xref: /openbmc/linux/drivers/s390/block/dasd.c (revision ef19298b)
1 /*
2  * File...........: linux/drivers/s390/block/dasd.c
3  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
4  *		    Horst Hummel <Horst.Hummel@de.ibm.com>
5  *		    Carsten Otte <Cotte@de.ibm.com>
6  *		    Martin Schwidefsky <schwidefsky@de.ibm.com>
7  * Bugreports.to..: <Linux390@de.ibm.com>
8  * Copyright IBM Corp. 1999, 2009
9  */
10 
11 #define KMSG_COMPONENT "dasd"
12 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
13 
14 #include <linux/kernel_stat.h>
15 #include <linux/kmod.h>
16 #include <linux/init.h>
17 #include <linux/interrupt.h>
18 #include <linux/ctype.h>
19 #include <linux/major.h>
20 #include <linux/slab.h>
21 #include <linux/buffer_head.h>
22 #include <linux/hdreg.h>
23 #include <linux/async.h>
24 #include <linux/mutex.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_SLEEPON_START_TAG	(void *) 1
42 #define DASD_SLEEPON_END_TAG	(void *) 2
43 
44 /*
45  * SECTION: exported variables of dasd.c
46  */
47 debug_info_t *dasd_debug_area;
48 struct dasd_discipline *dasd_diag_discipline_pointer;
49 void dasd_int_handler(struct ccw_device *, unsigned long, struct irb *);
50 
51 MODULE_AUTHOR("Holger Smolinski <Holger.Smolinski@de.ibm.com>");
52 MODULE_DESCRIPTION("Linux on S/390 DASD device driver,"
53 		   " Copyright 2000 IBM Corporation");
54 MODULE_SUPPORTED_DEVICE("dasd");
55 MODULE_LICENSE("GPL");
56 
57 /*
58  * SECTION: prototypes for static functions of dasd.c
59  */
60 static int  dasd_alloc_queue(struct dasd_block *);
61 static void dasd_setup_queue(struct dasd_block *);
62 static void dasd_free_queue(struct dasd_block *);
63 static void dasd_flush_request_queue(struct dasd_block *);
64 static int dasd_flush_block_queue(struct dasd_block *);
65 static void dasd_device_tasklet(struct dasd_device *);
66 static void dasd_block_tasklet(struct dasd_block *);
67 static void do_kick_device(struct work_struct *);
68 static void do_restore_device(struct work_struct *);
69 static void do_reload_device(struct work_struct *);
70 static void dasd_return_cqr_cb(struct dasd_ccw_req *, void *);
71 static void dasd_device_timeout(unsigned long);
72 static void dasd_block_timeout(unsigned long);
73 static void __dasd_process_erp(struct dasd_device *, struct dasd_ccw_req *);
74 
75 /*
76  * SECTION: Operations on the device structure.
77  */
78 static wait_queue_head_t dasd_init_waitq;
79 static wait_queue_head_t dasd_flush_wq;
80 static wait_queue_head_t generic_waitq;
81 
82 /*
83  * Allocate memory for a new device structure.
84  */
85 struct dasd_device *dasd_alloc_device(void)
86 {
87 	struct dasd_device *device;
88 
89 	device = kzalloc(sizeof(struct dasd_device), GFP_ATOMIC);
90 	if (!device)
91 		return ERR_PTR(-ENOMEM);
92 
93 	/* Get two pages for normal block device operations. */
94 	device->ccw_mem = (void *) __get_free_pages(GFP_ATOMIC | GFP_DMA, 1);
95 	if (!device->ccw_mem) {
96 		kfree(device);
97 		return ERR_PTR(-ENOMEM);
98 	}
99 	/* Get one page for error recovery. */
100 	device->erp_mem = (void *) get_zeroed_page(GFP_ATOMIC | GFP_DMA);
101 	if (!device->erp_mem) {
102 		free_pages((unsigned long) device->ccw_mem, 1);
103 		kfree(device);
104 		return ERR_PTR(-ENOMEM);
105 	}
106 
107 	dasd_init_chunklist(&device->ccw_chunks, device->ccw_mem, PAGE_SIZE*2);
108 	dasd_init_chunklist(&device->erp_chunks, device->erp_mem, PAGE_SIZE);
109 	spin_lock_init(&device->mem_lock);
110 	atomic_set(&device->tasklet_scheduled, 0);
111 	tasklet_init(&device->tasklet,
112 		     (void (*)(unsigned long)) dasd_device_tasklet,
113 		     (unsigned long) device);
114 	INIT_LIST_HEAD(&device->ccw_queue);
115 	init_timer(&device->timer);
116 	device->timer.function = dasd_device_timeout;
117 	device->timer.data = (unsigned long) device;
118 	INIT_WORK(&device->kick_work, do_kick_device);
119 	INIT_WORK(&device->restore_device, do_restore_device);
120 	INIT_WORK(&device->reload_device, do_reload_device);
121 	device->state = DASD_STATE_NEW;
122 	device->target = DASD_STATE_NEW;
123 	mutex_init(&device->state_mutex);
124 
125 	return device;
126 }
127 
128 /*
129  * Free memory of a device structure.
130  */
131 void dasd_free_device(struct dasd_device *device)
132 {
133 	kfree(device->private);
134 	free_page((unsigned long) device->erp_mem);
135 	free_pages((unsigned long) device->ccw_mem, 1);
136 	kfree(device);
137 }
138 
139 /*
140  * Allocate memory for a new device structure.
141  */
142 struct dasd_block *dasd_alloc_block(void)
143 {
144 	struct dasd_block *block;
145 
146 	block = kzalloc(sizeof(*block), GFP_ATOMIC);
147 	if (!block)
148 		return ERR_PTR(-ENOMEM);
149 	/* open_count = 0 means device online but not in use */
150 	atomic_set(&block->open_count, -1);
151 
152 	spin_lock_init(&block->request_queue_lock);
153 	atomic_set(&block->tasklet_scheduled, 0);
154 	tasklet_init(&block->tasklet,
155 		     (void (*)(unsigned long)) dasd_block_tasklet,
156 		     (unsigned long) block);
157 	INIT_LIST_HEAD(&block->ccw_queue);
158 	spin_lock_init(&block->queue_lock);
159 	init_timer(&block->timer);
160 	block->timer.function = dasd_block_timeout;
161 	block->timer.data = (unsigned long) block;
162 
163 	return block;
164 }
165 
166 /*
167  * Free memory of a device structure.
168  */
169 void dasd_free_block(struct dasd_block *block)
170 {
171 	kfree(block);
172 }
173 
174 /*
175  * Make a new device known to the system.
176  */
177 static int dasd_state_new_to_known(struct dasd_device *device)
178 {
179 	int rc;
180 
181 	/*
182 	 * As long as the device is not in state DASD_STATE_NEW we want to
183 	 * keep the reference count > 0.
184 	 */
185 	dasd_get_device(device);
186 
187 	if (device->block) {
188 		rc = dasd_alloc_queue(device->block);
189 		if (rc) {
190 			dasd_put_device(device);
191 			return rc;
192 		}
193 	}
194 	device->state = DASD_STATE_KNOWN;
195 	return 0;
196 }
197 
198 /*
199  * Let the system forget about a device.
200  */
201 static int dasd_state_known_to_new(struct dasd_device *device)
202 {
203 	/* Disable extended error reporting for this device. */
204 	dasd_eer_disable(device);
205 	/* Forget the discipline information. */
206 	if (device->discipline) {
207 		if (device->discipline->uncheck_device)
208 			device->discipline->uncheck_device(device);
209 		module_put(device->discipline->owner);
210 	}
211 	device->discipline = NULL;
212 	if (device->base_discipline)
213 		module_put(device->base_discipline->owner);
214 	device->base_discipline = NULL;
215 	device->state = DASD_STATE_NEW;
216 
217 	if (device->block)
218 		dasd_free_queue(device->block);
219 
220 	/* Give up reference we took in dasd_state_new_to_known. */
221 	dasd_put_device(device);
222 	return 0;
223 }
224 
225 /*
226  * Request the irq line for the device.
227  */
228 static int dasd_state_known_to_basic(struct dasd_device *device)
229 {
230 	int rc;
231 
232 	/* Allocate and register gendisk structure. */
233 	if (device->block) {
234 		rc = dasd_gendisk_alloc(device->block);
235 		if (rc)
236 			return rc;
237 	}
238 	/* register 'device' debug area, used for all DBF_DEV_XXX calls */
239 	device->debug_area = debug_register(dev_name(&device->cdev->dev), 4, 1,
240 					    8 * sizeof(long));
241 	debug_register_view(device->debug_area, &debug_sprintf_view);
242 	debug_set_level(device->debug_area, DBF_WARNING);
243 	DBF_DEV_EVENT(DBF_EMERG, device, "%s", "debug area created");
244 
245 	device->state = DASD_STATE_BASIC;
246 	return 0;
247 }
248 
249 /*
250  * Release the irq line for the device. Terminate any running i/o.
251  */
252 static int dasd_state_basic_to_known(struct dasd_device *device)
253 {
254 	int rc;
255 	if (device->block) {
256 		dasd_gendisk_free(device->block);
257 		dasd_block_clear_timer(device->block);
258 	}
259 	rc = dasd_flush_device_queue(device);
260 	if (rc)
261 		return rc;
262 	dasd_device_clear_timer(device);
263 
264 	DBF_DEV_EVENT(DBF_EMERG, device, "%p debug area deleted", device);
265 	if (device->debug_area != NULL) {
266 		debug_unregister(device->debug_area);
267 		device->debug_area = NULL;
268 	}
269 	device->state = DASD_STATE_KNOWN;
270 	return 0;
271 }
272 
273 /*
274  * Do the initial analysis. The do_analysis function may return
275  * -EAGAIN in which case the device keeps the state DASD_STATE_BASIC
276  * until the discipline decides to continue the startup sequence
277  * by calling the function dasd_change_state. The eckd disciplines
278  * uses this to start a ccw that detects the format. The completion
279  * interrupt for this detection ccw uses the kernel event daemon to
280  * trigger the call to dasd_change_state. All this is done in the
281  * discipline code, see dasd_eckd.c.
282  * After the analysis ccw is done (do_analysis returned 0) the block
283  * device is setup.
284  * In case the analysis returns an error, the device setup is stopped
285  * (a fake disk was already added to allow formatting).
286  */
287 static int dasd_state_basic_to_ready(struct dasd_device *device)
288 {
289 	int rc;
290 	struct dasd_block *block;
291 
292 	rc = 0;
293 	block = device->block;
294 	/* make disk known with correct capacity */
295 	if (block) {
296 		if (block->base->discipline->do_analysis != NULL)
297 			rc = block->base->discipline->do_analysis(block);
298 		if (rc) {
299 			if (rc != -EAGAIN)
300 				device->state = DASD_STATE_UNFMT;
301 			return rc;
302 		}
303 		dasd_setup_queue(block);
304 		set_capacity(block->gdp,
305 			     block->blocks << block->s2b_shift);
306 		device->state = DASD_STATE_READY;
307 		rc = dasd_scan_partitions(block);
308 		if (rc)
309 			device->state = DASD_STATE_BASIC;
310 	} else {
311 		device->state = DASD_STATE_READY;
312 	}
313 	return rc;
314 }
315 
316 /*
317  * Remove device from block device layer. Destroy dirty buffers.
318  * Forget format information. Check if the target level is basic
319  * and if it is create fake disk for formatting.
320  */
321 static int dasd_state_ready_to_basic(struct dasd_device *device)
322 {
323 	int rc;
324 
325 	device->state = DASD_STATE_BASIC;
326 	if (device->block) {
327 		struct dasd_block *block = device->block;
328 		rc = dasd_flush_block_queue(block);
329 		if (rc) {
330 			device->state = DASD_STATE_READY;
331 			return rc;
332 		}
333 		dasd_flush_request_queue(block);
334 		dasd_destroy_partitions(block);
335 		block->blocks = 0;
336 		block->bp_block = 0;
337 		block->s2b_shift = 0;
338 	}
339 	return 0;
340 }
341 
342 /*
343  * Back to basic.
344  */
345 static int dasd_state_unfmt_to_basic(struct dasd_device *device)
346 {
347 	device->state = DASD_STATE_BASIC;
348 	return 0;
349 }
350 
351 /*
352  * Make the device online and schedule the bottom half to start
353  * the requeueing of requests from the linux request queue to the
354  * ccw queue.
355  */
356 static int
357 dasd_state_ready_to_online(struct dasd_device * device)
358 {
359 	int rc;
360 	struct gendisk *disk;
361 	struct disk_part_iter piter;
362 	struct hd_struct *part;
363 
364 	if (device->discipline->ready_to_online) {
365 		rc = device->discipline->ready_to_online(device);
366 		if (rc)
367 			return rc;
368 	}
369 	device->state = DASD_STATE_ONLINE;
370 	if (device->block) {
371 		dasd_schedule_block_bh(device->block);
372 		disk = device->block->bdev->bd_disk;
373 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
374 		while ((part = disk_part_iter_next(&piter)))
375 			kobject_uevent(&part_to_dev(part)->kobj, KOBJ_CHANGE);
376 		disk_part_iter_exit(&piter);
377 	}
378 	return 0;
379 }
380 
381 /*
382  * Stop the requeueing of requests again.
383  */
384 static int dasd_state_online_to_ready(struct dasd_device *device)
385 {
386 	int rc;
387 	struct gendisk *disk;
388 	struct disk_part_iter piter;
389 	struct hd_struct *part;
390 
391 	if (device->discipline->online_to_ready) {
392 		rc = device->discipline->online_to_ready(device);
393 		if (rc)
394 			return rc;
395 	}
396 	device->state = DASD_STATE_READY;
397 	if (device->block) {
398 		disk = device->block->bdev->bd_disk;
399 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
400 		while ((part = disk_part_iter_next(&piter)))
401 			kobject_uevent(&part_to_dev(part)->kobj, KOBJ_CHANGE);
402 		disk_part_iter_exit(&piter);
403 	}
404 	return 0;
405 }
406 
407 /*
408  * Device startup state changes.
409  */
410 static int dasd_increase_state(struct dasd_device *device)
411 {
412 	int rc;
413 
414 	rc = 0;
415 	if (device->state == DASD_STATE_NEW &&
416 	    device->target >= DASD_STATE_KNOWN)
417 		rc = dasd_state_new_to_known(device);
418 
419 	if (!rc &&
420 	    device->state == DASD_STATE_KNOWN &&
421 	    device->target >= DASD_STATE_BASIC)
422 		rc = dasd_state_known_to_basic(device);
423 
424 	if (!rc &&
425 	    device->state == DASD_STATE_BASIC &&
426 	    device->target >= DASD_STATE_READY)
427 		rc = dasd_state_basic_to_ready(device);
428 
429 	if (!rc &&
430 	    device->state == DASD_STATE_UNFMT &&
431 	    device->target > DASD_STATE_UNFMT)
432 		rc = -EPERM;
433 
434 	if (!rc &&
435 	    device->state == DASD_STATE_READY &&
436 	    device->target >= DASD_STATE_ONLINE)
437 		rc = dasd_state_ready_to_online(device);
438 
439 	return rc;
440 }
441 
442 /*
443  * Device shutdown state changes.
444  */
445 static int dasd_decrease_state(struct dasd_device *device)
446 {
447 	int rc;
448 
449 	rc = 0;
450 	if (device->state == DASD_STATE_ONLINE &&
451 	    device->target <= DASD_STATE_READY)
452 		rc = dasd_state_online_to_ready(device);
453 
454 	if (!rc &&
455 	    device->state == DASD_STATE_READY &&
456 	    device->target <= DASD_STATE_BASIC)
457 		rc = dasd_state_ready_to_basic(device);
458 
459 	if (!rc &&
460 	    device->state == DASD_STATE_UNFMT &&
461 	    device->target <= DASD_STATE_BASIC)
462 		rc = dasd_state_unfmt_to_basic(device);
463 
464 	if (!rc &&
465 	    device->state == DASD_STATE_BASIC &&
466 	    device->target <= DASD_STATE_KNOWN)
467 		rc = dasd_state_basic_to_known(device);
468 
469 	if (!rc &&
470 	    device->state == DASD_STATE_KNOWN &&
471 	    device->target <= DASD_STATE_NEW)
472 		rc = dasd_state_known_to_new(device);
473 
474 	return rc;
475 }
476 
477 /*
478  * This is the main startup/shutdown routine.
479  */
480 static void dasd_change_state(struct dasd_device *device)
481 {
482 	int rc;
483 
484 	if (device->state == device->target)
485 		/* Already where we want to go today... */
486 		return;
487 	if (device->state < device->target)
488 		rc = dasd_increase_state(device);
489 	else
490 		rc = dasd_decrease_state(device);
491 	if (rc == -EAGAIN)
492 		return;
493 	if (rc)
494 		device->target = device->state;
495 
496 	if (device->state == device->target)
497 		wake_up(&dasd_init_waitq);
498 
499 	/* let user-space know that the device status changed */
500 	kobject_uevent(&device->cdev->dev.kobj, KOBJ_CHANGE);
501 }
502 
503 /*
504  * Kick starter for devices that did not complete the startup/shutdown
505  * procedure or were sleeping because of a pending state.
506  * dasd_kick_device will schedule a call do do_kick_device to the kernel
507  * event daemon.
508  */
509 static void do_kick_device(struct work_struct *work)
510 {
511 	struct dasd_device *device = container_of(work, struct dasd_device, kick_work);
512 	mutex_lock(&device->state_mutex);
513 	dasd_change_state(device);
514 	mutex_unlock(&device->state_mutex);
515 	dasd_schedule_device_bh(device);
516 	dasd_put_device(device);
517 }
518 
519 void dasd_kick_device(struct dasd_device *device)
520 {
521 	dasd_get_device(device);
522 	/* queue call to dasd_kick_device to the kernel event daemon. */
523 	schedule_work(&device->kick_work);
524 }
525 
526 /*
527  * dasd_reload_device will schedule a call do do_reload_device to the kernel
528  * event daemon.
529  */
530 static void do_reload_device(struct work_struct *work)
531 {
532 	struct dasd_device *device = container_of(work, struct dasd_device,
533 						  reload_device);
534 	device->discipline->reload(device);
535 	dasd_put_device(device);
536 }
537 
538 void dasd_reload_device(struct dasd_device *device)
539 {
540 	dasd_get_device(device);
541 	/* queue call to dasd_reload_device to the kernel event daemon. */
542 	schedule_work(&device->reload_device);
543 }
544 EXPORT_SYMBOL(dasd_reload_device);
545 
546 /*
547  * dasd_restore_device will schedule a call do do_restore_device to the kernel
548  * event daemon.
549  */
550 static void do_restore_device(struct work_struct *work)
551 {
552 	struct dasd_device *device = container_of(work, struct dasd_device,
553 						  restore_device);
554 	device->cdev->drv->restore(device->cdev);
555 	dasd_put_device(device);
556 }
557 
558 void dasd_restore_device(struct dasd_device *device)
559 {
560 	dasd_get_device(device);
561 	/* queue call to dasd_restore_device to the kernel event daemon. */
562 	schedule_work(&device->restore_device);
563 }
564 
565 /*
566  * Set the target state for a device and starts the state change.
567  */
568 void dasd_set_target_state(struct dasd_device *device, int target)
569 {
570 	dasd_get_device(device);
571 	mutex_lock(&device->state_mutex);
572 	/* If we are in probeonly mode stop at DASD_STATE_READY. */
573 	if (dasd_probeonly && target > DASD_STATE_READY)
574 		target = DASD_STATE_READY;
575 	if (device->target != target) {
576 		if (device->state == target)
577 			wake_up(&dasd_init_waitq);
578 		device->target = target;
579 	}
580 	if (device->state != device->target)
581 		dasd_change_state(device);
582 	mutex_unlock(&device->state_mutex);
583 	dasd_put_device(device);
584 }
585 
586 /*
587  * Enable devices with device numbers in [from..to].
588  */
589 static inline int _wait_for_device(struct dasd_device *device)
590 {
591 	return (device->state == device->target);
592 }
593 
594 void dasd_enable_device(struct dasd_device *device)
595 {
596 	dasd_set_target_state(device, DASD_STATE_ONLINE);
597 	if (device->state <= DASD_STATE_KNOWN)
598 		/* No discipline for device found. */
599 		dasd_set_target_state(device, DASD_STATE_NEW);
600 	/* Now wait for the devices to come up. */
601 	wait_event(dasd_init_waitq, _wait_for_device(device));
602 }
603 
604 /*
605  * SECTION: device operation (interrupt handler, start i/o, term i/o ...)
606  */
607 #ifdef CONFIG_DASD_PROFILE
608 
609 struct dasd_profile_info_t dasd_global_profile;
610 unsigned int dasd_profile_level = DASD_PROFILE_OFF;
611 
612 /*
613  * Increments counter in global and local profiling structures.
614  */
615 #define dasd_profile_counter(value, counter, block) \
616 { \
617 	int index; \
618 	for (index = 0; index < 31 && value >> (2+index); index++); \
619 	dasd_global_profile.counter[index]++; \
620 	block->profile.counter[index]++; \
621 }
622 
623 /*
624  * Add profiling information for cqr before execution.
625  */
626 static void dasd_profile_start(struct dasd_block *block,
627 			       struct dasd_ccw_req *cqr,
628 			       struct request *req)
629 {
630 	struct list_head *l;
631 	unsigned int counter;
632 
633 	if (dasd_profile_level != DASD_PROFILE_ON)
634 		return;
635 
636 	/* count the length of the chanq for statistics */
637 	counter = 0;
638 	list_for_each(l, &block->ccw_queue)
639 		if (++counter >= 31)
640 			break;
641 	dasd_global_profile.dasd_io_nr_req[counter]++;
642 	block->profile.dasd_io_nr_req[counter]++;
643 }
644 
645 /*
646  * Add profiling information for cqr after execution.
647  */
648 static void dasd_profile_end(struct dasd_block *block,
649 			     struct dasd_ccw_req *cqr,
650 			     struct request *req)
651 {
652 	long strtime, irqtime, endtime, tottime;	/* in microseconds */
653 	long tottimeps, sectors;
654 
655 	if (dasd_profile_level != DASD_PROFILE_ON)
656 		return;
657 
658 	sectors = blk_rq_sectors(req);
659 	if (!cqr->buildclk || !cqr->startclk ||
660 	    !cqr->stopclk || !cqr->endclk ||
661 	    !sectors)
662 		return;
663 
664 	strtime = ((cqr->startclk - cqr->buildclk) >> 12);
665 	irqtime = ((cqr->stopclk - cqr->startclk) >> 12);
666 	endtime = ((cqr->endclk - cqr->stopclk) >> 12);
667 	tottime = ((cqr->endclk - cqr->buildclk) >> 12);
668 	tottimeps = tottime / sectors;
669 
670 	if (!dasd_global_profile.dasd_io_reqs)
671 		memset(&dasd_global_profile, 0,
672 		       sizeof(struct dasd_profile_info_t));
673 	dasd_global_profile.dasd_io_reqs++;
674 	dasd_global_profile.dasd_io_sects += sectors;
675 
676 	if (!block->profile.dasd_io_reqs)
677 		memset(&block->profile, 0,
678 		       sizeof(struct dasd_profile_info_t));
679 	block->profile.dasd_io_reqs++;
680 	block->profile.dasd_io_sects += sectors;
681 
682 	dasd_profile_counter(sectors, dasd_io_secs, block);
683 	dasd_profile_counter(tottime, dasd_io_times, block);
684 	dasd_profile_counter(tottimeps, dasd_io_timps, block);
685 	dasd_profile_counter(strtime, dasd_io_time1, block);
686 	dasd_profile_counter(irqtime, dasd_io_time2, block);
687 	dasd_profile_counter(irqtime / sectors, dasd_io_time2ps, block);
688 	dasd_profile_counter(endtime, dasd_io_time3, block);
689 }
690 #else
691 #define dasd_profile_start(block, cqr, req) do {} while (0)
692 #define dasd_profile_end(block, cqr, req) do {} while (0)
693 #endif				/* CONFIG_DASD_PROFILE */
694 
695 /*
696  * Allocate memory for a channel program with 'cplength' channel
697  * command words and 'datasize' additional space. There are two
698  * variantes: 1) dasd_kmalloc_request uses kmalloc to get the needed
699  * memory and 2) dasd_smalloc_request uses the static ccw memory
700  * that gets allocated for each device.
701  */
702 struct dasd_ccw_req *dasd_kmalloc_request(int magic, int cplength,
703 					  int datasize,
704 					  struct dasd_device *device)
705 {
706 	struct dasd_ccw_req *cqr;
707 
708 	/* Sanity checks */
709 	BUG_ON(datasize > PAGE_SIZE ||
710 	     (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
711 
712 	cqr = kzalloc(sizeof(struct dasd_ccw_req), GFP_ATOMIC);
713 	if (cqr == NULL)
714 		return ERR_PTR(-ENOMEM);
715 	cqr->cpaddr = NULL;
716 	if (cplength > 0) {
717 		cqr->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
718 				      GFP_ATOMIC | GFP_DMA);
719 		if (cqr->cpaddr == NULL) {
720 			kfree(cqr);
721 			return ERR_PTR(-ENOMEM);
722 		}
723 	}
724 	cqr->data = NULL;
725 	if (datasize > 0) {
726 		cqr->data = kzalloc(datasize, GFP_ATOMIC | GFP_DMA);
727 		if (cqr->data == NULL) {
728 			kfree(cqr->cpaddr);
729 			kfree(cqr);
730 			return ERR_PTR(-ENOMEM);
731 		}
732 	}
733 	cqr->magic =  magic;
734 	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
735 	dasd_get_device(device);
736 	return cqr;
737 }
738 
739 struct dasd_ccw_req *dasd_smalloc_request(int magic, int cplength,
740 					  int datasize,
741 					  struct dasd_device *device)
742 {
743 	unsigned long flags;
744 	struct dasd_ccw_req *cqr;
745 	char *data;
746 	int size;
747 
748 	size = (sizeof(struct dasd_ccw_req) + 7L) & -8L;
749 	if (cplength > 0)
750 		size += cplength * sizeof(struct ccw1);
751 	if (datasize > 0)
752 		size += datasize;
753 	spin_lock_irqsave(&device->mem_lock, flags);
754 	cqr = (struct dasd_ccw_req *)
755 		dasd_alloc_chunk(&device->ccw_chunks, size);
756 	spin_unlock_irqrestore(&device->mem_lock, flags);
757 	if (cqr == NULL)
758 		return ERR_PTR(-ENOMEM);
759 	memset(cqr, 0, sizeof(struct dasd_ccw_req));
760 	data = (char *) cqr + ((sizeof(struct dasd_ccw_req) + 7L) & -8L);
761 	cqr->cpaddr = NULL;
762 	if (cplength > 0) {
763 		cqr->cpaddr = (struct ccw1 *) data;
764 		data += cplength*sizeof(struct ccw1);
765 		memset(cqr->cpaddr, 0, cplength*sizeof(struct ccw1));
766 	}
767 	cqr->data = NULL;
768 	if (datasize > 0) {
769 		cqr->data = data;
770  		memset(cqr->data, 0, datasize);
771 	}
772 	cqr->magic = magic;
773 	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
774 	dasd_get_device(device);
775 	return cqr;
776 }
777 
778 /*
779  * Free memory of a channel program. This function needs to free all the
780  * idal lists that might have been created by dasd_set_cda and the
781  * struct dasd_ccw_req itself.
782  */
783 void dasd_kfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
784 {
785 #ifdef CONFIG_64BIT
786 	struct ccw1 *ccw;
787 
788 	/* Clear any idals used for the request. */
789 	ccw = cqr->cpaddr;
790 	do {
791 		clear_normalized_cda(ccw);
792 	} while (ccw++->flags & (CCW_FLAG_CC | CCW_FLAG_DC));
793 #endif
794 	kfree(cqr->cpaddr);
795 	kfree(cqr->data);
796 	kfree(cqr);
797 	dasd_put_device(device);
798 }
799 
800 void dasd_sfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
801 {
802 	unsigned long flags;
803 
804 	spin_lock_irqsave(&device->mem_lock, flags);
805 	dasd_free_chunk(&device->ccw_chunks, cqr);
806 	spin_unlock_irqrestore(&device->mem_lock, flags);
807 	dasd_put_device(device);
808 }
809 
810 /*
811  * Check discipline magic in cqr.
812  */
813 static inline int dasd_check_cqr(struct dasd_ccw_req *cqr)
814 {
815 	struct dasd_device *device;
816 
817 	if (cqr == NULL)
818 		return -EINVAL;
819 	device = cqr->startdev;
820 	if (strncmp((char *) &cqr->magic, device->discipline->ebcname, 4)) {
821 		DBF_DEV_EVENT(DBF_WARNING, device,
822 			    " dasd_ccw_req 0x%08x magic doesn't match"
823 			    " discipline 0x%08x",
824 			    cqr->magic,
825 			    *(unsigned int *) device->discipline->name);
826 		return -EINVAL;
827 	}
828 	return 0;
829 }
830 
831 /*
832  * Terminate the current i/o and set the request to clear_pending.
833  * Timer keeps device runnig.
834  * ccw_device_clear can fail if the i/o subsystem
835  * is in a bad mood.
836  */
837 int dasd_term_IO(struct dasd_ccw_req *cqr)
838 {
839 	struct dasd_device *device;
840 	int retries, rc;
841 	char errorstring[ERRORLENGTH];
842 
843 	/* Check the cqr */
844 	rc = dasd_check_cqr(cqr);
845 	if (rc)
846 		return rc;
847 	retries = 0;
848 	device = (struct dasd_device *) cqr->startdev;
849 	while ((retries < 5) && (cqr->status == DASD_CQR_IN_IO)) {
850 		rc = ccw_device_clear(device->cdev, (long) cqr);
851 		switch (rc) {
852 		case 0:	/* termination successful */
853 			cqr->retries--;
854 			cqr->status = DASD_CQR_CLEAR_PENDING;
855 			cqr->stopclk = get_clock();
856 			cqr->starttime = 0;
857 			DBF_DEV_EVENT(DBF_DEBUG, device,
858 				      "terminate cqr %p successful",
859 				      cqr);
860 			break;
861 		case -ENODEV:
862 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
863 				      "device gone, retry");
864 			break;
865 		case -EIO:
866 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
867 				      "I/O error, retry");
868 			break;
869 		case -EINVAL:
870 		case -EBUSY:
871 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
872 				      "device busy, retry later");
873 			break;
874 		default:
875 			/* internal error 10 - unknown rc*/
876 			snprintf(errorstring, ERRORLENGTH, "10 %d", rc);
877 			dev_err(&device->cdev->dev, "An error occurred in the "
878 				"DASD device driver, reason=%s\n", errorstring);
879 			BUG();
880 			break;
881 		}
882 		retries++;
883 	}
884 	dasd_schedule_device_bh(device);
885 	return rc;
886 }
887 
888 /*
889  * Start the i/o. This start_IO can fail if the channel is really busy.
890  * In that case set up a timer to start the request later.
891  */
892 int dasd_start_IO(struct dasd_ccw_req *cqr)
893 {
894 	struct dasd_device *device;
895 	int rc;
896 	char errorstring[ERRORLENGTH];
897 
898 	/* Check the cqr */
899 	rc = dasd_check_cqr(cqr);
900 	if (rc) {
901 		cqr->intrc = rc;
902 		return rc;
903 	}
904 	device = (struct dasd_device *) cqr->startdev;
905 	if (cqr->retries < 0) {
906 		/* internal error 14 - start_IO run out of retries */
907 		sprintf(errorstring, "14 %p", cqr);
908 		dev_err(&device->cdev->dev, "An error occurred in the DASD "
909 			"device driver, reason=%s\n", errorstring);
910 		cqr->status = DASD_CQR_ERROR;
911 		return -EIO;
912 	}
913 	cqr->startclk = get_clock();
914 	cqr->starttime = jiffies;
915 	cqr->retries--;
916 	if (cqr->cpmode == 1) {
917 		rc = ccw_device_tm_start(device->cdev, cqr->cpaddr,
918 					 (long) cqr, cqr->lpm);
919 	} else {
920 		rc = ccw_device_start(device->cdev, cqr->cpaddr,
921 				      (long) cqr, cqr->lpm, 0);
922 	}
923 	switch (rc) {
924 	case 0:
925 		cqr->status = DASD_CQR_IN_IO;
926 		break;
927 	case -EBUSY:
928 		DBF_DEV_EVENT(DBF_DEBUG, device, "%s",
929 			      "start_IO: device busy, retry later");
930 		break;
931 	case -ETIMEDOUT:
932 		DBF_DEV_EVENT(DBF_DEBUG, device, "%s",
933 			      "start_IO: request timeout, retry later");
934 		break;
935 	case -EACCES:
936 		/* -EACCES indicates that the request used only a
937 		 * subset of the available pathes and all these
938 		 * pathes are gone.
939 		 * Do a retry with all available pathes.
940 		 */
941 		cqr->lpm = LPM_ANYPATH;
942 		DBF_DEV_EVENT(DBF_DEBUG, device, "%s",
943 			      "start_IO: selected pathes gone,"
944 			      " retry on all pathes");
945 		break;
946 	case -ENODEV:
947 		DBF_DEV_EVENT(DBF_DEBUG, device, "%s",
948 			      "start_IO: -ENODEV device gone, retry");
949 		break;
950 	case -EIO:
951 		DBF_DEV_EVENT(DBF_DEBUG, device, "%s",
952 			      "start_IO: -EIO device gone, retry");
953 		break;
954 	case -EINVAL:
955 		/* most likely caused in power management context */
956 		DBF_DEV_EVENT(DBF_DEBUG, device, "%s",
957 			      "start_IO: -EINVAL device currently "
958 			      "not accessible");
959 		break;
960 	default:
961 		/* internal error 11 - unknown rc */
962 		snprintf(errorstring, ERRORLENGTH, "11 %d", rc);
963 		dev_err(&device->cdev->dev,
964 			"An error occurred in the DASD device driver, "
965 			"reason=%s\n", errorstring);
966 		BUG();
967 		break;
968 	}
969 	cqr->intrc = rc;
970 	return rc;
971 }
972 
973 /*
974  * Timeout function for dasd devices. This is used for different purposes
975  *  1) missing interrupt handler for normal operation
976  *  2) delayed start of request where start_IO failed with -EBUSY
977  *  3) timeout for missing state change interrupts
978  * The head of the ccw queue will have status DASD_CQR_IN_IO for 1),
979  * DASD_CQR_QUEUED for 2) and 3).
980  */
981 static void dasd_device_timeout(unsigned long ptr)
982 {
983 	unsigned long flags;
984 	struct dasd_device *device;
985 
986 	device = (struct dasd_device *) ptr;
987 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
988 	/* re-activate request queue */
989 	dasd_device_remove_stop_bits(device, DASD_STOPPED_PENDING);
990 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
991 	dasd_schedule_device_bh(device);
992 }
993 
994 /*
995  * Setup timeout for a device in jiffies.
996  */
997 void dasd_device_set_timer(struct dasd_device *device, int expires)
998 {
999 	if (expires == 0)
1000 		del_timer(&device->timer);
1001 	else
1002 		mod_timer(&device->timer, jiffies + expires);
1003 }
1004 
1005 /*
1006  * Clear timeout for a device.
1007  */
1008 void dasd_device_clear_timer(struct dasd_device *device)
1009 {
1010 	del_timer(&device->timer);
1011 }
1012 
1013 static void dasd_handle_killed_request(struct ccw_device *cdev,
1014 				       unsigned long intparm)
1015 {
1016 	struct dasd_ccw_req *cqr;
1017 	struct dasd_device *device;
1018 
1019 	if (!intparm)
1020 		return;
1021 	cqr = (struct dasd_ccw_req *) intparm;
1022 	if (cqr->status != DASD_CQR_IN_IO) {
1023 		DBF_EVENT_DEVID(DBF_DEBUG, cdev,
1024 				"invalid status in handle_killed_request: "
1025 				"%02x", cqr->status);
1026 		return;
1027 	}
1028 
1029 	device = dasd_device_from_cdev_locked(cdev);
1030 	if (IS_ERR(device)) {
1031 		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
1032 				"unable to get device from cdev");
1033 		return;
1034 	}
1035 
1036 	if (!cqr->startdev ||
1037 	    device != cqr->startdev ||
1038 	    strncmp(cqr->startdev->discipline->ebcname,
1039 		    (char *) &cqr->magic, 4)) {
1040 		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
1041 				"invalid device in request");
1042 		dasd_put_device(device);
1043 		return;
1044 	}
1045 
1046 	/* Schedule request to be retried. */
1047 	cqr->status = DASD_CQR_QUEUED;
1048 
1049 	dasd_device_clear_timer(device);
1050 	dasd_schedule_device_bh(device);
1051 	dasd_put_device(device);
1052 }
1053 
1054 void dasd_generic_handle_state_change(struct dasd_device *device)
1055 {
1056 	/* First of all start sense subsystem status request. */
1057 	dasd_eer_snss(device);
1058 
1059 	dasd_device_remove_stop_bits(device, DASD_STOPPED_PENDING);
1060 	dasd_schedule_device_bh(device);
1061 	if (device->block)
1062 		dasd_schedule_block_bh(device->block);
1063 }
1064 
1065 /*
1066  * Interrupt handler for "normal" ssch-io based dasd devices.
1067  */
1068 void dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
1069 		      struct irb *irb)
1070 {
1071 	struct dasd_ccw_req *cqr, *next;
1072 	struct dasd_device *device;
1073 	unsigned long long now;
1074 	int expires;
1075 
1076 	kstat_cpu(smp_processor_id()).irqs[IOINT_DAS]++;
1077 	if (IS_ERR(irb)) {
1078 		switch (PTR_ERR(irb)) {
1079 		case -EIO:
1080 			break;
1081 		case -ETIMEDOUT:
1082 			DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
1083 					"request timed out\n", __func__);
1084 			break;
1085 		default:
1086 			DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
1087 					"unknown error %ld\n", __func__,
1088 					PTR_ERR(irb));
1089 		}
1090 		dasd_handle_killed_request(cdev, intparm);
1091 		return;
1092 	}
1093 
1094 	now = get_clock();
1095 
1096 	/* check for unsolicited interrupts */
1097 	cqr = (struct dasd_ccw_req *) intparm;
1098 	if (!cqr || ((scsw_cc(&irb->scsw) == 1) &&
1099 		     (scsw_fctl(&irb->scsw) & SCSW_FCTL_START_FUNC) &&
1100 		     ((scsw_stctl(&irb->scsw) == SCSW_STCTL_STATUS_PEND) ||
1101 		      (scsw_stctl(&irb->scsw) == (SCSW_STCTL_STATUS_PEND |
1102 						  SCSW_STCTL_ALERT_STATUS))))) {
1103 		if (cqr && cqr->status == DASD_CQR_IN_IO)
1104 			cqr->status = DASD_CQR_QUEUED;
1105 		if (cqr)
1106 			memcpy(&cqr->irb, irb, sizeof(*irb));
1107 		device = dasd_device_from_cdev_locked(cdev);
1108 		if (IS_ERR(device))
1109 			return;
1110 		/* ignore unsolicited interrupts for DIAG discipline */
1111 		if (device->discipline == dasd_diag_discipline_pointer) {
1112 			dasd_put_device(device);
1113 			return;
1114 		}
1115 		device->discipline->dump_sense_dbf(device, irb,
1116 						   "unsolicited");
1117 		if ((device->features & DASD_FEATURE_ERPLOG))
1118 			device->discipline->dump_sense(device, cqr,
1119 						       irb);
1120 		dasd_device_clear_timer(device);
1121 		device->discipline->handle_unsolicited_interrupt(device,
1122 								 irb);
1123 		dasd_put_device(device);
1124 		return;
1125 	}
1126 
1127 	device = (struct dasd_device *) cqr->startdev;
1128 	if (!device ||
1129 	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
1130 		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
1131 				"invalid device in request");
1132 		return;
1133 	}
1134 
1135 	/* Check for clear pending */
1136 	if (cqr->status == DASD_CQR_CLEAR_PENDING &&
1137 	    scsw_fctl(&irb->scsw) & SCSW_FCTL_CLEAR_FUNC) {
1138 		cqr->status = DASD_CQR_CLEARED;
1139 		dasd_device_clear_timer(device);
1140 		wake_up(&dasd_flush_wq);
1141 		dasd_schedule_device_bh(device);
1142 		return;
1143 	}
1144 
1145 	/* check status - the request might have been killed by dyn detach */
1146 	if (cqr->status != DASD_CQR_IN_IO) {
1147 		DBF_DEV_EVENT(DBF_DEBUG, device, "invalid status: bus_id %s, "
1148 			      "status %02x", dev_name(&cdev->dev), cqr->status);
1149 		return;
1150 	}
1151 
1152 	next = NULL;
1153 	expires = 0;
1154 	if (scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
1155 	    scsw_cstat(&irb->scsw) == 0) {
1156 		/* request was completed successfully */
1157 		cqr->status = DASD_CQR_SUCCESS;
1158 		cqr->stopclk = now;
1159 		/* Start first request on queue if possible -> fast_io. */
1160 		if (cqr->devlist.next != &device->ccw_queue) {
1161 			next = list_entry(cqr->devlist.next,
1162 					  struct dasd_ccw_req, devlist);
1163 		}
1164 	} else {  /* error */
1165 		memcpy(&cqr->irb, irb, sizeof(struct irb));
1166 		/* log sense for every failed I/O to s390 debugfeature */
1167 		dasd_log_sense_dbf(cqr, irb);
1168 		if (device->features & DASD_FEATURE_ERPLOG) {
1169 			dasd_log_sense(cqr, irb);
1170 		}
1171 
1172 		/*
1173 		 * If we don't want complex ERP for this request, then just
1174 		 * reset this and retry it in the fastpath
1175 		 */
1176 		if (!test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags) &&
1177 		    cqr->retries > 0) {
1178 			if (cqr->lpm == LPM_ANYPATH)
1179 				DBF_DEV_EVENT(DBF_DEBUG, device,
1180 					      "default ERP in fastpath "
1181 					      "(%i retries left)",
1182 					      cqr->retries);
1183 			cqr->lpm    = LPM_ANYPATH;
1184 			cqr->status = DASD_CQR_QUEUED;
1185 			next = cqr;
1186 		} else
1187 			cqr->status = DASD_CQR_ERROR;
1188 	}
1189 	if (next && (next->status == DASD_CQR_QUEUED) &&
1190 	    (!device->stopped)) {
1191 		if (device->discipline->start_IO(next) == 0)
1192 			expires = next->expires;
1193 	}
1194 	if (expires != 0)
1195 		dasd_device_set_timer(device, expires);
1196 	else
1197 		dasd_device_clear_timer(device);
1198 	dasd_schedule_device_bh(device);
1199 }
1200 
1201 enum uc_todo dasd_generic_uc_handler(struct ccw_device *cdev, struct irb *irb)
1202 {
1203 	struct dasd_device *device;
1204 
1205 	device = dasd_device_from_cdev_locked(cdev);
1206 
1207 	if (IS_ERR(device))
1208 		goto out;
1209 	if (test_bit(DASD_FLAG_OFFLINE, &device->flags) ||
1210 	   device->state != device->target ||
1211 	   !device->discipline->handle_unsolicited_interrupt){
1212 		dasd_put_device(device);
1213 		goto out;
1214 	}
1215 
1216 	dasd_device_clear_timer(device);
1217 	device->discipline->handle_unsolicited_interrupt(device, irb);
1218 	dasd_put_device(device);
1219 out:
1220 	return UC_TODO_RETRY;
1221 }
1222 EXPORT_SYMBOL_GPL(dasd_generic_uc_handler);
1223 
1224 /*
1225  * If we have an error on a dasd_block layer request then we cancel
1226  * and return all further requests from the same dasd_block as well.
1227  */
1228 static void __dasd_device_recovery(struct dasd_device *device,
1229 				   struct dasd_ccw_req *ref_cqr)
1230 {
1231 	struct list_head *l, *n;
1232 	struct dasd_ccw_req *cqr;
1233 
1234 	/*
1235 	 * only requeue request that came from the dasd_block layer
1236 	 */
1237 	if (!ref_cqr->block)
1238 		return;
1239 
1240 	list_for_each_safe(l, n, &device->ccw_queue) {
1241 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1242 		if (cqr->status == DASD_CQR_QUEUED &&
1243 		    ref_cqr->block == cqr->block) {
1244 			cqr->status = DASD_CQR_CLEARED;
1245 		}
1246 	}
1247 };
1248 
1249 /*
1250  * Remove those ccw requests from the queue that need to be returned
1251  * to the upper layer.
1252  */
1253 static void __dasd_device_process_ccw_queue(struct dasd_device *device,
1254 					    struct list_head *final_queue)
1255 {
1256 	struct list_head *l, *n;
1257 	struct dasd_ccw_req *cqr;
1258 
1259 	/* Process request with final status. */
1260 	list_for_each_safe(l, n, &device->ccw_queue) {
1261 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1262 
1263 		/* Stop list processing at the first non-final request. */
1264 		if (cqr->status == DASD_CQR_QUEUED ||
1265 		    cqr->status == DASD_CQR_IN_IO ||
1266 		    cqr->status == DASD_CQR_CLEAR_PENDING)
1267 			break;
1268 		if (cqr->status == DASD_CQR_ERROR) {
1269 			__dasd_device_recovery(device, cqr);
1270 		}
1271 		/* Rechain finished requests to final queue */
1272 		list_move_tail(&cqr->devlist, final_queue);
1273 	}
1274 }
1275 
1276 /*
1277  * the cqrs from the final queue are returned to the upper layer
1278  * by setting a dasd_block state and calling the callback function
1279  */
1280 static void __dasd_device_process_final_queue(struct dasd_device *device,
1281 					      struct list_head *final_queue)
1282 {
1283 	struct list_head *l, *n;
1284 	struct dasd_ccw_req *cqr;
1285 	struct dasd_block *block;
1286 	void (*callback)(struct dasd_ccw_req *, void *data);
1287 	void *callback_data;
1288 	char errorstring[ERRORLENGTH];
1289 
1290 	list_for_each_safe(l, n, final_queue) {
1291 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1292 		list_del_init(&cqr->devlist);
1293 		block = cqr->block;
1294 		callback = cqr->callback;
1295 		callback_data = cqr->callback_data;
1296 		if (block)
1297 			spin_lock_bh(&block->queue_lock);
1298 		switch (cqr->status) {
1299 		case DASD_CQR_SUCCESS:
1300 			cqr->status = DASD_CQR_DONE;
1301 			break;
1302 		case DASD_CQR_ERROR:
1303 			cqr->status = DASD_CQR_NEED_ERP;
1304 			break;
1305 		case DASD_CQR_CLEARED:
1306 			cqr->status = DASD_CQR_TERMINATED;
1307 			break;
1308 		default:
1309 			/* internal error 12 - wrong cqr status*/
1310 			snprintf(errorstring, ERRORLENGTH, "12 %p %x02", cqr, cqr->status);
1311 			dev_err(&device->cdev->dev,
1312 				"An error occurred in the DASD device driver, "
1313 				"reason=%s\n", errorstring);
1314 			BUG();
1315 		}
1316 		if (cqr->callback != NULL)
1317 			(callback)(cqr, callback_data);
1318 		if (block)
1319 			spin_unlock_bh(&block->queue_lock);
1320 	}
1321 }
1322 
1323 /*
1324  * Take a look at the first request on the ccw queue and check
1325  * if it reached its expire time. If so, terminate the IO.
1326  */
1327 static void __dasd_device_check_expire(struct dasd_device *device)
1328 {
1329 	struct dasd_ccw_req *cqr;
1330 
1331 	if (list_empty(&device->ccw_queue))
1332 		return;
1333 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1334 	if ((cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) &&
1335 	    (time_after_eq(jiffies, cqr->expires + cqr->starttime))) {
1336 		if (device->discipline->term_IO(cqr) != 0) {
1337 			/* Hmpf, try again in 5 sec */
1338 			dev_err(&device->cdev->dev,
1339 				"cqr %p timed out (%lus) but cannot be "
1340 				"ended, retrying in 5 s\n",
1341 				cqr, (cqr->expires/HZ));
1342 			cqr->expires += 5*HZ;
1343 			dasd_device_set_timer(device, 5*HZ);
1344 		} else {
1345 			dev_err(&device->cdev->dev,
1346 				"cqr %p timed out (%lus), %i retries "
1347 				"remaining\n", cqr, (cqr->expires/HZ),
1348 				cqr->retries);
1349 		}
1350 	}
1351 }
1352 
1353 /*
1354  * Take a look at the first request on the ccw queue and check
1355  * if it needs to be started.
1356  */
1357 static void __dasd_device_start_head(struct dasd_device *device)
1358 {
1359 	struct dasd_ccw_req *cqr;
1360 	int rc;
1361 
1362 	if (list_empty(&device->ccw_queue))
1363 		return;
1364 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1365 	if (cqr->status != DASD_CQR_QUEUED)
1366 		return;
1367 	/* when device is stopped, return request to previous layer */
1368 	if (device->stopped) {
1369 		cqr->status = DASD_CQR_CLEARED;
1370 		dasd_schedule_device_bh(device);
1371 		return;
1372 	}
1373 
1374 	rc = device->discipline->start_IO(cqr);
1375 	if (rc == 0)
1376 		dasd_device_set_timer(device, cqr->expires);
1377 	else if (rc == -EACCES) {
1378 		dasd_schedule_device_bh(device);
1379 	} else
1380 		/* Hmpf, try again in 1/2 sec */
1381 		dasd_device_set_timer(device, 50);
1382 }
1383 
1384 /*
1385  * Go through all request on the dasd_device request queue,
1386  * terminate them on the cdev if necessary, and return them to the
1387  * submitting layer via callback.
1388  * Note:
1389  * Make sure that all 'submitting layers' still exist when
1390  * this function is called!. In other words, when 'device' is a base
1391  * device then all block layer requests must have been removed before
1392  * via dasd_flush_block_queue.
1393  */
1394 int dasd_flush_device_queue(struct dasd_device *device)
1395 {
1396 	struct dasd_ccw_req *cqr, *n;
1397 	int rc;
1398 	struct list_head flush_queue;
1399 
1400 	INIT_LIST_HEAD(&flush_queue);
1401 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1402 	rc = 0;
1403 	list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
1404 		/* Check status and move request to flush_queue */
1405 		switch (cqr->status) {
1406 		case DASD_CQR_IN_IO:
1407 			rc = device->discipline->term_IO(cqr);
1408 			if (rc) {
1409 				/* unable to terminate requeust */
1410 				dev_err(&device->cdev->dev,
1411 					"Flushing the DASD request queue "
1412 					"failed for request %p\n", cqr);
1413 				/* stop flush processing */
1414 				goto finished;
1415 			}
1416 			break;
1417 		case DASD_CQR_QUEUED:
1418 			cqr->stopclk = get_clock();
1419 			cqr->status = DASD_CQR_CLEARED;
1420 			break;
1421 		default: /* no need to modify the others */
1422 			break;
1423 		}
1424 		list_move_tail(&cqr->devlist, &flush_queue);
1425 	}
1426 finished:
1427 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1428 	/*
1429 	 * After this point all requests must be in state CLEAR_PENDING,
1430 	 * CLEARED, SUCCESS or ERROR. Now wait for CLEAR_PENDING to become
1431 	 * one of the others.
1432 	 */
1433 	list_for_each_entry_safe(cqr, n, &flush_queue, devlist)
1434 		wait_event(dasd_flush_wq,
1435 			   (cqr->status != DASD_CQR_CLEAR_PENDING));
1436 	/*
1437 	 * Now set each request back to TERMINATED, DONE or NEED_ERP
1438 	 * and call the callback function of flushed requests
1439 	 */
1440 	__dasd_device_process_final_queue(device, &flush_queue);
1441 	return rc;
1442 }
1443 
1444 /*
1445  * Acquire the device lock and process queues for the device.
1446  */
1447 static void dasd_device_tasklet(struct dasd_device *device)
1448 {
1449 	struct list_head final_queue;
1450 
1451 	atomic_set (&device->tasklet_scheduled, 0);
1452 	INIT_LIST_HEAD(&final_queue);
1453 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1454 	/* Check expire time of first request on the ccw queue. */
1455 	__dasd_device_check_expire(device);
1456 	/* find final requests on ccw queue */
1457 	__dasd_device_process_ccw_queue(device, &final_queue);
1458 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1459 	/* Now call the callback function of requests with final status */
1460 	__dasd_device_process_final_queue(device, &final_queue);
1461 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1462 	/* Now check if the head of the ccw queue needs to be started. */
1463 	__dasd_device_start_head(device);
1464 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1465 	dasd_put_device(device);
1466 }
1467 
1468 /*
1469  * Schedules a call to dasd_tasklet over the device tasklet.
1470  */
1471 void dasd_schedule_device_bh(struct dasd_device *device)
1472 {
1473 	/* Protect against rescheduling. */
1474 	if (atomic_cmpxchg (&device->tasklet_scheduled, 0, 1) != 0)
1475 		return;
1476 	dasd_get_device(device);
1477 	tasklet_hi_schedule(&device->tasklet);
1478 }
1479 
1480 void dasd_device_set_stop_bits(struct dasd_device *device, int bits)
1481 {
1482 	device->stopped |= bits;
1483 }
1484 EXPORT_SYMBOL_GPL(dasd_device_set_stop_bits);
1485 
1486 void dasd_device_remove_stop_bits(struct dasd_device *device, int bits)
1487 {
1488 	device->stopped &= ~bits;
1489 	if (!device->stopped)
1490 		wake_up(&generic_waitq);
1491 }
1492 EXPORT_SYMBOL_GPL(dasd_device_remove_stop_bits);
1493 
1494 /*
1495  * Queue a request to the head of the device ccw_queue.
1496  * Start the I/O if possible.
1497  */
1498 void dasd_add_request_head(struct dasd_ccw_req *cqr)
1499 {
1500 	struct dasd_device *device;
1501 	unsigned long flags;
1502 
1503 	device = cqr->startdev;
1504 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
1505 	cqr->status = DASD_CQR_QUEUED;
1506 	list_add(&cqr->devlist, &device->ccw_queue);
1507 	/* let the bh start the request to keep them in order */
1508 	dasd_schedule_device_bh(device);
1509 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
1510 }
1511 
1512 /*
1513  * Queue a request to the tail of the device ccw_queue.
1514  * Start the I/O if possible.
1515  */
1516 void dasd_add_request_tail(struct dasd_ccw_req *cqr)
1517 {
1518 	struct dasd_device *device;
1519 	unsigned long flags;
1520 
1521 	device = cqr->startdev;
1522 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
1523 	cqr->status = DASD_CQR_QUEUED;
1524 	list_add_tail(&cqr->devlist, &device->ccw_queue);
1525 	/* let the bh start the request to keep them in order */
1526 	dasd_schedule_device_bh(device);
1527 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
1528 }
1529 
1530 /*
1531  * Wakeup helper for the 'sleep_on' functions.
1532  */
1533 static void dasd_wakeup_cb(struct dasd_ccw_req *cqr, void *data)
1534 {
1535 	spin_lock_irq(get_ccwdev_lock(cqr->startdev->cdev));
1536 	cqr->callback_data = DASD_SLEEPON_END_TAG;
1537 	spin_unlock_irq(get_ccwdev_lock(cqr->startdev->cdev));
1538 	wake_up(&generic_waitq);
1539 }
1540 
1541 static inline int _wait_for_wakeup(struct dasd_ccw_req *cqr)
1542 {
1543 	struct dasd_device *device;
1544 	int rc;
1545 
1546 	device = cqr->startdev;
1547 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1548 	rc = (cqr->callback_data == DASD_SLEEPON_END_TAG);
1549 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1550 	return rc;
1551 }
1552 
1553 /*
1554  * checks if error recovery is necessary, returns 1 if yes, 0 otherwise.
1555  */
1556 static int __dasd_sleep_on_erp(struct dasd_ccw_req *cqr)
1557 {
1558 	struct dasd_device *device;
1559 	dasd_erp_fn_t erp_fn;
1560 
1561 	if (cqr->status == DASD_CQR_FILLED)
1562 		return 0;
1563 	device = cqr->startdev;
1564 	if (test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) {
1565 		if (cqr->status == DASD_CQR_TERMINATED) {
1566 			device->discipline->handle_terminated_request(cqr);
1567 			return 1;
1568 		}
1569 		if (cqr->status == DASD_CQR_NEED_ERP) {
1570 			erp_fn = device->discipline->erp_action(cqr);
1571 			erp_fn(cqr);
1572 			return 1;
1573 		}
1574 		if (cqr->status == DASD_CQR_FAILED)
1575 			dasd_log_sense(cqr, &cqr->irb);
1576 		if (cqr->refers) {
1577 			__dasd_process_erp(device, cqr);
1578 			return 1;
1579 		}
1580 	}
1581 	return 0;
1582 }
1583 
1584 static int __dasd_sleep_on_loop_condition(struct dasd_ccw_req *cqr)
1585 {
1586 	if (test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) {
1587 		if (cqr->refers) /* erp is not done yet */
1588 			return 1;
1589 		return ((cqr->status != DASD_CQR_DONE) &&
1590 			(cqr->status != DASD_CQR_FAILED));
1591 	} else
1592 		return (cqr->status == DASD_CQR_FILLED);
1593 }
1594 
1595 static int _dasd_sleep_on(struct dasd_ccw_req *maincqr, int interruptible)
1596 {
1597 	struct dasd_device *device;
1598 	int rc;
1599 	struct list_head ccw_queue;
1600 	struct dasd_ccw_req *cqr;
1601 
1602 	INIT_LIST_HEAD(&ccw_queue);
1603 	maincqr->status = DASD_CQR_FILLED;
1604 	device = maincqr->startdev;
1605 	list_add(&maincqr->blocklist, &ccw_queue);
1606 	for (cqr = maincqr;  __dasd_sleep_on_loop_condition(cqr);
1607 	     cqr = list_first_entry(&ccw_queue,
1608 				    struct dasd_ccw_req, blocklist)) {
1609 
1610 		if (__dasd_sleep_on_erp(cqr))
1611 			continue;
1612 		if (cqr->status != DASD_CQR_FILLED) /* could be failed */
1613 			continue;
1614 
1615 		/* Non-temporary stop condition will trigger fail fast */
1616 		if (device->stopped & ~DASD_STOPPED_PENDING &&
1617 		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
1618 		    (!dasd_eer_enabled(device))) {
1619 			cqr->status = DASD_CQR_FAILED;
1620 			continue;
1621 		}
1622 
1623 		/* Don't try to start requests if device is stopped */
1624 		if (interruptible) {
1625 			rc = wait_event_interruptible(
1626 				generic_waitq, !(device->stopped));
1627 			if (rc == -ERESTARTSYS) {
1628 				cqr->status = DASD_CQR_FAILED;
1629 				maincqr->intrc = rc;
1630 				continue;
1631 			}
1632 		} else
1633 			wait_event(generic_waitq, !(device->stopped));
1634 
1635 		cqr->callback = dasd_wakeup_cb;
1636 		cqr->callback_data = DASD_SLEEPON_START_TAG;
1637 		dasd_add_request_tail(cqr);
1638 		if (interruptible) {
1639 			rc = wait_event_interruptible(
1640 				generic_waitq, _wait_for_wakeup(cqr));
1641 			if (rc == -ERESTARTSYS) {
1642 				dasd_cancel_req(cqr);
1643 				/* wait (non-interruptible) for final status */
1644 				wait_event(generic_waitq,
1645 					   _wait_for_wakeup(cqr));
1646 				cqr->status = DASD_CQR_FAILED;
1647 				maincqr->intrc = rc;
1648 				continue;
1649 			}
1650 		} else
1651 			wait_event(generic_waitq, _wait_for_wakeup(cqr));
1652 	}
1653 
1654 	maincqr->endclk = get_clock();
1655 	if ((maincqr->status != DASD_CQR_DONE) &&
1656 	    (maincqr->intrc != -ERESTARTSYS))
1657 		dasd_log_sense(maincqr, &maincqr->irb);
1658 	if (maincqr->status == DASD_CQR_DONE)
1659 		rc = 0;
1660 	else if (maincqr->intrc)
1661 		rc = maincqr->intrc;
1662 	else
1663 		rc = -EIO;
1664 	return rc;
1665 }
1666 
1667 /*
1668  * Queue a request to the tail of the device ccw_queue and wait for
1669  * it's completion.
1670  */
1671 int dasd_sleep_on(struct dasd_ccw_req *cqr)
1672 {
1673 	return _dasd_sleep_on(cqr, 0);
1674 }
1675 
1676 /*
1677  * Queue a request to the tail of the device ccw_queue and wait
1678  * interruptible for it's completion.
1679  */
1680 int dasd_sleep_on_interruptible(struct dasd_ccw_req *cqr)
1681 {
1682 	return _dasd_sleep_on(cqr, 1);
1683 }
1684 
1685 /*
1686  * Whoa nelly now it gets really hairy. For some functions (e.g. steal lock
1687  * for eckd devices) the currently running request has to be terminated
1688  * and be put back to status queued, before the special request is added
1689  * to the head of the queue. Then the special request is waited on normally.
1690  */
1691 static inline int _dasd_term_running_cqr(struct dasd_device *device)
1692 {
1693 	struct dasd_ccw_req *cqr;
1694 
1695 	if (list_empty(&device->ccw_queue))
1696 		return 0;
1697 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1698 	return device->discipline->term_IO(cqr);
1699 }
1700 
1701 int dasd_sleep_on_immediatly(struct dasd_ccw_req *cqr)
1702 {
1703 	struct dasd_device *device;
1704 	int rc;
1705 
1706 	device = cqr->startdev;
1707 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1708 	rc = _dasd_term_running_cqr(device);
1709 	if (rc) {
1710 		spin_unlock_irq(get_ccwdev_lock(device->cdev));
1711 		return rc;
1712 	}
1713 
1714 	cqr->callback = dasd_wakeup_cb;
1715 	cqr->callback_data = DASD_SLEEPON_START_TAG;
1716 	cqr->status = DASD_CQR_QUEUED;
1717 	list_add(&cqr->devlist, &device->ccw_queue);
1718 
1719 	/* let the bh start the request to keep them in order */
1720 	dasd_schedule_device_bh(device);
1721 
1722 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1723 
1724 	wait_event(generic_waitq, _wait_for_wakeup(cqr));
1725 
1726 	if (cqr->status == DASD_CQR_DONE)
1727 		rc = 0;
1728 	else if (cqr->intrc)
1729 		rc = cqr->intrc;
1730 	else
1731 		rc = -EIO;
1732 	return rc;
1733 }
1734 
1735 /*
1736  * Cancels a request that was started with dasd_sleep_on_req.
1737  * This is useful to timeout requests. The request will be
1738  * terminated if it is currently in i/o.
1739  * Returns 1 if the request has been terminated.
1740  *	   0 if there was no need to terminate the request (not started yet)
1741  *	   negative error code if termination failed
1742  * Cancellation of a request is an asynchronous operation! The calling
1743  * function has to wait until the request is properly returned via callback.
1744  */
1745 int dasd_cancel_req(struct dasd_ccw_req *cqr)
1746 {
1747 	struct dasd_device *device = cqr->startdev;
1748 	unsigned long flags;
1749 	int rc;
1750 
1751 	rc = 0;
1752 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
1753 	switch (cqr->status) {
1754 	case DASD_CQR_QUEUED:
1755 		/* request was not started - just set to cleared */
1756 		cqr->status = DASD_CQR_CLEARED;
1757 		break;
1758 	case DASD_CQR_IN_IO:
1759 		/* request in IO - terminate IO and release again */
1760 		rc = device->discipline->term_IO(cqr);
1761 		if (rc) {
1762 			dev_err(&device->cdev->dev,
1763 				"Cancelling request %p failed with rc=%d\n",
1764 				cqr, rc);
1765 		} else {
1766 			cqr->stopclk = get_clock();
1767 		}
1768 		break;
1769 	default: /* already finished or clear pending - do nothing */
1770 		break;
1771 	}
1772 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
1773 	dasd_schedule_device_bh(device);
1774 	return rc;
1775 }
1776 
1777 
1778 /*
1779  * SECTION: Operations of the dasd_block layer.
1780  */
1781 
1782 /*
1783  * Timeout function for dasd_block. This is used when the block layer
1784  * is waiting for something that may not come reliably, (e.g. a state
1785  * change interrupt)
1786  */
1787 static void dasd_block_timeout(unsigned long ptr)
1788 {
1789 	unsigned long flags;
1790 	struct dasd_block *block;
1791 
1792 	block = (struct dasd_block *) ptr;
1793 	spin_lock_irqsave(get_ccwdev_lock(block->base->cdev), flags);
1794 	/* re-activate request queue */
1795 	dasd_device_remove_stop_bits(block->base, DASD_STOPPED_PENDING);
1796 	spin_unlock_irqrestore(get_ccwdev_lock(block->base->cdev), flags);
1797 	dasd_schedule_block_bh(block);
1798 }
1799 
1800 /*
1801  * Setup timeout for a dasd_block in jiffies.
1802  */
1803 void dasd_block_set_timer(struct dasd_block *block, int expires)
1804 {
1805 	if (expires == 0)
1806 		del_timer(&block->timer);
1807 	else
1808 		mod_timer(&block->timer, jiffies + expires);
1809 }
1810 
1811 /*
1812  * Clear timeout for a dasd_block.
1813  */
1814 void dasd_block_clear_timer(struct dasd_block *block)
1815 {
1816 	del_timer(&block->timer);
1817 }
1818 
1819 /*
1820  * Process finished error recovery ccw.
1821  */
1822 static void __dasd_process_erp(struct dasd_device *device,
1823 			       struct dasd_ccw_req *cqr)
1824 {
1825 	dasd_erp_fn_t erp_fn;
1826 
1827 	if (cqr->status == DASD_CQR_DONE)
1828 		DBF_DEV_EVENT(DBF_NOTICE, device, "%s", "ERP successful");
1829 	else
1830 		dev_err(&device->cdev->dev, "ERP failed for the DASD\n");
1831 	erp_fn = device->discipline->erp_postaction(cqr);
1832 	erp_fn(cqr);
1833 }
1834 
1835 /*
1836  * Fetch requests from the block device queue.
1837  */
1838 static void __dasd_process_request_queue(struct dasd_block *block)
1839 {
1840 	struct request_queue *queue;
1841 	struct request *req;
1842 	struct dasd_ccw_req *cqr;
1843 	struct dasd_device *basedev;
1844 	unsigned long flags;
1845 	queue = block->request_queue;
1846 	basedev = block->base;
1847 	/* No queue ? Then there is nothing to do. */
1848 	if (queue == NULL)
1849 		return;
1850 
1851 	/*
1852 	 * We requeue request from the block device queue to the ccw
1853 	 * queue only in two states. In state DASD_STATE_READY the
1854 	 * partition detection is done and we need to requeue requests
1855 	 * for that. State DASD_STATE_ONLINE is normal block device
1856 	 * operation.
1857 	 */
1858 	if (basedev->state < DASD_STATE_READY) {
1859 		while ((req = blk_fetch_request(block->request_queue)))
1860 			__blk_end_request_all(req, -EIO);
1861 		return;
1862 	}
1863 	/* Now we try to fetch requests from the request queue */
1864 	while (!blk_queue_plugged(queue) && (req = blk_peek_request(queue))) {
1865 		if (basedev->features & DASD_FEATURE_READONLY &&
1866 		    rq_data_dir(req) == WRITE) {
1867 			DBF_DEV_EVENT(DBF_ERR, basedev,
1868 				      "Rejecting write request %p",
1869 				      req);
1870 			blk_start_request(req);
1871 			__blk_end_request_all(req, -EIO);
1872 			continue;
1873 		}
1874 		cqr = basedev->discipline->build_cp(basedev, block, req);
1875 		if (IS_ERR(cqr)) {
1876 			if (PTR_ERR(cqr) == -EBUSY)
1877 				break;	/* normal end condition */
1878 			if (PTR_ERR(cqr) == -ENOMEM)
1879 				break;	/* terminate request queue loop */
1880 			if (PTR_ERR(cqr) == -EAGAIN) {
1881 				/*
1882 				 * The current request cannot be build right
1883 				 * now, we have to try later. If this request
1884 				 * is the head-of-queue we stop the device
1885 				 * for 1/2 second.
1886 				 */
1887 				if (!list_empty(&block->ccw_queue))
1888 					break;
1889 				spin_lock_irqsave(
1890 					get_ccwdev_lock(basedev->cdev), flags);
1891 				dasd_device_set_stop_bits(basedev,
1892 							  DASD_STOPPED_PENDING);
1893 				spin_unlock_irqrestore(
1894 					get_ccwdev_lock(basedev->cdev), flags);
1895 				dasd_block_set_timer(block, HZ/2);
1896 				break;
1897 			}
1898 			DBF_DEV_EVENT(DBF_ERR, basedev,
1899 				      "CCW creation failed (rc=%ld) "
1900 				      "on request %p",
1901 				      PTR_ERR(cqr), req);
1902 			blk_start_request(req);
1903 			__blk_end_request_all(req, -EIO);
1904 			continue;
1905 		}
1906 		/*
1907 		 *  Note: callback is set to dasd_return_cqr_cb in
1908 		 * __dasd_block_start_head to cover erp requests as well
1909 		 */
1910 		cqr->callback_data = (void *) req;
1911 		cqr->status = DASD_CQR_FILLED;
1912 		blk_start_request(req);
1913 		list_add_tail(&cqr->blocklist, &block->ccw_queue);
1914 		dasd_profile_start(block, cqr, req);
1915 	}
1916 }
1917 
1918 static void __dasd_cleanup_cqr(struct dasd_ccw_req *cqr)
1919 {
1920 	struct request *req;
1921 	int status;
1922 	int error = 0;
1923 
1924 	req = (struct request *) cqr->callback_data;
1925 	dasd_profile_end(cqr->block, cqr, req);
1926 	status = cqr->block->base->discipline->free_cp(cqr, req);
1927 	if (status <= 0)
1928 		error = status ? status : -EIO;
1929 	__blk_end_request_all(req, error);
1930 }
1931 
1932 /*
1933  * Process ccw request queue.
1934  */
1935 static void __dasd_process_block_ccw_queue(struct dasd_block *block,
1936 					   struct list_head *final_queue)
1937 {
1938 	struct list_head *l, *n;
1939 	struct dasd_ccw_req *cqr;
1940 	dasd_erp_fn_t erp_fn;
1941 	unsigned long flags;
1942 	struct dasd_device *base = block->base;
1943 
1944 restart:
1945 	/* Process request with final status. */
1946 	list_for_each_safe(l, n, &block->ccw_queue) {
1947 		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
1948 		if (cqr->status != DASD_CQR_DONE &&
1949 		    cqr->status != DASD_CQR_FAILED &&
1950 		    cqr->status != DASD_CQR_NEED_ERP &&
1951 		    cqr->status != DASD_CQR_TERMINATED)
1952 			continue;
1953 
1954 		if (cqr->status == DASD_CQR_TERMINATED) {
1955 			base->discipline->handle_terminated_request(cqr);
1956 			goto restart;
1957 		}
1958 
1959 		/*  Process requests that may be recovered */
1960 		if (cqr->status == DASD_CQR_NEED_ERP) {
1961 			erp_fn = base->discipline->erp_action(cqr);
1962 			if (IS_ERR(erp_fn(cqr)))
1963 				continue;
1964 			goto restart;
1965 		}
1966 
1967 		/* log sense for fatal error */
1968 		if (cqr->status == DASD_CQR_FAILED) {
1969 			dasd_log_sense(cqr, &cqr->irb);
1970 		}
1971 
1972 		/* First of all call extended error reporting. */
1973 		if (dasd_eer_enabled(base) &&
1974 		    cqr->status == DASD_CQR_FAILED) {
1975 			dasd_eer_write(base, cqr, DASD_EER_FATALERROR);
1976 
1977 			/* restart request  */
1978 			cqr->status = DASD_CQR_FILLED;
1979 			cqr->retries = 255;
1980 			spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
1981 			dasd_device_set_stop_bits(base, DASD_STOPPED_QUIESCE);
1982 			spin_unlock_irqrestore(get_ccwdev_lock(base->cdev),
1983 					       flags);
1984 			goto restart;
1985 		}
1986 
1987 		/* Process finished ERP request. */
1988 		if (cqr->refers) {
1989 			__dasd_process_erp(base, cqr);
1990 			goto restart;
1991 		}
1992 
1993 		/* Rechain finished requests to final queue */
1994 		cqr->endclk = get_clock();
1995 		list_move_tail(&cqr->blocklist, final_queue);
1996 	}
1997 }
1998 
1999 static void dasd_return_cqr_cb(struct dasd_ccw_req *cqr, void *data)
2000 {
2001 	dasd_schedule_block_bh(cqr->block);
2002 }
2003 
2004 static void __dasd_block_start_head(struct dasd_block *block)
2005 {
2006 	struct dasd_ccw_req *cqr;
2007 
2008 	if (list_empty(&block->ccw_queue))
2009 		return;
2010 	/* We allways begin with the first requests on the queue, as some
2011 	 * of previously started requests have to be enqueued on a
2012 	 * dasd_device again for error recovery.
2013 	 */
2014 	list_for_each_entry(cqr, &block->ccw_queue, blocklist) {
2015 		if (cqr->status != DASD_CQR_FILLED)
2016 			continue;
2017 		/* Non-temporary stop condition will trigger fail fast */
2018 		if (block->base->stopped & ~DASD_STOPPED_PENDING &&
2019 		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
2020 		    (!dasd_eer_enabled(block->base))) {
2021 			cqr->status = DASD_CQR_FAILED;
2022 			dasd_schedule_block_bh(block);
2023 			continue;
2024 		}
2025 		/* Don't try to start requests if device is stopped */
2026 		if (block->base->stopped)
2027 			return;
2028 
2029 		/* just a fail safe check, should not happen */
2030 		if (!cqr->startdev)
2031 			cqr->startdev = block->base;
2032 
2033 		/* make sure that the requests we submit find their way back */
2034 		cqr->callback = dasd_return_cqr_cb;
2035 
2036 		dasd_add_request_tail(cqr);
2037 	}
2038 }
2039 
2040 /*
2041  * Central dasd_block layer routine. Takes requests from the generic
2042  * block layer request queue, creates ccw requests, enqueues them on
2043  * a dasd_device and processes ccw requests that have been returned.
2044  */
2045 static void dasd_block_tasklet(struct dasd_block *block)
2046 {
2047 	struct list_head final_queue;
2048 	struct list_head *l, *n;
2049 	struct dasd_ccw_req *cqr;
2050 
2051 	atomic_set(&block->tasklet_scheduled, 0);
2052 	INIT_LIST_HEAD(&final_queue);
2053 	spin_lock(&block->queue_lock);
2054 	/* Finish off requests on ccw queue */
2055 	__dasd_process_block_ccw_queue(block, &final_queue);
2056 	spin_unlock(&block->queue_lock);
2057 	/* Now call the callback function of requests with final status */
2058 	spin_lock_irq(&block->request_queue_lock);
2059 	list_for_each_safe(l, n, &final_queue) {
2060 		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
2061 		list_del_init(&cqr->blocklist);
2062 		__dasd_cleanup_cqr(cqr);
2063 	}
2064 	spin_lock(&block->queue_lock);
2065 	/* Get new request from the block device request queue */
2066 	__dasd_process_request_queue(block);
2067 	/* Now check if the head of the ccw queue needs to be started. */
2068 	__dasd_block_start_head(block);
2069 	spin_unlock(&block->queue_lock);
2070 	spin_unlock_irq(&block->request_queue_lock);
2071 	dasd_put_device(block->base);
2072 }
2073 
2074 static void _dasd_wake_block_flush_cb(struct dasd_ccw_req *cqr, void *data)
2075 {
2076 	wake_up(&dasd_flush_wq);
2077 }
2078 
2079 /*
2080  * Go through all request on the dasd_block request queue, cancel them
2081  * on the respective dasd_device, and return them to the generic
2082  * block layer.
2083  */
2084 static int dasd_flush_block_queue(struct dasd_block *block)
2085 {
2086 	struct dasd_ccw_req *cqr, *n;
2087 	int rc, i;
2088 	struct list_head flush_queue;
2089 
2090 	INIT_LIST_HEAD(&flush_queue);
2091 	spin_lock_bh(&block->queue_lock);
2092 	rc = 0;
2093 restart:
2094 	list_for_each_entry_safe(cqr, n, &block->ccw_queue, blocklist) {
2095 		/* if this request currently owned by a dasd_device cancel it */
2096 		if (cqr->status >= DASD_CQR_QUEUED)
2097 			rc = dasd_cancel_req(cqr);
2098 		if (rc < 0)
2099 			break;
2100 		/* Rechain request (including erp chain) so it won't be
2101 		 * touched by the dasd_block_tasklet anymore.
2102 		 * Replace the callback so we notice when the request
2103 		 * is returned from the dasd_device layer.
2104 		 */
2105 		cqr->callback = _dasd_wake_block_flush_cb;
2106 		for (i = 0; cqr != NULL; cqr = cqr->refers, i++)
2107 			list_move_tail(&cqr->blocklist, &flush_queue);
2108 		if (i > 1)
2109 			/* moved more than one request - need to restart */
2110 			goto restart;
2111 	}
2112 	spin_unlock_bh(&block->queue_lock);
2113 	/* Now call the callback function of flushed requests */
2114 restart_cb:
2115 	list_for_each_entry_safe(cqr, n, &flush_queue, blocklist) {
2116 		wait_event(dasd_flush_wq, (cqr->status < DASD_CQR_QUEUED));
2117 		/* Process finished ERP request. */
2118 		if (cqr->refers) {
2119 			spin_lock_bh(&block->queue_lock);
2120 			__dasd_process_erp(block->base, cqr);
2121 			spin_unlock_bh(&block->queue_lock);
2122 			/* restart list_for_xx loop since dasd_process_erp
2123 			 * might remove multiple elements */
2124 			goto restart_cb;
2125 		}
2126 		/* call the callback function */
2127 		spin_lock_irq(&block->request_queue_lock);
2128 		cqr->endclk = get_clock();
2129 		list_del_init(&cqr->blocklist);
2130 		__dasd_cleanup_cqr(cqr);
2131 		spin_unlock_irq(&block->request_queue_lock);
2132 	}
2133 	return rc;
2134 }
2135 
2136 /*
2137  * Schedules a call to dasd_tasklet over the device tasklet.
2138  */
2139 void dasd_schedule_block_bh(struct dasd_block *block)
2140 {
2141 	/* Protect against rescheduling. */
2142 	if (atomic_cmpxchg(&block->tasklet_scheduled, 0, 1) != 0)
2143 		return;
2144 	/* life cycle of block is bound to it's base device */
2145 	dasd_get_device(block->base);
2146 	tasklet_hi_schedule(&block->tasklet);
2147 }
2148 
2149 
2150 /*
2151  * SECTION: external block device operations
2152  * (request queue handling, open, release, etc.)
2153  */
2154 
2155 /*
2156  * Dasd request queue function. Called from ll_rw_blk.c
2157  */
2158 static void do_dasd_request(struct request_queue *queue)
2159 {
2160 	struct dasd_block *block;
2161 
2162 	block = queue->queuedata;
2163 	spin_lock(&block->queue_lock);
2164 	/* Get new request from the block device request queue */
2165 	__dasd_process_request_queue(block);
2166 	/* Now check if the head of the ccw queue needs to be started. */
2167 	__dasd_block_start_head(block);
2168 	spin_unlock(&block->queue_lock);
2169 }
2170 
2171 /*
2172  * Allocate and initialize request queue and default I/O scheduler.
2173  */
2174 static int dasd_alloc_queue(struct dasd_block *block)
2175 {
2176 	int rc;
2177 
2178 	block->request_queue = blk_init_queue(do_dasd_request,
2179 					       &block->request_queue_lock);
2180 	if (block->request_queue == NULL)
2181 		return -ENOMEM;
2182 
2183 	block->request_queue->queuedata = block;
2184 
2185 	elevator_exit(block->request_queue->elevator);
2186 	block->request_queue->elevator = NULL;
2187 	rc = elevator_init(block->request_queue, "deadline");
2188 	if (rc) {
2189 		blk_cleanup_queue(block->request_queue);
2190 		return rc;
2191 	}
2192 	return 0;
2193 }
2194 
2195 /*
2196  * Allocate and initialize request queue.
2197  */
2198 static void dasd_setup_queue(struct dasd_block *block)
2199 {
2200 	int max;
2201 
2202 	blk_queue_logical_block_size(block->request_queue, block->bp_block);
2203 	max = block->base->discipline->max_blocks << block->s2b_shift;
2204 	blk_queue_max_hw_sectors(block->request_queue, max);
2205 	blk_queue_max_segments(block->request_queue, -1L);
2206 	/* with page sized segments we can translate each segement into
2207 	 * one idaw/tidaw
2208 	 */
2209 	blk_queue_max_segment_size(block->request_queue, PAGE_SIZE);
2210 	blk_queue_segment_boundary(block->request_queue, PAGE_SIZE - 1);
2211 }
2212 
2213 /*
2214  * Deactivate and free request queue.
2215  */
2216 static void dasd_free_queue(struct dasd_block *block)
2217 {
2218 	if (block->request_queue) {
2219 		blk_cleanup_queue(block->request_queue);
2220 		block->request_queue = NULL;
2221 	}
2222 }
2223 
2224 /*
2225  * Flush request on the request queue.
2226  */
2227 static void dasd_flush_request_queue(struct dasd_block *block)
2228 {
2229 	struct request *req;
2230 
2231 	if (!block->request_queue)
2232 		return;
2233 
2234 	spin_lock_irq(&block->request_queue_lock);
2235 	while ((req = blk_fetch_request(block->request_queue)))
2236 		__blk_end_request_all(req, -EIO);
2237 	spin_unlock_irq(&block->request_queue_lock);
2238 }
2239 
2240 static int dasd_open(struct block_device *bdev, fmode_t mode)
2241 {
2242 	struct dasd_block *block = bdev->bd_disk->private_data;
2243 	struct dasd_device *base;
2244 	int rc;
2245 
2246 	if (!block)
2247 		return -ENODEV;
2248 
2249 	base = block->base;
2250 	atomic_inc(&block->open_count);
2251 	if (test_bit(DASD_FLAG_OFFLINE, &base->flags)) {
2252 		rc = -ENODEV;
2253 		goto unlock;
2254 	}
2255 
2256 	if (!try_module_get(base->discipline->owner)) {
2257 		rc = -EINVAL;
2258 		goto unlock;
2259 	}
2260 
2261 	if (dasd_probeonly) {
2262 		dev_info(&base->cdev->dev,
2263 			 "Accessing the DASD failed because it is in "
2264 			 "probeonly mode\n");
2265 		rc = -EPERM;
2266 		goto out;
2267 	}
2268 
2269 	if (base->state <= DASD_STATE_BASIC) {
2270 		DBF_DEV_EVENT(DBF_ERR, base, " %s",
2271 			      " Cannot open unrecognized device");
2272 		rc = -ENODEV;
2273 		goto out;
2274 	}
2275 
2276 	if ((mode & FMODE_WRITE) &&
2277 	    (test_bit(DASD_FLAG_DEVICE_RO, &base->flags) ||
2278 	     (base->features & DASD_FEATURE_READONLY))) {
2279 		rc = -EROFS;
2280 		goto out;
2281 	}
2282 
2283 	return 0;
2284 
2285 out:
2286 	module_put(base->discipline->owner);
2287 unlock:
2288 	atomic_dec(&block->open_count);
2289 	return rc;
2290 }
2291 
2292 static int dasd_release(struct gendisk *disk, fmode_t mode)
2293 {
2294 	struct dasd_block *block = disk->private_data;
2295 
2296 	atomic_dec(&block->open_count);
2297 	module_put(block->base->discipline->owner);
2298 	return 0;
2299 }
2300 
2301 /*
2302  * Return disk geometry.
2303  */
2304 static int dasd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
2305 {
2306 	struct dasd_block *block;
2307 	struct dasd_device *base;
2308 
2309 	block = bdev->bd_disk->private_data;
2310 	if (!block)
2311 		return -ENODEV;
2312 	base = block->base;
2313 
2314 	if (!base->discipline ||
2315 	    !base->discipline->fill_geometry)
2316 		return -EINVAL;
2317 
2318 	base->discipline->fill_geometry(block, geo);
2319 	geo->start = get_start_sect(bdev) >> block->s2b_shift;
2320 	return 0;
2321 }
2322 
2323 const struct block_device_operations
2324 dasd_device_operations = {
2325 	.owner		= THIS_MODULE,
2326 	.open		= dasd_open,
2327 	.release	= dasd_release,
2328 	.ioctl		= dasd_ioctl,
2329 	.compat_ioctl	= dasd_ioctl,
2330 	.getgeo		= dasd_getgeo,
2331 };
2332 
2333 /*******************************************************************************
2334  * end of block device operations
2335  */
2336 
2337 static void
2338 dasd_exit(void)
2339 {
2340 #ifdef CONFIG_PROC_FS
2341 	dasd_proc_exit();
2342 #endif
2343 	dasd_eer_exit();
2344         if (dasd_page_cache != NULL) {
2345 		kmem_cache_destroy(dasd_page_cache);
2346 		dasd_page_cache = NULL;
2347 	}
2348 	dasd_gendisk_exit();
2349 	dasd_devmap_exit();
2350 	if (dasd_debug_area != NULL) {
2351 		debug_unregister(dasd_debug_area);
2352 		dasd_debug_area = NULL;
2353 	}
2354 }
2355 
2356 /*
2357  * SECTION: common functions for ccw_driver use
2358  */
2359 
2360 /*
2361  * Is the device read-only?
2362  * Note that this function does not report the setting of the
2363  * readonly device attribute, but how it is configured in z/VM.
2364  */
2365 int dasd_device_is_ro(struct dasd_device *device)
2366 {
2367 	struct ccw_dev_id dev_id;
2368 	struct diag210 diag_data;
2369 	int rc;
2370 
2371 	if (!MACHINE_IS_VM)
2372 		return 0;
2373 	ccw_device_get_id(device->cdev, &dev_id);
2374 	memset(&diag_data, 0, sizeof(diag_data));
2375 	diag_data.vrdcdvno = dev_id.devno;
2376 	diag_data.vrdclen = sizeof(diag_data);
2377 	rc = diag210(&diag_data);
2378 	if (rc == 0 || rc == 2) {
2379 		return diag_data.vrdcvfla & 0x80;
2380 	} else {
2381 		DBF_EVENT(DBF_WARNING, "diag210 failed for dev=%04x with rc=%d",
2382 			  dev_id.devno, rc);
2383 		return 0;
2384 	}
2385 }
2386 EXPORT_SYMBOL_GPL(dasd_device_is_ro);
2387 
2388 static void dasd_generic_auto_online(void *data, async_cookie_t cookie)
2389 {
2390 	struct ccw_device *cdev = data;
2391 	int ret;
2392 
2393 	ret = ccw_device_set_online(cdev);
2394 	if (ret)
2395 		pr_warning("%s: Setting the DASD online failed with rc=%d\n",
2396 			   dev_name(&cdev->dev), ret);
2397 }
2398 
2399 /*
2400  * Initial attempt at a probe function. this can be simplified once
2401  * the other detection code is gone.
2402  */
2403 int dasd_generic_probe(struct ccw_device *cdev,
2404 		       struct dasd_discipline *discipline)
2405 {
2406 	int ret;
2407 
2408 	ret = dasd_add_sysfs_files(cdev);
2409 	if (ret) {
2410 		DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s",
2411 				"dasd_generic_probe: could not add "
2412 				"sysfs entries");
2413 		return ret;
2414 	}
2415 	cdev->handler = &dasd_int_handler;
2416 
2417 	/*
2418 	 * Automatically online either all dasd devices (dasd_autodetect)
2419 	 * or all devices specified with dasd= parameters during
2420 	 * initial probe.
2421 	 */
2422 	if ((dasd_get_feature(cdev, DASD_FEATURE_INITIAL_ONLINE) > 0 ) ||
2423 	    (dasd_autodetect && dasd_busid_known(dev_name(&cdev->dev)) != 0))
2424 		async_schedule(dasd_generic_auto_online, cdev);
2425 	return 0;
2426 }
2427 
2428 /*
2429  * This will one day be called from a global not_oper handler.
2430  * It is also used by driver_unregister during module unload.
2431  */
2432 void dasd_generic_remove(struct ccw_device *cdev)
2433 {
2434 	struct dasd_device *device;
2435 	struct dasd_block *block;
2436 
2437 	cdev->handler = NULL;
2438 
2439 	dasd_remove_sysfs_files(cdev);
2440 	device = dasd_device_from_cdev(cdev);
2441 	if (IS_ERR(device))
2442 		return;
2443 	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
2444 		/* Already doing offline processing */
2445 		dasd_put_device(device);
2446 		return;
2447 	}
2448 	/*
2449 	 * This device is removed unconditionally. Set offline
2450 	 * flag to prevent dasd_open from opening it while it is
2451 	 * no quite down yet.
2452 	 */
2453 	dasd_set_target_state(device, DASD_STATE_NEW);
2454 	/* dasd_delete_device destroys the device reference. */
2455 	block = device->block;
2456 	device->block = NULL;
2457 	dasd_delete_device(device);
2458 	/*
2459 	 * life cycle of block is bound to device, so delete it after
2460 	 * device was safely removed
2461 	 */
2462 	if (block)
2463 		dasd_free_block(block);
2464 }
2465 
2466 /*
2467  * Activate a device. This is called from dasd_{eckd,fba}_probe() when either
2468  * the device is detected for the first time and is supposed to be used
2469  * or the user has started activation through sysfs.
2470  */
2471 int dasd_generic_set_online(struct ccw_device *cdev,
2472 			    struct dasd_discipline *base_discipline)
2473 {
2474 	struct dasd_discipline *discipline;
2475 	struct dasd_device *device;
2476 	int rc;
2477 
2478 	/* first online clears initial online feature flag */
2479 	dasd_set_feature(cdev, DASD_FEATURE_INITIAL_ONLINE, 0);
2480 	device = dasd_create_device(cdev);
2481 	if (IS_ERR(device))
2482 		return PTR_ERR(device);
2483 
2484 	discipline = base_discipline;
2485 	if (device->features & DASD_FEATURE_USEDIAG) {
2486 	  	if (!dasd_diag_discipline_pointer) {
2487 			pr_warning("%s Setting the DASD online failed because "
2488 				   "of missing DIAG discipline\n",
2489 				   dev_name(&cdev->dev));
2490 			dasd_delete_device(device);
2491 			return -ENODEV;
2492 		}
2493 		discipline = dasd_diag_discipline_pointer;
2494 	}
2495 	if (!try_module_get(base_discipline->owner)) {
2496 		dasd_delete_device(device);
2497 		return -EINVAL;
2498 	}
2499 	if (!try_module_get(discipline->owner)) {
2500 		module_put(base_discipline->owner);
2501 		dasd_delete_device(device);
2502 		return -EINVAL;
2503 	}
2504 	device->base_discipline = base_discipline;
2505 	device->discipline = discipline;
2506 
2507 	/* check_device will allocate block device if necessary */
2508 	rc = discipline->check_device(device);
2509 	if (rc) {
2510 		pr_warning("%s Setting the DASD online with discipline %s "
2511 			   "failed with rc=%i\n",
2512 			   dev_name(&cdev->dev), discipline->name, rc);
2513 		module_put(discipline->owner);
2514 		module_put(base_discipline->owner);
2515 		dasd_delete_device(device);
2516 		return rc;
2517 	}
2518 
2519 	dasd_set_target_state(device, DASD_STATE_ONLINE);
2520 	if (device->state <= DASD_STATE_KNOWN) {
2521 		pr_warning("%s Setting the DASD online failed because of a "
2522 			   "missing discipline\n", dev_name(&cdev->dev));
2523 		rc = -ENODEV;
2524 		dasd_set_target_state(device, DASD_STATE_NEW);
2525 		if (device->block)
2526 			dasd_free_block(device->block);
2527 		dasd_delete_device(device);
2528 	} else
2529 		pr_debug("dasd_generic device %s found\n",
2530 				dev_name(&cdev->dev));
2531 
2532 	wait_event(dasd_init_waitq, _wait_for_device(device));
2533 
2534 	dasd_put_device(device);
2535 	return rc;
2536 }
2537 
2538 int dasd_generic_set_offline(struct ccw_device *cdev)
2539 {
2540 	struct dasd_device *device;
2541 	struct dasd_block *block;
2542 	int max_count, open_count;
2543 
2544 	device = dasd_device_from_cdev(cdev);
2545 	if (IS_ERR(device))
2546 		return PTR_ERR(device);
2547 	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
2548 		/* Already doing offline processing */
2549 		dasd_put_device(device);
2550 		return 0;
2551 	}
2552 	/*
2553 	 * We must make sure that this device is currently not in use.
2554 	 * The open_count is increased for every opener, that includes
2555 	 * the blkdev_get in dasd_scan_partitions. We are only interested
2556 	 * in the other openers.
2557 	 */
2558 	if (device->block) {
2559 		max_count = device->block->bdev ? 0 : -1;
2560 		open_count = atomic_read(&device->block->open_count);
2561 		if (open_count > max_count) {
2562 			if (open_count > 0)
2563 				pr_warning("%s: The DASD cannot be set offline "
2564 					   "with open count %i\n",
2565 					   dev_name(&cdev->dev), open_count);
2566 			else
2567 				pr_warning("%s: The DASD cannot be set offline "
2568 					   "while it is in use\n",
2569 					   dev_name(&cdev->dev));
2570 			clear_bit(DASD_FLAG_OFFLINE, &device->flags);
2571 			dasd_put_device(device);
2572 			return -EBUSY;
2573 		}
2574 	}
2575 	dasd_set_target_state(device, DASD_STATE_NEW);
2576 	/* dasd_delete_device destroys the device reference. */
2577 	block = device->block;
2578 	device->block = NULL;
2579 	dasd_delete_device(device);
2580 	/*
2581 	 * life cycle of block is bound to device, so delete it after
2582 	 * device was safely removed
2583 	 */
2584 	if (block)
2585 		dasd_free_block(block);
2586 	return 0;
2587 }
2588 
2589 int dasd_generic_notify(struct ccw_device *cdev, int event)
2590 {
2591 	struct dasd_device *device;
2592 	struct dasd_ccw_req *cqr;
2593 	int ret;
2594 
2595 	device = dasd_device_from_cdev_locked(cdev);
2596 	if (IS_ERR(device))
2597 		return 0;
2598 	ret = 0;
2599 	switch (event) {
2600 	case CIO_GONE:
2601 	case CIO_BOXED:
2602 	case CIO_NO_PATH:
2603 		/* First of all call extended error reporting. */
2604 		dasd_eer_write(device, NULL, DASD_EER_NOPATH);
2605 
2606 		if (device->state < DASD_STATE_BASIC)
2607 			break;
2608 		/* Device is active. We want to keep it. */
2609 		list_for_each_entry(cqr, &device->ccw_queue, devlist)
2610 			if (cqr->status == DASD_CQR_IN_IO) {
2611 				cqr->status = DASD_CQR_QUEUED;
2612 				cqr->retries++;
2613 			}
2614 		dasd_device_set_stop_bits(device, DASD_STOPPED_DC_WAIT);
2615 		dasd_device_clear_timer(device);
2616 		dasd_schedule_device_bh(device);
2617 		ret = 1;
2618 		break;
2619 	case CIO_OPER:
2620 		/* FIXME: add a sanity check. */
2621 		dasd_device_remove_stop_bits(device, DASD_STOPPED_DC_WAIT);
2622 		if (device->stopped & DASD_UNRESUMED_PM) {
2623 			dasd_device_remove_stop_bits(device, DASD_UNRESUMED_PM);
2624 			dasd_restore_device(device);
2625 			ret = 1;
2626 			break;
2627 		}
2628 		dasd_schedule_device_bh(device);
2629 		if (device->block)
2630 			dasd_schedule_block_bh(device->block);
2631 		ret = 1;
2632 		break;
2633 	}
2634 	dasd_put_device(device);
2635 	return ret;
2636 }
2637 
2638 int dasd_generic_pm_freeze(struct ccw_device *cdev)
2639 {
2640 	struct dasd_ccw_req *cqr, *n;
2641 	int rc;
2642 	struct list_head freeze_queue;
2643 	struct dasd_device *device = dasd_device_from_cdev(cdev);
2644 
2645 	if (IS_ERR(device))
2646 		return PTR_ERR(device);
2647 	/* disallow new I/O  */
2648 	dasd_device_set_stop_bits(device, DASD_STOPPED_PM);
2649 	/* clear active requests */
2650 	INIT_LIST_HEAD(&freeze_queue);
2651 	spin_lock_irq(get_ccwdev_lock(cdev));
2652 	rc = 0;
2653 	list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
2654 		/* Check status and move request to flush_queue */
2655 		if (cqr->status == DASD_CQR_IN_IO) {
2656 			rc = device->discipline->term_IO(cqr);
2657 			if (rc) {
2658 				/* unable to terminate requeust */
2659 				dev_err(&device->cdev->dev,
2660 					"Unable to terminate request %p "
2661 					"on suspend\n", cqr);
2662 				spin_unlock_irq(get_ccwdev_lock(cdev));
2663 				dasd_put_device(device);
2664 				return rc;
2665 			}
2666 		}
2667 		list_move_tail(&cqr->devlist, &freeze_queue);
2668 	}
2669 
2670 	spin_unlock_irq(get_ccwdev_lock(cdev));
2671 
2672 	list_for_each_entry_safe(cqr, n, &freeze_queue, devlist) {
2673 		wait_event(dasd_flush_wq,
2674 			   (cqr->status != DASD_CQR_CLEAR_PENDING));
2675 		if (cqr->status == DASD_CQR_CLEARED)
2676 			cqr->status = DASD_CQR_QUEUED;
2677 	}
2678 	/* move freeze_queue to start of the ccw_queue */
2679 	spin_lock_irq(get_ccwdev_lock(cdev));
2680 	list_splice_tail(&freeze_queue, &device->ccw_queue);
2681 	spin_unlock_irq(get_ccwdev_lock(cdev));
2682 
2683 	if (device->discipline->freeze)
2684 		rc = device->discipline->freeze(device);
2685 
2686 	dasd_put_device(device);
2687 	return rc;
2688 }
2689 EXPORT_SYMBOL_GPL(dasd_generic_pm_freeze);
2690 
2691 int dasd_generic_restore_device(struct ccw_device *cdev)
2692 {
2693 	struct dasd_device *device = dasd_device_from_cdev(cdev);
2694 	int rc = 0;
2695 
2696 	if (IS_ERR(device))
2697 		return PTR_ERR(device);
2698 
2699 	/* allow new IO again */
2700 	dasd_device_remove_stop_bits(device,
2701 				     (DASD_STOPPED_PM | DASD_UNRESUMED_PM));
2702 
2703 	dasd_schedule_device_bh(device);
2704 
2705 	/*
2706 	 * call discipline restore function
2707 	 * if device is stopped do nothing e.g. for disconnected devices
2708 	 */
2709 	if (device->discipline->restore && !(device->stopped))
2710 		rc = device->discipline->restore(device);
2711 	if (rc || device->stopped)
2712 		/*
2713 		 * if the resume failed for the DASD we put it in
2714 		 * an UNRESUMED stop state
2715 		 */
2716 		device->stopped |= DASD_UNRESUMED_PM;
2717 
2718 	if (device->block)
2719 		dasd_schedule_block_bh(device->block);
2720 
2721 	dasd_put_device(device);
2722 	return 0;
2723 }
2724 EXPORT_SYMBOL_GPL(dasd_generic_restore_device);
2725 
2726 static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
2727 						   void *rdc_buffer,
2728 						   int rdc_buffer_size,
2729 						   int magic)
2730 {
2731 	struct dasd_ccw_req *cqr;
2732 	struct ccw1 *ccw;
2733 	unsigned long *idaw;
2734 
2735 	cqr = dasd_smalloc_request(magic, 1 /* RDC */, rdc_buffer_size, device);
2736 
2737 	if (IS_ERR(cqr)) {
2738 		/* internal error 13 - Allocating the RDC request failed*/
2739 		dev_err(&device->cdev->dev,
2740 			 "An error occurred in the DASD device driver, "
2741 			 "reason=%s\n", "13");
2742 		return cqr;
2743 	}
2744 
2745 	ccw = cqr->cpaddr;
2746 	ccw->cmd_code = CCW_CMD_RDC;
2747 	if (idal_is_needed(rdc_buffer, rdc_buffer_size)) {
2748 		idaw = (unsigned long *) (cqr->data);
2749 		ccw->cda = (__u32)(addr_t) idaw;
2750 		ccw->flags = CCW_FLAG_IDA;
2751 		idaw = idal_create_words(idaw, rdc_buffer, rdc_buffer_size);
2752 	} else {
2753 		ccw->cda = (__u32)(addr_t) rdc_buffer;
2754 		ccw->flags = 0;
2755 	}
2756 
2757 	ccw->count = rdc_buffer_size;
2758 	cqr->startdev = device;
2759 	cqr->memdev = device;
2760 	cqr->expires = 10*HZ;
2761 	cqr->retries = 256;
2762 	cqr->buildclk = get_clock();
2763 	cqr->status = DASD_CQR_FILLED;
2764 	return cqr;
2765 }
2766 
2767 
2768 int dasd_generic_read_dev_chars(struct dasd_device *device, int magic,
2769 				void *rdc_buffer, int rdc_buffer_size)
2770 {
2771 	int ret;
2772 	struct dasd_ccw_req *cqr;
2773 
2774 	cqr = dasd_generic_build_rdc(device, rdc_buffer, rdc_buffer_size,
2775 				     magic);
2776 	if (IS_ERR(cqr))
2777 		return PTR_ERR(cqr);
2778 
2779 	ret = dasd_sleep_on(cqr);
2780 	dasd_sfree_request(cqr, cqr->memdev);
2781 	return ret;
2782 }
2783 EXPORT_SYMBOL_GPL(dasd_generic_read_dev_chars);
2784 
2785 /*
2786  *   In command mode and transport mode we need to look for sense
2787  *   data in different places. The sense data itself is allways
2788  *   an array of 32 bytes, so we can unify the sense data access
2789  *   for both modes.
2790  */
2791 char *dasd_get_sense(struct irb *irb)
2792 {
2793 	struct tsb *tsb = NULL;
2794 	char *sense = NULL;
2795 
2796 	if (scsw_is_tm(&irb->scsw) && (irb->scsw.tm.fcxs == 0x01)) {
2797 		if (irb->scsw.tm.tcw)
2798 			tsb = tcw_get_tsb((struct tcw *)(unsigned long)
2799 					  irb->scsw.tm.tcw);
2800 		if (tsb && tsb->length == 64 && tsb->flags)
2801 			switch (tsb->flags & 0x07) {
2802 			case 1:	/* tsa_iostat */
2803 				sense = tsb->tsa.iostat.sense;
2804 				break;
2805 			case 2: /* tsa_ddpc */
2806 				sense = tsb->tsa.ddpc.sense;
2807 				break;
2808 			default:
2809 				/* currently we don't use interrogate data */
2810 				break;
2811 			}
2812 	} else if (irb->esw.esw0.erw.cons) {
2813 		sense = irb->ecw;
2814 	}
2815 	return sense;
2816 }
2817 EXPORT_SYMBOL_GPL(dasd_get_sense);
2818 
2819 static int __init dasd_init(void)
2820 {
2821 	int rc;
2822 
2823 	init_waitqueue_head(&dasd_init_waitq);
2824 	init_waitqueue_head(&dasd_flush_wq);
2825 	init_waitqueue_head(&generic_waitq);
2826 
2827 	/* register 'common' DASD debug area, used for all DBF_XXX calls */
2828 	dasd_debug_area = debug_register("dasd", 1, 1, 8 * sizeof(long));
2829 	if (dasd_debug_area == NULL) {
2830 		rc = -ENOMEM;
2831 		goto failed;
2832 	}
2833 	debug_register_view(dasd_debug_area, &debug_sprintf_view);
2834 	debug_set_level(dasd_debug_area, DBF_WARNING);
2835 
2836 	DBF_EVENT(DBF_EMERG, "%s", "debug area created");
2837 
2838 	dasd_diag_discipline_pointer = NULL;
2839 
2840 	rc = dasd_devmap_init();
2841 	if (rc)
2842 		goto failed;
2843 	rc = dasd_gendisk_init();
2844 	if (rc)
2845 		goto failed;
2846 	rc = dasd_parse();
2847 	if (rc)
2848 		goto failed;
2849 	rc = dasd_eer_init();
2850 	if (rc)
2851 		goto failed;
2852 #ifdef CONFIG_PROC_FS
2853 	rc = dasd_proc_init();
2854 	if (rc)
2855 		goto failed;
2856 #endif
2857 
2858 	return 0;
2859 failed:
2860 	pr_info("The DASD device driver could not be initialized\n");
2861 	dasd_exit();
2862 	return rc;
2863 }
2864 
2865 module_init(dasd_init);
2866 module_exit(dasd_exit);
2867 
2868 EXPORT_SYMBOL(dasd_debug_area);
2869 EXPORT_SYMBOL(dasd_diag_discipline_pointer);
2870 
2871 EXPORT_SYMBOL(dasd_add_request_head);
2872 EXPORT_SYMBOL(dasd_add_request_tail);
2873 EXPORT_SYMBOL(dasd_cancel_req);
2874 EXPORT_SYMBOL(dasd_device_clear_timer);
2875 EXPORT_SYMBOL(dasd_block_clear_timer);
2876 EXPORT_SYMBOL(dasd_enable_device);
2877 EXPORT_SYMBOL(dasd_int_handler);
2878 EXPORT_SYMBOL(dasd_kfree_request);
2879 EXPORT_SYMBOL(dasd_kick_device);
2880 EXPORT_SYMBOL(dasd_kmalloc_request);
2881 EXPORT_SYMBOL(dasd_schedule_device_bh);
2882 EXPORT_SYMBOL(dasd_schedule_block_bh);
2883 EXPORT_SYMBOL(dasd_set_target_state);
2884 EXPORT_SYMBOL(dasd_device_set_timer);
2885 EXPORT_SYMBOL(dasd_block_set_timer);
2886 EXPORT_SYMBOL(dasd_sfree_request);
2887 EXPORT_SYMBOL(dasd_sleep_on);
2888 EXPORT_SYMBOL(dasd_sleep_on_immediatly);
2889 EXPORT_SYMBOL(dasd_sleep_on_interruptible);
2890 EXPORT_SYMBOL(dasd_smalloc_request);
2891 EXPORT_SYMBOL(dasd_start_IO);
2892 EXPORT_SYMBOL(dasd_term_IO);
2893 
2894 EXPORT_SYMBOL_GPL(dasd_generic_probe);
2895 EXPORT_SYMBOL_GPL(dasd_generic_remove);
2896 EXPORT_SYMBOL_GPL(dasd_generic_notify);
2897 EXPORT_SYMBOL_GPL(dasd_generic_set_online);
2898 EXPORT_SYMBOL_GPL(dasd_generic_set_offline);
2899 EXPORT_SYMBOL_GPL(dasd_generic_handle_state_change);
2900 EXPORT_SYMBOL_GPL(dasd_flush_device_queue);
2901 EXPORT_SYMBOL_GPL(dasd_alloc_block);
2902 EXPORT_SYMBOL_GPL(dasd_free_block);
2903