVENT(DBF_WARNING, device,
1282 			    " dasd_ccw_req 0x%08x magic doesn't match"
1283 			    " discipline 0x%08x",
1284 			    cqr->magic,
1285 			    *(unsigned int *) device->discipline->name);
1286 		return -EINVAL;
1287 	}
1288 	return 0;
1289 }
1290 
1291 /*
1292  * Terminate the current i/o and set the request to clear_pending.
1293  * Timer keeps device runnig.
1294  * ccw_device_clear can fail if the i/o subsystem
1295  * is in a bad mood.
1296  */
1297 int dasd_term_IO(struct dasd_ccw_req *cqr)
1298 {
1299 	struct dasd_device *device;
1300 	int retries, rc;
1301 	char errorstring[ERRORLENGTH];
1302 
1303 	/* Check the cqr */
1304 	rc = dasd_check_cqr(cqr);
1305 	if (rc)
1306 		return rc;
1307 	retries = 0;
1308 	device = (struct dasd_device *) cqr->startdev;
1309 	while ((retries < 5) && (cqr->status == DASD_CQR_IN_IO)) {
1310 		rc = ccw_device_clear(device->cdev, (long) cqr);
1311 		switch (rc) {
1312 		case 0:	/* termination successful */
1313 			cqr->status = DASD_CQR_CLEAR_PENDING;
1314 			cqr->stopclk = get_tod_clock();
1315 			cqr->starttime = 0;
1316 			DBF_DEV_EVENT(DBF_DEBUG, device,
1317 				      "terminate cqr %p successful",
1318 				      cqr);
1319 			break;
1320 		case -ENODEV:
1321 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
1322 				      "device gone, retry");
1323 			break;
1324 		case -EIO:
1325 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
1326 				      "I/O error, retry");
1327 			break;
1328 		case -EINVAL:
1329 			/*
1330 			 * device not valid so no I/O could be running
1331 			 * handle CQR as termination successful
1332 			 */
1333 			cqr->status = DASD_CQR_CLEARED;
1334 			cqr->stopclk = get_tod_clock();
1335 			cqr->starttime = 0;
1336 			/* no retries for invalid devices */
1337 			cqr->retries = -1;
1338 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
1339 				      "EINVAL, handle as terminated");
1340 			/* fake rc to success */
1341 			rc = 0;
1342 			break;
1343 		case -EBUSY:
1344 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
1345 				      "device busy, retry later");
1346 			break;
1347 		default:
1348 			/* internal error 10 - unknown rc*/
1349 			snprintf(errorstring, ERRORLENGTH, "10 %d", rc);
1350 			dev_err(&device->cdev->dev, "An error occurred in the "
1351 				"DASD device driver, reason=%s\n", errorstring);
1352 			BUG();
1353 			break;
1354 		}
1355 		retries++;
1356 	}
1357 	dasd_schedule_device_bh(device);
1358 	return rc;
1359 }
1360 EXPORT_SYMBOL(dasd_term_IO);
1361 
1362 /*
1363  * Start the i/o. This start_IO can fail if the channel is really busy.
1364  * In that case set up a timer to start the request later.
1365  */
1366 int dasd_start_IO(struct dasd_ccw_req *cqr)
1367 {
1368 	struct dasd_device *device;
1369 	int rc;
1370 	char errorstring[ERRORLENGTH];
1371 
1372 	/* Check the cqr */
1373 	rc = dasd_check_cqr(cqr);
1374 	if (rc) {
1375 		cqr->intrc = rc;
1376 		return rc;
1377 	}
1378 	device = (struct dasd_device *) cqr->startdev;
1379 	if (((cqr->block &&
1380 	      test_bit(DASD_FLAG_LOCK_STOLEN, &cqr->block->base->flags)) ||
1381 	     test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags)) &&
1382 	    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
1383 		DBF_DEV_EVENT(DBF_DEBUG, device, "start_IO: return request %p "
1384 			      "because of stolen lock", cqr);
1385 		cqr->status = DASD_CQR_ERROR;
1386 		cqr->intrc = -EPERM;
1387 		return -EPERM;
1388 	}
1389 	if (cqr->retries < 0) {
1390 		/* internal error 14 - start_IO run out of retries */
1391 		sprintf(errorstring, "14 %p", cqr);
1392 		dev_err(&device->cdev->dev, "An error occurred in the DASD "
1393 			"device driver, reason=%s\n", errorstring);
1394 		cqr->status = DASD_CQR_ERROR;
1395 		return -EIO;
1396 	}
1397 	cqr->startclk = get_tod_clock();
1398 	cqr->starttime = jiffies;
1399 	cqr->retries--;
1400 	if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
1401 		cqr->lpm &= device->path_data.opm;
1402 		if (!cqr->lpm)
1403 			cqr->lpm = device->path_data.opm;
1404 	}
1405 	if (cqr->cpmode == 1) {
1406 		rc = ccw_device_tm_start(device->cdev, cqr->cpaddr,
1407 					 (long) cqr, cqr->lpm);
1408 	} else {
1409 		rc = ccw_device_start(device->cdev, cqr->cpaddr,
1410 				      (long) cqr, cqr->lpm, 0);
1411 	}
1412 	switch (rc) {
1413 	case 0:
1414 		cqr->status = DASD_CQR_IN_IO;
1415 		break;
1416 	case -EBUSY:
1417 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1418 			      "start_IO: device busy, retry later");
1419 		break;
1420 	case -ETIMEDOUT:
1421 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1422 			      "start_IO: request timeout, retry later");
1423 		break;
1424 	case -EACCES:
1425 		/* -EACCES indicates that the request used only a subset of the
1426 		 * available paths and all these paths are gone. If the lpm of
1427 		 * this request was only a subset of the opm (e.g. the ppm) then
1428 		 * we just do a retry with all available paths.
1429 		 * If we already use the full opm, something is amiss, and we
1430 		 * need a full path verification.
1431 		 */
1432 		if (test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
1433 			DBF_DEV_EVENT(DBF_WARNING, device,
1434 				      "start_IO: selected paths gone (%x)",
1435 				      cqr->lpm);
1436 		} else if (cqr->lpm != device->path_data.opm) {
1437 			cqr->lpm = device->path_data.opm;
1438 			DBF_DEV_EVENT(DBF_DEBUG, device, "%s",
1439 				      "start_IO: selected paths gone,"
1440 				      " retry on all paths");
1441 		} else {
1442 			DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1443 				      "start_IO: all paths in opm gone,"
1444 				      " do path verification");
1445 			dasd_generic_last_path_gone(device);
1446 			device->path_data.opm = 0;
1447 			device->path_data.ppm = 0;
1448 			device->path_data.npm = 0;
1449 			device->path_data.tbvpm =
1450 				ccw_device_get_path_mask(device->cdev);
1451 		}
1452 		break;
1453 	case -ENODEV:
1454 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1455 			      "start_IO: -ENODEV device gone, retry");
1456 		break;
1457 	case -EIO:
1458 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1459 			      "start_IO: -EIO device gone, retry");
1460 		break;
1461 	case -EINVAL:
1462 		/* most likely caused in power management context */
1463 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1464 			      "start_IO: -EINVAL device currently "
1465 			      "not accessible");
1466 		break;
1467 	default:
1468 		/* internal error 11 - unknown rc */
1469 		snprintf(errorstring, ERRORLENGTH, "11 %d", rc);
1470 		dev_err(&device->cdev->dev,
1471 			"An error occurred in the DASD device driver, "
1472 			"reason=%s\n", errorstring);
1473 		BUG();
1474 		break;
1475 	}
1476 	cqr->intrc = rc;
1477 	return rc;
1478 }
1479 EXPORT_SYMBOL(dasd_start_IO);
1480 
1481 /*
1482  * Timeout function for dasd devices. This is used for different purposes
1483  *  1) missing interrupt handler for normal operation
1484  *  2) delayed start of request where start_IO failed with -EBUSY
1485  *  3) timeout for missing state change interrupts
1486  * The head of the ccw queue will have status DASD_CQR_IN_IO for 1),
1487  * DASD_CQR_QUEUED for 2) and 3).
1488  */
1489 static void dasd_device_timeout(unsigned long ptr)
1490 {
1491 	unsigned long flags;
1492 	struct dasd_device *device;
1493 
1494 	device = (struct dasd_device *) ptr;
1495 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
1496 	/* re-activate request queue */
1497 	dasd_device_remove_stop_bits(device, DASD_STOPPED_PENDING);
1498 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
1499 	dasd_schedule_device_bh(device);
1500 }
1501 
1502 /*
1503  * Setup timeout for a device in jiffies.
1504  */
1505 void dasd_device_set_timer(struct dasd_device *device, int expires)
1506 {
1507 	if (expires == 0)
1508 		del_timer(&device->timer);
1509 	else
1510 		mod_timer(&device->timer, jiffies + expires);
1511 }
1512 EXPORT_SYMBOL(dasd_device_set_timer);
1513 
1514 /*
1515  * Clear timeout for a device.
1516  */
1517 void dasd_device_clear_timer(struct dasd_device *device)
1518 {
1519 	del_timer(&device->timer);
1520 }
1521 EXPORT_SYMBOL(dasd_device_clear_timer);
1522 
1523 static void dasd_handle_killed_request(struct ccw_device *cdev,
1524 				       unsigned long intparm)
1525 {
1526 	struct dasd_ccw_req *cqr;
1527 	struct dasd_device *device;
1528 
1529 	if (!intparm)
1530 		return;
1531 	cqr = (struct dasd_ccw_req *) intparm;
1532 	if (cqr->status != DASD_CQR_IN_IO) {
1533 		DBF_EVENT_DEVID(DBF_DEBUG, cdev,
1534 				"invalid status in handle_killed_request: "
1535 				"%02x", cqr->status);
1536 		return;
1537 	}
1538 
1539 	device = dasd_device_from_cdev_locked(cdev);
1540 	if (IS_ERR(device)) {
1541 		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
1542 				"unable to get device from cdev");
1543 		return;
1544 	}
1545 
1546 	if (!cqr->startdev ||
1547 	    device != cqr->startdev ||
1548 	    strncmp(cqr->startdev->discipline->ebcname,
1549 		    (char *) &cqr->magic, 4)) {
1550 		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
1551 				"invalid device in request");
1552 		dasd_put_device(device);
1553 		return;
1554 	}
1555 
1556 	/* Schedule request to be retried. */
1557 	cqr->status = DASD_CQR_QUEUED;
1558 
1559 	dasd_device_clear_timer(device);
1560 	dasd_schedule_device_bh(device);
1561 	dasd_put_device(device);
1562 }
1563 
1564 void dasd_generic_handle_state_change(struct dasd_device *device)
1565 {
1566 	/* First of all start sense subsystem status request. */
1567 	dasd_eer_snss(device);
1568 
1569 	dasd_device_remove_stop_bits(device, DASD_STOPPED_PENDING);
1570 	dasd_schedule_device_bh(device);
1571 	if (device->block)
1572 		dasd_schedule_block_bh(device->block);
1573 }
1574 EXPORT_SYMBOL_GPL(dasd_generic_handle_state_change);
1575 
1576 /*
1577  * Interrupt handler for "normal" ssch-io based dasd devices.
1578  */
1579 void dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
1580 		      struct irb *irb)
1581 {
1582 	struct dasd_ccw_req *cqr, *next;
1583 	struct dasd_device *device;
1584 	unsigned long long now;
1585 	int expires;
1586 
1587 	if (IS_ERR(irb)) {
1588 		switch (PTR_ERR(irb)) {
1589 		case -EIO:
1590 			break;
1591 		case -ETIMEDOUT:
1592 			DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
1593 					"request timed out\n", __func__);
1594 			break;
1595 		default:
1596 			DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
1597 					"unknown error %ld\n", __func__,
1598 					PTR_ERR(irb));
1599 		}
1600 		dasd_handle_killed_request(cdev, intparm);
1601 		return;
1602 	}
1603 
1604 	now = get_tod_clock();
1605 	cqr = (struct dasd_ccw_req *) intparm;
1606 	/* check for conditions that should be handled immediately */
1607 	if (!cqr ||
1608 	    !(scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
1609 	      scsw_cstat(&irb->scsw) == 0)) {
1610 		if (cqr)
1611 			memcpy(&cqr->irb, irb, sizeof(*irb));
1612 		device = dasd_device_from_cdev_locked(cdev);
1613 		if (IS_ERR(device))
1614 			return;
1615 		/* ignore unsolicited interrupts for DIAG discipline */
1616 		if (device->discipline == dasd_diag_discipline_pointer) {
1617 			dasd_put_device(device);
1618 			return;
1619 		}
1620 		device->discipline->dump_sense_dbf(device, irb, "int");
1621 		if (device->features & DASD_FEATURE_ERPLOG)
1622 			device->discipline->dump_sense(device, cqr, irb);
1623 		device->discipline->check_for_device_change(device, cqr, irb);
1624 		dasd_put_device(device);
1625 	}
1626 
1627 	/* check for for attention message */
1628 	if (scsw_dstat(&irb->scsw) & DEV_STAT_ATTENTION) {
1629 		device = dasd_device_from_cdev_locked(cdev);
1630 		device->discipline->check_attention(device, irb->esw.esw1.lpum);
1631 		dasd_put_device(device);
1632 	}
1633 
1634 	if (!cqr)
1635 		return;
1636 
1637 	device = (struct dasd_device *) cqr->startdev;
1638 	if (!device ||
1639 	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
1640 		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
1641 				"invalid device in request");
1642 		return;
1643 	}
1644 
1645 	/* Check for clear pending */
1646 	if (cqr->status == DASD_CQR_CLEAR_PENDING &&
1647 	    scsw_fctl(&irb->scsw) & SCSW_FCTL_CLEAR_FUNC) {
1648 		cqr->status = DASD_CQR_CLEARED;
1649 		dasd_device_clear_timer(device);
1650 		wake_up(&dasd_flush_wq);
1651 		dasd_schedule_device_bh(device);
1652 		return;
1653 	}
1654 
1655 	/* check status - the request might have been killed by dyn detach */
1656 	if (cqr->status != DASD_CQR_IN_IO) {
1657 		DBF_DEV_EVENT(DBF_DEBUG, device, "invalid status: bus_id %s, "
1658 			      "status %02x", dev_name(&cdev->dev), cqr->status);
1659 		return;
1660 	}
1661 
1662 	next = NULL;
1663 	expires = 0;
1664 	if (scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
1665 	    scsw_cstat(&irb->scsw) == 0) {
1666 		/* request was completed successfully */
1667 		cqr->status = DASD_CQR_SUCCESS;
1668 		cqr->stopclk = now;
1669 		/* Start first request on queue if possible -> fast_io. */
1670 		if (cqr->devlist.next != &device->ccw_queue) {
1671 			next = list_entry(cqr->devlist.next,
1672 					  struct dasd_ccw_req, devlist);
1673 		}
1674 	} else {  /* error */
1675 		/*
1676 		 * If we don't want complex ERP for this request, then just
1677 		 * reset this and retry it in the fastpath
1678 		 */
1679 		if (!test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags) &&
1680 		    cqr->retries > 0) {
1681 			if (cqr->lpm == device->path_data.opm)
1682 				DBF_DEV_EVENT(DBF_DEBUG, device,
1683 					      "default ERP in fastpath "
1684 					      "(%i retries left)",
1685 					      cqr->retries);
1686 			if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags))
1687 				cqr->lpm = device->path_data.opm;
1688 			cqr->status = DASD_CQR_QUEUED;
1689 			next = cqr;
1690 		} else
1691 			cqr->status = DASD_CQR_ERROR;
1692 	}
1693 	if (next && (next->status == DASD_CQR_QUEUED) &&
1694 	    (!device->stopped)) {
1695 		if (device->discipline->start_IO(next) == 0)
1696 			expires = next->expires;
1697 	}
1698 	if (expires != 0)
1699 		dasd_device_set_timer(device, expires);
1700 	else
1701 		dasd_device_clear_timer(device);
1702 	dasd_schedule_device_bh(device);
1703 }
1704 EXPORT_SYMBOL(dasd_int_handler);
1705 
1706 enum uc_todo dasd_generic_uc_handler(struct ccw_device *cdev, struct irb *irb)
1707 {
1708 	struct dasd_device *device;
1709 
1710 	device = dasd_device_from_cdev_locked(cdev);
1711 
1712 	if (IS_ERR(device))
1713 		goto out;
1714 	if (test_bit(DASD_FLAG_OFFLINE, &device->flags) ||
1715 	   device->state != device->target ||
1716 	   !device->discipline->check_for_device_change){
1717 		dasd_put_device(device);
1718 		goto out;
1719 	}
1720 	if (device->discipline->dump_sense_dbf)
1721 		device->discipline->dump_sense_dbf(device, irb, "uc");
1722 	device->discipline->check_for_device_change(device, NULL, irb);
1723 	dasd_put_device(device);
1724 out:
1725 	return UC_TODO_RETRY;
1726 }
1727 EXPORT_SYMBOL_GPL(dasd_generic_uc_handler);
1728 
1729 /*
1730  * If we have an error on a dasd_block layer request then we cancel
1731  * and return all further requests from the same dasd_block as well.
1732  */
1733 static void __dasd_device_recovery(struct dasd_device *device,
1734 				   struct dasd_ccw_req *ref_cqr)
1735 {
1736 	struct list_head *l, *n;
1737 	struct dasd_ccw_req *cqr;
1738 
1739 	/*
1740 	 * only requeue request that came from the dasd_block layer
1741 	 */
1742 	if (!ref_cqr->block)
1743 		return;
1744 
1745 	list_for_each_safe(l, n, &device->ccw_queue) {
1746 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1747 		if (cqr->status == DASD_CQR_QUEUED &&
1748 		    ref_cqr->block == cqr->block) {
1749 			cqr->status = DASD_CQR_CLEARED;
1750 		}
1751 	}
1752 };
1753 
1754 /*
1755  * Remove those ccw requests from the queue that need to be returned
1756  * to the upper layer.
1757  */
1758 static void __dasd_device_process_ccw_queue(struct dasd_device *device,
1759 					    struct list_head *final_queue)
1760 {
1761 	struct list_head *l, *n;
1762 	struct dasd_ccw_req *cqr;
1763 
1764 	/* Process request with final status. */
1765 	list_for_each_safe(l, n, &device->ccw_queue) {
1766 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1767 
1768 		/* Skip any non-final request. */
1769 		if (cqr->status == DASD_CQR_QUEUED ||
1770 		    cqr->status == DASD_CQR_IN_IO ||
1771 		    cqr->status == DASD_CQR_CLEAR_PENDING)
1772 			continue;
1773 		if (cqr->status == DASD_CQR_ERROR) {
1774 			__dasd_device_recovery(device, cqr);
1775 		}
1776 		/* Rechain finished requests to final queue */
1777 		list_move_tail(&cqr->devlist, final_queue);
1778 	}
1779 }
1780 
1781 /*
1782  * the cqrs from the final queue are returned to the upper layer
1783  * by setting a dasd_block state and calling the callback function
1784  */
1785 static void __dasd_device_process_final_queue(struct dasd_device *device,
1786 					      struct list_head *final_queue)
1787 {
1788 	struct list_head *l, *n;
1789 	struct dasd_ccw_req *cqr;
1790 	struct dasd_block *block;
1791 	void (*callback)(struct dasd_ccw_req *, void *data);
1792 	void *callback_data;
1793 	char errorstring[ERRORLENGTH];
1794 
1795 	list_for_each_safe(l, n, final_queue) {
1796 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1797 		list_del_init(&cqr->devlist);
1798 		block = cqr->block;
1799 		callback = cqr->callback;
1800 		callback_data = cqr->callback_data;
1801 		if (block)
1802 			spin_lock_bh(&block->queue_lock);
1803 		switch (cqr->status) {
1804 		case DASD_CQR_SUCCESS:
1805 			cqr->status = DASD_CQR_DONE;
1806 			break;
1807 		case DASD_CQR_ERROR:
1808 			cqr->status = DASD_CQR_NEED_ERP;
1809 			break;
1810 		case DASD_CQR_CLEARED:
1811 			cqr->status = DASD_CQR_TERMINATED;
1812 			break;
1813 		default:
1814 			/* internal error 12 - wrong cqr status*/
1815 			snprintf(errorstring, ERRORLENGTH, "12 %p %x02", cqr, cqr->status);
1816 			dev_err(&device->cdev->dev,
1817 				"An error occurred in the DASD device driver, "
1818 				"reason=%s\n", errorstring);
1819 			BUG();
1820 		}
1821 		if (cqr->callback != NULL)
1822 			(callback)(cqr, callback_data);
1823 		if (block)
1824 			spin_unlock_bh(&block->queue_lock);
1825 	}
1826 }
1827 
1828 /*
1829  * Take a look at the first request on the ccw queue and check
1830  * if it reached its expire time. If so, terminate the IO.
1831  */
1832 static void __dasd_device_check_expire(struct dasd_device *device)
1833 {
1834 	struct dasd_ccw_req *cqr;
1835 
1836 	if (list_empty(&device->ccw_queue))
1837 		return;
1838 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1839 	if ((cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) &&
1840 	    (time_after_eq(jiffies, cqr->expires + cqr->starttime))) {
1841 		if (test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
1842 			/*
1843 			 * IO in safe offline processing should not
1844 			 * run out of retries
1845 			 */
1846 			cqr->retries++;
1847 		}
1848 		if (device->discipline->term_IO(cqr) != 0) {
1849 			/* Hmpf, try again in 5 sec */
1850 			dev_err(&device->cdev->dev,
1851 				"cqr %p timed out (%lus) but cannot be "
1852 				"ended, retrying in 5 s\n",
1853 				cqr, (cqr->expires/HZ));
1854 			cqr->expires += 5*HZ;
1855 			dasd_device_set_timer(device, 5*HZ);
1856 		} else {
1857 			dev_err(&device->cdev->dev,
1858 				"cqr %p timed out (%lus), %i retries "
1859 				"remaining\n", cqr, (cqr->expires/HZ),
1860 				cqr->retries);
1861 		}
1862 	}
1863 }
1864 
1865 /*
1866  * return 1 when device is not eligible for IO
1867  */
1868 static int __dasd_device_is_unusable(struct dasd_device *device,
1869 				     struct dasd_ccw_req *cqr)
1870 {
1871 	int mask = ~(DASD_STOPPED_DC_WAIT | DASD_UNRESUMED_PM);
1872 
1873 	if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
1874 		/* dasd is being set offline. */
1875 		return 1;
1876 	}
1877 	if (device->stopped) {
1878 		if (device->stopped & mask) {
1879 			/* stopped and CQR will not change that. */
1880 			return 1;
1881 		}
1882 		if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
1883 			/* CQR is not able to change device to
1884 			 * operational. */
1885 			return 1;
1886 		}
1887 		/* CQR required to get device operational. */
1888 	}
1889 	return 0;
1890 }
1891 
1892 /*
1893  * Take a look at the first request on the ccw queue and check
1894  * if it needs to be started.
1895  */
1896 static void __dasd_device_start_head(struct dasd_device *device)
1897 {
1898 	struct dasd_ccw_req *cqr;
1899 	int rc;
1900 
1901 	if (list_empty(&device->ccw_queue))
1902 		return;
1903 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1904 	if (cqr->status != DASD_CQR_QUEUED)
1905 		return;
1906 	/* if device is not usable return request to upper layer */
1907 	if (__dasd_device_is_unusable(device, cqr)) {
1908 		cqr->intrc = -EAGAIN;
1909 		cqr->status = DASD_CQR_CLEARED;
1910 		dasd_schedule_device_bh(device);
1911 		return;
1912 	}
1913 
1914 	rc = device->discipline->start_IO(cqr);
1915 	if (rc == 0)
1916 		dasd_device_set_timer(device, cqr->expires);
1917 	else if (rc == -EACCES) {
1918 		dasd_schedule_device_bh(device);
1919 	} else
1920 		/* Hmpf, try again in 1/2 sec */
1921 		dasd_device_set_timer(device, 50);
1922 }
1923 
1924 static void __dasd_device_check_path_events(struct dasd_device *device)
1925 {
1926 	int rc;
1927 
1928 	if (device->path_data.tbvpm) {
1929 		if (device->stopped & ~(DASD_STOPPED_DC_WAIT |
1930 					DASD_UNRESUMED_PM))
1931 			return;
1932 		rc = device->discipline->verify_path(
1933 			device, device->path_data.tbvpm);
1934 		if (rc)
1935 			dasd_device_set_timer(device, 50);
1936 		else
1937 			device->path_data.tbvpm = 0;
1938 	}
1939 };
1940 
1941 /*
1942  * Go through all request on the dasd_device request queue,
1943  * terminate them on the cdev if necessary, and return them to the
1944  * submitting layer via callback.
1945  * Note:
1946  * Make sure that all 'submitting layers' still exist when
1947  * this function is called!. In other words, when 'device' is a base
1948  * device then all block layer requests must have been removed before
1949  * via dasd_flush_block_queue.
1950  */
1951 int dasd_flush_device_queue(struct dasd_device *device)
1952 {
1953 	struct dasd_ccw_req *cqr, *n;
1954 	int rc;
1955 	struct list_head flush_queue;
1956 
1957 	INIT_LIST_HEAD(&flush_queue);
1958 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1959 	rc = 0;
1960 	list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
1961 		/* Check status and move request to flush_queue */
1962 		switch (cqr->status) {
1963 		case DASD_CQR_IN_IO:
1964 			rc = device->discipline->term_IO(cqr);
1965 			if (rc) {
1966 				/* unable to terminate requeust */
1967 				dev_err(&device->cdev->dev,
1968 					"Flushing the DASD request queue "
1969 					"failed for request %p\n", cqr);
1970 				/* stop flush processing */
1971 				goto finished;
1972 			}
1973 			break;
1974 		case DASD_CQR_QUEUED:
1975 			cqr->stopclk = get_tod_clock();
1976 			cqr->status = DASD_CQR_CLEARED;
1977 			break;
1978 		default: /* no need to modify the others */
1979 			break;
1980 		}
1981 		list_move_tail(&cqr->devlist, &flush_queue);
1982 	}
1983 finished:
1984 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1985 	/*
1986 	 * After this point all requests must be in state CLEAR_PENDING,
1987 	 * CLEARED, SUCCESS or ERROR. Now wait for CLEAR_PENDING to become
1988 	 * one of the others.
1989 	 */
1990 	list_for_each_entry_safe(cqr, n, &flush_queue, devlist)
1991 		wait_event(dasd_flush_wq,
1992 			   (cqr->status != DASD_CQR_CLEAR_PENDING));
1993 	/*
1994 	 * Now set each request back to TERMINATED, DONE or NEED_ERP
1995 	 * and call the callback function of flushed requests
1996 	 */
1997 	__dasd_device_process_final_queue(device, &flush_queue);
1998 	return rc;
1999 }
2000 EXPORT_SYMBOL_GPL(dasd_flush_device_queue);
2001 
2002 /*
2003  * Acquire the device lock and process queues for the device.
2004  */
2005 static void dasd_device_tasklet(struct dasd_device *device)
2006 {
2007 	struct list_head final_queue;
2008 
2009 	atomic_set (&device->tasklet_scheduled, 0);
2010 	INIT_LIST_HEAD(&final_queue);
2011 	spin_lock_irq(get_ccwdev_lock(device->cdev));
2012 	/* Check expire time of first request on the ccw queue. */
2013 	__dasd_device_check_expire(device);
2014 	/* find final requests on ccw queue */
2015 	__dasd_device_process_ccw_queue(device, &final_queue);
2016 	__dasd_device_check_path_events(device);
2017 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
2018 	/* Now call the callback function of requests with final status */
2019 	__dasd_device_process_final_queue(device, &final_queue);
2020 	spin_lock_irq(get_ccwdev_lock(device->cdev));
2021 	/* Now check if the head of the ccw queue needs to be started. */
2022 	__dasd_device_start_head(device);
2023 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
2024 	if (waitqueue_active(&shutdown_waitq))
2025 		wake_up(&shutdown_waitq);
2026 	dasd_put_device(device);
2027 }
2028 
2029 /*
2030  * Schedules a call to dasd_tasklet over the device tasklet.
2031  */
2032 void dasd_schedule_device_bh(struct dasd_device *device)
2033 {
2034 	/* Protect against rescheduling. */
2035 	if (atomic_cmpxchg (&device->tasklet_scheduled, 0, 1) != 0)
2036 		return;
2037 	dasd_get_device(device);
2038 	tasklet_hi_schedule(&device->tasklet);
2039 }
2040 EXPORT_SYMBOL(dasd_schedule_device_bh);
2041 
2042 void dasd_device_set_stop_bits(struct dasd_device *device, int bits)
2043 {
2044 	device->stopped |= bits;
2045 }
2046 EXPORT_SYMBOL_GPL(dasd_device_set_stop_bits);
2047 
2048 void dasd_device_remove_stop_bits(struct dasd_device *device, int bits)
2049 {
2050 	device->stopped &= ~bits;
2051 	if (!device->stopped)
2052 		wake_up(&generic_waitq);
2053 }
2054 EXPORT_SYMBOL_GPL(dasd_device_remove_stop_bits);
2055 
2056 /*
2057  * Queue a request to the head of the device ccw_queue.
2058  * Start the I/O if possible.
2059  */
2060 void dasd_add_request_head(struct dasd_ccw_req *cqr)
2061 {
2062 	struct dasd_device *device;
2063 	unsigned long flags;
2064 
2065 	device = cqr->startdev;
2066 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
2067 	cqr->status = DASD_CQR_QUEUED;
2068 	list_add(&cqr->devlist, &device->ccw_queue);
2069 	/* let the bh start the request to keep them in order */
2070 	dasd_schedule_device_bh(device);
2071 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
2072 }
2073 EXPORT_SYMBOL(dasd_add_request_head);
2074 
2075 /*
2076  * Queue a request to the tail of the device ccw_queue.
2077  * Start the I/O if possible.
2078  */
2079 void dasd_add_request_tail(struct dasd_ccw_req *cqr)
2080 {
2081 	struct dasd_device *device;
2082 	unsigned long flags;
2083 
2084 	device = cqr->startdev;
2085 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
2086 	cqr->status = DASD_CQR_QUEUED;
2087 	list_add_tail(&cqr->devlist, &device->ccw_queue);
2088 	/* let the bh start the request to keep them in order */
2089 	dasd_schedule_device_bh(device);
2090 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
2091 }
2092 EXPORT_SYMBOL(dasd_add_request_tail);
2093 
2094 /*
2095  * Wakeup helper for the 'sleep_on' functions.
2096  */
2097 void dasd_wakeup_cb(struct dasd_ccw_req *cqr, void *data)
2098 {
2099 	spin_lock_irq(get_ccwdev_lock(cqr->startdev->cdev));
2100 	cqr->callback_data = DASD_SLEEPON_END_TAG;
2101 	spin_unlock_irq(get_ccwdev_lock(cqr->startdev->cdev));
2102 	wake_up(&generic_waitq);
2103 }
2104 EXPORT_SYMBOL_GPL(dasd_wakeup_cb);
2105 
2106 static inline int _wait_for_wakeup(struct dasd_ccw_req *cqr)
2107 {
2108 	struct dasd_device *device;
2109 	int rc;
2110 
2111 	device = cqr->startdev;
2112 	spin_lock_irq(get_ccwdev_lock(device->cdev));
2113 	rc = (cqr->callback_data == DASD_SLEEPON_END_TAG);
2114 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
2115 	return rc;
2116 }
2117 
2118 /*
2119  * checks if error recovery is necessary, returns 1 if yes, 0 otherwise.
2120  */
2121 static int __dasd_sleep_on_erp(struct dasd_ccw_req *cqr)
2122 {
2123 	struct dasd_device *device;
2124 	dasd_erp_fn_t erp_fn;
2125 
2126 	if (cqr->status == DASD_CQR_FILLED)
2127 		return 0;
2128 	device = cqr->startdev;
2129 	if (test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) {
2130 		if (cqr->status == DASD_CQR_TERMINATED) {
2131 			device->discipline->handle_terminated_request(cqr);
2132 			return 1;
2133 		}
2134 		if (cqr->status == DASD_CQR_NEED_ERP) {
2135 			erp_fn = device->discipline->erp_action(cqr);
2136 			erp_fn(cqr);
2137 			return 1;
2138 		}
2139 		if (cqr->status == DASD_CQR_FAILED)
2140 			dasd_log_sense(cqr, &cqr->irb);
2141 		if (cqr->refers) {
2142 			__dasd_process_erp(device, cqr);
2143 			return 1;
2144 		}
2145 	}
2146 	return 0;
2147 }
2148 
2149 static int __dasd_sleep_on_loop_condition(struct dasd_ccw_req *cqr)
2150 {
2151 	if (test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) {
2152 		if (cqr->refers) /* erp is not done yet */
2153 			return 1;
2154 		return ((cqr->status != DASD_CQR_DONE) &&
2155 			(cqr->status != DASD_CQR_FAILED));
2156 	} else
2157 		return (cqr->status == DASD_CQR_FILLED);
2158 }
2159 
2160 static int _dasd_sleep_on(struct dasd_ccw_req *maincqr, int interruptible)
2161 {
2162 	struct dasd_device *device;
2163 	int rc;
2164 	struct list_head ccw_queue;
2165 	struct dasd_ccw_req *cqr;
2166 
2167 	INIT_LIST_HEAD(&ccw_queue);
2168 	maincqr->status = DASD_CQR_FILLED;
2169 	device = maincqr->startdev;
2170 	list_add(&maincqr->blocklist, &ccw_queue);
2171 	for (cqr = maincqr;  __dasd_sleep_on_loop_condition(cqr);
2172 	     cqr = list_first_entry(&ccw_queue,
2173 				    struct dasd_ccw_req, blocklist)) {
2174 
2175 		if (__dasd_sleep_on_erp(cqr))
2176 			continue;
2177 		if (cqr->status != DASD_CQR_FILLED) /* could be failed */
2178 			continue;
2179 		if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
2180 		    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
2181 			cqr->status = DASD_CQR_FAILED;
2182 			cqr->intrc = -EPERM;
2183 			continue;
2184 		}
2185 		/* Non-temporary stop condition will trigger fail fast */
2186 		if (device->stopped & ~DASD_STOPPED_PENDING &&
2187 		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
2188 		    (!dasd_eer_enabled(device))) {
2189 			cqr->status = DASD_CQR_FAILED;
2190 			cqr->intrc = -ENOLINK;
2191 			continue;
2192 		}
2193 		/*
2194 		 * Don't try to start requests if device is stopped
2195 		 * except path verification requests
2196 		 */
2197 		if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
2198 			if (interruptible) {
2199 				rc = wait_event_interruptible(
2200 					generic_waitq, !(device->stopped));
2201 				if (rc == -ERESTARTSYS) {
2202 					cqr->status = DASD_CQR_FAILED;
2203 					maincqr->intrc = rc;
2204 					continue;
2205 				}
2206 			} else
2207 				wait_event(generic_waitq, !(device->stopped));
2208 		}
2209 		if (!cqr->callback)
2210 			cqr->callback = dasd_wakeup_cb;
2211 
2212 		cqr->callback_data = DASD_SLEEPON_START_TAG;
2213 		dasd_add_request_tail(cqr);
2214 		if (interruptible) {
2215 			rc = wait_event_interruptible(
2216 				generic_waitq, _wait_for_wakeup(cqr));
2217 			if (rc == -ERESTARTSYS) {
2218 				dasd_cancel_req(cqr);
2219 				/* wait (non-interruptible) for final status */
2220 				wait_event(generic_waitq,
2221 					   _wait_for_wakeup(cqr));
2222 				cqr->status = DASD_CQR_FAILED;
2223 				maincqr->intrc = rc;
2224 				continue;
2225 			}
2226 		} else
2227 			wait_event(generic_waitq, _wait_for_wakeup(cqr));
2228 	}
2229 
2230 	maincqr->endclk = get_tod_clock();
2231 	if ((maincqr->status != DASD_CQR_DONE) &&
2232 	    (maincqr->intrc != -ERESTARTSYS))
2233 		dasd_log_sense(maincqr, &maincqr->irb);
2234 	if (maincqr->status == DASD_CQR_DONE)
2235 		rc = 0;
2236 	else if (maincqr->intrc)
2237 		rc = maincqr->intrc;
2238 	else
2239 		rc = -EIO;
2240 	return rc;
2241 }
2242 
2243 static inline int _wait_for_wakeup_queue(struct list_head *ccw_queue)
2244 {
2245 	struct dasd_ccw_req *cqr;
2246 
2247 	list_for_each_entry(cqr, ccw_queue, blocklist) {
2248 		if (cqr->callback_data != DASD_SLEEPON_END_TAG)
2249 			return 0;
2250 	}
2251 
2252 	return 1;
2253 }
2254 
2255 static int _dasd_sleep_on_queue(struct list_head *ccw_queue, int interruptible)
2256 {
2257 	struct dasd_device *device;
2258 	struct dasd_ccw_req *cqr, *n;
2259 	int rc;
2260 
2261 retry:
2262 	list_for_each_entry_safe(cqr, n, ccw_queue, blocklist) {
2263 		device = cqr->startdev;
2264 		if (cqr->status != DASD_CQR_FILLED) /*could be failed*/
2265 			continue;
2266 
2267 		if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
2268 		    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
2269 			cqr->status = DASD_CQR_FAILED;
2270 			cqr->intrc = -EPERM;
2271 			continue;
2272 		}
2273 		/*Non-temporary stop condition will trigger fail fast*/
2274 		if (device->stopped & ~DASD_STOPPED_PENDING &&
2275 		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
2276 		    !dasd_eer_enabled(device)) {
2277 			cqr->status = DASD_CQR_FAILED;
2278 			cqr->intrc = -EAGAIN;
2279 			continue;
2280 		}
2281 
2282 		/*Don't try to start requests if device is stopped*/
2283 		if (interruptible) {
2284 			rc = wait_event_interruptible(
2285 				generic_waitq, !device->stopped);
2286 			if (rc == -ERESTARTSYS) {
2287 				cqr->status = DASD_CQR_FAILED;
2288 				cqr->intrc = rc;
2289 				continue;
2290 			}
2291 		} else
2292 			wait_event(generic_waitq, !(device->stopped));
2293 
2294 		if (!cqr->callback)
2295 			cqr->callback = dasd_wakeup_cb;
2296 		cqr->callback_data = DASD_SLEEPON_START_TAG;
2297 		dasd_add_request_tail(cqr);
2298 	}
2299 
2300 	wait_event(generic_waitq, _wait_for_wakeup_queue(ccw_queue));
2301 
2302 	rc = 0;
2303 	list_for_each_entry_safe(cqr, n, ccw_queue, blocklist) {
2304 		/*
2305 		 * for alias devices simplify error recovery and
2306 		 * return to upper layer
2307 		 * do not skip ERP requests
2308 		 */
2309 		if (cqr->startdev != cqr->basedev && !cqr->refers &&
2310 		    (cqr->status == DASD_CQR_TERMINATED ||
2311 		     cqr->status == DASD_CQR_NEED_ERP))
2312 			return -EAGAIN;
2313 
2314 		/* normal recovery for basedev IO */
2315 		if (__dasd_sleep_on_erp(cqr))
2316 			/* handle erp first */
2317 			goto retry;
2318 	}
2319 
2320 	return 0;
2321 }
2322 
2323 /*
2324  * Queue a request to the tail of the device ccw_queue and wait for
2325  * it's completion.
2326  */
2327 int dasd_sleep_on(struct dasd_ccw_req *cqr)
2328 {
2329 	return _dasd_sleep_on(cqr, 0);
2330 }
2331 EXPORT_SYMBOL(dasd_sleep_on);
2332 
2333 /*
2334  * Start requests from a ccw_queue and wait for their completion.
2335  */
2336 int dasd_sleep_on_queue(struct list_head *ccw_queue)
2337 {
2338 	return _dasd_sleep_on_queue(ccw_queue, 0);
2339 }
2340 EXPORT_SYMBOL(dasd_sleep_on_queue);
2341 
2342 /*
2343  * Queue a request to the tail of the device ccw_queue and wait
2344  * interruptible for it's completion.
2345  */
2346 int dasd_sleep_on_interruptible(struct dasd_ccw_req *cqr)
2347 {
2348 	return _dasd_sleep_on(cqr, 1);
2349 }
2350 EXPORT_SYMBOL(dasd_sleep_on_interruptible);
2351 
2352 /*
2353  * Whoa nelly now it gets really hairy. For some functions (e.g. steal lock
2354  * for eckd devices) the currently running request has to be terminated
2355  * and be put back to status queued, before the special request is added
2356  * to the head of the queue. Then the special request is waited on normally.
2357  */
2358 static inline int _dasd_term_running_cqr(struct dasd_device *device)
2359 {
2360 	struct dasd_ccw_req *cqr;
2361 	int rc;
2362 
2363 	if (list_empty(&device->ccw_queue))
2364 		return 0;
2365 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
2366 	rc = device->discipline->term_IO(cqr);
2367 	if (!rc)
2368 		/*
2369 		 * CQR terminated because a more important request is pending.
2370 		 * Undo decreasing of retry counter because this is
2371 		 * not an error case.
2372 		 */
2373 		cqr->retries++;
2374 	return rc;
2375 }
2376 
2377 int dasd_sleep_on_immediatly(struct dasd_ccw_req *cqr)
2378 {
2379 	struct dasd_device *device;
2380 	int rc;
2381 
2382 	device = cqr->startdev;
2383 	if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
2384 	    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
2385 		cqr->status = DASD_CQR_FAILED;
2386 		cqr->intrc = -EPERM;
2387 		return -EIO;
2388 	}
2389 	spin_lock_irq(get_ccwdev_lock(device->cdev));
2390 	rc = _dasd_term_running_cqr(device);
2391 	if (rc) {
2392 		spin_unlock_irq(get_ccwdev_lock(device->cdev));
2393 		return rc;
2394 	}
2395 	cqr->callback = dasd_wakeup_cb;
2396 	cqr->callback_data = DASD_SLEEPON_START_TAG;
2397 	cqr->status = DASD_CQR_QUEUED;
2398 	/*
2399 	 * add new request as second
2400 	 * first the terminated cqr needs to be finished
2401 	 */
2402 	list_add(&cqr->devlist, device->ccw_queue.next);
2403 
2404 	/* let the bh start the request to keep them in order */
2405 	dasd_schedule_device_bh(device);
2406 
2407 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
2408 
2409 	wait_event(generic_waitq, _wait_for_wakeup(cqr));
2410 
2411 	if (cqr->status == DASD_CQR_DONE)
2412 		rc = 0;
2413 	else if (cqr->intrc)
2414 		rc = cqr->intrc;
2415 	else
2416 		rc = -EIO;
2417 
2418 	/* kick tasklets */
2419 	dasd_schedule_device_bh(device);
2420 	if (device->block)
2421 		dasd_schedule_block_bh(device->block);
2422 
2423 	return rc;
2424 }
2425 EXPORT_SYMBOL(dasd_sleep_on_immediatly);
2426 
2427 /*
2428  * Cancels a request that was started with dasd_sleep_on_req.
2429  * This is useful to timeout requests. The request will be
2430  * terminated if it is currently in i/o.
2431  * Returns 0 if request termination was successful
2432  *	   negative error code if termination failed
2433  * Cancellation of a request is an asynchronous operation! The calling
2434  * function has to wait until the request is properly returned via callback.
2435  */
2436 int dasd_cancel_req(struct dasd_ccw_req *cqr)
2437 {
2438 	struct dasd_device *device = cqr->startdev;
2439 	unsigned long flags;
2440 	int rc;
2441 
2442 	rc = 0;
2443 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
2444 	switch (cqr->status) {
2445 	case DASD_CQR_QUEUED:
2446 		/* request was not started - just set to cleared */
2447 		cqr->status = DASD_CQR_CLEARED;
2448 		if (cqr->callback_data == DASD_SLEEPON_START_TAG)
2449 			cqr->callback_data = DASD_SLEEPON_END_TAG;
2450 		break;
2451 	case DASD_CQR_IN_IO:
2452 		/* request in IO - terminate IO and release again */
2453 		rc = device->discipline->term_IO(cqr);
2454 		if (rc) {
2455 			dev_err(&device->cdev->dev,
2456 				"Cancelling request %p failed with rc=%d\n",
2457 				cqr, rc);
2458 		} else {
2459 			cqr->stopclk = get_tod_clock();
2460 		}
2461 		break;
2462 	default: /* already finished or clear pending - do nothing */
2463 		break;
2464 	}
2465 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
2466 	dasd_schedule_device_bh(device);
2467 	return rc;
2468 }
2469 EXPORT_SYMBOL(dasd_cancel_req);
2470 
2471 /*
2472  * SECTION: Operations of the dasd_block layer.
2473  */
2474 
2475 /*
2476  * Timeout function for dasd_block. This is used when the block layer
2477  * is waiting for something that may not come reliably, (e.g. a state
2478  * change interrupt)
2479  */
2480 static void dasd_block_timeout(unsigned long ptr)
2481 {
2482 	unsigned long flags;
2483 	struct dasd_block *block;
2484 
2485 	block = (struct dasd_block *) ptr;
2486 	spin_lock_irqsave(get_ccwdev_lock(block->base->cdev), flags);
2487 	/* re-activate request queue */
2488 	dasd_device_remove_stop_bits(block->base, DASD_STOPPED_PENDING);
2489 	spin_unlock_irqrestore(get_ccwdev_lock(block->base->cdev), flags);
2490 	dasd_schedule_block_bh(block);
2491 }
2492 
2493 /*
2494  * Setup timeout for a dasd_block in jiffies.
2495  */
2496 void dasd_block_set_timer(struct dasd_block *block, int expires)
2497 {
2498 	if (expires == 0)
2499 		del_timer(&block->timer);
2500 	else
2501 		mod_timer(&block->timer, jiffies + expires);
2502 }
2503 EXPORT_SYMBOL(dasd_block_set_timer);
2504 
2505 /*
2506  * Clear timeout for a dasd_block.
2507  */
2508 void dasd_block_clear_timer(struct dasd_block *block)
2509 {
2510 	del_timer(&block->timer);
2511 }
2512 EXPORT_SYMBOL(dasd_block_clear_timer);
2513 
2514 /*
2515  * Process finished error recovery ccw.
2516  */
2517 static void __dasd_process_erp(struct dasd_device *device,
2518 			       struct dasd_ccw_req *cqr)
2519 {
2520 	dasd_erp_fn_t erp_fn;
2521 
2522 	if (cqr->status == DASD_CQR_DONE)
2523 		DBF_DEV_EVENT(DBF_NOTICE, device, "%s", "ERP successful");
2524 	else
2525 		dev_err(&device->cdev->dev, "ERP failed for the DASD\n");
2526 	erp_fn = device->discipline->erp_postaction(cqr);
2527 	erp_fn(cqr);
2528 }
2529 
2530 /*
2531  * Fetch requests from the block device queue.
2532  */
2533 static void __dasd_process_request_queue(struct dasd_block *block)
2534 {
2535 	struct request_queue *queue;
2536 	struct request *req;
2537 	struct dasd_ccw_req *cqr;
2538 	struct dasd_device *basedev;
2539 	unsigned long flags;
2540 	queue = block->request_queue;
2541 	basedev = block->base;
2542 	/* No queue ? Then there is nothing to do. */
2543 	if (queue == NULL)
2544 		return;
2545 
2546 	/*
2547 	 * We requeue request from the block device queue to the ccw
2548 	 * queue only in two states. In state DASD_STATE_READY the
2549 	 * partition detection is done and we need to requeue requests
2550 	 * for that. State DASD_STATE_ONLINE is normal block device
2551 	 * operation.
2552 	 */
2553 	if (basedev->state < DASD_STATE_READY) {
2554 		while ((req = blk_fetch_request(block->request_queue)))
2555 			__blk_end_request_all(req, -EIO);
2556 		return;
2557 	}
2558 
2559 	/*
2560 	 * if device is stopped do not fetch new requests
2561 	 * except failfast is active which will let requests fail
2562 	 * immediately in __dasd_block_start_head()
2563 	 */
2564 	if (basedev->stopped && !(basedev->features & DASD_FEATURE_FAILFAST))
2565 		return;
2566 
2567 	/* Now we try to fetch requests from the request queue */
2568 	while ((req = blk_peek_request(queue))) {
2569 		if (basedev->features & DASD_FEATURE_READONLY &&
2570 		    rq_data_dir(req) == WRITE) {
2571 			DBF_DEV_EVENT(DBF_ERR, basedev,
2572 				      "Rejecting write request %p",
2573 				      req);
2574 			blk_start_request(req);
2575 			__blk_end_request_all(req, -EIO);
2576 			continue;
2577 		}
2578 		if (test_bit(DASD_FLAG_ABORTALL, &basedev->flags) &&
2579 		    (basedev->features & DASD_FEATURE_FAILFAST ||
2580 		     blk_noretry_request(req))) {
2581 			DBF_DEV_EVENT(DBF_ERR, basedev,
2582 				      "Rejecting failfast request %p",
2583 				      req);
2584 			blk_start_request(req);
2585 			__blk_end_request_all(req, -ETIMEDOUT);
2586 			continue;
2587 		}
2588 		cqr = basedev->discipline->build_cp(basedev, block, req);
2589 		if (IS_ERR(cqr)) {
2590 			if (PTR_ERR(cqr) == -EBUSY)
2591 				break;	/* normal end condition */
2592 			if (PTR_ERR(cqr) == -ENOMEM)
2593 				break;	/* terminate request queue loop */
2594 			if (PTR_ERR(cqr) == -EAGAIN) {
2595 				/*
2596 				 * The current request cannot be build right
2597 				 * now, we have to try later. If this request
2598 				 * is the head-of-queue we stop the device
2599 				 * for 1/2 second.
2600 				 */
2601 				if (!list_empty(&block->ccw_queue))
2602 					break;
2603 				spin_lock_irqsave(
2604 					get_ccwdev_lock(basedev->cdev), flags);
2605 				dasd_device_set_stop_bits(basedev,
2606 							  DASD_STOPPED_PENDING);
2607 				spin_unlock_irqrestore(
2608 					get_ccwdev_lock(basedev->cdev), flags);
2609 				dasd_block_set_timer(block, HZ/2);
2610 				break;
2611 			}
2612 			DBF_DEV_EVENT(DBF_ERR, basedev,
2613 				      "CCW creation failed (rc=%ld) "
2614 				      "on request %p",
2615 				      PTR_ERR(cqr), req);
2616 			blk_start_request(req);
2617 			__blk_end_request_all(req, -EIO);
2618 			continue;
2619 		}
2620 		/*
2621 		 *  Note: callback is set to dasd_return_cqr_cb in
2622 		 * __dasd_block_start_head to cover erp requests as well
2623 		 */
2624 		cqr->callback_data = (void *) req;
2625 		cqr->status = DASD_CQR_FILLED;
2626 		req->completion_data = cqr;
2627 		blk_start_request(req);
2628 		list_add_tail(&cqr->blocklist, &block->ccw_queue);
2629 		INIT_LIST_HEAD(&cqr->devlist);
2630 		dasd_profile_start(block, cqr, req);
2631 	}
2632 }
2633 
2634 static void __dasd_cleanup_cqr(struct dasd_ccw_req *cqr)
2635 {
2636 	struct request *req;
2637 	int status;
2638 	int error = 0;
2639 
2640 	req = (struct request *) cqr->callback_data;
2641 	dasd_profile_end(cqr->block, cqr, req);
2642 	status = cqr->block->base->discipline->free_cp(cqr, req);
2643 	if (status < 0)
2644 		error = status;
2645 	else if (status == 0) {
2646 		if (cqr->intrc == -EPERM)
2647 			error = -EBADE;
2648 		else if (cqr->intrc == -ENOLINK ||
2649 			 cqr->intrc == -ETIMEDOUT)
2650 			error = cqr->intrc;
2651 		else
2652 			error = -EIO;
2653 	}
2654 	__blk_end_request_all(req, error);
2655 }
2656 
2657 /*
2658  * Process ccw request queue.
2659  */
2660 static void __dasd_process_block_ccw_queue(struct dasd_block *block,
2661 					   struct list_head *final_queue)
2662 {
2663 	struct list_head *l, *n;
2664 	struct dasd_ccw_req *cqr;
2665 	dasd_erp_fn_t erp_fn;
2666 	unsigned long flags;
2667 	struct dasd_device *base = block->base;
2668 
2669 restart:
2670 	/* Process request with final status. */
2671 	list_for_each_safe(l, n, &block->ccw_queue) {
2672 		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
2673 		if (cqr->status != DASD_CQR_DONE &&
2674 		    cqr->status != DASD_CQR_FAILED &&
2675 		    cqr->status != DASD_CQR_NEED_ERP &&
2676 		    cqr->status != DASD_CQR_TERMINATED)
2677 			continue;
2678 
2679 		if (cqr->status == DASD_CQR_TERMINATED) {
2680 			base->discipline->handle_terminated_request(cqr);
2681 			goto restart;
2682 		}
2683 
2684 		/*  Process requests that may be recovered */
2685 		if (cqr->status == DASD_CQR_NEED_ERP) {
2686 			erp_fn = base->discipline->erp_action(cqr);
2687 			if (IS_ERR(erp_fn(cqr)))
2688 				continue;
2689 			goto restart;
2690 		}
2691 
2692 		/* log sense for fatal error */
2693 		if (cqr->status == DASD_CQR_FAILED) {
2694 			dasd_log_sense(cqr, &cqr->irb);
2695 		}
2696 
2697 		/* First of all call extended error reporting. */
2698 		if (dasd_eer_enabled(base) &&
2699 		    cqr->status == DASD_CQR_FAILED) {
2700 			dasd_eer_write(base, cqr, DASD_EER_FATALERROR);
2701 
2702 			/* restart request  */
2703 			cqr->status = DASD_CQR_FILLED;
2704 			cqr->retries = 255;
2705 			spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
2706 			dasd_device_set_stop_bits(base, DASD_STOPPED_QUIESCE);
2707 			spin_unlock_irqrestore(get_ccwdev_lock(base->cdev),
2708 					       flags);
2709 			goto restart;
2710 		}
2711 
2712 		/* Process finished ERP request. */
2713 		if (cqr->refers) {
2714 			__dasd_process_erp(base, cqr);
2715 			goto restart;
2716 		}
2717 
2718 		/* Rechain finished requests to final queue */
2719 		cqr->endclk = get_tod_clock();
2720 		list_move_tail(&cqr->blocklist, final_queue);
2721 	}
2722 }
2723 
2724 static void dasd_return_cqr_cb(struct dasd_ccw_req *cqr, void *data)
2725 {
2726 	dasd_schedule_block_bh(cqr->block);
2727 }
2728 
2729 static void __dasd_block_start_head(struct dasd_block *block)
2730 {
2731 	struct dasd_ccw_req *cqr;
2732 
2733 	if (list_empty(&block->ccw_queue))
2734 		return;
2735 	/* We allways begin with the first requests on the queue, as some
2736 	 * of previously started requests have to be enqueued on a
2737 	 * dasd_device again for error recovery.
2738 	 */
2739 	list_for_each_entry(cqr, &block->ccw_queue, blocklist) {
2740 		if (cqr->status != DASD_CQR_FILLED)
2741 			continue;
2742 		if (test_bit(DASD_FLAG_LOCK_STOLEN, &block->base->flags) &&
2743 		    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
2744 			cqr->status = DASD_CQR_FAILED;
2745 			cqr->intrc = -EPERM;
2746 			dasd_schedule_block_bh(block);
2747 			continue;
2748 		}
2749 		/* Non-temporary stop condition will trigger fail fast */
2750 		if (block->base->stopped & ~DASD_STOPPED_PENDING &&
2751 		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
2752 		    (!dasd_eer_enabled(block->base))) {
2753 			cqr->status = DASD_CQR_FAILED;
2754 			cqr->intrc = -ENOLINK;
2755 			dasd_schedule_block_bh(block);
2756 			continue;
2757 		}
2758 		/* Don't try to start requests if device is stopped */
2759 		if (block->base->stopped)
2760 			return;
2761 
2762 		/* just a fail safe check, should not happen */
2763 		if (!cqr->startdev)
2764 			cqr->startdev = block->base;
2765 
2766 		/* make sure that the requests we submit find their way back */
2767 		cqr->callback = dasd_return_cqr_cb;
2768 
2769 		dasd_add_request_tail(cqr);
2770 	}
2771 }
2772 
2773 /*
2774  * Central dasd_block layer routine. Takes requests from the generic
2775  * block layer request queue, creates ccw requests, enqueues them on
2776  * a dasd_device and processes ccw requests that have been returned.
2777  */
2778 static void dasd_block_tasklet(struct dasd_block *block)
2779 {
2780 	struct list_head final_queue;
2781 	struct list_head *l, *n;
2782 	struct dasd_ccw_req *cqr;
2783 
2784 	atomic_set(&block->tasklet_scheduled, 0);
2785 	INIT_LIST_HEAD(&final_queue);
2786 	spin_lock(&block->queue_lock);
2787 	/* Finish off requests on ccw queue */
2788 	__dasd_process_block_ccw_queue(block, &final_queue);
2789 	spin_unlock(&block->queue_lock);
2790 	/* Now call the callback function of requests with final status */
2791 	spin_lock_irq(&block->request_queue_lock);
2792 	list_for_each_safe(l, n, &final_queue) {
2793 		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
2794 		list_del_init(&cqr->blocklist);
2795 		__dasd_cleanup_cqr(cqr);
2796 	}
2797 	spin_lock(&block->queue_lock);
2798 	/* Get new request from the block device request queue */
2799 	__dasd_process_request_queue(block);
2800 	/* Now check if the head of the ccw queue needs to be started. */
2801 	__dasd_block_start_head(block);
2802 	spin_unlock(&block->queue_lock);
2803 	spin_unlock_irq(&block->request_queue_lock);
2804 	if (waitqueue_active(&shutdown_waitq))
2805 		wake_up(&shutdown_waitq);
2806 	dasd_put_device(block->base);
2807 }
2808 
2809 static void _dasd_wake_block_flush_cb(struct dasd_ccw_req *cqr, void *data)
2810 {
2811 	wake_up(&dasd_flush_wq);
2812 }
2813 
2814 /*
2815  * Requeue a request back to the block request queue
2816  * only works for block requests
2817  */
2818 static int _dasd_requeue_request(struct dasd_ccw_req *cqr)
2819 {
2820 	struct dasd_block *block = cqr->block;
2821 	struct request *req;
2822 	unsigned long flags;
2823 
2824 	if (!block)
2825 		return -EINVAL;
2826 	spin_lock_irqsave(&block->queue_lock, flags);
2827 	req = (struct request *) cqr->callback_data;
2828 	blk_requeue_request(block->request_queue, req);
2829 	spin_unlock_irqrestore(&block->queue_lock, flags);
2830 
2831 	return 0;
2832 }
2833 
2834 /*
2835  * Go through all request on the dasd_block request queue, cancel them
2836  * on the respective dasd_device, and return them to the generic
2837  * block layer.
2838  */
2839 static int dasd_flush_block_queue(struct dasd_block *block)
2840 {
2841 	struct dasd_ccw_req *cqr, *n;
2842 	int rc, i;
2843 	struct list_head flush_queue;
2844 
2845 	INIT_LIST_HEAD(&flush_queue);
2846 	spin_lock_bh(&block->queue_lock);
2847 	rc = 0;
2848 restart:
2849 	list_for_each_entry_safe(cqr, n, &block->ccw_queue, blocklist) {
2850 		/* if this request currently owned by a dasd_device cancel it */
2851 		if (cqr->status >= DASD_CQR_QUEUED)
2852 			rc = dasd_cancel_req(cqr);
2853 		if (rc < 0)
2854 			break;
2855 		/* Rechain request (including erp chain) so it won't be
2856 		 * touched by the dasd_block_tasklet anymore.
2857 		 * Replace the callback so we notice when the request
2858 		 * is returned from the dasd_device layer.
2859 		 */
2860 		cqr->callback = _dasd_wake_block_flush_cb;
2861 		for (i = 0; cqr != NULL; cqr = cqr->refers, i++)
2862 			list_move_tail(&cqr->blocklist, &flush_queue);
2863 		if (i > 1)
2864 			/* moved more than one request - need to restart */
2865 			goto restart;
2866 	}
2867 	spin_unlock_bh(&block->queue_lock);
2868 	/* Now call the callback function of flushed requests */
2869 restart_cb:
2870 	list_for_each_entry_safe(cqr, n, &flush_queue, blocklist) {
2871 		wait_event(dasd_flush_wq, (cqr->status < DASD_CQR_QUEUED));
2872 		/* Process finished ERP request. */
2873 		if (cqr->refers) {
2874 			spin_lock_bh(&block->queue_lock);
2875 			__dasd_process_erp(block->base, cqr);
2876 			spin_unlock_bh(&block->queue_lock);
2877 			/* restart list_for_xx loop since dasd_process_erp
2878 			 * might remove multiple elements */
2879 			goto restart_cb;
2880 		}
2881 		/* call the callback function */
2882 		spin_lock_irq(&block->request_queue_lock);
2883 		cqr->endclk = get_tod_clock();
2884 		list_del_init(&cqr->blocklist);
2885 		__dasd_cleanup_cqr(cqr);
2886 		spin_unlock_irq(&block->request_queue_lock);
2887 	}
2888 	return rc;
2889 }
2890 
2891 /*
2892  * Schedules a call to dasd_tasklet over the device tasklet.
2893  */
2894 void dasd_schedule_block_bh(struct dasd_block *block)
2895 {
2896 	/* Protect against rescheduling. */
2897 	if (atomic_cmpxchg(&block->tasklet_scheduled, 0, 1) != 0)
2898 		return;
2899 	/* life cycle of block is bound to it's base device */
2900 	dasd_get_device(block->base);
2901 	tasklet_hi_schedule(&block->tasklet);
2902 }
2903 EXPORT_SYMBOL(dasd_schedule_block_bh);
2904 
2905 
2906 /*
2907  * SECTION: external block device operations
2908  * (request queue handling, open, release, etc.)
2909  */
2910 
2911 /*
2912  * Dasd request queue function. Called from ll_rw_blk.c
2913  */
2914 static void do_dasd_request(struct request_queue *queue)
2915 {
2916 	struct dasd_block *block;
2917 
2918 	block = queue->queuedata;
2919 	spin_lock(&block->queue_lock);
2920 	/* Get new request from the block device request queue */
2921 	__dasd_process_request_queue(block);
2922 	/* Now check if the head of the ccw queue needs to be started. */
2923 	__dasd_block_start_head(block);
2924 	spin_unlock(&block->queue_lock);
2925 }
2926 
2927 /*
2928  * Block timeout callback, called from the block layer
2929  *
2930  * request_queue lock is held on entry.
2931  *
2932  * Return values:
2933  * BLK_EH_RESET_TIMER if the request should be left running
2934  * BLK_EH_NOT_HANDLED if the request is handled or terminated
2935  *		      by the driver.
2936  */
2937 enum blk_eh_timer_return dasd_times_out(struct request *req)
2938 {
2939 	struct dasd_ccw_req *cqr = req->completion_data;
2940 	struct dasd_block *block = req->q->queuedata;
2941 	struct dasd_device *device;
2942 	int rc = 0;
2943 
2944 	if (!cqr)
2945 		return BLK_EH_NOT_HANDLED;
2946 
2947 	device = cqr->startdev ? cqr->startdev : block->base;
2948 	if (!device->blk_timeout)
2949 		return BLK_EH_RESET_TIMER;
2950 	DBF_DEV_EVENT(DBF_WARNING, device,
2951 		      " dasd_times_out cqr %p status %x",
2952 		      cqr, cqr->status);
2953 
2954 	spin_lock(&block->queue_lock);
2955 	spin_lock(get_ccwdev_lock(device->cdev));
2956 	cqr->retries = -1;
2957 	cqr->intrc = -ETIMEDOUT;
2958 	if (cqr->status >= DASD_CQR_QUEUED) {
2959 		spin_unlock(get_ccwdev_lock(device->cdev));
2960 		rc = dasd_cancel_req(cqr);
2961 	} else if (cqr->status == DASD_CQR_FILLED ||
2962 		   cqr->status == DASD_CQR_NEED_ERP) {
2963 		cqr->status = DASD_CQR_TERMINATED;
2964 		spin_unlock(get_ccwdev_lock(device->cdev));
2965 	} else if (cqr->status == DASD_CQR_IN_ERP) {
2966 		struct dasd_ccw_req *searchcqr, *nextcqr, *tmpcqr;
2967 
2968 		list_for_each_entry_safe(searchcqr, nextcqr,
2969 					 &block->ccw_queue, blocklist) {
2970 			tmpcqr = searchcqr;
2971 			while (tmpcqr->refers)
2972 				tmpcqr = tmpcqr->refers;
2973 			if (tmpcqr != cqr)
2974 				continue;
2975 			/* searchcqr is an ERP request for cqr */
2976 			searchcqr->retries = -1;
2977 			searchcqr->intrc = -ETIMEDOUT;
2978 			if (searchcqr->status >= DASD_CQR_QUEUED) {
2979 				spin_unlock(get_ccwdev_lock(device->cdev));
2980 				rc = dasd_cancel_req(searchcqr);
2981 				spin_lock(get_ccwdev_lock(device->cdev));
2982 			} else if ((searchcqr->status == DASD_CQR_FILLED) ||
2983 				   (searchcqr->status == DASD_CQR_NEED_ERP)) {
2984 				searchcqr->status = DASD_CQR_TERMINATED;
2985 				rc = 0;
2986 			} else if (searchcqr->status == DASD_CQR_IN_ERP) {
2987 				/*
2988 				 * Shouldn't happen; most recent ERP
2989 				 * request is at the front of queue
2990 				 */
2991 				continue;
2992 			}
2993 			break;
2994 		}
2995 		spin_unlock(get_ccwdev_lock(device->cdev));
2996 	}
2997 	dasd_schedule_block_bh(block);
2998 	spin_unlock(&block->queue_lock);
2999 
3000 	return rc ? BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED;
3001 }
3002 
3003 /*
3004  * Allocate and initialize request queue and default I/O scheduler.
3005  */
3006 static int dasd_alloc_queue(struct dasd_block *block)
3007 {
3008 	block->request_queue = blk_init_queue(do_dasd_request,
3009 					       &block->request_queue_lock);
3010 	if (block->request_queue == NULL)
3011 		return -ENOMEM;
3012 
3013 	block->request_queue->queuedata = block;
3014 
3015 	return 0;
3016 }
3017 
3018 /*
3019  * Allocate and initialize request queue.
3020  */
3021 static void dasd_setup_queue(struct dasd_block *block)
3022 {
3023 	int max;
3024 
3025 	if (block->base->features & DASD_FEATURE_USERAW) {
3026 		/*
3027 		 * the max_blocks value for raw_track access is 256
3028 		 * it is higher than the native ECKD value because we
3029 		 * only need one ccw per track
3030 		 * so the max_hw_sectors are
3031 		 * 2048 x 512B = 1024kB = 16 tracks
3032 		 */
3033 		max = 2048;
3034 	} else {
3035 		max = block->base->discipline->max_blocks << block->s2b_shift;
3036 	}
3037 	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, block->request_queue);
3038 	block->request_queue->limits.max_dev_sectors = max;
3039 	blk_queue_logical_block_size(block->request_queue,
3040 				     block->bp_block);
3041 	blk_queue_max_hw_sectors(block->request_queue, max);
3042 	blk_queue_max_segments(block->request_queue, -1L);
3043 	/* with page sized segments we can translate each segement into
3044 	 * one idaw/tidaw
3045 	 */
3046 	blk_queue_max_segment_size(block->request_queue, PAGE_SIZE);
3047 	blk_queue_segment_boundary(block->request_queue, PAGE_SIZE - 1);
3048 }
3049 
3050 /*
3051  * Deactivate and free request queue.
3052  */
3053 static void dasd_free_queue(struct dasd_block *block)
3054 {
3055 	if (block->request_queue) {
3056 		blk_cleanup_queue(block->request_queue);
3057 		block->request_queue = NULL;
3058 	}
3059 }
3060 
3061 /*
3062  * Flush request on the request queue.
3063  */
3064 static void dasd_flush_request_queue(struct dasd_block *block)
3065 {
3066 	struct request *req;
3067 
3068 	if (!block->request_queue)
3069 		return;
3070 
3071 	spin_lock_irq(&block->request_queue_lock);
3072 	while ((req = blk_fetch_request(block->request_queue)))
3073 		__blk_end_request_all(req, -EIO);
3074 	spin_unlock_irq(&block->request_queue_lock);
3075 }
3076 
3077 static int dasd_open(struct block_device *bdev, fmode_t mode)
3078 {
3079 	struct dasd_device *base;
3080 	int rc;
3081 
3082 	base = dasd_device_from_gendisk(bdev->bd_disk);
3083 	if (!base)
3084 		return -ENODEV;
3085 
3086 	atomic_inc(&base->block->open_count);
3087 	if (test_bit(DASD_FLAG_OFFLINE, &base->flags)) {
3088 		rc = -ENODEV;
3089 		goto unlock;
3090 	}
3091 
3092 	if (!try_module_get(base->discipline->owner)) {
3093 		rc = -EINVAL;
3094 		goto unlock;
3095 	}
3096 
3097 	if (dasd_probeonly) {
3098 		dev_info(&base->cdev->dev,
3099 			 "Accessing the DASD failed because it is in "
3100 			 "probeonly mode\n");
3101 		rc = -EPERM;
3102 		goto out;
3103 	}
3104 
3105 	if (base->state <= DASD_STATE_BASIC) {
3106 		DBF_DEV_EVENT(DBF_ERR, base, " %s",
3107 			      " Cannot open unrecognized device");
3108 		rc = -ENODEV;
3109 		goto out;
3110 	}
3111 
3112 	if ((mode & FMODE_WRITE) &&
3113 	    (test_bit(DASD_FLAG_DEVICE_RO, &base->flags) ||
3114 	     (base->features & DASD_FEATURE_READONLY))) {
3115 		rc = -EROFS;
3116 		goto out;
3117 	}
3118 
3119 	dasd_put_device(base);
3120 	return 0;
3121 
3122 out:
3123 	module_put(base->discipline->owner);
3124 unlock:
3125 	atomic_dec(&base->block->open_count);
3126 	dasd_put_device(base);
3127 	return rc;
3128 }
3129 
3130 static void dasd_release(struct gendisk *disk, fmode_t mode)
3131 {
3132 	struct dasd_device *base = dasd_device_from_gendisk(disk);
3133 	if (base) {
3134 		atomic_dec(&base->block->open_count);
3135 		module_put(base->discipline->owner);
3136 		dasd_put_device(base);
3137 	}
3138 }
3139 
3140 /*
3141  * Return disk geometry.
3142  */
3143 static int dasd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
3144 {
3145 	struct dasd_device *base;
3146 
3147 	base = dasd_device_from_gendisk(bdev->bd_disk);
3148 	if (!base)
3149 		return -ENODEV;
3150 
3151 	if (!base->discipline ||
3152 	    !base->discipline->fill_geometry) {
3153 		dasd_put_device(base);
3154 		return -EINVAL;
3155 	}
3156 	base->discipline->fill_geometry(base->block, geo);
3157 	geo->start = get_start_sect(bdev) >> base->block->s2b_shift;
3158 	dasd_put_device(base);
3159 	return 0;
3160 }
3161 
3162 const struct block_device_operations
3163 dasd_device_operations = {
3164 	.owner		= THIS_MODULE,
3165 	.open		= dasd_open,
3166 	.release	= dasd_release,
3167 	.ioctl		= dasd_ioctl,
3168 	.compat_ioctl	= dasd_ioctl,
3169 	.getgeo		= dasd_getgeo,
3170 };
3171 
3172 /*******************************************************************************
3173  * end of block device operations
3174  */
3175 
3176 static void
3177 dasd_exit(void)
3178 {
3179 #ifdef CONFIG_PROC_FS
3180 	dasd_proc_exit();
3181 #endif
3182 	dasd_eer_exit();
3183         if (dasd_page_cache != NULL) {
3184 		kmem_cache_destroy(dasd_page_cache);
3185 		dasd_page_cache = NULL;
3186 	}
3187 	dasd_gendisk_exit();
3188 	dasd_devmap_exit();
3189 	if (dasd_debug_area != NULL) {
3190 		debug_unregister(dasd_debug_area);
3191 		dasd_debug_area = NULL;
3192 	}
3193 	dasd_statistics_removeroot();
3194 }
3195 
3196 /*
3197  * SECTION: common functions for ccw_driver use
3198  */
3199 
3200 /*
3201  * Is the device read-only?
3202  * Note that this function does not report the setting of the
3203  * readonly device attribute, but how it is configured in z/VM.
3204  */
3205 int dasd_device_is_ro(struct dasd_device *device)
3206 {
3207 	struct ccw_dev_id dev_id;
3208 	struct diag210 diag_data;
3209 	int rc;
3210 
3211 	if (!MACHINE_IS_VM)
3212 		return 0;
3213 	ccw_device_get_id(device->cdev, &dev_id);
3214 	memset(&diag_data, 0, sizeof(diag_data));
3215 	diag_data.vrdcdvno = dev_id.devno;
3216 	diag_data.vrdclen = sizeof(diag_data);
3217 	rc = diag210(&diag_data);
3218 	if (rc == 0 || rc == 2) {
3219 		return diag_data.vrdcvfla & 0x80;
3220 	} else {
3221 		DBF_EVENT(DBF_WARNING, "diag210 failed for dev=%04x with rc=%d",
3222 			  dev_id.devno, rc);
3223 		return 0;
3224 	}
3225 }
3226 EXPORT_SYMBOL_GPL(dasd_device_is_ro);
3227 
3228 static void dasd_generic_auto_online(void *data, async_cookie_t cookie)
3229 {
3230 	struct ccw_device *cdev = data;
3231 	int ret;
3232 
3233 	ret = ccw_device_set_online(cdev);
3234 	if (ret)
3235 		pr_warn("%s: Setting the DASD online failed with rc=%d\n",
3236 			dev_name(&cdev->dev), ret);
3237 }
3238 
3239 /*
3240  * Initial attempt at a probe function. this can be simplified once
3241  * the other detection code is gone.
3242  */
3243 int dasd_generic_probe(struct ccw_device *cdev,
3244 		       struct dasd_discipline *discipline)
3245 {
3246 	int ret;
3247 
3248 	ret = dasd_add_sysfs_files(cdev);
3249 	if (ret) {
3250 		DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s",
3251 				"dasd_generic_probe: could not add "
3252 				"sysfs entries");
3253 		return ret;
3254 	}
3255 	cdev->handler = &dasd_int_handler;
3256 
3257 	/*
3258 	 * Automatically online either all dasd devices (dasd_autodetect)
3259 	 * or all devices specified with dasd= parameters during
3260 	 * initial probe.
3261 	 */
3262 	if ((dasd_get_feature(cdev, DASD_FEATURE_INITIAL_ONLINE) > 0 ) ||
3263 	    (dasd_autodetect && dasd_busid_known(dev_name(&cdev->dev)) != 0))
3264 		async_schedule(dasd_generic_auto_online, cdev);
3265 	return 0;
3266 }
3267 EXPORT_SYMBOL_GPL(dasd_generic_probe);
3268 
3269 /*
3270  * This will one day be called from a global not_oper handler.
3271  * It is also used by driver_unregister during module unload.
3272  */
3273 void dasd_generic_remove(struct ccw_device *cdev)
3274 {
3275 	struct dasd_device *device;
3276 	struct dasd_block *block;
3277 
3278 	cdev->handler = NULL;
3279 
3280 	device = dasd_device_from_cdev(cdev);
3281 	if (IS_ERR(device)) {
3282 		dasd_remove_sysfs_files(cdev);
3283 		return;
3284 	}
3285 	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags) &&
3286 	    !test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
3287 		/* Already doing offline processing */
3288 		dasd_put_device(device);
3289 		dasd_remove_sysfs_files(cdev);
3290 		return;
3291 	}
3292 	/*
3293 	 * This device is removed unconditionally. Set offline
3294 	 * flag to prevent dasd_open from opening it while it is
3295 	 * no quite down yet.
3296 	 */
3297 	dasd_set_target_state(device, DASD_STATE_NEW);
3298 	/* dasd_delete_device destroys the device reference. */
3299 	block = device->block;
3300 	dasd_delete_device(device);
3301 	/*
3302 	 * life cycle of block is bound to device, so delete it after
3303 	 * device was safely removed
3304 	 */
3305 	if (block)
3306 		dasd_free_block(block);
3307 
3308 	dasd_remove_sysfs_files(cdev);
3309 }
3310 EXPORT_SYMBOL_GPL(dasd_generic_remove);
3311 
3312 /*
3313  * Activate a device. This is called from dasd_{eckd,fba}_probe() when either
3314  * the device is detected for the first time and is supposed to be used
3315  * or the user has started activation through sysfs.
3316  */
3317 int dasd_generic_set_online(struct ccw_device *cdev,
3318 			    struct dasd_discipline *base_discipline)
3319 {
3320 	struct dasd_discipline *discipline;
3321 	struct dasd_device *device;
3322 	int rc;
3323 
3324 	/* first online clears initial online feature flag */
3325 	dasd_set_feature(cdev, DASD_FEATURE_INITIAL_ONLINE, 0);
3326 	device = dasd_create_device(cdev);
3327 	if (IS_ERR(device))
3328 		return PTR_ERR(device);
3329 
3330 	discipline = base_discipline;
3331 	if (device->features & DASD_FEATURE_USEDIAG) {
3332 	  	if (!dasd_diag_discipline_pointer) {
3333 			/* Try to load the required module. */
3334 			rc = request_module(DASD_DIAG_MOD);
3335 			if (rc) {
3336 				pr_warn("%s Setting the DASD online failed "
3337 					"because the required module %s "
3338 					"could not be loaded (rc=%d)\n",
3339 					dev_name(&cdev->dev), DASD_DIAG_MOD,
3340 					rc);
3341 				dasd_delete_device(device);
3342 				return -ENODEV;
3343 			}
3344 		}
3345 		/* Module init could have failed, so check again here after
3346 		 * request_module(). */
3347 		if (!dasd_diag_discipline_pointer) {
3348 			pr_warn("%s Setting the DASD online failed because of missing DIAG discipline\n",
3349 				dev_name(&cdev->dev));
3350 			dasd_delete_device(device);
3351 			return -ENODEV;
3352 		}
3353 		discipline = dasd_diag_discipline_pointer;
3354 	}
3355 	if (!try_module_get(base_discipline->owner)) {
3356 		dasd_delete_device(device);
3357 		return -EINVAL;
3358 	}
3359 	if (!try_module_get(discipline->owner)) {
3360 		module_put(base_discipline->owner);
3361 		dasd_delete_device(device);
3362 		return -EINVAL;
3363 	}
3364 	device->base_discipline = base_discipline;
3365 	device->discipline = discipline;
3366 
3367 	/* check_device will allocate block device if necessary */
3368 	rc = discipline->check_device(device);
3369 	if (rc) {
3370 		pr_warn("%s Setting the DASD online with discipline %s failed with rc=%i\n",
3371 			dev_name(&cdev->dev), discipline->name, rc);
3372 		module_put(discipline->owner);
3373 		module_put(base_discipline->owner);
3374 		dasd_delete_device(device);
3375 		return rc;
3376 	}
3377 
3378 	dasd_set_target_state(device, DASD_STATE_ONLINE);
3379 	if (device->state <= DASD_STATE_KNOWN) {
3380 		pr_warn("%s Setting the DASD online failed because of a missing discipline\n",
3381 			dev_name(&cdev->dev));
3382 		rc = -ENODEV;
3383 		dasd_set_target_state(device, DASD_STATE_NEW);
3384 		if (device->block)
3385 			dasd_free_block(device->block);
3386 		dasd_delete_device(device);
3387 	} else
3388 		pr_debug("dasd_generic device %s found\n",
3389 				dev_name(&cdev->dev));
3390 
3391 	wait_event(dasd_init_waitq, _wait_for_device(device));
3392 
3393 	dasd_put_device(device);
3394 	return rc;
3395 }
3396 EXPORT_SYMBOL_GPL(dasd_generic_set_online);
3397 
3398 int dasd_generic_set_offline(struct ccw_device *cdev)
3399 {
3400 	struct dasd_device *device;
3401 	struct dasd_block *block;
3402 	int max_count, open_count, rc;
3403 
3404 	rc = 0;
3405 	device = dasd_device_from_cdev(cdev);
3406 	if (IS_ERR(device))
3407 		return PTR_ERR(device);
3408 
3409 	/*
3410 	 * We must make sure that this device is currently not in use.
3411 	 * The open_count is increased for every opener, that includes
3412 	 * the blkdev_get in dasd_scan_partitions. We are only interested
3413 	 * in the other openers.
3414 	 */
3415 	if (device->block) {
3416 		max_count = device->block->bdev ? 0 : -1;
3417 		open_count = atomic_read(&device->block->open_count);
3418 		if (open_count > max_count) {
3419 			if (open_count > 0)
3420 				pr_warn("%s: The DASD cannot be set offline with open count %i\n",
3421 					dev_name(&cdev->dev), open_count);
3422 			else
3423 				pr_warn("%s: The DASD cannot be set offline while it is in use\n",
3424 					dev_name(&cdev->dev));
3425 			clear_bit(DASD_FLAG_OFFLINE, &device->flags);
3426 			dasd_put_device(device);
3427 			return -EBUSY;
3428 		}
3429 	}
3430 
3431 	if (test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
3432 		/*
3433 		 * safe offline already running
3434 		 * could only be called by normal offline so safe_offline flag
3435 		 * needs to be removed to run normal offline and kill all I/O
3436 		 */
3437 		if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
3438 			/* Already doing normal offline processing */
3439 			dasd_put_device(device);
3440 			return -EBUSY;
3441 		} else
3442 			clear_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags);
3443 
3444 	} else
3445 		if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
3446 			/* Already doing offline processing */
3447 			dasd_put_device(device);
3448 			return -EBUSY;
3449 		}
3450 
3451 	/*
3452 	 * if safe_offline called set safe_offline_running flag and
3453 	 * clear safe_offline so that a call to normal offline
3454 	 * can overrun safe_offline processing
3455 	 */
3456 	if (test_and_clear_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags) &&
3457 	    !test_and_set_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
3458 		/*
3459 		 * If we want to set the device safe offline all IO operations
3460 		 * should be finished before continuing the offline process
3461 		 * so sync bdev first and then wait for our queues to become
3462 		 * empty
3463 		 */
3464 		/* sync blockdev and partitions */
3465 		rc = fsync_bdev(device->block->bdev);
3466 		if (rc != 0)
3467 			goto interrupted;
3468 
3469 		/* schedule device tasklet and wait for completion */
3470 		dasd_schedule_device_bh(device);
3471 		rc = wait_event_interruptible(shutdown_waitq,
3472 					      _wait_for_empty_queues(device));
3473 		if (rc != 0)
3474 			goto interrupted;
3475 	}
3476 
3477 	set_bit(DASD_FLAG_OFFLINE, &device->flags);
3478 	dasd_set_target_state(device, DASD_STATE_NEW);
3479 	/* dasd_delete_device destroys the device reference. */
3480 	block = device->block;
3481 	dasd_delete_device(device);
3482 	/*
3483 	 * life cycle of block is bound to device, so delete it after
3484 	 * device was safely removed
3485 	 */
3486 	if (block)
3487 		dasd_free_block(block);
3488 	return 0;
3489 
3490 interrupted:
3491 	/* interrupted by signal */
3492 	clear_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags);
3493 	clear_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags);
3494 	clear_bit(DASD_FLAG_OFFLINE, &device->flags);
3495 	dasd_put_device(device);
3496 	return rc;
3497 }
3498 EXPORT_SYMBOL_GPL(dasd_generic_set_offline);
3499 
3500 int dasd_generic_last_path_gone(struct dasd_device *device)
3501 {
3502 	struct dasd_ccw_req *cqr;
3503 
3504 	dev_warn(&device->cdev->dev, "No operational channel path is left "
3505 		 "for the device\n");
3506 	DBF_DEV_EVENT(DBF_WARNING, device, "%s", "last path gone");
3507 	/* First of all call extended error reporting. */
3508 	dasd_eer_write(device, NULL, DASD_EER_NOPATH);
3509 
3510 	if (device->state < DASD_STATE_BASIC)
3511 		return 0;
3512 	/* Device is active. We want to keep it. */
3513 	list_for_each_entry(cqr, &device->ccw_queue, devlist)
3514 		if ((cqr->status == DASD_CQR_IN_IO) ||
3515 		    (cqr->status == DASD_CQR_CLEAR_PENDING)) {
3516 			cqr->status = DASD_CQR_QUEUED;
3517 			cqr->retries++;
3518 		}
3519 	dasd_device_set_stop_bits(device, DASD_STOPPED_DC_WAIT);
3520 	dasd_device_clear_timer(device);
3521 	dasd_schedule_device_bh(device);
3522 	return 1;
3523 }
3524 EXPORT_SYMBOL_GPL(dasd_generic_last_path_gone);
3525 
3526 int dasd_generic_path_operational(struct dasd_device *device)
3527 {
3528 	dev_info(&device->cdev->dev, "A channel path to the device has become "
3529 		 "operational\n");
3530 	DBF_DEV_EVENT(DBF_WARNING, device, "%s", "path operational");
3531 	dasd_device_remove_stop_bits(device, DASD_STOPPED_DC_WAIT);
3532 	if (device->stopped & DASD_UNRESUMED_PM) {
3533 		dasd_device_remove_stop_bits(device, DASD_UNRESUMED_PM);
3534 		dasd_restore_device(device);
3535 		return 1;
3536 	}
3537 	dasd_schedule_device_bh(device);
3538 	if (device->block)
3539 		dasd_schedule_block_bh(device->block);
3540 
3541 	if (!device->stopped)
3542 		wake_up(&generic_waitq);
3543 
3544 	return 1;
3545 }
3546 EXPORT_SYMBOL_GPL(dasd_generic_path_operational);
3547 
3548 int dasd_generic_notify(struct ccw_device *cdev, int event)
3549 {
3550 	struct dasd_device *device;
3551 	int ret;
3552 
3553 	device = dasd_device_from_cdev_locked(cdev);
3554 	if (IS_ERR(device))
3555 		return 0;
3556 	ret = 0;
3557 	switch (event) {
3558 	case CIO_GONE:
3559 	case CIO_BOXED:
3560 	case CIO_NO_PATH:
3561 		device->path_data.opm = 0;
3562 		device->path_data.ppm = 0;
3563 		device->path_data.npm = 0;
3564 		ret = dasd_generic_last_path_gone(device);
3565 		break;
3566 	case CIO_OPER:
3567 		ret = 1;
3568 		if (device->path_data.opm)
3569 			ret = dasd_generic_path_operational(device);
3570 		break;
3571 	}
3572 	dasd_put_device(device);
3573 	return ret;
3574 }
3575 EXPORT_SYMBOL_GPL(dasd_generic_notify);
3576 
3577 void dasd_generic_path_event(struct ccw_device *cdev, int *path_event)
3578 {
3579 	int chp;
3580 	__u8 oldopm, eventlpm;
3581 	struct dasd_device *device;
3582 
3583 	device = dasd_device_from_cdev_locked(cdev);
3584 	if (IS_ERR(device))
3585 		return;
3586 	for (chp = 0; chp < 8; chp++) {
3587 		eventlpm = 0x80 >> chp;
3588 		if (path_event[chp] & PE_PATH_GONE) {
3589 			oldopm = device->path_data.opm;
3590 			device->path_data.opm &= ~eventlpm;
3591 			device->path_data.ppm &= ~eventlpm;
3592 			device->path_data.npm &= ~eventlpm;
3593 			if (oldopm && !device->path_data.opm) {
3594 				dev_warn(&device->cdev->dev,
3595 					 "No verified channel paths remain "
3596 					 "for the device\n");
3597 				DBF_DEV_EVENT(DBF_WARNING, device,
3598 					      "%s", "last verified path gone");
3599 				dasd_eer_write(device, NULL, DASD_EER_NOPATH);
3600 				dasd_device_set_stop_bits(device,
3601 							  DASD_STOPPED_DC_WAIT);
3602 			}
3603 		}
3604 		if (path_event[chp] & PE_PATH_AVAILABLE) {
3605 			device->path_data.opm &= ~eventlpm;
3606 			device->path_data.ppm &= ~eventlpm;
3607 			device->path_data.npm &= ~eventlpm;
3608 			device->path_data.tbvpm |= eventlpm;
3609 			dasd_schedule_device_bh(device);
3610 		}
3611 		if (path_event[chp] & PE_PATHGROUP_ESTABLISHED) {
3612 			if (!(device->path_data.opm & eventlpm) &&
3613 			    !(device->path_data.tbvpm & eventlpm)) {
3614 				/*
3615 				 * we can not establish a pathgroup on an
3616 				 * unavailable path, so trigger a path
3617 				 * verification first
3618 				 */
3619 				device->path_data.tbvpm |= eventlpm;
3620 				dasd_schedule_device_bh(device);
3621 			}
3622 			DBF_DEV_EVENT(DBF_WARNING, device, "%s",
3623 				      "Pathgroup re-established\n");
3624 			if (device->discipline->kick_validate)
3625 				device->discipline->kick_validate(device);
3626 		}
3627 	}
3628 	dasd_put_device(device);
3629 }
3630 EXPORT_SYMBOL_GPL(dasd_generic_path_event);
3631 
3632 int dasd_generic_verify_path(struct dasd_device *device, __u8 lpm)
3633 {
3634 	if (!device->path_data.opm && lpm) {
3635 		device->path_data.opm = lpm;
3636 		dasd_generic_path_operational(device);
3637 	} else
3638 		device->path_data.opm |= lpm;
3639 	return 0;
3640 }
3641 EXPORT_SYMBOL_GPL(dasd_generic_verify_path);
3642 
3643 
3644 int dasd_generic_pm_freeze(struct ccw_device *cdev)
3645 {
3646 	struct dasd_device *device = dasd_device_from_cdev(cdev);
3647 	struct list_head freeze_queue;
3648 	struct dasd_ccw_req *cqr, *n;
3649 	struct dasd_ccw_req *refers;
3650 	int rc;
3651 
3652 	if (IS_ERR(device))
3653 		return PTR_ERR(device);
3654 
3655 	/* mark device as suspended */
3656 	set_bit(DASD_FLAG_SUSPENDED, &device->flags);
3657 
3658 	if (device->discipline->freeze)
3659 		rc = device->discipline->freeze(device);
3660 
3661 	/* disallow new I/O  */
3662 	dasd_device_set_stop_bits(device, DASD_STOPPED_PM);
3663 
3664 	/* clear active requests and requeue them to block layer if possible */
3665 	INIT_LIST_HEAD(&freeze_queue);
3666 	spin_lock_irq(get_ccwdev_lock(cdev));
3667 	rc = 0;
3668 	list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
3669 		/* Check status and move request to flush_queue */
3670 		if (cqr->status == DASD_CQR_IN_IO) {
3671 			rc = device->discipline->term_IO(cqr);
3672 			if (rc) {
3673 				/* unable to terminate requeust */
3674 				dev_err(&device->cdev->dev,
3675 					"Unable to terminate request %p "
3676 					"on suspend\n", cqr);
3677 				spin_unlock_irq(get_ccwdev_lock(cdev));
3678 				dasd_put_device(device);
3679 				return rc;
3680 			}
3681 		}
3682 		list_move_tail(&cqr->devlist, &freeze_queue);
3683 	}
3684 	spin_unlock_irq(get_ccwdev_lock(cdev));
3685 
3686 	list_for_each_entry_safe(cqr, n, &freeze_queue, devlist) {
3687 		wait_event(dasd_flush_wq,
3688 			   (cqr->status != DASD_CQR_CLEAR_PENDING));
3689 		if (cqr->status == DASD_CQR_CLEARED)
3690 			cqr->status = DASD_CQR_QUEUED;
3691 
3692 		/* requeue requests to blocklayer will only work for
3693 		   block device requests */
3694 		if (_dasd_requeue_request(cqr))
3695 			continue;
3696 
3697 		/* remove requests from device and block queue */
3698 		list_del_init(&cqr->devlist);
3699 		while (cqr->refers != NULL) {
3700 			refers = cqr->refers;
3701 			/* remove the request from the block queue */
3702 			list_del(&cqr->blocklist);
3703 			/* free the finished erp request */
3704 			dasd_free_erp_request(cqr, cqr->memdev);
3705 			cqr = refers;
3706 		}
3707 		if (cqr->block)
3708 			list_del_init(&cqr->blocklist);
3709 		cqr->block->base->discipline->free_cp(
3710 			cqr, (struct request *) cqr->callback_data);
3711 	}
3712 
3713 	/*
3714 	 * if requests remain then they are internal request
3715 	 * and go back to the device queue
3716 	 */
3717 	if (!list_empty(&freeze_queue)) {
3718 		/* move freeze_queue to start of the ccw_queue */
3719 		spin_lock_irq(get_ccwdev_lock(cdev));
3720 		list_splice_tail(&freeze_queue, &device->ccw_queue);
3721 		spin_unlock_irq(get_ccwdev_lock(cdev));
3722 	}
3723 	dasd_put_device(device);
3724 	return rc;
3725 }
3726 EXPORT_SYMBOL_GPL(dasd_generic_pm_freeze);
3727 
3728 int dasd_generic_restore_device(struct ccw_device *cdev)
3729 {
3730 	struct dasd_device *device = dasd_device_from_cdev(cdev);
3731 	int rc = 0;
3732 
3733 	if (IS_ERR(device))
3734 		return PTR_ERR(device);
3735 
3736 	/* allow new IO again */
3737 	dasd_device_remove_stop_bits(device,
3738 				     (DASD_STOPPED_PM | DASD_UNRESUMED_PM));
3739 
3740 	dasd_schedule_device_bh(device);
3741 
3742 	/*
3743 	 * call discipline restore function
3744 	 * if device is stopped do nothing e.g. for disconnected devices
3745 	 */
3746 	if (device->discipline->restore && !(device->stopped))
3747 		rc = device->discipline->restore(device);
3748 	if (rc || device->stopped)
3749 		/*
3750 		 * if the resume failed for the DASD we put it in
3751 		 * an UNRESUMED stop state
3752 		 */
3753 		device->stopped |= DASD_UNRESUMED_PM;
3754 
3755 	if (device->block)
3756 		dasd_schedule_block_bh(device->block);
3757 
3758 	clear_bit(DASD_FLAG_SUSPENDED, &device->flags);
3759 	dasd_put_device(device);
3760 	return 0;
3761 }
3762 EXPORT_SYMBOL_GPL(dasd_generic_restore_device);
3763 
3764 static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
3765 						   void *rdc_buffer,
3766 						   int rdc_buffer_size,
3767 						   int magic)
3768 {
3769 	struct dasd_ccw_req *cqr;
3770 	struct ccw1 *ccw;
3771 	unsigned long *idaw;
3772 
3773 	cqr = dasd_smalloc_request(magic, 1 /* RDC */, rdc_buffer_size, device);
3774 
3775 	if (IS_ERR(cqr)) {
3776 		/* internal error 13 - Allocating the RDC request failed*/
3777 		dev_err(&device->cdev->dev,
3778 			 "An error occurred in the DASD device driver, "
3779 			 "reason=%s\n", "13");
3780 		return cqr;
3781 	}
3782 
3783 	ccw = cqr->cpaddr;
3784 	ccw->cmd_code = CCW_CMD_RDC;
3785 	if (idal_is_needed(rdc_buffer, rdc_buffer_size)) {
3786 		idaw = (unsigned long *) (cqr->data);
3787 		ccw->cda = (__u32)(addr_t) idaw;
3788 		ccw->flags = CCW_FLAG_IDA;
3789 		idaw = idal_create_words(idaw, rdc_buffer, rdc_buffer_size);
3790 	} else {
3791 		ccw->cda = (__u32)(addr_t) rdc_buffer;
3792 		ccw->flags = 0;
3793 	}
3794 
3795 	ccw->count = rdc_buffer_size;
3796 	cqr->startdev = device;
3797 	cqr->memdev = device;
3798 	cqr->expires = 10*HZ;
3799 	cqr->retries = 256;
3800 	cqr->buildclk = get_tod_clock();
3801 	cqr->status = DASD_CQR_FILLED;
3802 	return cqr;
3803 }
3804 
3805 
3806 int dasd_generic_read_dev_chars(struct dasd_device *device, int magic,
3807 				void *rdc_buffer, int rdc_buffer_size)
3808 {
3809 	int ret;
3810 	struct dasd_ccw_req *cqr;
3811 
3812 	cqr = dasd_generic_build_rdc(device, rdc_buffer, rdc_buffer_size,
3813 				     magic);
3814 	if (IS_ERR(cqr))
3815 		return PTR_ERR(cqr);
3816 
3817 	ret = dasd_sleep_on(cqr);
3818 	dasd_sfree_request(cqr, cqr->memdev);
3819 	return ret;
3820 }
3821 EXPORT_SYMBOL_GPL(dasd_generic_read_dev_chars);
3822 
3823 /*
3824  *   In command mode and transport mode we need to look for sense
3825  *   data in different places. The sense data itself is allways
3826  *   an array of 32 bytes, so we can unify the sense data access
3827  *   for both modes.
3828  */
3829 char *dasd_get_sense(struct irb *irb)
3830 {
3831 	struct tsb *tsb = NULL;
3832 	char *sense = NULL;
3833 
3834 	if (scsw_is_tm(&irb->scsw) && (irb->scsw.tm.fcxs == 0x01)) {
3835 		if (irb->scsw.tm.tcw)
3836 			tsb = tcw_get_tsb((struct tcw *)(unsigned long)
3837 					  irb->scsw.tm.tcw);
3838 		if (tsb && tsb->length == 64 && tsb->flags)
3839 			switch (tsb->flags & 0x07) {
3840 			case 1:	/* tsa_iostat */
3841 				sense = tsb->tsa.iostat.sense;
3842 				break;
3843 			case 2: /* tsa_ddpc */
3844 				sense = tsb->tsa.ddpc.sense;
3845 				break;
3846 			default:
3847 				/* currently we don't use interrogate data */
3848 				break;
3849 			}
3850 	} else if (irb->esw.esw0.erw.cons) {
3851 		sense = irb->ecw;
3852 	}
3853 	return sense;
3854 }
3855 EXPORT_SYMBOL_GPL(dasd_get_sense);
3856 
3857 void dasd_generic_shutdown(struct ccw_device *cdev)
3858 {
3859 	struct dasd_device *device;
3860 
3861 	device = dasd_device_from_cdev(cdev);
3862 	if (IS_ERR(device))
3863 		return;
3864 
3865 	if (device->block)
3866 		dasd_schedule_block_bh(device->block);
3867 
3868 	dasd_schedule_device_bh(device);
3869 
3870 	wait_event(shutdown_waitq, _wait_for_empty_queues(device));
3871 }
3872 EXPORT_SYMBOL_GPL(dasd_generic_shutdown);
3873 
3874 static int __init dasd_init(void)
3875 {
3876 	int rc;
3877 
3878 	init_waitqueue_head(&dasd_init_waitq);
3879 	init_waitqueue_head(&dasd_flush_wq);
3880 	init_waitqueue_head(&generic_waitq);
3881 	init_waitqueue_head(&shutdown_waitq);
3882 
3883 	/* register 'common' DASD debug area, used for all DBF_XXX calls */
3884 	dasd_debug_area = debug_register("dasd", 1, 1, 8 * sizeof(long));
3885 	if (dasd_debug_area == NULL) {
3886 		rc = -ENOMEM;
3887 		goto failed;
3888 	}
3889 	debug_register_view(dasd_debug_area, &debug_sprintf_view);
3890 	debug_set_level(dasd_debug_area, DBF_WARNING);
3891 
3892 	DBF_EVENT(DBF_EMERG, "%s", "debug area created");
3893 
3894 	dasd_diag_discipline_pointer = NULL;
3895 
3896 	dasd_statistics_createroot();
3897 
3898 	rc = dasd_devmap_init();
3899 	if (rc)
3900 		goto failed;
3901 	rc = dasd_gendisk_init();
3902 	if (rc)
3903 		goto failed;
3904 	rc = dasd_parse();
3905 	if (rc)
3906 		goto failed;
3907 	rc = dasd_eer_init();
3908 	if (rc)
3909 		goto failed;
3910 #ifdef CONFIG_PROC_FS
3911 	rc = dasd_proc_init();
3912 	if (rc)
3913 		goto failed;
3914 #endif
3915 
3916 	return 0;
3917 failed:
3918 	pr_info("The DASD device driver could not be initialized\n");
3919 	dasd_exit();
3920 	return rc;
3921 }
3922 
3923 module_init(dasd_init);
3924 module_exit(dasd_exit);
3925