xref: /openbmc/linux/drivers/s390/block/dasd.c (revision 1eb4c977)
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/kmod.h>
15 #include <linux/init.h>
16 #include <linux/interrupt.h>
17 #include <linux/ctype.h>
18 #include <linux/major.h>
19 #include <linux/slab.h>
20 #include <linux/hdreg.h>
21 #include <linux/async.h>
22 #include <linux/mutex.h>
23 #include <linux/debugfs.h>
24 #include <linux/seq_file.h>
25 #include <linux/vmalloc.h>
26 
27 #include <asm/ccwdev.h>
28 #include <asm/ebcdic.h>
29 #include <asm/idals.h>
30 #include <asm/itcw.h>
31 #include <asm/diag.h>
32 
33 /* This is ugly... */
34 #define PRINTK_HEADER "dasd:"
35 
36 #include "dasd_int.h"
37 /*
38  * SECTION: Constant definitions to be used within this file
39  */
40 #define DASD_CHANQ_MAX_SIZE 4
41 
42 #define DASD_SLEEPON_START_TAG	(void *) 1
43 #define DASD_SLEEPON_END_TAG	(void *) 2
44 
45 /*
46  * SECTION: exported variables of dasd.c
47  */
48 debug_info_t *dasd_debug_area;
49 static struct dentry *dasd_debugfs_root_entry;
50 struct dasd_discipline *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 2000 IBM Corporation");
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 
86 /*
87  * Allocate memory for a new device structure.
88  */
89 struct dasd_device *dasd_alloc_device(void)
90 {
91 	struct dasd_device *device;
92 
93 	device = kzalloc(sizeof(struct dasd_device), GFP_ATOMIC);
94 	if (!device)
95 		return ERR_PTR(-ENOMEM);
96 
97 	/* Get two pages for normal block device operations. */
98 	device->ccw_mem = (void *) __get_free_pages(GFP_ATOMIC | GFP_DMA, 1);
99 	if (!device->ccw_mem) {
100 		kfree(device);
101 		return ERR_PTR(-ENOMEM);
102 	}
103 	/* Get one page for error recovery. */
104 	device->erp_mem = (void *) get_zeroed_page(GFP_ATOMIC | GFP_DMA);
105 	if (!device->erp_mem) {
106 		free_pages((unsigned long) device->ccw_mem, 1);
107 		kfree(device);
108 		return ERR_PTR(-ENOMEM);
109 	}
110 
111 	dasd_init_chunklist(&device->ccw_chunks, device->ccw_mem, PAGE_SIZE*2);
112 	dasd_init_chunklist(&device->erp_chunks, device->erp_mem, PAGE_SIZE);
113 	spin_lock_init(&device->mem_lock);
114 	atomic_set(&device->tasklet_scheduled, 0);
115 	tasklet_init(&device->tasklet,
116 		     (void (*)(unsigned long)) dasd_device_tasklet,
117 		     (unsigned long) device);
118 	INIT_LIST_HEAD(&device->ccw_queue);
119 	init_timer(&device->timer);
120 	device->timer.function = dasd_device_timeout;
121 	device->timer.data = (unsigned long) device;
122 	INIT_WORK(&device->kick_work, do_kick_device);
123 	INIT_WORK(&device->restore_device, do_restore_device);
124 	INIT_WORK(&device->reload_device, do_reload_device);
125 	device->state = DASD_STATE_NEW;
126 	device->target = DASD_STATE_NEW;
127 	mutex_init(&device->state_mutex);
128 	spin_lock_init(&device->profile.lock);
129 	return device;
130 }
131 
132 /*
133  * Free memory of a device structure.
134  */
135 void dasd_free_device(struct dasd_device *device)
136 {
137 	kfree(device->private);
138 	free_page((unsigned long) device->erp_mem);
139 	free_pages((unsigned long) device->ccw_mem, 1);
140 	kfree(device);
141 }
142 
143 /*
144  * Allocate memory for a new device structure.
145  */
146 struct dasd_block *dasd_alloc_block(void)
147 {
148 	struct dasd_block *block;
149 
150 	block = kzalloc(sizeof(*block), GFP_ATOMIC);
151 	if (!block)
152 		return ERR_PTR(-ENOMEM);
153 	/* open_count = 0 means device online but not in use */
154 	atomic_set(&block->open_count, -1);
155 
156 	spin_lock_init(&block->request_queue_lock);
157 	atomic_set(&block->tasklet_scheduled, 0);
158 	tasklet_init(&block->tasklet,
159 		     (void (*)(unsigned long)) dasd_block_tasklet,
160 		     (unsigned long) block);
161 	INIT_LIST_HEAD(&block->ccw_queue);
162 	spin_lock_init(&block->queue_lock);
163 	init_timer(&block->timer);
164 	block->timer.function = dasd_block_timeout;
165 	block->timer.data = (unsigned long) block;
166 	spin_lock_init(&block->profile.lock);
167 
168 	return block;
169 }
170 
171 /*
172  * Free memory of a device structure.
173  */
174 void dasd_free_block(struct dasd_block *block)
175 {
176 	kfree(block);
177 }
178 
179 /*
180  * Make a new device known to the system.
181  */
182 static int dasd_state_new_to_known(struct dasd_device *device)
183 {
184 	int rc;
185 
186 	/*
187 	 * As long as the device is not in state DASD_STATE_NEW we want to
188 	 * keep the reference count > 0.
189 	 */
190 	dasd_get_device(device);
191 
192 	if (device->block) {
193 		rc = dasd_alloc_queue(device->block);
194 		if (rc) {
195 			dasd_put_device(device);
196 			return rc;
197 		}
198 	}
199 	device->state = DASD_STATE_KNOWN;
200 	return 0;
201 }
202 
203 /*
204  * Let the system forget about a device.
205  */
206 static int dasd_state_known_to_new(struct dasd_device *device)
207 {
208 	/* Disable extended error reporting for this device. */
209 	dasd_eer_disable(device);
210 	/* Forget the discipline information. */
211 	if (device->discipline) {
212 		if (device->discipline->uncheck_device)
213 			device->discipline->uncheck_device(device);
214 		module_put(device->discipline->owner);
215 	}
216 	device->discipline = NULL;
217 	if (device->base_discipline)
218 		module_put(device->base_discipline->owner);
219 	device->base_discipline = NULL;
220 	device->state = DASD_STATE_NEW;
221 
222 	if (device->block)
223 		dasd_free_queue(device->block);
224 
225 	/* Give up reference we took in dasd_state_new_to_known. */
226 	dasd_put_device(device);
227 	return 0;
228 }
229 
230 static struct dentry *dasd_debugfs_setup(const char *name,
231 					 struct dentry *base_dentry)
232 {
233 	struct dentry *pde;
234 
235 	if (!base_dentry)
236 		return NULL;
237 	pde = debugfs_create_dir(name, base_dentry);
238 	if (!pde || IS_ERR(pde))
239 		return NULL;
240 	return pde;
241 }
242 
243 /*
244  * Request the irq line for the device.
245  */
246 static int dasd_state_known_to_basic(struct dasd_device *device)
247 {
248 	struct dasd_block *block = device->block;
249 	int rc;
250 
251 	/* Allocate and register gendisk structure. */
252 	if (block) {
253 		rc = dasd_gendisk_alloc(block);
254 		if (rc)
255 			return rc;
256 		block->debugfs_dentry =
257 			dasd_debugfs_setup(block->gdp->disk_name,
258 					   dasd_debugfs_root_entry);
259 		dasd_profile_init(&block->profile, block->debugfs_dentry);
260 		if (dasd_global_profile_level == DASD_PROFILE_ON)
261 			dasd_profile_on(&device->block->profile);
262 	}
263 	device->debugfs_dentry =
264 		dasd_debugfs_setup(dev_name(&device->cdev->dev),
265 				   dasd_debugfs_root_entry);
266 	dasd_profile_init(&device->profile, device->debugfs_dentry);
267 
268 	/* register 'device' debug area, used for all DBF_DEV_XXX calls */
269 	device->debug_area = debug_register(dev_name(&device->cdev->dev), 4, 1,
270 					    8 * sizeof(long));
271 	debug_register_view(device->debug_area, &debug_sprintf_view);
272 	debug_set_level(device->debug_area, DBF_WARNING);
273 	DBF_DEV_EVENT(DBF_EMERG, device, "%s", "debug area created");
274 
275 	device->state = DASD_STATE_BASIC;
276 	return 0;
277 }
278 
279 /*
280  * Release the irq line for the device. Terminate any running i/o.
281  */
282 static int dasd_state_basic_to_known(struct dasd_device *device)
283 {
284 	int rc;
285 	if (device->block) {
286 		dasd_profile_exit(&device->block->profile);
287 		if (device->block->debugfs_dentry)
288 			debugfs_remove(device->block->debugfs_dentry);
289 		dasd_gendisk_free(device->block);
290 		dasd_block_clear_timer(device->block);
291 	}
292 	rc = dasd_flush_device_queue(device);
293 	if (rc)
294 		return rc;
295 	dasd_device_clear_timer(device);
296 	dasd_profile_exit(&device->profile);
297 	if (device->debugfs_dentry)
298 		debugfs_remove(device->debugfs_dentry);
299 
300 	DBF_DEV_EVENT(DBF_EMERG, device, "%p debug area deleted", device);
301 	if (device->debug_area != NULL) {
302 		debug_unregister(device->debug_area);
303 		device->debug_area = NULL;
304 	}
305 	device->state = DASD_STATE_KNOWN;
306 	return 0;
307 }
308 
309 /*
310  * Do the initial analysis. The do_analysis function may return
311  * -EAGAIN in which case the device keeps the state DASD_STATE_BASIC
312  * until the discipline decides to continue the startup sequence
313  * by calling the function dasd_change_state. The eckd disciplines
314  * uses this to start a ccw that detects the format. The completion
315  * interrupt for this detection ccw uses the kernel event daemon to
316  * trigger the call to dasd_change_state. All this is done in the
317  * discipline code, see dasd_eckd.c.
318  * After the analysis ccw is done (do_analysis returned 0) the block
319  * device is setup.
320  * In case the analysis returns an error, the device setup is stopped
321  * (a fake disk was already added to allow formatting).
322  */
323 static int dasd_state_basic_to_ready(struct dasd_device *device)
324 {
325 	int rc;
326 	struct dasd_block *block;
327 
328 	rc = 0;
329 	block = device->block;
330 	/* make disk known with correct capacity */
331 	if (block) {
332 		if (block->base->discipline->do_analysis != NULL)
333 			rc = block->base->discipline->do_analysis(block);
334 		if (rc) {
335 			if (rc != -EAGAIN)
336 				device->state = DASD_STATE_UNFMT;
337 			return rc;
338 		}
339 		dasd_setup_queue(block);
340 		set_capacity(block->gdp,
341 			     block->blocks << block->s2b_shift);
342 		device->state = DASD_STATE_READY;
343 		rc = dasd_scan_partitions(block);
344 		if (rc)
345 			device->state = DASD_STATE_BASIC;
346 	} else {
347 		device->state = DASD_STATE_READY;
348 	}
349 	return rc;
350 }
351 
352 /*
353  * Remove device from block device layer. Destroy dirty buffers.
354  * Forget format information. Check if the target level is basic
355  * and if it is create fake disk for formatting.
356  */
357 static int dasd_state_ready_to_basic(struct dasd_device *device)
358 {
359 	int rc;
360 
361 	device->state = DASD_STATE_BASIC;
362 	if (device->block) {
363 		struct dasd_block *block = device->block;
364 		rc = dasd_flush_block_queue(block);
365 		if (rc) {
366 			device->state = DASD_STATE_READY;
367 			return rc;
368 		}
369 		dasd_flush_request_queue(block);
370 		dasd_destroy_partitions(block);
371 		block->blocks = 0;
372 		block->bp_block = 0;
373 		block->s2b_shift = 0;
374 	}
375 	return 0;
376 }
377 
378 /*
379  * Back to basic.
380  */
381 static int dasd_state_unfmt_to_basic(struct dasd_device *device)
382 {
383 	device->state = DASD_STATE_BASIC;
384 	return 0;
385 }
386 
387 /*
388  * Make the device online and schedule the bottom half to start
389  * the requeueing of requests from the linux request queue to the
390  * ccw queue.
391  */
392 static int
393 dasd_state_ready_to_online(struct dasd_device * device)
394 {
395 	int rc;
396 	struct gendisk *disk;
397 	struct disk_part_iter piter;
398 	struct hd_struct *part;
399 
400 	if (device->discipline->ready_to_online) {
401 		rc = device->discipline->ready_to_online(device);
402 		if (rc)
403 			return rc;
404 	}
405 	device->state = DASD_STATE_ONLINE;
406 	if (device->block) {
407 		dasd_schedule_block_bh(device->block);
408 		if ((device->features & DASD_FEATURE_USERAW)) {
409 			disk = device->block->gdp;
410 			kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
411 			return 0;
412 		}
413 		disk = device->block->bdev->bd_disk;
414 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
415 		while ((part = disk_part_iter_next(&piter)))
416 			kobject_uevent(&part_to_dev(part)->kobj, KOBJ_CHANGE);
417 		disk_part_iter_exit(&piter);
418 	}
419 	return 0;
420 }
421 
422 /*
423  * Stop the requeueing of requests again.
424  */
425 static int dasd_state_online_to_ready(struct dasd_device *device)
426 {
427 	int rc;
428 	struct gendisk *disk;
429 	struct disk_part_iter piter;
430 	struct hd_struct *part;
431 
432 	if (device->discipline->online_to_ready) {
433 		rc = device->discipline->online_to_ready(device);
434 		if (rc)
435 			return rc;
436 	}
437 	device->state = DASD_STATE_READY;
438 	if (device->block && !(device->features & DASD_FEATURE_USERAW)) {
439 		disk = device->block->bdev->bd_disk;
440 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
441 		while ((part = disk_part_iter_next(&piter)))
442 			kobject_uevent(&part_to_dev(part)->kobj, KOBJ_CHANGE);
443 		disk_part_iter_exit(&piter);
444 	}
445 	return 0;
446 }
447 
448 /*
449  * Device startup state changes.
450  */
451 static int dasd_increase_state(struct dasd_device *device)
452 {
453 	int rc;
454 
455 	rc = 0;
456 	if (device->state == DASD_STATE_NEW &&
457 	    device->target >= DASD_STATE_KNOWN)
458 		rc = dasd_state_new_to_known(device);
459 
460 	if (!rc &&
461 	    device->state == DASD_STATE_KNOWN &&
462 	    device->target >= DASD_STATE_BASIC)
463 		rc = dasd_state_known_to_basic(device);
464 
465 	if (!rc &&
466 	    device->state == DASD_STATE_BASIC &&
467 	    device->target >= DASD_STATE_READY)
468 		rc = dasd_state_basic_to_ready(device);
469 
470 	if (!rc &&
471 	    device->state == DASD_STATE_UNFMT &&
472 	    device->target > DASD_STATE_UNFMT)
473 		rc = -EPERM;
474 
475 	if (!rc &&
476 	    device->state == DASD_STATE_READY &&
477 	    device->target >= DASD_STATE_ONLINE)
478 		rc = dasd_state_ready_to_online(device);
479 
480 	return rc;
481 }
482 
483 /*
484  * Device shutdown state changes.
485  */
486 static int dasd_decrease_state(struct dasd_device *device)
487 {
488 	int rc;
489 
490 	rc = 0;
491 	if (device->state == DASD_STATE_ONLINE &&
492 	    device->target <= DASD_STATE_READY)
493 		rc = dasd_state_online_to_ready(device);
494 
495 	if (!rc &&
496 	    device->state == DASD_STATE_READY &&
497 	    device->target <= DASD_STATE_BASIC)
498 		rc = dasd_state_ready_to_basic(device);
499 
500 	if (!rc &&
501 	    device->state == DASD_STATE_UNFMT &&
502 	    device->target <= DASD_STATE_BASIC)
503 		rc = dasd_state_unfmt_to_basic(device);
504 
505 	if (!rc &&
506 	    device->state == DASD_STATE_BASIC &&
507 	    device->target <= DASD_STATE_KNOWN)
508 		rc = dasd_state_basic_to_known(device);
509 
510 	if (!rc &&
511 	    device->state == DASD_STATE_KNOWN &&
512 	    device->target <= DASD_STATE_NEW)
513 		rc = dasd_state_known_to_new(device);
514 
515 	return rc;
516 }
517 
518 /*
519  * This is the main startup/shutdown routine.
520  */
521 static void dasd_change_state(struct dasd_device *device)
522 {
523 	int rc;
524 
525 	if (device->state == device->target)
526 		/* Already where we want to go today... */
527 		return;
528 	if (device->state < device->target)
529 		rc = dasd_increase_state(device);
530 	else
531 		rc = dasd_decrease_state(device);
532 	if (rc == -EAGAIN)
533 		return;
534 	if (rc)
535 		device->target = device->state;
536 
537 	if (device->state == device->target)
538 		wake_up(&dasd_init_waitq);
539 
540 	/* let user-space know that the device status changed */
541 	kobject_uevent(&device->cdev->dev.kobj, KOBJ_CHANGE);
542 }
543 
544 /*
545  * Kick starter for devices that did not complete the startup/shutdown
546  * procedure or were sleeping because of a pending state.
547  * dasd_kick_device will schedule a call do do_kick_device to the kernel
548  * event daemon.
549  */
550 static void do_kick_device(struct work_struct *work)
551 {
552 	struct dasd_device *device = container_of(work, struct dasd_device, kick_work);
553 	mutex_lock(&device->state_mutex);
554 	dasd_change_state(device);
555 	mutex_unlock(&device->state_mutex);
556 	dasd_schedule_device_bh(device);
557 	dasd_put_device(device);
558 }
559 
560 void dasd_kick_device(struct dasd_device *device)
561 {
562 	dasd_get_device(device);
563 	/* queue call to dasd_kick_device to the kernel event daemon. */
564 	schedule_work(&device->kick_work);
565 }
566 
567 /*
568  * dasd_reload_device will schedule a call do do_reload_device to the kernel
569  * event daemon.
570  */
571 static void do_reload_device(struct work_struct *work)
572 {
573 	struct dasd_device *device = container_of(work, struct dasd_device,
574 						  reload_device);
575 	device->discipline->reload(device);
576 	dasd_put_device(device);
577 }
578 
579 void dasd_reload_device(struct dasd_device *device)
580 {
581 	dasd_get_device(device);
582 	/* queue call to dasd_reload_device to the kernel event daemon. */
583 	schedule_work(&device->reload_device);
584 }
585 EXPORT_SYMBOL(dasd_reload_device);
586 
587 /*
588  * dasd_restore_device will schedule a call do do_restore_device to the kernel
589  * event daemon.
590  */
591 static void do_restore_device(struct work_struct *work)
592 {
593 	struct dasd_device *device = container_of(work, struct dasd_device,
594 						  restore_device);
595 	device->cdev->drv->restore(device->cdev);
596 	dasd_put_device(device);
597 }
598 
599 void dasd_restore_device(struct dasd_device *device)
600 {
601 	dasd_get_device(device);
602 	/* queue call to dasd_restore_device to the kernel event daemon. */
603 	schedule_work(&device->restore_device);
604 }
605 
606 /*
607  * Set the target state for a device and starts the state change.
608  */
609 void dasd_set_target_state(struct dasd_device *device, int target)
610 {
611 	dasd_get_device(device);
612 	mutex_lock(&device->state_mutex);
613 	/* If we are in probeonly mode stop at DASD_STATE_READY. */
614 	if (dasd_probeonly && target > DASD_STATE_READY)
615 		target = DASD_STATE_READY;
616 	if (device->target != target) {
617 		if (device->state == target)
618 			wake_up(&dasd_init_waitq);
619 		device->target = target;
620 	}
621 	if (device->state != device->target)
622 		dasd_change_state(device);
623 	mutex_unlock(&device->state_mutex);
624 	dasd_put_device(device);
625 }
626 
627 /*
628  * Enable devices with device numbers in [from..to].
629  */
630 static inline int _wait_for_device(struct dasd_device *device)
631 {
632 	return (device->state == device->target);
633 }
634 
635 void dasd_enable_device(struct dasd_device *device)
636 {
637 	dasd_set_target_state(device, DASD_STATE_ONLINE);
638 	if (device->state <= DASD_STATE_KNOWN)
639 		/* No discipline for device found. */
640 		dasd_set_target_state(device, DASD_STATE_NEW);
641 	/* Now wait for the devices to come up. */
642 	wait_event(dasd_init_waitq, _wait_for_device(device));
643 
644 	dasd_reload_device(device);
645 	if (device->discipline->kick_validate)
646 		device->discipline->kick_validate(device);
647 }
648 
649 /*
650  * SECTION: device operation (interrupt handler, start i/o, term i/o ...)
651  */
652 
653 unsigned int dasd_global_profile_level = DASD_PROFILE_OFF;
654 
655 #ifdef CONFIG_DASD_PROFILE
656 struct dasd_profile_info dasd_global_profile_data;
657 static struct dentry *dasd_global_profile_dentry;
658 static struct dentry *dasd_debugfs_global_entry;
659 
660 /*
661  * Add profiling information for cqr before execution.
662  */
663 static void dasd_profile_start(struct dasd_block *block,
664 			       struct dasd_ccw_req *cqr,
665 			       struct request *req)
666 {
667 	struct list_head *l;
668 	unsigned int counter;
669 	struct dasd_device *device;
670 
671 	/* count the length of the chanq for statistics */
672 	counter = 0;
673 	if (dasd_global_profile_level || block->profile.data)
674 		list_for_each(l, &block->ccw_queue)
675 			if (++counter >= 31)
676 				break;
677 
678 	if (dasd_global_profile_level) {
679 		dasd_global_profile_data.dasd_io_nr_req[counter]++;
680 		if (rq_data_dir(req) == READ)
681 			dasd_global_profile_data.dasd_read_nr_req[counter]++;
682 	}
683 
684 	spin_lock(&block->profile.lock);
685 	if (block->profile.data)
686 		block->profile.data->dasd_io_nr_req[counter]++;
687 		if (rq_data_dir(req) == READ)
688 			block->profile.data->dasd_read_nr_req[counter]++;
689 	spin_unlock(&block->profile.lock);
690 
691 	/*
692 	 * We count the request for the start device, even though it may run on
693 	 * some other device due to error recovery. This way we make sure that
694 	 * we count each request only once.
695 	 */
696 	device = cqr->startdev;
697 	if (device->profile.data) {
698 		counter = 1; /* request is not yet queued on the start device */
699 		list_for_each(l, &device->ccw_queue)
700 			if (++counter >= 31)
701 				break;
702 	}
703 	spin_lock(&device->profile.lock);
704 	if (device->profile.data) {
705 		device->profile.data->dasd_io_nr_req[counter]++;
706 		if (rq_data_dir(req) == READ)
707 			device->profile.data->dasd_read_nr_req[counter]++;
708 	}
709 	spin_unlock(&device->profile.lock);
710 }
711 
712 /*
713  * Add profiling information for cqr after execution.
714  */
715 
716 #define dasd_profile_counter(value, index)			   \
717 {								   \
718 	for (index = 0; index < 31 && value >> (2+index); index++) \
719 		;						   \
720 }
721 
722 static void dasd_profile_end_add_data(struct dasd_profile_info *data,
723 				      int is_alias,
724 				      int is_tpm,
725 				      int is_read,
726 				      long sectors,
727 				      int sectors_ind,
728 				      int tottime_ind,
729 				      int tottimeps_ind,
730 				      int strtime_ind,
731 				      int irqtime_ind,
732 				      int irqtimeps_ind,
733 				      int endtime_ind)
734 {
735 	/* in case of an overflow, reset the whole profile */
736 	if (data->dasd_io_reqs == UINT_MAX) {
737 			memset(data, 0, sizeof(*data));
738 			getnstimeofday(&data->starttod);
739 	}
740 	data->dasd_io_reqs++;
741 	data->dasd_io_sects += sectors;
742 	if (is_alias)
743 		data->dasd_io_alias++;
744 	if (is_tpm)
745 		data->dasd_io_tpm++;
746 
747 	data->dasd_io_secs[sectors_ind]++;
748 	data->dasd_io_times[tottime_ind]++;
749 	data->dasd_io_timps[tottimeps_ind]++;
750 	data->dasd_io_time1[strtime_ind]++;
751 	data->dasd_io_time2[irqtime_ind]++;
752 	data->dasd_io_time2ps[irqtimeps_ind]++;
753 	data->dasd_io_time3[endtime_ind]++;
754 
755 	if (is_read) {
756 		data->dasd_read_reqs++;
757 		data->dasd_read_sects += sectors;
758 		if (is_alias)
759 			data->dasd_read_alias++;
760 		if (is_tpm)
761 			data->dasd_read_tpm++;
762 		data->dasd_read_secs[sectors_ind]++;
763 		data->dasd_read_times[tottime_ind]++;
764 		data->dasd_read_time1[strtime_ind]++;
765 		data->dasd_read_time2[irqtime_ind]++;
766 		data->dasd_read_time3[endtime_ind]++;
767 	}
768 }
769 
770 static void dasd_profile_end(struct dasd_block *block,
771 			     struct dasd_ccw_req *cqr,
772 			     struct request *req)
773 {
774 	long strtime, irqtime, endtime, tottime;	/* in microseconds */
775 	long tottimeps, sectors;
776 	struct dasd_device *device;
777 	int sectors_ind, tottime_ind, tottimeps_ind, strtime_ind;
778 	int irqtime_ind, irqtimeps_ind, endtime_ind;
779 
780 	device = cqr->startdev;
781 	if (!(dasd_global_profile_level ||
782 	      block->profile.data ||
783 	      device->profile.data))
784 		return;
785 
786 	sectors = blk_rq_sectors(req);
787 	if (!cqr->buildclk || !cqr->startclk ||
788 	    !cqr->stopclk || !cqr->endclk ||
789 	    !sectors)
790 		return;
791 
792 	strtime = ((cqr->startclk - cqr->buildclk) >> 12);
793 	irqtime = ((cqr->stopclk - cqr->startclk) >> 12);
794 	endtime = ((cqr->endclk - cqr->stopclk) >> 12);
795 	tottime = ((cqr->endclk - cqr->buildclk) >> 12);
796 	tottimeps = tottime / sectors;
797 
798 	dasd_profile_counter(sectors, sectors_ind);
799 	dasd_profile_counter(tottime, tottime_ind);
800 	dasd_profile_counter(tottimeps, tottimeps_ind);
801 	dasd_profile_counter(strtime, strtime_ind);
802 	dasd_profile_counter(irqtime, irqtime_ind);
803 	dasd_profile_counter(irqtime / sectors, irqtimeps_ind);
804 	dasd_profile_counter(endtime, endtime_ind);
805 
806 	if (dasd_global_profile_level) {
807 		dasd_profile_end_add_data(&dasd_global_profile_data,
808 					  cqr->startdev != block->base,
809 					  cqr->cpmode == 1,
810 					  rq_data_dir(req) == READ,
811 					  sectors, sectors_ind, tottime_ind,
812 					  tottimeps_ind, strtime_ind,
813 					  irqtime_ind, irqtimeps_ind,
814 					  endtime_ind);
815 	}
816 
817 	spin_lock(&block->profile.lock);
818 	if (block->profile.data)
819 		dasd_profile_end_add_data(block->profile.data,
820 					  cqr->startdev != block->base,
821 					  cqr->cpmode == 1,
822 					  rq_data_dir(req) == READ,
823 					  sectors, sectors_ind, tottime_ind,
824 					  tottimeps_ind, strtime_ind,
825 					  irqtime_ind, irqtimeps_ind,
826 					  endtime_ind);
827 	spin_unlock(&block->profile.lock);
828 
829 	spin_lock(&device->profile.lock);
830 	if (device->profile.data)
831 		dasd_profile_end_add_data(device->profile.data,
832 					  cqr->startdev != block->base,
833 					  cqr->cpmode == 1,
834 					  rq_data_dir(req) == READ,
835 					  sectors, sectors_ind, tottime_ind,
836 					  tottimeps_ind, strtime_ind,
837 					  irqtime_ind, irqtimeps_ind,
838 					  endtime_ind);
839 	spin_unlock(&device->profile.lock);
840 }
841 
842 void dasd_profile_reset(struct dasd_profile *profile)
843 {
844 	struct dasd_profile_info *data;
845 
846 	spin_lock_bh(&profile->lock);
847 	data = profile->data;
848 	if (!data) {
849 		spin_unlock_bh(&profile->lock);
850 		return;
851 	}
852 	memset(data, 0, sizeof(*data));
853 	getnstimeofday(&data->starttod);
854 	spin_unlock_bh(&profile->lock);
855 }
856 
857 void dasd_global_profile_reset(void)
858 {
859 	memset(&dasd_global_profile_data, 0, sizeof(dasd_global_profile_data));
860 	getnstimeofday(&dasd_global_profile_data.starttod);
861 }
862 
863 int dasd_profile_on(struct dasd_profile *profile)
864 {
865 	struct dasd_profile_info *data;
866 
867 	data = kzalloc(sizeof(*data), GFP_KERNEL);
868 	if (!data)
869 		return -ENOMEM;
870 	spin_lock_bh(&profile->lock);
871 	if (profile->data) {
872 		spin_unlock_bh(&profile->lock);
873 		kfree(data);
874 		return 0;
875 	}
876 	getnstimeofday(&data->starttod);
877 	profile->data = data;
878 	spin_unlock_bh(&profile->lock);
879 	return 0;
880 }
881 
882 void dasd_profile_off(struct dasd_profile *profile)
883 {
884 	spin_lock_bh(&profile->lock);
885 	kfree(profile->data);
886 	profile->data = NULL;
887 	spin_unlock_bh(&profile->lock);
888 }
889 
890 char *dasd_get_user_string(const char __user *user_buf, size_t user_len)
891 {
892 	char *buffer;
893 
894 	buffer = vmalloc(user_len + 1);
895 	if (buffer == NULL)
896 		return ERR_PTR(-ENOMEM);
897 	if (copy_from_user(buffer, user_buf, user_len) != 0) {
898 		vfree(buffer);
899 		return ERR_PTR(-EFAULT);
900 	}
901 	/* got the string, now strip linefeed. */
902 	if (buffer[user_len - 1] == '\n')
903 		buffer[user_len - 1] = 0;
904 	else
905 		buffer[user_len] = 0;
906 	return buffer;
907 }
908 
909 static ssize_t dasd_stats_write(struct file *file,
910 				const char __user *user_buf,
911 				size_t user_len, loff_t *pos)
912 {
913 	char *buffer, *str;
914 	int rc;
915 	struct seq_file *m = (struct seq_file *)file->private_data;
916 	struct dasd_profile *prof = m->private;
917 
918 	if (user_len > 65536)
919 		user_len = 65536;
920 	buffer = dasd_get_user_string(user_buf, user_len);
921 	if (IS_ERR(buffer))
922 		return PTR_ERR(buffer);
923 
924 	str = skip_spaces(buffer);
925 	rc = user_len;
926 	if (strncmp(str, "reset", 5) == 0) {
927 		dasd_profile_reset(prof);
928 	} else if (strncmp(str, "on", 2) == 0) {
929 		rc = dasd_profile_on(prof);
930 		if (!rc)
931 			rc = user_len;
932 	} else if (strncmp(str, "off", 3) == 0) {
933 		dasd_profile_off(prof);
934 	} else
935 		rc = -EINVAL;
936 	vfree(buffer);
937 	return rc;
938 }
939 
940 static void dasd_stats_array(struct seq_file *m, unsigned int *array)
941 {
942 	int i;
943 
944 	for (i = 0; i < 32; i++)
945 		seq_printf(m, "%u ", array[i]);
946 	seq_putc(m, '\n');
947 }
948 
949 static void dasd_stats_seq_print(struct seq_file *m,
950 				 struct dasd_profile_info *data)
951 {
952 	seq_printf(m, "start_time %ld.%09ld\n",
953 		   data->starttod.tv_sec, data->starttod.tv_nsec);
954 	seq_printf(m, "total_requests %u\n", data->dasd_io_reqs);
955 	seq_printf(m, "total_sectors %u\n", data->dasd_io_sects);
956 	seq_printf(m, "total_pav %u\n", data->dasd_io_alias);
957 	seq_printf(m, "total_hpf %u\n", data->dasd_io_tpm);
958 	seq_printf(m, "histogram_sectors ");
959 	dasd_stats_array(m, data->dasd_io_secs);
960 	seq_printf(m, "histogram_io_times ");
961 	dasd_stats_array(m, data->dasd_io_times);
962 	seq_printf(m, "histogram_io_times_weighted ");
963 	dasd_stats_array(m, data->dasd_io_timps);
964 	seq_printf(m, "histogram_time_build_to_ssch ");
965 	dasd_stats_array(m, data->dasd_io_time1);
966 	seq_printf(m, "histogram_time_ssch_to_irq ");
967 	dasd_stats_array(m, data->dasd_io_time2);
968 	seq_printf(m, "histogram_time_ssch_to_irq_weighted ");
969 	dasd_stats_array(m, data->dasd_io_time2ps);
970 	seq_printf(m, "histogram_time_irq_to_end ");
971 	dasd_stats_array(m, data->dasd_io_time3);
972 	seq_printf(m, "histogram_ccw_queue_length ");
973 	dasd_stats_array(m, data->dasd_io_nr_req);
974 	seq_printf(m, "total_read_requests %u\n", data->dasd_read_reqs);
975 	seq_printf(m, "total_read_sectors %u\n", data->dasd_read_sects);
976 	seq_printf(m, "total_read_pav %u\n", data->dasd_read_alias);
977 	seq_printf(m, "total_read_hpf %u\n", data->dasd_read_tpm);
978 	seq_printf(m, "histogram_read_sectors ");
979 	dasd_stats_array(m, data->dasd_read_secs);
980 	seq_printf(m, "histogram_read_times ");
981 	dasd_stats_array(m, data->dasd_read_times);
982 	seq_printf(m, "histogram_read_time_build_to_ssch ");
983 	dasd_stats_array(m, data->dasd_read_time1);
984 	seq_printf(m, "histogram_read_time_ssch_to_irq ");
985 	dasd_stats_array(m, data->dasd_read_time2);
986 	seq_printf(m, "histogram_read_time_irq_to_end ");
987 	dasd_stats_array(m, data->dasd_read_time3);
988 	seq_printf(m, "histogram_read_ccw_queue_length ");
989 	dasd_stats_array(m, data->dasd_read_nr_req);
990 }
991 
992 static int dasd_stats_show(struct seq_file *m, void *v)
993 {
994 	struct dasd_profile *profile;
995 	struct dasd_profile_info *data;
996 
997 	profile = m->private;
998 	spin_lock_bh(&profile->lock);
999 	data = profile->data;
1000 	if (!data) {
1001 		spin_unlock_bh(&profile->lock);
1002 		seq_printf(m, "disabled\n");
1003 		return 0;
1004 	}
1005 	dasd_stats_seq_print(m, data);
1006 	spin_unlock_bh(&profile->lock);
1007 	return 0;
1008 }
1009 
1010 static int dasd_stats_open(struct inode *inode, struct file *file)
1011 {
1012 	struct dasd_profile *profile = inode->i_private;
1013 	return single_open(file, dasd_stats_show, profile);
1014 }
1015 
1016 static const struct file_operations dasd_stats_raw_fops = {
1017 	.owner		= THIS_MODULE,
1018 	.open		= dasd_stats_open,
1019 	.read		= seq_read,
1020 	.llseek		= seq_lseek,
1021 	.release	= single_release,
1022 	.write		= dasd_stats_write,
1023 };
1024 
1025 static ssize_t dasd_stats_global_write(struct file *file,
1026 				       const char __user *user_buf,
1027 				       size_t user_len, loff_t *pos)
1028 {
1029 	char *buffer, *str;
1030 	ssize_t rc;
1031 
1032 	if (user_len > 65536)
1033 		user_len = 65536;
1034 	buffer = dasd_get_user_string(user_buf, user_len);
1035 	if (IS_ERR(buffer))
1036 		return PTR_ERR(buffer);
1037 	str = skip_spaces(buffer);
1038 	rc = user_len;
1039 	if (strncmp(str, "reset", 5) == 0) {
1040 		dasd_global_profile_reset();
1041 	} else if (strncmp(str, "on", 2) == 0) {
1042 		dasd_global_profile_reset();
1043 		dasd_global_profile_level = DASD_PROFILE_GLOBAL_ONLY;
1044 	} else if (strncmp(str, "off", 3) == 0) {
1045 		dasd_global_profile_level = DASD_PROFILE_OFF;
1046 	} else
1047 		rc = -EINVAL;
1048 	vfree(buffer);
1049 	return rc;
1050 }
1051 
1052 static int dasd_stats_global_show(struct seq_file *m, void *v)
1053 {
1054 	if (!dasd_global_profile_level) {
1055 		seq_printf(m, "disabled\n");
1056 		return 0;
1057 	}
1058 	dasd_stats_seq_print(m, &dasd_global_profile_data);
1059 	return 0;
1060 }
1061 
1062 static int dasd_stats_global_open(struct inode *inode, struct file *file)
1063 {
1064 	return single_open(file, dasd_stats_global_show, NULL);
1065 }
1066 
1067 static const struct file_operations dasd_stats_global_fops = {
1068 	.owner		= THIS_MODULE,
1069 	.open		= dasd_stats_global_open,
1070 	.read		= seq_read,
1071 	.llseek		= seq_lseek,
1072 	.release	= single_release,
1073 	.write		= dasd_stats_global_write,
1074 };
1075 
1076 static void dasd_profile_init(struct dasd_profile *profile,
1077 			      struct dentry *base_dentry)
1078 {
1079 	umode_t mode;
1080 	struct dentry *pde;
1081 
1082 	if (!base_dentry)
1083 		return;
1084 	profile->dentry = NULL;
1085 	profile->data = NULL;
1086 	mode = (S_IRUSR | S_IWUSR | S_IFREG);
1087 	pde = debugfs_create_file("statistics", mode, base_dentry,
1088 				  profile, &dasd_stats_raw_fops);
1089 	if (pde && !IS_ERR(pde))
1090 		profile->dentry = pde;
1091 	return;
1092 }
1093 
1094 static void dasd_profile_exit(struct dasd_profile *profile)
1095 {
1096 	dasd_profile_off(profile);
1097 	if (profile->dentry) {
1098 		debugfs_remove(profile->dentry);
1099 		profile->dentry = NULL;
1100 	}
1101 }
1102 
1103 static void dasd_statistics_removeroot(void)
1104 {
1105 	dasd_global_profile_level = DASD_PROFILE_OFF;
1106 	if (dasd_global_profile_dentry) {
1107 		debugfs_remove(dasd_global_profile_dentry);
1108 		dasd_global_profile_dentry = NULL;
1109 	}
1110 	if (dasd_debugfs_global_entry)
1111 		debugfs_remove(dasd_debugfs_global_entry);
1112 	if (dasd_debugfs_root_entry)
1113 		debugfs_remove(dasd_debugfs_root_entry);
1114 }
1115 
1116 static void dasd_statistics_createroot(void)
1117 {
1118 	umode_t mode;
1119 	struct dentry *pde;
1120 
1121 	dasd_debugfs_root_entry = NULL;
1122 	dasd_debugfs_global_entry = NULL;
1123 	dasd_global_profile_dentry = NULL;
1124 	pde = debugfs_create_dir("dasd", NULL);
1125 	if (!pde || IS_ERR(pde))
1126 		goto error;
1127 	dasd_debugfs_root_entry = pde;
1128 	pde = debugfs_create_dir("global", dasd_debugfs_root_entry);
1129 	if (!pde || IS_ERR(pde))
1130 		goto error;
1131 	dasd_debugfs_global_entry = pde;
1132 
1133 	mode = (S_IRUSR | S_IWUSR | S_IFREG);
1134 	pde = debugfs_create_file("statistics", mode, dasd_debugfs_global_entry,
1135 				  NULL, &dasd_stats_global_fops);
1136 	if (!pde || IS_ERR(pde))
1137 		goto error;
1138 	dasd_global_profile_dentry = pde;
1139 	return;
1140 
1141 error:
1142 	DBF_EVENT(DBF_ERR, "%s",
1143 		  "Creation of the dasd debugfs interface failed");
1144 	dasd_statistics_removeroot();
1145 	return;
1146 }
1147 
1148 #else
1149 #define dasd_profile_start(block, cqr, req) do {} while (0)
1150 #define dasd_profile_end(block, cqr, req) do {} while (0)
1151 
1152 static void dasd_statistics_createroot(void)
1153 {
1154 	return;
1155 }
1156 
1157 static void dasd_statistics_removeroot(void)
1158 {
1159 	return;
1160 }
1161 
1162 int dasd_stats_generic_show(struct seq_file *m, void *v)
1163 {
1164 	seq_printf(m, "Statistics are not activated in this kernel\n");
1165 	return 0;
1166 }
1167 
1168 static void dasd_profile_init(struct dasd_profile *profile,
1169 			      struct dentry *base_dentry)
1170 {
1171 	return;
1172 }
1173 
1174 static void dasd_profile_exit(struct dasd_profile *profile)
1175 {
1176 	return;
1177 }
1178 
1179 int dasd_profile_on(struct dasd_profile *profile)
1180 {
1181 	return 0;
1182 }
1183 
1184 #endif				/* CONFIG_DASD_PROFILE */
1185 
1186 /*
1187  * Allocate memory for a channel program with 'cplength' channel
1188  * command words and 'datasize' additional space. There are two
1189  * variantes: 1) dasd_kmalloc_request uses kmalloc to get the needed
1190  * memory and 2) dasd_smalloc_request uses the static ccw memory
1191  * that gets allocated for each device.
1192  */
1193 struct dasd_ccw_req *dasd_kmalloc_request(int magic, int cplength,
1194 					  int datasize,
1195 					  struct dasd_device *device)
1196 {
1197 	struct dasd_ccw_req *cqr;
1198 
1199 	/* Sanity checks */
1200 	BUG_ON(datasize > PAGE_SIZE ||
1201 	     (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
1202 
1203 	cqr = kzalloc(sizeof(struct dasd_ccw_req), GFP_ATOMIC);
1204 	if (cqr == NULL)
1205 		return ERR_PTR(-ENOMEM);
1206 	cqr->cpaddr = NULL;
1207 	if (cplength > 0) {
1208 		cqr->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
1209 				      GFP_ATOMIC | GFP_DMA);
1210 		if (cqr->cpaddr == NULL) {
1211 			kfree(cqr);
1212 			return ERR_PTR(-ENOMEM);
1213 		}
1214 	}
1215 	cqr->data = NULL;
1216 	if (datasize > 0) {
1217 		cqr->data = kzalloc(datasize, GFP_ATOMIC | GFP_DMA);
1218 		if (cqr->data == NULL) {
1219 			kfree(cqr->cpaddr);
1220 			kfree(cqr);
1221 			return ERR_PTR(-ENOMEM);
1222 		}
1223 	}
1224 	cqr->magic =  magic;
1225 	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
1226 	dasd_get_device(device);
1227 	return cqr;
1228 }
1229 
1230 struct dasd_ccw_req *dasd_smalloc_request(int magic, int cplength,
1231 					  int datasize,
1232 					  struct dasd_device *device)
1233 {
1234 	unsigned long flags;
1235 	struct dasd_ccw_req *cqr;
1236 	char *data;
1237 	int size;
1238 
1239 	size = (sizeof(struct dasd_ccw_req) + 7L) & -8L;
1240 	if (cplength > 0)
1241 		size += cplength * sizeof(struct ccw1);
1242 	if (datasize > 0)
1243 		size += datasize;
1244 	spin_lock_irqsave(&device->mem_lock, flags);
1245 	cqr = (struct dasd_ccw_req *)
1246 		dasd_alloc_chunk(&device->ccw_chunks, size);
1247 	spin_unlock_irqrestore(&device->mem_lock, flags);
1248 	if (cqr == NULL)
1249 		return ERR_PTR(-ENOMEM);
1250 	memset(cqr, 0, sizeof(struct dasd_ccw_req));
1251 	data = (char *) cqr + ((sizeof(struct dasd_ccw_req) + 7L) & -8L);
1252 	cqr->cpaddr = NULL;
1253 	if (cplength > 0) {
1254 		cqr->cpaddr = (struct ccw1 *) data;
1255 		data += cplength*sizeof(struct ccw1);
1256 		memset(cqr->cpaddr, 0, cplength*sizeof(struct ccw1));
1257 	}
1258 	cqr->data = NULL;
1259 	if (datasize > 0) {
1260 		cqr->data = data;
1261  		memset(cqr->data, 0, datasize);
1262 	}
1263 	cqr->magic = magic;
1264 	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
1265 	dasd_get_device(device);
1266 	return cqr;
1267 }
1268 
1269 /*
1270  * Free memory of a channel program. This function needs to free all the
1271  * idal lists that might have been created by dasd_set_cda and the
1272  * struct dasd_ccw_req itself.
1273  */
1274 void dasd_kfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
1275 {
1276 #ifdef CONFIG_64BIT
1277 	struct ccw1 *ccw;
1278 
1279 	/* Clear any idals used for the request. */
1280 	ccw = cqr->cpaddr;
1281 	do {
1282 		clear_normalized_cda(ccw);
1283 	} while (ccw++->flags & (CCW_FLAG_CC | CCW_FLAG_DC));
1284 #endif
1285 	kfree(cqr->cpaddr);
1286 	kfree(cqr->data);
1287 	kfree(cqr);
1288 	dasd_put_device(device);
1289 }
1290 
1291 void dasd_sfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
1292 {
1293 	unsigned long flags;
1294 
1295 	spin_lock_irqsave(&device->mem_lock, flags);
1296 	dasd_free_chunk(&device->ccw_chunks, cqr);
1297 	spin_unlock_irqrestore(&device->mem_lock, flags);
1298 	dasd_put_device(device);
1299 }
1300 
1301 /*
1302  * Check discipline magic in cqr.
1303  */
1304 static inline int dasd_check_cqr(struct dasd_ccw_req *cqr)
1305 {
1306 	struct dasd_device *device;
1307 
1308 	if (cqr == NULL)
1309 		return -EINVAL;
1310 	device = cqr->startdev;
1311 	if (strncmp((char *) &cqr->magic, device->discipline->ebcname, 4)) {
1312 		DBF_DEV_EVENT(DBF_WARNING, device,
1313 			    " dasd_ccw_req 0x%08x magic doesn't match"
1314 			    " discipline 0x%08x",
1315 			    cqr->magic,
1316 			    *(unsigned int *) device->discipline->name);
1317 		return -EINVAL;
1318 	}
1319 	return 0;
1320 }
1321 
1322 /*
1323  * Terminate the current i/o and set the request to clear_pending.
1324  * Timer keeps device runnig.
1325  * ccw_device_clear can fail if the i/o subsystem
1326  * is in a bad mood.
1327  */
1328 int dasd_term_IO(struct dasd_ccw_req *cqr)
1329 {
1330 	struct dasd_device *device;
1331 	int retries, rc;
1332 	char errorstring[ERRORLENGTH];
1333 
1334 	/* Check the cqr */
1335 	rc = dasd_check_cqr(cqr);
1336 	if (rc)
1337 		return rc;
1338 	retries = 0;
1339 	device = (struct dasd_device *) cqr->startdev;
1340 	while ((retries < 5) && (cqr->status == DASD_CQR_IN_IO)) {
1341 		rc = ccw_device_clear(device->cdev, (long) cqr);
1342 		switch (rc) {
1343 		case 0:	/* termination successful */
1344 			cqr->status = DASD_CQR_CLEAR_PENDING;
1345 			cqr->stopclk = get_clock();
1346 			cqr->starttime = 0;
1347 			DBF_DEV_EVENT(DBF_DEBUG, device,
1348 				      "terminate cqr %p successful",
1349 				      cqr);
1350 			break;
1351 		case -ENODEV:
1352 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
1353 				      "device gone, retry");
1354 			break;
1355 		case -EIO:
1356 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
1357 				      "I/O error, retry");
1358 			break;
1359 		case -EINVAL:
1360 		case -EBUSY:
1361 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
1362 				      "device busy, retry later");
1363 			break;
1364 		default:
1365 			/* internal error 10 - unknown rc*/
1366 			snprintf(errorstring, ERRORLENGTH, "10 %d", rc);
1367 			dev_err(&device->cdev->dev, "An error occurred in the "
1368 				"DASD device driver, reason=%s\n", errorstring);
1369 			BUG();
1370 			break;
1371 		}
1372 		retries++;
1373 	}
1374 	dasd_schedule_device_bh(device);
1375 	return rc;
1376 }
1377 
1378 /*
1379  * Start the i/o. This start_IO can fail if the channel is really busy.
1380  * In that case set up a timer to start the request later.
1381  */
1382 int dasd_start_IO(struct dasd_ccw_req *cqr)
1383 {
1384 	struct dasd_device *device;
1385 	int rc;
1386 	char errorstring[ERRORLENGTH];
1387 
1388 	/* Check the cqr */
1389 	rc = dasd_check_cqr(cqr);
1390 	if (rc) {
1391 		cqr->intrc = rc;
1392 		return rc;
1393 	}
1394 	device = (struct dasd_device *) cqr->startdev;
1395 	if (((cqr->block &&
1396 	      test_bit(DASD_FLAG_LOCK_STOLEN, &cqr->block->base->flags)) ||
1397 	     test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags)) &&
1398 	    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
1399 		DBF_DEV_EVENT(DBF_DEBUG, device, "start_IO: return request %p "
1400 			      "because of stolen lock", cqr);
1401 		cqr->status = DASD_CQR_ERROR;
1402 		cqr->intrc = -EPERM;
1403 		return -EPERM;
1404 	}
1405 	if (cqr->retries < 0) {
1406 		/* internal error 14 - start_IO run out of retries */
1407 		sprintf(errorstring, "14 %p", cqr);
1408 		dev_err(&device->cdev->dev, "An error occurred in the DASD "
1409 			"device driver, reason=%s\n", errorstring);
1410 		cqr->status = DASD_CQR_ERROR;
1411 		return -EIO;
1412 	}
1413 	cqr->startclk = get_clock();
1414 	cqr->starttime = jiffies;
1415 	cqr->retries--;
1416 	if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
1417 		cqr->lpm &= device->path_data.opm;
1418 		if (!cqr->lpm)
1419 			cqr->lpm = device->path_data.opm;
1420 	}
1421 	if (cqr->cpmode == 1) {
1422 		rc = ccw_device_tm_start(device->cdev, cqr->cpaddr,
1423 					 (long) cqr, cqr->lpm);
1424 	} else {
1425 		rc = ccw_device_start(device->cdev, cqr->cpaddr,
1426 				      (long) cqr, cqr->lpm, 0);
1427 	}
1428 	switch (rc) {
1429 	case 0:
1430 		cqr->status = DASD_CQR_IN_IO;
1431 		break;
1432 	case -EBUSY:
1433 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1434 			      "start_IO: device busy, retry later");
1435 		break;
1436 	case -ETIMEDOUT:
1437 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1438 			      "start_IO: request timeout, retry later");
1439 		break;
1440 	case -EACCES:
1441 		/* -EACCES indicates that the request used only a subset of the
1442 		 * available paths and all these paths are gone. If the lpm of
1443 		 * this request was only a subset of the opm (e.g. the ppm) then
1444 		 * we just do a retry with all available paths.
1445 		 * If we already use the full opm, something is amiss, and we
1446 		 * need a full path verification.
1447 		 */
1448 		if (test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
1449 			DBF_DEV_EVENT(DBF_WARNING, device,
1450 				      "start_IO: selected paths gone (%x)",
1451 				      cqr->lpm);
1452 		} else if (cqr->lpm != device->path_data.opm) {
1453 			cqr->lpm = device->path_data.opm;
1454 			DBF_DEV_EVENT(DBF_DEBUG, device, "%s",
1455 				      "start_IO: selected paths gone,"
1456 				      " retry on all paths");
1457 		} else {
1458 			DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1459 				      "start_IO: all paths in opm gone,"
1460 				      " do path verification");
1461 			dasd_generic_last_path_gone(device);
1462 			device->path_data.opm = 0;
1463 			device->path_data.ppm = 0;
1464 			device->path_data.npm = 0;
1465 			device->path_data.tbvpm =
1466 				ccw_device_get_path_mask(device->cdev);
1467 		}
1468 		break;
1469 	case -ENODEV:
1470 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1471 			      "start_IO: -ENODEV device gone, retry");
1472 		break;
1473 	case -EIO:
1474 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1475 			      "start_IO: -EIO device gone, retry");
1476 		break;
1477 	case -EINVAL:
1478 		/* most likely caused in power management context */
1479 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1480 			      "start_IO: -EINVAL device currently "
1481 			      "not accessible");
1482 		break;
1483 	default:
1484 		/* internal error 11 - unknown rc */
1485 		snprintf(errorstring, ERRORLENGTH, "11 %d", rc);
1486 		dev_err(&device->cdev->dev,
1487 			"An error occurred in the DASD device driver, "
1488 			"reason=%s\n", errorstring);
1489 		BUG();
1490 		break;
1491 	}
1492 	cqr->intrc = rc;
1493 	return rc;
1494 }
1495 
1496 /*
1497  * Timeout function for dasd devices. This is used for different purposes
1498  *  1) missing interrupt handler for normal operation
1499  *  2) delayed start of request where start_IO failed with -EBUSY
1500  *  3) timeout for missing state change interrupts
1501  * The head of the ccw queue will have status DASD_CQR_IN_IO for 1),
1502  * DASD_CQR_QUEUED for 2) and 3).
1503  */
1504 static void dasd_device_timeout(unsigned long ptr)
1505 {
1506 	unsigned long flags;
1507 	struct dasd_device *device;
1508 
1509 	device = (struct dasd_device *) ptr;
1510 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
1511 	/* re-activate request queue */
1512 	dasd_device_remove_stop_bits(device, DASD_STOPPED_PENDING);
1513 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
1514 	dasd_schedule_device_bh(device);
1515 }
1516 
1517 /*
1518  * Setup timeout for a device in jiffies.
1519  */
1520 void dasd_device_set_timer(struct dasd_device *device, int expires)
1521 {
1522 	if (expires == 0)
1523 		del_timer(&device->timer);
1524 	else
1525 		mod_timer(&device->timer, jiffies + expires);
1526 }
1527 
1528 /*
1529  * Clear timeout for a device.
1530  */
1531 void dasd_device_clear_timer(struct dasd_device *device)
1532 {
1533 	del_timer(&device->timer);
1534 }
1535 
1536 static void dasd_handle_killed_request(struct ccw_device *cdev,
1537 				       unsigned long intparm)
1538 {
1539 	struct dasd_ccw_req *cqr;
1540 	struct dasd_device *device;
1541 
1542 	if (!intparm)
1543 		return;
1544 	cqr = (struct dasd_ccw_req *) intparm;
1545 	if (cqr->status != DASD_CQR_IN_IO) {
1546 		DBF_EVENT_DEVID(DBF_DEBUG, cdev,
1547 				"invalid status in handle_killed_request: "
1548 				"%02x", cqr->status);
1549 		return;
1550 	}
1551 
1552 	device = dasd_device_from_cdev_locked(cdev);
1553 	if (IS_ERR(device)) {
1554 		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
1555 				"unable to get device from cdev");
1556 		return;
1557 	}
1558 
1559 	if (!cqr->startdev ||
1560 	    device != cqr->startdev ||
1561 	    strncmp(cqr->startdev->discipline->ebcname,
1562 		    (char *) &cqr->magic, 4)) {
1563 		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
1564 				"invalid device in request");
1565 		dasd_put_device(device);
1566 		return;
1567 	}
1568 
1569 	/* Schedule request to be retried. */
1570 	cqr->status = DASD_CQR_QUEUED;
1571 
1572 	dasd_device_clear_timer(device);
1573 	dasd_schedule_device_bh(device);
1574 	dasd_put_device(device);
1575 }
1576 
1577 void dasd_generic_handle_state_change(struct dasd_device *device)
1578 {
1579 	/* First of all start sense subsystem status request. */
1580 	dasd_eer_snss(device);
1581 
1582 	dasd_device_remove_stop_bits(device, DASD_STOPPED_PENDING);
1583 	dasd_schedule_device_bh(device);
1584 	if (device->block)
1585 		dasd_schedule_block_bh(device->block);
1586 }
1587 
1588 /*
1589  * Interrupt handler for "normal" ssch-io based dasd devices.
1590  */
1591 void dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
1592 		      struct irb *irb)
1593 {
1594 	struct dasd_ccw_req *cqr, *next;
1595 	struct dasd_device *device;
1596 	unsigned long long now;
1597 	int expires;
1598 
1599 	if (IS_ERR(irb)) {
1600 		switch (PTR_ERR(irb)) {
1601 		case -EIO:
1602 			break;
1603 		case -ETIMEDOUT:
1604 			DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
1605 					"request timed out\n", __func__);
1606 			break;
1607 		default:
1608 			DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
1609 					"unknown error %ld\n", __func__,
1610 					PTR_ERR(irb));
1611 		}
1612 		dasd_handle_killed_request(cdev, intparm);
1613 		return;
1614 	}
1615 
1616 	now = get_clock();
1617 	cqr = (struct dasd_ccw_req *) intparm;
1618 	/* check for conditions that should be handled immediately */
1619 	if (!cqr ||
1620 	    !(scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
1621 	      scsw_cstat(&irb->scsw) == 0)) {
1622 		if (cqr)
1623 			memcpy(&cqr->irb, irb, sizeof(*irb));
1624 		device = dasd_device_from_cdev_locked(cdev);
1625 		if (IS_ERR(device))
1626 			return;
1627 		/* ignore unsolicited interrupts for DIAG discipline */
1628 		if (device->discipline == dasd_diag_discipline_pointer) {
1629 			dasd_put_device(device);
1630 			return;
1631 		}
1632 		device->discipline->dump_sense_dbf(device, irb, "int");
1633 		if (device->features & DASD_FEATURE_ERPLOG)
1634 			device->discipline->dump_sense(device, cqr, irb);
1635 		device->discipline->check_for_device_change(device, cqr, irb);
1636 		dasd_put_device(device);
1637 	}
1638 	if (!cqr)
1639 		return;
1640 
1641 	device = (struct dasd_device *) cqr->startdev;
1642 	if (!device ||
1643 	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
1644 		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
1645 				"invalid device in request");
1646 		return;
1647 	}
1648 
1649 	/* Check for clear pending */
1650 	if (cqr->status == DASD_CQR_CLEAR_PENDING &&
1651 	    scsw_fctl(&irb->scsw) & SCSW_FCTL_CLEAR_FUNC) {
1652 		cqr->status = DASD_CQR_CLEARED;
1653 		dasd_device_clear_timer(device);
1654 		wake_up(&dasd_flush_wq);
1655 		dasd_schedule_device_bh(device);
1656 		return;
1657 	}
1658 
1659 	/* check status - the request might have been killed by dyn detach */
1660 	if (cqr->status != DASD_CQR_IN_IO) {
1661 		DBF_DEV_EVENT(DBF_DEBUG, device, "invalid status: bus_id %s, "
1662 			      "status %02x", dev_name(&cdev->dev), cqr->status);
1663 		return;
1664 	}
1665 
1666 	next = NULL;
1667 	expires = 0;
1668 	if (scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
1669 	    scsw_cstat(&irb->scsw) == 0) {
1670 		/* request was completed successfully */
1671 		cqr->status = DASD_CQR_SUCCESS;
1672 		cqr->stopclk = now;
1673 		/* Start first request on queue if possible -> fast_io. */
1674 		if (cqr->devlist.next != &device->ccw_queue) {
1675 			next = list_entry(cqr->devlist.next,
1676 					  struct dasd_ccw_req, devlist);
1677 		}
1678 	} else {  /* error */
1679 		/*
1680 		 * If we don't want complex ERP for this request, then just
1681 		 * reset this and retry it in the fastpath
1682 		 */
1683 		if (!test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags) &&
1684 		    cqr->retries > 0) {
1685 			if (cqr->lpm == device->path_data.opm)
1686 				DBF_DEV_EVENT(DBF_DEBUG, device,
1687 					      "default ERP in fastpath "
1688 					      "(%i retries left)",
1689 					      cqr->retries);
1690 			if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags))
1691 				cqr->lpm = device->path_data.opm;
1692 			cqr->status = DASD_CQR_QUEUED;
1693 			next = cqr;
1694 		} else
1695 			cqr->status = DASD_CQR_ERROR;
1696 	}
1697 	if (next && (next->status == DASD_CQR_QUEUED) &&
1698 	    (!device->stopped)) {
1699 		if (device->discipline->start_IO(next) == 0)
1700 			expires = next->expires;
1701 	}
1702 	if (expires != 0)
1703 		dasd_device_set_timer(device, expires);
1704 	else
1705 		dasd_device_clear_timer(device);
1706 	dasd_schedule_device_bh(device);
1707 }
1708 
1709 enum uc_todo dasd_generic_uc_handler(struct ccw_device *cdev, struct irb *irb)
1710 {
1711 	struct dasd_device *device;
1712 
1713 	device = dasd_device_from_cdev_locked(cdev);
1714 
1715 	if (IS_ERR(device))
1716 		goto out;
1717 	if (test_bit(DASD_FLAG_OFFLINE, &device->flags) ||
1718 	   device->state != device->target ||
1719 	   !device->discipline->check_for_device_change){
1720 		dasd_put_device(device);
1721 		goto out;
1722 	}
1723 	if (device->discipline->dump_sense_dbf)
1724 		device->discipline->dump_sense_dbf(device, irb, "uc");
1725 	device->discipline->check_for_device_change(device, NULL, irb);
1726 	dasd_put_device(device);
1727 out:
1728 	return UC_TODO_RETRY;
1729 }
1730 EXPORT_SYMBOL_GPL(dasd_generic_uc_handler);
1731 
1732 /*
1733  * If we have an error on a dasd_block layer request then we cancel
1734  * and return all further requests from the same dasd_block as well.
1735  */
1736 static void __dasd_device_recovery(struct dasd_device *device,
1737 				   struct dasd_ccw_req *ref_cqr)
1738 {
1739 	struct list_head *l, *n;
1740 	struct dasd_ccw_req *cqr;
1741 
1742 	/*
1743 	 * only requeue request that came from the dasd_block layer
1744 	 */
1745 	if (!ref_cqr->block)
1746 		return;
1747 
1748 	list_for_each_safe(l, n, &device->ccw_queue) {
1749 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1750 		if (cqr->status == DASD_CQR_QUEUED &&
1751 		    ref_cqr->block == cqr->block) {
1752 			cqr->status = DASD_CQR_CLEARED;
1753 		}
1754 	}
1755 };
1756 
1757 /*
1758  * Remove those ccw requests from the queue that need to be returned
1759  * to the upper layer.
1760  */
1761 static void __dasd_device_process_ccw_queue(struct dasd_device *device,
1762 					    struct list_head *final_queue)
1763 {
1764 	struct list_head *l, *n;
1765 	struct dasd_ccw_req *cqr;
1766 
1767 	/* Process request with final status. */
1768 	list_for_each_safe(l, n, &device->ccw_queue) {
1769 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1770 
1771 		/* Stop list processing at the first non-final request. */
1772 		if (cqr->status == DASD_CQR_QUEUED ||
1773 		    cqr->status == DASD_CQR_IN_IO ||
1774 		    cqr->status == DASD_CQR_CLEAR_PENDING)
1775 			break;
1776 		if (cqr->status == DASD_CQR_ERROR) {
1777 			__dasd_device_recovery(device, cqr);
1778 		}
1779 		/* Rechain finished requests to final queue */
1780 		list_move_tail(&cqr->devlist, final_queue);
1781 	}
1782 }
1783 
1784 /*
1785  * the cqrs from the final queue are returned to the upper layer
1786  * by setting a dasd_block state and calling the callback function
1787  */
1788 static void __dasd_device_process_final_queue(struct dasd_device *device,
1789 					      struct list_head *final_queue)
1790 {
1791 	struct list_head *l, *n;
1792 	struct dasd_ccw_req *cqr;
1793 	struct dasd_block *block;
1794 	void (*callback)(struct dasd_ccw_req *, void *data);
1795 	void *callback_data;
1796 	char errorstring[ERRORLENGTH];
1797 
1798 	list_for_each_safe(l, n, final_queue) {
1799 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1800 		list_del_init(&cqr->devlist);
1801 		block = cqr->block;
1802 		callback = cqr->callback;
1803 		callback_data = cqr->callback_data;
1804 		if (block)
1805 			spin_lock_bh(&block->queue_lock);
1806 		switch (cqr->status) {
1807 		case DASD_CQR_SUCCESS:
1808 			cqr->status = DASD_CQR_DONE;
1809 			break;
1810 		case DASD_CQR_ERROR:
1811 			cqr->status = DASD_CQR_NEED_ERP;
1812 			break;
1813 		case DASD_CQR_CLEARED:
1814 			cqr->status = DASD_CQR_TERMINATED;
1815 			break;
1816 		default:
1817 			/* internal error 12 - wrong cqr status*/
1818 			snprintf(errorstring, ERRORLENGTH, "12 %p %x02", cqr, cqr->status);
1819 			dev_err(&device->cdev->dev,
1820 				"An error occurred in the DASD device driver, "
1821 				"reason=%s\n", errorstring);
1822 			BUG();
1823 		}
1824 		if (cqr->callback != NULL)
1825 			(callback)(cqr, callback_data);
1826 		if (block)
1827 			spin_unlock_bh(&block->queue_lock);
1828 	}
1829 }
1830 
1831 /*
1832  * Take a look at the first request on the ccw queue and check
1833  * if it reached its expire time. If so, terminate the IO.
1834  */
1835 static void __dasd_device_check_expire(struct dasd_device *device)
1836 {
1837 	struct dasd_ccw_req *cqr;
1838 
1839 	if (list_empty(&device->ccw_queue))
1840 		return;
1841 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1842 	if ((cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) &&
1843 	    (time_after_eq(jiffies, cqr->expires + cqr->starttime))) {
1844 		if (device->discipline->term_IO(cqr) != 0) {
1845 			/* Hmpf, try again in 5 sec */
1846 			dev_err(&device->cdev->dev,
1847 				"cqr %p timed out (%lus) but cannot be "
1848 				"ended, retrying in 5 s\n",
1849 				cqr, (cqr->expires/HZ));
1850 			cqr->expires += 5*HZ;
1851 			dasd_device_set_timer(device, 5*HZ);
1852 		} else {
1853 			dev_err(&device->cdev->dev,
1854 				"cqr %p timed out (%lus), %i retries "
1855 				"remaining\n", cqr, (cqr->expires/HZ),
1856 				cqr->retries);
1857 		}
1858 	}
1859 }
1860 
1861 /*
1862  * Take a look at the first request on the ccw queue and check
1863  * if it needs to be started.
1864  */
1865 static void __dasd_device_start_head(struct dasd_device *device)
1866 {
1867 	struct dasd_ccw_req *cqr;
1868 	int rc;
1869 
1870 	if (list_empty(&device->ccw_queue))
1871 		return;
1872 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1873 	if (cqr->status != DASD_CQR_QUEUED)
1874 		return;
1875 	/* when device is stopped, return request to previous layer
1876 	 * exception: only the disconnect or unresumed bits are set and the
1877 	 * cqr is a path verification request
1878 	 */
1879 	if (device->stopped &&
1880 	    !(!(device->stopped & ~(DASD_STOPPED_DC_WAIT | DASD_UNRESUMED_PM))
1881 	      && test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags))) {
1882 		cqr->intrc = -EAGAIN;
1883 		cqr->status = DASD_CQR_CLEARED;
1884 		dasd_schedule_device_bh(device);
1885 		return;
1886 	}
1887 
1888 	rc = device->discipline->start_IO(cqr);
1889 	if (rc == 0)
1890 		dasd_device_set_timer(device, cqr->expires);
1891 	else if (rc == -EACCES) {
1892 		dasd_schedule_device_bh(device);
1893 	} else
1894 		/* Hmpf, try again in 1/2 sec */
1895 		dasd_device_set_timer(device, 50);
1896 }
1897 
1898 static void __dasd_device_check_path_events(struct dasd_device *device)
1899 {
1900 	int rc;
1901 
1902 	if (device->path_data.tbvpm) {
1903 		if (device->stopped & ~(DASD_STOPPED_DC_WAIT |
1904 					DASD_UNRESUMED_PM))
1905 			return;
1906 		rc = device->discipline->verify_path(
1907 			device, device->path_data.tbvpm);
1908 		if (rc)
1909 			dasd_device_set_timer(device, 50);
1910 		else
1911 			device->path_data.tbvpm = 0;
1912 	}
1913 };
1914 
1915 /*
1916  * Go through all request on the dasd_device request queue,
1917  * terminate them on the cdev if necessary, and return them to the
1918  * submitting layer via callback.
1919  * Note:
1920  * Make sure that all 'submitting layers' still exist when
1921  * this function is called!. In other words, when 'device' is a base
1922  * device then all block layer requests must have been removed before
1923  * via dasd_flush_block_queue.
1924  */
1925 int dasd_flush_device_queue(struct dasd_device *device)
1926 {
1927 	struct dasd_ccw_req *cqr, *n;
1928 	int rc;
1929 	struct list_head flush_queue;
1930 
1931 	INIT_LIST_HEAD(&flush_queue);
1932 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1933 	rc = 0;
1934 	list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
1935 		/* Check status and move request to flush_queue */
1936 		switch (cqr->status) {
1937 		case DASD_CQR_IN_IO:
1938 			rc = device->discipline->term_IO(cqr);
1939 			if (rc) {
1940 				/* unable to terminate requeust */
1941 				dev_err(&device->cdev->dev,
1942 					"Flushing the DASD request queue "
1943 					"failed for request %p\n", cqr);
1944 				/* stop flush processing */
1945 				goto finished;
1946 			}
1947 			break;
1948 		case DASD_CQR_QUEUED:
1949 			cqr->stopclk = get_clock();
1950 			cqr->status = DASD_CQR_CLEARED;
1951 			break;
1952 		default: /* no need to modify the others */
1953 			break;
1954 		}
1955 		list_move_tail(&cqr->devlist, &flush_queue);
1956 	}
1957 finished:
1958 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1959 	/*
1960 	 * After this point all requests must be in state CLEAR_PENDING,
1961 	 * CLEARED, SUCCESS or ERROR. Now wait for CLEAR_PENDING to become
1962 	 * one of the others.
1963 	 */
1964 	list_for_each_entry_safe(cqr, n, &flush_queue, devlist)
1965 		wait_event(dasd_flush_wq,
1966 			   (cqr->status != DASD_CQR_CLEAR_PENDING));
1967 	/*
1968 	 * Now set each request back to TERMINATED, DONE or NEED_ERP
1969 	 * and call the callback function of flushed requests
1970 	 */
1971 	__dasd_device_process_final_queue(device, &flush_queue);
1972 	return rc;
1973 }
1974 
1975 /*
1976  * Acquire the device lock and process queues for the device.
1977  */
1978 static void dasd_device_tasklet(struct dasd_device *device)
1979 {
1980 	struct list_head final_queue;
1981 
1982 	atomic_set (&device->tasklet_scheduled, 0);
1983 	INIT_LIST_HEAD(&final_queue);
1984 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1985 	/* Check expire time of first request on the ccw queue. */
1986 	__dasd_device_check_expire(device);
1987 	/* find final requests on ccw queue */
1988 	__dasd_device_process_ccw_queue(device, &final_queue);
1989 	__dasd_device_check_path_events(device);
1990 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1991 	/* Now call the callback function of requests with final status */
1992 	__dasd_device_process_final_queue(device, &final_queue);
1993 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1994 	/* Now check if the head of the ccw queue needs to be started. */
1995 	__dasd_device_start_head(device);
1996 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1997 	dasd_put_device(device);
1998 }
1999 
2000 /*
2001  * Schedules a call to dasd_tasklet over the device tasklet.
2002  */
2003 void dasd_schedule_device_bh(struct dasd_device *device)
2004 {
2005 	/* Protect against rescheduling. */
2006 	if (atomic_cmpxchg (&device->tasklet_scheduled, 0, 1) != 0)
2007 		return;
2008 	dasd_get_device(device);
2009 	tasklet_hi_schedule(&device->tasklet);
2010 }
2011 
2012 void dasd_device_set_stop_bits(struct dasd_device *device, int bits)
2013 {
2014 	device->stopped |= bits;
2015 }
2016 EXPORT_SYMBOL_GPL(dasd_device_set_stop_bits);
2017 
2018 void dasd_device_remove_stop_bits(struct dasd_device *device, int bits)
2019 {
2020 	device->stopped &= ~bits;
2021 	if (!device->stopped)
2022 		wake_up(&generic_waitq);
2023 }
2024 EXPORT_SYMBOL_GPL(dasd_device_remove_stop_bits);
2025 
2026 /*
2027  * Queue a request to the head of the device ccw_queue.
2028  * Start the I/O if possible.
2029  */
2030 void dasd_add_request_head(struct dasd_ccw_req *cqr)
2031 {
2032 	struct dasd_device *device;
2033 	unsigned long flags;
2034 
2035 	device = cqr->startdev;
2036 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
2037 	cqr->status = DASD_CQR_QUEUED;
2038 	list_add(&cqr->devlist, &device->ccw_queue);
2039 	/* let the bh start the request to keep them in order */
2040 	dasd_schedule_device_bh(device);
2041 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
2042 }
2043 
2044 /*
2045  * Queue a request to the tail of the device ccw_queue.
2046  * Start the I/O if possible.
2047  */
2048 void dasd_add_request_tail(struct dasd_ccw_req *cqr)
2049 {
2050 	struct dasd_device *device;
2051 	unsigned long flags;
2052 
2053 	device = cqr->startdev;
2054 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
2055 	cqr->status = DASD_CQR_QUEUED;
2056 	list_add_tail(&cqr->devlist, &device->ccw_queue);
2057 	/* let the bh start the request to keep them in order */
2058 	dasd_schedule_device_bh(device);
2059 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
2060 }
2061 
2062 /*
2063  * Wakeup helper for the 'sleep_on' functions.
2064  */
2065 void dasd_wakeup_cb(struct dasd_ccw_req *cqr, void *data)
2066 {
2067 	spin_lock_irq(get_ccwdev_lock(cqr->startdev->cdev));
2068 	cqr->callback_data = DASD_SLEEPON_END_TAG;
2069 	spin_unlock_irq(get_ccwdev_lock(cqr->startdev->cdev));
2070 	wake_up(&generic_waitq);
2071 }
2072 EXPORT_SYMBOL_GPL(dasd_wakeup_cb);
2073 
2074 static inline int _wait_for_wakeup(struct dasd_ccw_req *cqr)
2075 {
2076 	struct dasd_device *device;
2077 	int rc;
2078 
2079 	device = cqr->startdev;
2080 	spin_lock_irq(get_ccwdev_lock(device->cdev));
2081 	rc = (cqr->callback_data == DASD_SLEEPON_END_TAG);
2082 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
2083 	return rc;
2084 }
2085 
2086 /*
2087  * checks if error recovery is necessary, returns 1 if yes, 0 otherwise.
2088  */
2089 static int __dasd_sleep_on_erp(struct dasd_ccw_req *cqr)
2090 {
2091 	struct dasd_device *device;
2092 	dasd_erp_fn_t erp_fn;
2093 
2094 	if (cqr->status == DASD_CQR_FILLED)
2095 		return 0;
2096 	device = cqr->startdev;
2097 	if (test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) {
2098 		if (cqr->status == DASD_CQR_TERMINATED) {
2099 			device->discipline->handle_terminated_request(cqr);
2100 			return 1;
2101 		}
2102 		if (cqr->status == DASD_CQR_NEED_ERP) {
2103 			erp_fn = device->discipline->erp_action(cqr);
2104 			erp_fn(cqr);
2105 			return 1;
2106 		}
2107 		if (cqr->status == DASD_CQR_FAILED)
2108 			dasd_log_sense(cqr, &cqr->irb);
2109 		if (cqr->refers) {
2110 			__dasd_process_erp(device, cqr);
2111 			return 1;
2112 		}
2113 	}
2114 	return 0;
2115 }
2116 
2117 static int __dasd_sleep_on_loop_condition(struct dasd_ccw_req *cqr)
2118 {
2119 	if (test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) {
2120 		if (cqr->refers) /* erp is not done yet */
2121 			return 1;
2122 		return ((cqr->status != DASD_CQR_DONE) &&
2123 			(cqr->status != DASD_CQR_FAILED));
2124 	} else
2125 		return (cqr->status == DASD_CQR_FILLED);
2126 }
2127 
2128 static int _dasd_sleep_on(struct dasd_ccw_req *maincqr, int interruptible)
2129 {
2130 	struct dasd_device *device;
2131 	int rc;
2132 	struct list_head ccw_queue;
2133 	struct dasd_ccw_req *cqr;
2134 
2135 	INIT_LIST_HEAD(&ccw_queue);
2136 	maincqr->status = DASD_CQR_FILLED;
2137 	device = maincqr->startdev;
2138 	list_add(&maincqr->blocklist, &ccw_queue);
2139 	for (cqr = maincqr;  __dasd_sleep_on_loop_condition(cqr);
2140 	     cqr = list_first_entry(&ccw_queue,
2141 				    struct dasd_ccw_req, blocklist)) {
2142 
2143 		if (__dasd_sleep_on_erp(cqr))
2144 			continue;
2145 		if (cqr->status != DASD_CQR_FILLED) /* could be failed */
2146 			continue;
2147 		if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
2148 		    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
2149 			cqr->status = DASD_CQR_FAILED;
2150 			cqr->intrc = -EPERM;
2151 			continue;
2152 		}
2153 		/* Non-temporary stop condition will trigger fail fast */
2154 		if (device->stopped & ~DASD_STOPPED_PENDING &&
2155 		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
2156 		    (!dasd_eer_enabled(device))) {
2157 			cqr->status = DASD_CQR_FAILED;
2158 			continue;
2159 		}
2160 		/* Don't try to start requests if device is stopped */
2161 		if (interruptible) {
2162 			rc = wait_event_interruptible(
2163 				generic_waitq, !(device->stopped));
2164 			if (rc == -ERESTARTSYS) {
2165 				cqr->status = DASD_CQR_FAILED;
2166 				maincqr->intrc = rc;
2167 				continue;
2168 			}
2169 		} else
2170 			wait_event(generic_waitq, !(device->stopped));
2171 
2172 		if (!cqr->callback)
2173 			cqr->callback = dasd_wakeup_cb;
2174 
2175 		cqr->callback_data = DASD_SLEEPON_START_TAG;
2176 		dasd_add_request_tail(cqr);
2177 		if (interruptible) {
2178 			rc = wait_event_interruptible(
2179 				generic_waitq, _wait_for_wakeup(cqr));
2180 			if (rc == -ERESTARTSYS) {
2181 				dasd_cancel_req(cqr);
2182 				/* wait (non-interruptible) for final status */
2183 				wait_event(generic_waitq,
2184 					   _wait_for_wakeup(cqr));
2185 				cqr->status = DASD_CQR_FAILED;
2186 				maincqr->intrc = rc;
2187 				continue;
2188 			}
2189 		} else
2190 			wait_event(generic_waitq, _wait_for_wakeup(cqr));
2191 	}
2192 
2193 	maincqr->endclk = get_clock();
2194 	if ((maincqr->status != DASD_CQR_DONE) &&
2195 	    (maincqr->intrc != -ERESTARTSYS))
2196 		dasd_log_sense(maincqr, &maincqr->irb);
2197 	if (maincqr->status == DASD_CQR_DONE)
2198 		rc = 0;
2199 	else if (maincqr->intrc)
2200 		rc = maincqr->intrc;
2201 	else
2202 		rc = -EIO;
2203 	return rc;
2204 }
2205 
2206 /*
2207  * Queue a request to the tail of the device ccw_queue and wait for
2208  * it's completion.
2209  */
2210 int dasd_sleep_on(struct dasd_ccw_req *cqr)
2211 {
2212 	return _dasd_sleep_on(cqr, 0);
2213 }
2214 
2215 /*
2216  * Queue a request to the tail of the device ccw_queue and wait
2217  * interruptible for it's completion.
2218  */
2219 int dasd_sleep_on_interruptible(struct dasd_ccw_req *cqr)
2220 {
2221 	return _dasd_sleep_on(cqr, 1);
2222 }
2223 
2224 /*
2225  * Whoa nelly now it gets really hairy. For some functions (e.g. steal lock
2226  * for eckd devices) the currently running request has to be terminated
2227  * and be put back to status queued, before the special request is added
2228  * to the head of the queue. Then the special request is waited on normally.
2229  */
2230 static inline int _dasd_term_running_cqr(struct dasd_device *device)
2231 {
2232 	struct dasd_ccw_req *cqr;
2233 	int rc;
2234 
2235 	if (list_empty(&device->ccw_queue))
2236 		return 0;
2237 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
2238 	rc = device->discipline->term_IO(cqr);
2239 	if (!rc)
2240 		/*
2241 		 * CQR terminated because a more important request is pending.
2242 		 * Undo decreasing of retry counter because this is
2243 		 * not an error case.
2244 		 */
2245 		cqr->retries++;
2246 	return rc;
2247 }
2248 
2249 int dasd_sleep_on_immediatly(struct dasd_ccw_req *cqr)
2250 {
2251 	struct dasd_device *device;
2252 	int rc;
2253 
2254 	device = cqr->startdev;
2255 	if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
2256 	    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
2257 		cqr->status = DASD_CQR_FAILED;
2258 		cqr->intrc = -EPERM;
2259 		return -EIO;
2260 	}
2261 	spin_lock_irq(get_ccwdev_lock(device->cdev));
2262 	rc = _dasd_term_running_cqr(device);
2263 	if (rc) {
2264 		spin_unlock_irq(get_ccwdev_lock(device->cdev));
2265 		return rc;
2266 	}
2267 	cqr->callback = dasd_wakeup_cb;
2268 	cqr->callback_data = DASD_SLEEPON_START_TAG;
2269 	cqr->status = DASD_CQR_QUEUED;
2270 	/*
2271 	 * add new request as second
2272 	 * first the terminated cqr needs to be finished
2273 	 */
2274 	list_add(&cqr->devlist, device->ccw_queue.next);
2275 
2276 	/* let the bh start the request to keep them in order */
2277 	dasd_schedule_device_bh(device);
2278 
2279 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
2280 
2281 	wait_event(generic_waitq, _wait_for_wakeup(cqr));
2282 
2283 	if (cqr->status == DASD_CQR_DONE)
2284 		rc = 0;
2285 	else if (cqr->intrc)
2286 		rc = cqr->intrc;
2287 	else
2288 		rc = -EIO;
2289 	return rc;
2290 }
2291 
2292 /*
2293  * Cancels a request that was started with dasd_sleep_on_req.
2294  * This is useful to timeout requests. The request will be
2295  * terminated if it is currently in i/o.
2296  * Returns 1 if the request has been terminated.
2297  *	   0 if there was no need to terminate the request (not started yet)
2298  *	   negative error code if termination failed
2299  * Cancellation of a request is an asynchronous operation! The calling
2300  * function has to wait until the request is properly returned via callback.
2301  */
2302 int dasd_cancel_req(struct dasd_ccw_req *cqr)
2303 {
2304 	struct dasd_device *device = cqr->startdev;
2305 	unsigned long flags;
2306 	int rc;
2307 
2308 	rc = 0;
2309 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
2310 	switch (cqr->status) {
2311 	case DASD_CQR_QUEUED:
2312 		/* request was not started - just set to cleared */
2313 		cqr->status = DASD_CQR_CLEARED;
2314 		break;
2315 	case DASD_CQR_IN_IO:
2316 		/* request in IO - terminate IO and release again */
2317 		rc = device->discipline->term_IO(cqr);
2318 		if (rc) {
2319 			dev_err(&device->cdev->dev,
2320 				"Cancelling request %p failed with rc=%d\n",
2321 				cqr, rc);
2322 		} else {
2323 			cqr->stopclk = get_clock();
2324 		}
2325 		break;
2326 	default: /* already finished or clear pending - do nothing */
2327 		break;
2328 	}
2329 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
2330 	dasd_schedule_device_bh(device);
2331 	return rc;
2332 }
2333 
2334 
2335 /*
2336  * SECTION: Operations of the dasd_block layer.
2337  */
2338 
2339 /*
2340  * Timeout function for dasd_block. This is used when the block layer
2341  * is waiting for something that may not come reliably, (e.g. a state
2342  * change interrupt)
2343  */
2344 static void dasd_block_timeout(unsigned long ptr)
2345 {
2346 	unsigned long flags;
2347 	struct dasd_block *block;
2348 
2349 	block = (struct dasd_block *) ptr;
2350 	spin_lock_irqsave(get_ccwdev_lock(block->base->cdev), flags);
2351 	/* re-activate request queue */
2352 	dasd_device_remove_stop_bits(block->base, DASD_STOPPED_PENDING);
2353 	spin_unlock_irqrestore(get_ccwdev_lock(block->base->cdev), flags);
2354 	dasd_schedule_block_bh(block);
2355 }
2356 
2357 /*
2358  * Setup timeout for a dasd_block in jiffies.
2359  */
2360 void dasd_block_set_timer(struct dasd_block *block, int expires)
2361 {
2362 	if (expires == 0)
2363 		del_timer(&block->timer);
2364 	else
2365 		mod_timer(&block->timer, jiffies + expires);
2366 }
2367 
2368 /*
2369  * Clear timeout for a dasd_block.
2370  */
2371 void dasd_block_clear_timer(struct dasd_block *block)
2372 {
2373 	del_timer(&block->timer);
2374 }
2375 
2376 /*
2377  * Process finished error recovery ccw.
2378  */
2379 static void __dasd_process_erp(struct dasd_device *device,
2380 			       struct dasd_ccw_req *cqr)
2381 {
2382 	dasd_erp_fn_t erp_fn;
2383 
2384 	if (cqr->status == DASD_CQR_DONE)
2385 		DBF_DEV_EVENT(DBF_NOTICE, device, "%s", "ERP successful");
2386 	else
2387 		dev_err(&device->cdev->dev, "ERP failed for the DASD\n");
2388 	erp_fn = device->discipline->erp_postaction(cqr);
2389 	erp_fn(cqr);
2390 }
2391 
2392 /*
2393  * Fetch requests from the block device queue.
2394  */
2395 static void __dasd_process_request_queue(struct dasd_block *block)
2396 {
2397 	struct request_queue *queue;
2398 	struct request *req;
2399 	struct dasd_ccw_req *cqr;
2400 	struct dasd_device *basedev;
2401 	unsigned long flags;
2402 	queue = block->request_queue;
2403 	basedev = block->base;
2404 	/* No queue ? Then there is nothing to do. */
2405 	if (queue == NULL)
2406 		return;
2407 
2408 	/*
2409 	 * We requeue request from the block device queue to the ccw
2410 	 * queue only in two states. In state DASD_STATE_READY the
2411 	 * partition detection is done and we need to requeue requests
2412 	 * for that. State DASD_STATE_ONLINE is normal block device
2413 	 * operation.
2414 	 */
2415 	if (basedev->state < DASD_STATE_READY) {
2416 		while ((req = blk_fetch_request(block->request_queue)))
2417 			__blk_end_request_all(req, -EIO);
2418 		return;
2419 	}
2420 	/* Now we try to fetch requests from the request queue */
2421 	while ((req = blk_peek_request(queue))) {
2422 		if (basedev->features & DASD_FEATURE_READONLY &&
2423 		    rq_data_dir(req) == WRITE) {
2424 			DBF_DEV_EVENT(DBF_ERR, basedev,
2425 				      "Rejecting write request %p",
2426 				      req);
2427 			blk_start_request(req);
2428 			__blk_end_request_all(req, -EIO);
2429 			continue;
2430 		}
2431 		cqr = basedev->discipline->build_cp(basedev, block, req);
2432 		if (IS_ERR(cqr)) {
2433 			if (PTR_ERR(cqr) == -EBUSY)
2434 				break;	/* normal end condition */
2435 			if (PTR_ERR(cqr) == -ENOMEM)
2436 				break;	/* terminate request queue loop */
2437 			if (PTR_ERR(cqr) == -EAGAIN) {
2438 				/*
2439 				 * The current request cannot be build right
2440 				 * now, we have to try later. If this request
2441 				 * is the head-of-queue we stop the device
2442 				 * for 1/2 second.
2443 				 */
2444 				if (!list_empty(&block->ccw_queue))
2445 					break;
2446 				spin_lock_irqsave(
2447 					get_ccwdev_lock(basedev->cdev), flags);
2448 				dasd_device_set_stop_bits(basedev,
2449 							  DASD_STOPPED_PENDING);
2450 				spin_unlock_irqrestore(
2451 					get_ccwdev_lock(basedev->cdev), flags);
2452 				dasd_block_set_timer(block, HZ/2);
2453 				break;
2454 			}
2455 			DBF_DEV_EVENT(DBF_ERR, basedev,
2456 				      "CCW creation failed (rc=%ld) "
2457 				      "on request %p",
2458 				      PTR_ERR(cqr), req);
2459 			blk_start_request(req);
2460 			__blk_end_request_all(req, -EIO);
2461 			continue;
2462 		}
2463 		/*
2464 		 *  Note: callback is set to dasd_return_cqr_cb in
2465 		 * __dasd_block_start_head to cover erp requests as well
2466 		 */
2467 		cqr->callback_data = (void *) req;
2468 		cqr->status = DASD_CQR_FILLED;
2469 		blk_start_request(req);
2470 		list_add_tail(&cqr->blocklist, &block->ccw_queue);
2471 		dasd_profile_start(block, cqr, req);
2472 	}
2473 }
2474 
2475 static void __dasd_cleanup_cqr(struct dasd_ccw_req *cqr)
2476 {
2477 	struct request *req;
2478 	int status;
2479 	int error = 0;
2480 
2481 	req = (struct request *) cqr->callback_data;
2482 	dasd_profile_end(cqr->block, cqr, req);
2483 	status = cqr->block->base->discipline->free_cp(cqr, req);
2484 	if (status <= 0)
2485 		error = status ? status : -EIO;
2486 	__blk_end_request_all(req, error);
2487 }
2488 
2489 /*
2490  * Process ccw request queue.
2491  */
2492 static void __dasd_process_block_ccw_queue(struct dasd_block *block,
2493 					   struct list_head *final_queue)
2494 {
2495 	struct list_head *l, *n;
2496 	struct dasd_ccw_req *cqr;
2497 	dasd_erp_fn_t erp_fn;
2498 	unsigned long flags;
2499 	struct dasd_device *base = block->base;
2500 
2501 restart:
2502 	/* Process request with final status. */
2503 	list_for_each_safe(l, n, &block->ccw_queue) {
2504 		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
2505 		if (cqr->status != DASD_CQR_DONE &&
2506 		    cqr->status != DASD_CQR_FAILED &&
2507 		    cqr->status != DASD_CQR_NEED_ERP &&
2508 		    cqr->status != DASD_CQR_TERMINATED)
2509 			continue;
2510 
2511 		if (cqr->status == DASD_CQR_TERMINATED) {
2512 			base->discipline->handle_terminated_request(cqr);
2513 			goto restart;
2514 		}
2515 
2516 		/*  Process requests that may be recovered */
2517 		if (cqr->status == DASD_CQR_NEED_ERP) {
2518 			erp_fn = base->discipline->erp_action(cqr);
2519 			if (IS_ERR(erp_fn(cqr)))
2520 				continue;
2521 			goto restart;
2522 		}
2523 
2524 		/* log sense for fatal error */
2525 		if (cqr->status == DASD_CQR_FAILED) {
2526 			dasd_log_sense(cqr, &cqr->irb);
2527 		}
2528 
2529 		/* First of all call extended error reporting. */
2530 		if (dasd_eer_enabled(base) &&
2531 		    cqr->status == DASD_CQR_FAILED) {
2532 			dasd_eer_write(base, cqr, DASD_EER_FATALERROR);
2533 
2534 			/* restart request  */
2535 			cqr->status = DASD_CQR_FILLED;
2536 			cqr->retries = 255;
2537 			spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
2538 			dasd_device_set_stop_bits(base, DASD_STOPPED_QUIESCE);
2539 			spin_unlock_irqrestore(get_ccwdev_lock(base->cdev),
2540 					       flags);
2541 			goto restart;
2542 		}
2543 
2544 		/* Process finished ERP request. */
2545 		if (cqr->refers) {
2546 			__dasd_process_erp(base, cqr);
2547 			goto restart;
2548 		}
2549 
2550 		/* Rechain finished requests to final queue */
2551 		cqr->endclk = get_clock();
2552 		list_move_tail(&cqr->blocklist, final_queue);
2553 	}
2554 }
2555 
2556 static void dasd_return_cqr_cb(struct dasd_ccw_req *cqr, void *data)
2557 {
2558 	dasd_schedule_block_bh(cqr->block);
2559 }
2560 
2561 static void __dasd_block_start_head(struct dasd_block *block)
2562 {
2563 	struct dasd_ccw_req *cqr;
2564 
2565 	if (list_empty(&block->ccw_queue))
2566 		return;
2567 	/* We allways begin with the first requests on the queue, as some
2568 	 * of previously started requests have to be enqueued on a
2569 	 * dasd_device again for error recovery.
2570 	 */
2571 	list_for_each_entry(cqr, &block->ccw_queue, blocklist) {
2572 		if (cqr->status != DASD_CQR_FILLED)
2573 			continue;
2574 		if (test_bit(DASD_FLAG_LOCK_STOLEN, &block->base->flags) &&
2575 		    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
2576 			cqr->status = DASD_CQR_FAILED;
2577 			cqr->intrc = -EPERM;
2578 			dasd_schedule_block_bh(block);
2579 			continue;
2580 		}
2581 		/* Non-temporary stop condition will trigger fail fast */
2582 		if (block->base->stopped & ~DASD_STOPPED_PENDING &&
2583 		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
2584 		    (!dasd_eer_enabled(block->base))) {
2585 			cqr->status = DASD_CQR_FAILED;
2586 			dasd_schedule_block_bh(block);
2587 			continue;
2588 		}
2589 		/* Don't try to start requests if device is stopped */
2590 		if (block->base->stopped)
2591 			return;
2592 
2593 		/* just a fail safe check, should not happen */
2594 		if (!cqr->startdev)
2595 			cqr->startdev = block->base;
2596 
2597 		/* make sure that the requests we submit find their way back */
2598 		cqr->callback = dasd_return_cqr_cb;
2599 
2600 		dasd_add_request_tail(cqr);
2601 	}
2602 }
2603 
2604 /*
2605  * Central dasd_block layer routine. Takes requests from the generic
2606  * block layer request queue, creates ccw requests, enqueues them on
2607  * a dasd_device and processes ccw requests that have been returned.
2608  */
2609 static void dasd_block_tasklet(struct dasd_block *block)
2610 {
2611 	struct list_head final_queue;
2612 	struct list_head *l, *n;
2613 	struct dasd_ccw_req *cqr;
2614 
2615 	atomic_set(&block->tasklet_scheduled, 0);
2616 	INIT_LIST_HEAD(&final_queue);
2617 	spin_lock(&block->queue_lock);
2618 	/* Finish off requests on ccw queue */
2619 	__dasd_process_block_ccw_queue(block, &final_queue);
2620 	spin_unlock(&block->queue_lock);
2621 	/* Now call the callback function of requests with final status */
2622 	spin_lock_irq(&block->request_queue_lock);
2623 	list_for_each_safe(l, n, &final_queue) {
2624 		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
2625 		list_del_init(&cqr->blocklist);
2626 		__dasd_cleanup_cqr(cqr);
2627 	}
2628 	spin_lock(&block->queue_lock);
2629 	/* Get new request from the block device request queue */
2630 	__dasd_process_request_queue(block);
2631 	/* Now check if the head of the ccw queue needs to be started. */
2632 	__dasd_block_start_head(block);
2633 	spin_unlock(&block->queue_lock);
2634 	spin_unlock_irq(&block->request_queue_lock);
2635 	dasd_put_device(block->base);
2636 }
2637 
2638 static void _dasd_wake_block_flush_cb(struct dasd_ccw_req *cqr, void *data)
2639 {
2640 	wake_up(&dasd_flush_wq);
2641 }
2642 
2643 /*
2644  * Go through all request on the dasd_block request queue, cancel them
2645  * on the respective dasd_device, and return them to the generic
2646  * block layer.
2647  */
2648 static int dasd_flush_block_queue(struct dasd_block *block)
2649 {
2650 	struct dasd_ccw_req *cqr, *n;
2651 	int rc, i;
2652 	struct list_head flush_queue;
2653 
2654 	INIT_LIST_HEAD(&flush_queue);
2655 	spin_lock_bh(&block->queue_lock);
2656 	rc = 0;
2657 restart:
2658 	list_for_each_entry_safe(cqr, n, &block->ccw_queue, blocklist) {
2659 		/* if this request currently owned by a dasd_device cancel it */
2660 		if (cqr->status >= DASD_CQR_QUEUED)
2661 			rc = dasd_cancel_req(cqr);
2662 		if (rc < 0)
2663 			break;
2664 		/* Rechain request (including erp chain) so it won't be
2665 		 * touched by the dasd_block_tasklet anymore.
2666 		 * Replace the callback so we notice when the request
2667 		 * is returned from the dasd_device layer.
2668 		 */
2669 		cqr->callback = _dasd_wake_block_flush_cb;
2670 		for (i = 0; cqr != NULL; cqr = cqr->refers, i++)
2671 			list_move_tail(&cqr->blocklist, &flush_queue);
2672 		if (i > 1)
2673 			/* moved more than one request - need to restart */
2674 			goto restart;
2675 	}
2676 	spin_unlock_bh(&block->queue_lock);
2677 	/* Now call the callback function of flushed requests */
2678 restart_cb:
2679 	list_for_each_entry_safe(cqr, n, &flush_queue, blocklist) {
2680 		wait_event(dasd_flush_wq, (cqr->status < DASD_CQR_QUEUED));
2681 		/* Process finished ERP request. */
2682 		if (cqr->refers) {
2683 			spin_lock_bh(&block->queue_lock);
2684 			__dasd_process_erp(block->base, cqr);
2685 			spin_unlock_bh(&block->queue_lock);
2686 			/* restart list_for_xx loop since dasd_process_erp
2687 			 * might remove multiple elements */
2688 			goto restart_cb;
2689 		}
2690 		/* call the callback function */
2691 		spin_lock_irq(&block->request_queue_lock);
2692 		cqr->endclk = get_clock();
2693 		list_del_init(&cqr->blocklist);
2694 		__dasd_cleanup_cqr(cqr);
2695 		spin_unlock_irq(&block->request_queue_lock);
2696 	}
2697 	return rc;
2698 }
2699 
2700 /*
2701  * Schedules a call to dasd_tasklet over the device tasklet.
2702  */
2703 void dasd_schedule_block_bh(struct dasd_block *block)
2704 {
2705 	/* Protect against rescheduling. */
2706 	if (atomic_cmpxchg(&block->tasklet_scheduled, 0, 1) != 0)
2707 		return;
2708 	/* life cycle of block is bound to it's base device */
2709 	dasd_get_device(block->base);
2710 	tasklet_hi_schedule(&block->tasklet);
2711 }
2712 
2713 
2714 /*
2715  * SECTION: external block device operations
2716  * (request queue handling, open, release, etc.)
2717  */
2718 
2719 /*
2720  * Dasd request queue function. Called from ll_rw_blk.c
2721  */
2722 static void do_dasd_request(struct request_queue *queue)
2723 {
2724 	struct dasd_block *block;
2725 
2726 	block = queue->queuedata;
2727 	spin_lock(&block->queue_lock);
2728 	/* Get new request from the block device request queue */
2729 	__dasd_process_request_queue(block);
2730 	/* Now check if the head of the ccw queue needs to be started. */
2731 	__dasd_block_start_head(block);
2732 	spin_unlock(&block->queue_lock);
2733 }
2734 
2735 /*
2736  * Allocate and initialize request queue and default I/O scheduler.
2737  */
2738 static int dasd_alloc_queue(struct dasd_block *block)
2739 {
2740 	int rc;
2741 
2742 	block->request_queue = blk_init_queue(do_dasd_request,
2743 					       &block->request_queue_lock);
2744 	if (block->request_queue == NULL)
2745 		return -ENOMEM;
2746 
2747 	block->request_queue->queuedata = block;
2748 
2749 	elevator_exit(block->request_queue->elevator);
2750 	block->request_queue->elevator = NULL;
2751 	rc = elevator_init(block->request_queue, "deadline");
2752 	if (rc) {
2753 		blk_cleanup_queue(block->request_queue);
2754 		return rc;
2755 	}
2756 	return 0;
2757 }
2758 
2759 /*
2760  * Allocate and initialize request queue.
2761  */
2762 static void dasd_setup_queue(struct dasd_block *block)
2763 {
2764 	int max;
2765 
2766 	if (block->base->features & DASD_FEATURE_USERAW) {
2767 		/*
2768 		 * the max_blocks value for raw_track access is 256
2769 		 * it is higher than the native ECKD value because we
2770 		 * only need one ccw per track
2771 		 * so the max_hw_sectors are
2772 		 * 2048 x 512B = 1024kB = 16 tracks
2773 		 */
2774 		max = 2048;
2775 	} else {
2776 		max = block->base->discipline->max_blocks << block->s2b_shift;
2777 	}
2778 	blk_queue_logical_block_size(block->request_queue,
2779 				     block->bp_block);
2780 	blk_queue_max_hw_sectors(block->request_queue, max);
2781 	blk_queue_max_segments(block->request_queue, -1L);
2782 	/* with page sized segments we can translate each segement into
2783 	 * one idaw/tidaw
2784 	 */
2785 	blk_queue_max_segment_size(block->request_queue, PAGE_SIZE);
2786 	blk_queue_segment_boundary(block->request_queue, PAGE_SIZE - 1);
2787 }
2788 
2789 /*
2790  * Deactivate and free request queue.
2791  */
2792 static void dasd_free_queue(struct dasd_block *block)
2793 {
2794 	if (block->request_queue) {
2795 		blk_cleanup_queue(block->request_queue);
2796 		block->request_queue = NULL;
2797 	}
2798 }
2799 
2800 /*
2801  * Flush request on the request queue.
2802  */
2803 static void dasd_flush_request_queue(struct dasd_block *block)
2804 {
2805 	struct request *req;
2806 
2807 	if (!block->request_queue)
2808 		return;
2809 
2810 	spin_lock_irq(&block->request_queue_lock);
2811 	while ((req = blk_fetch_request(block->request_queue)))
2812 		__blk_end_request_all(req, -EIO);
2813 	spin_unlock_irq(&block->request_queue_lock);
2814 }
2815 
2816 static int dasd_open(struct block_device *bdev, fmode_t mode)
2817 {
2818 	struct dasd_device *base;
2819 	int rc;
2820 
2821 	base = dasd_device_from_gendisk(bdev->bd_disk);
2822 	if (!base)
2823 		return -ENODEV;
2824 
2825 	atomic_inc(&base->block->open_count);
2826 	if (test_bit(DASD_FLAG_OFFLINE, &base->flags)) {
2827 		rc = -ENODEV;
2828 		goto unlock;
2829 	}
2830 
2831 	if (!try_module_get(base->discipline->owner)) {
2832 		rc = -EINVAL;
2833 		goto unlock;
2834 	}
2835 
2836 	if (dasd_probeonly) {
2837 		dev_info(&base->cdev->dev,
2838 			 "Accessing the DASD failed because it is in "
2839 			 "probeonly mode\n");
2840 		rc = -EPERM;
2841 		goto out;
2842 	}
2843 
2844 	if (base->state <= DASD_STATE_BASIC) {
2845 		DBF_DEV_EVENT(DBF_ERR, base, " %s",
2846 			      " Cannot open unrecognized device");
2847 		rc = -ENODEV;
2848 		goto out;
2849 	}
2850 
2851 	if ((mode & FMODE_WRITE) &&
2852 	    (test_bit(DASD_FLAG_DEVICE_RO, &base->flags) ||
2853 	     (base->features & DASD_FEATURE_READONLY))) {
2854 		rc = -EROFS;
2855 		goto out;
2856 	}
2857 
2858 	dasd_put_device(base);
2859 	return 0;
2860 
2861 out:
2862 	module_put(base->discipline->owner);
2863 unlock:
2864 	atomic_dec(&base->block->open_count);
2865 	dasd_put_device(base);
2866 	return rc;
2867 }
2868 
2869 static int dasd_release(struct gendisk *disk, fmode_t mode)
2870 {
2871 	struct dasd_device *base;
2872 
2873 	base = dasd_device_from_gendisk(disk);
2874 	if (!base)
2875 		return -ENODEV;
2876 
2877 	atomic_dec(&base->block->open_count);
2878 	module_put(base->discipline->owner);
2879 	dasd_put_device(base);
2880 	return 0;
2881 }
2882 
2883 /*
2884  * Return disk geometry.
2885  */
2886 static int dasd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
2887 {
2888 	struct dasd_device *base;
2889 
2890 	base = dasd_device_from_gendisk(bdev->bd_disk);
2891 	if (!base)
2892 		return -ENODEV;
2893 
2894 	if (!base->discipline ||
2895 	    !base->discipline->fill_geometry) {
2896 		dasd_put_device(base);
2897 		return -EINVAL;
2898 	}
2899 	base->discipline->fill_geometry(base->block, geo);
2900 	geo->start = get_start_sect(bdev) >> base->block->s2b_shift;
2901 	dasd_put_device(base);
2902 	return 0;
2903 }
2904 
2905 const struct block_device_operations
2906 dasd_device_operations = {
2907 	.owner		= THIS_MODULE,
2908 	.open		= dasd_open,
2909 	.release	= dasd_release,
2910 	.ioctl		= dasd_ioctl,
2911 	.compat_ioctl	= dasd_ioctl,
2912 	.getgeo		= dasd_getgeo,
2913 };
2914 
2915 /*******************************************************************************
2916  * end of block device operations
2917  */
2918 
2919 static void
2920 dasd_exit(void)
2921 {
2922 #ifdef CONFIG_PROC_FS
2923 	dasd_proc_exit();
2924 #endif
2925 	dasd_eer_exit();
2926         if (dasd_page_cache != NULL) {
2927 		kmem_cache_destroy(dasd_page_cache);
2928 		dasd_page_cache = NULL;
2929 	}
2930 	dasd_gendisk_exit();
2931 	dasd_devmap_exit();
2932 	if (dasd_debug_area != NULL) {
2933 		debug_unregister(dasd_debug_area);
2934 		dasd_debug_area = NULL;
2935 	}
2936 	dasd_statistics_removeroot();
2937 }
2938 
2939 /*
2940  * SECTION: common functions for ccw_driver use
2941  */
2942 
2943 /*
2944  * Is the device read-only?
2945  * Note that this function does not report the setting of the
2946  * readonly device attribute, but how it is configured in z/VM.
2947  */
2948 int dasd_device_is_ro(struct dasd_device *device)
2949 {
2950 	struct ccw_dev_id dev_id;
2951 	struct diag210 diag_data;
2952 	int rc;
2953 
2954 	if (!MACHINE_IS_VM)
2955 		return 0;
2956 	ccw_device_get_id(device->cdev, &dev_id);
2957 	memset(&diag_data, 0, sizeof(diag_data));
2958 	diag_data.vrdcdvno = dev_id.devno;
2959 	diag_data.vrdclen = sizeof(diag_data);
2960 	rc = diag210(&diag_data);
2961 	if (rc == 0 || rc == 2) {
2962 		return diag_data.vrdcvfla & 0x80;
2963 	} else {
2964 		DBF_EVENT(DBF_WARNING, "diag210 failed for dev=%04x with rc=%d",
2965 			  dev_id.devno, rc);
2966 		return 0;
2967 	}
2968 }
2969 EXPORT_SYMBOL_GPL(dasd_device_is_ro);
2970 
2971 static void dasd_generic_auto_online(void *data, async_cookie_t cookie)
2972 {
2973 	struct ccw_device *cdev = data;
2974 	int ret;
2975 
2976 	ret = ccw_device_set_online(cdev);
2977 	if (ret)
2978 		pr_warning("%s: Setting the DASD online failed with rc=%d\n",
2979 			   dev_name(&cdev->dev), ret);
2980 }
2981 
2982 /*
2983  * Initial attempt at a probe function. this can be simplified once
2984  * the other detection code is gone.
2985  */
2986 int dasd_generic_probe(struct ccw_device *cdev,
2987 		       struct dasd_discipline *discipline)
2988 {
2989 	int ret;
2990 
2991 	ret = dasd_add_sysfs_files(cdev);
2992 	if (ret) {
2993 		DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s",
2994 				"dasd_generic_probe: could not add "
2995 				"sysfs entries");
2996 		return ret;
2997 	}
2998 	cdev->handler = &dasd_int_handler;
2999 
3000 	/*
3001 	 * Automatically online either all dasd devices (dasd_autodetect)
3002 	 * or all devices specified with dasd= parameters during
3003 	 * initial probe.
3004 	 */
3005 	if ((dasd_get_feature(cdev, DASD_FEATURE_INITIAL_ONLINE) > 0 ) ||
3006 	    (dasd_autodetect && dasd_busid_known(dev_name(&cdev->dev)) != 0))
3007 		async_schedule(dasd_generic_auto_online, cdev);
3008 	return 0;
3009 }
3010 
3011 /*
3012  * This will one day be called from a global not_oper handler.
3013  * It is also used by driver_unregister during module unload.
3014  */
3015 void dasd_generic_remove(struct ccw_device *cdev)
3016 {
3017 	struct dasd_device *device;
3018 	struct dasd_block *block;
3019 
3020 	cdev->handler = NULL;
3021 
3022 	dasd_remove_sysfs_files(cdev);
3023 	device = dasd_device_from_cdev(cdev);
3024 	if (IS_ERR(device))
3025 		return;
3026 	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
3027 		/* Already doing offline processing */
3028 		dasd_put_device(device);
3029 		return;
3030 	}
3031 	/*
3032 	 * This device is removed unconditionally. Set offline
3033 	 * flag to prevent dasd_open from opening it while it is
3034 	 * no quite down yet.
3035 	 */
3036 	dasd_set_target_state(device, DASD_STATE_NEW);
3037 	/* dasd_delete_device destroys the device reference. */
3038 	block = device->block;
3039 	dasd_delete_device(device);
3040 	/*
3041 	 * life cycle of block is bound to device, so delete it after
3042 	 * device was safely removed
3043 	 */
3044 	if (block)
3045 		dasd_free_block(block);
3046 }
3047 
3048 /*
3049  * Activate a device. This is called from dasd_{eckd,fba}_probe() when either
3050  * the device is detected for the first time and is supposed to be used
3051  * or the user has started activation through sysfs.
3052  */
3053 int dasd_generic_set_online(struct ccw_device *cdev,
3054 			    struct dasd_discipline *base_discipline)
3055 {
3056 	struct dasd_discipline *discipline;
3057 	struct dasd_device *device;
3058 	int rc;
3059 
3060 	/* first online clears initial online feature flag */
3061 	dasd_set_feature(cdev, DASD_FEATURE_INITIAL_ONLINE, 0);
3062 	device = dasd_create_device(cdev);
3063 	if (IS_ERR(device))
3064 		return PTR_ERR(device);
3065 
3066 	discipline = base_discipline;
3067 	if (device->features & DASD_FEATURE_USEDIAG) {
3068 	  	if (!dasd_diag_discipline_pointer) {
3069 			pr_warning("%s Setting the DASD online failed because "
3070 				   "of missing DIAG discipline\n",
3071 				   dev_name(&cdev->dev));
3072 			dasd_delete_device(device);
3073 			return -ENODEV;
3074 		}
3075 		discipline = dasd_diag_discipline_pointer;
3076 	}
3077 	if (!try_module_get(base_discipline->owner)) {
3078 		dasd_delete_device(device);
3079 		return -EINVAL;
3080 	}
3081 	if (!try_module_get(discipline->owner)) {
3082 		module_put(base_discipline->owner);
3083 		dasd_delete_device(device);
3084 		return -EINVAL;
3085 	}
3086 	device->base_discipline = base_discipline;
3087 	device->discipline = discipline;
3088 
3089 	/* check_device will allocate block device if necessary */
3090 	rc = discipline->check_device(device);
3091 	if (rc) {
3092 		pr_warning("%s Setting the DASD online with discipline %s "
3093 			   "failed with rc=%i\n",
3094 			   dev_name(&cdev->dev), discipline->name, rc);
3095 		module_put(discipline->owner);
3096 		module_put(base_discipline->owner);
3097 		dasd_delete_device(device);
3098 		return rc;
3099 	}
3100 
3101 	dasd_set_target_state(device, DASD_STATE_ONLINE);
3102 	if (device->state <= DASD_STATE_KNOWN) {
3103 		pr_warning("%s Setting the DASD online failed because of a "
3104 			   "missing discipline\n", dev_name(&cdev->dev));
3105 		rc = -ENODEV;
3106 		dasd_set_target_state(device, DASD_STATE_NEW);
3107 		if (device->block)
3108 			dasd_free_block(device->block);
3109 		dasd_delete_device(device);
3110 	} else
3111 		pr_debug("dasd_generic device %s found\n",
3112 				dev_name(&cdev->dev));
3113 
3114 	wait_event(dasd_init_waitq, _wait_for_device(device));
3115 
3116 	dasd_put_device(device);
3117 	return rc;
3118 }
3119 
3120 int dasd_generic_set_offline(struct ccw_device *cdev)
3121 {
3122 	struct dasd_device *device;
3123 	struct dasd_block *block;
3124 	int max_count, open_count;
3125 
3126 	device = dasd_device_from_cdev(cdev);
3127 	if (IS_ERR(device))
3128 		return PTR_ERR(device);
3129 	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
3130 		/* Already doing offline processing */
3131 		dasd_put_device(device);
3132 		return 0;
3133 	}
3134 	/*
3135 	 * We must make sure that this device is currently not in use.
3136 	 * The open_count is increased for every opener, that includes
3137 	 * the blkdev_get in dasd_scan_partitions. We are only interested
3138 	 * in the other openers.
3139 	 */
3140 	if (device->block) {
3141 		max_count = device->block->bdev ? 0 : -1;
3142 		open_count = atomic_read(&device->block->open_count);
3143 		if (open_count > max_count) {
3144 			if (open_count > 0)
3145 				pr_warning("%s: The DASD cannot be set offline "
3146 					   "with open count %i\n",
3147 					   dev_name(&cdev->dev), open_count);
3148 			else
3149 				pr_warning("%s: The DASD cannot be set offline "
3150 					   "while it is in use\n",
3151 					   dev_name(&cdev->dev));
3152 			clear_bit(DASD_FLAG_OFFLINE, &device->flags);
3153 			dasd_put_device(device);
3154 			return -EBUSY;
3155 		}
3156 	}
3157 	dasd_set_target_state(device, DASD_STATE_NEW);
3158 	/* dasd_delete_device destroys the device reference. */
3159 	block = device->block;
3160 	dasd_delete_device(device);
3161 	/*
3162 	 * life cycle of block is bound to device, so delete it after
3163 	 * device was safely removed
3164 	 */
3165 	if (block)
3166 		dasd_free_block(block);
3167 	return 0;
3168 }
3169 
3170 int dasd_generic_last_path_gone(struct dasd_device *device)
3171 {
3172 	struct dasd_ccw_req *cqr;
3173 
3174 	dev_warn(&device->cdev->dev, "No operational channel path is left "
3175 		 "for the device\n");
3176 	DBF_DEV_EVENT(DBF_WARNING, device, "%s", "last path gone");
3177 	/* First of all call extended error reporting. */
3178 	dasd_eer_write(device, NULL, DASD_EER_NOPATH);
3179 
3180 	if (device->state < DASD_STATE_BASIC)
3181 		return 0;
3182 	/* Device is active. We want to keep it. */
3183 	list_for_each_entry(cqr, &device->ccw_queue, devlist)
3184 		if ((cqr->status == DASD_CQR_IN_IO) ||
3185 		    (cqr->status == DASD_CQR_CLEAR_PENDING)) {
3186 			cqr->status = DASD_CQR_QUEUED;
3187 			cqr->retries++;
3188 		}
3189 	dasd_device_set_stop_bits(device, DASD_STOPPED_DC_WAIT);
3190 	dasd_device_clear_timer(device);
3191 	dasd_schedule_device_bh(device);
3192 	return 1;
3193 }
3194 EXPORT_SYMBOL_GPL(dasd_generic_last_path_gone);
3195 
3196 int dasd_generic_path_operational(struct dasd_device *device)
3197 {
3198 	dev_info(&device->cdev->dev, "A channel path to the device has become "
3199 		 "operational\n");
3200 	DBF_DEV_EVENT(DBF_WARNING, device, "%s", "path operational");
3201 	dasd_device_remove_stop_bits(device, DASD_STOPPED_DC_WAIT);
3202 	if (device->stopped & DASD_UNRESUMED_PM) {
3203 		dasd_device_remove_stop_bits(device, DASD_UNRESUMED_PM);
3204 		dasd_restore_device(device);
3205 		return 1;
3206 	}
3207 	dasd_schedule_device_bh(device);
3208 	if (device->block)
3209 		dasd_schedule_block_bh(device->block);
3210 	return 1;
3211 }
3212 EXPORT_SYMBOL_GPL(dasd_generic_path_operational);
3213 
3214 int dasd_generic_notify(struct ccw_device *cdev, int event)
3215 {
3216 	struct dasd_device *device;
3217 	int ret;
3218 
3219 	device = dasd_device_from_cdev_locked(cdev);
3220 	if (IS_ERR(device))
3221 		return 0;
3222 	ret = 0;
3223 	switch (event) {
3224 	case CIO_GONE:
3225 	case CIO_BOXED:
3226 	case CIO_NO_PATH:
3227 		device->path_data.opm = 0;
3228 		device->path_data.ppm = 0;
3229 		device->path_data.npm = 0;
3230 		ret = dasd_generic_last_path_gone(device);
3231 		break;
3232 	case CIO_OPER:
3233 		ret = 1;
3234 		if (device->path_data.opm)
3235 			ret = dasd_generic_path_operational(device);
3236 		break;
3237 	}
3238 	dasd_put_device(device);
3239 	return ret;
3240 }
3241 
3242 void dasd_generic_path_event(struct ccw_device *cdev, int *path_event)
3243 {
3244 	int chp;
3245 	__u8 oldopm, eventlpm;
3246 	struct dasd_device *device;
3247 
3248 	device = dasd_device_from_cdev_locked(cdev);
3249 	if (IS_ERR(device))
3250 		return;
3251 	for (chp = 0; chp < 8; chp++) {
3252 		eventlpm = 0x80 >> chp;
3253 		if (path_event[chp] & PE_PATH_GONE) {
3254 			oldopm = device->path_data.opm;
3255 			device->path_data.opm &= ~eventlpm;
3256 			device->path_data.ppm &= ~eventlpm;
3257 			device->path_data.npm &= ~eventlpm;
3258 			if (oldopm && !device->path_data.opm)
3259 				dasd_generic_last_path_gone(device);
3260 		}
3261 		if (path_event[chp] & PE_PATH_AVAILABLE) {
3262 			device->path_data.opm &= ~eventlpm;
3263 			device->path_data.ppm &= ~eventlpm;
3264 			device->path_data.npm &= ~eventlpm;
3265 			device->path_data.tbvpm |= eventlpm;
3266 			dasd_schedule_device_bh(device);
3267 		}
3268 		if (path_event[chp] & PE_PATHGROUP_ESTABLISHED) {
3269 			DBF_DEV_EVENT(DBF_WARNING, device, "%s",
3270 				      "Pathgroup re-established\n");
3271 			if (device->discipline->kick_validate)
3272 				device->discipline->kick_validate(device);
3273 		}
3274 	}
3275 	dasd_put_device(device);
3276 }
3277 EXPORT_SYMBOL_GPL(dasd_generic_path_event);
3278 
3279 int dasd_generic_verify_path(struct dasd_device *device, __u8 lpm)
3280 {
3281 	if (!device->path_data.opm && lpm) {
3282 		device->path_data.opm = lpm;
3283 		dasd_generic_path_operational(device);
3284 	} else
3285 		device->path_data.opm |= lpm;
3286 	return 0;
3287 }
3288 EXPORT_SYMBOL_GPL(dasd_generic_verify_path);
3289 
3290 
3291 int dasd_generic_pm_freeze(struct ccw_device *cdev)
3292 {
3293 	struct dasd_ccw_req *cqr, *n;
3294 	int rc;
3295 	struct list_head freeze_queue;
3296 	struct dasd_device *device = dasd_device_from_cdev(cdev);
3297 
3298 	if (IS_ERR(device))
3299 		return PTR_ERR(device);
3300 
3301 	/* mark device as suspended */
3302 	set_bit(DASD_FLAG_SUSPENDED, &device->flags);
3303 
3304 	if (device->discipline->freeze)
3305 		rc = device->discipline->freeze(device);
3306 
3307 	/* disallow new I/O  */
3308 	dasd_device_set_stop_bits(device, DASD_STOPPED_PM);
3309 	/* clear active requests */
3310 	INIT_LIST_HEAD(&freeze_queue);
3311 	spin_lock_irq(get_ccwdev_lock(cdev));
3312 	rc = 0;
3313 	list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
3314 		/* Check status and move request to flush_queue */
3315 		if (cqr->status == DASD_CQR_IN_IO) {
3316 			rc = device->discipline->term_IO(cqr);
3317 			if (rc) {
3318 				/* unable to terminate requeust */
3319 				dev_err(&device->cdev->dev,
3320 					"Unable to terminate request %p "
3321 					"on suspend\n", cqr);
3322 				spin_unlock_irq(get_ccwdev_lock(cdev));
3323 				dasd_put_device(device);
3324 				return rc;
3325 			}
3326 		}
3327 		list_move_tail(&cqr->devlist, &freeze_queue);
3328 	}
3329 
3330 	spin_unlock_irq(get_ccwdev_lock(cdev));
3331 
3332 	list_for_each_entry_safe(cqr, n, &freeze_queue, devlist) {
3333 		wait_event(dasd_flush_wq,
3334 			   (cqr->status != DASD_CQR_CLEAR_PENDING));
3335 		if (cqr->status == DASD_CQR_CLEARED)
3336 			cqr->status = DASD_CQR_QUEUED;
3337 	}
3338 	/* move freeze_queue to start of the ccw_queue */
3339 	spin_lock_irq(get_ccwdev_lock(cdev));
3340 	list_splice_tail(&freeze_queue, &device->ccw_queue);
3341 	spin_unlock_irq(get_ccwdev_lock(cdev));
3342 
3343 	dasd_put_device(device);
3344 	return rc;
3345 }
3346 EXPORT_SYMBOL_GPL(dasd_generic_pm_freeze);
3347 
3348 int dasd_generic_restore_device(struct ccw_device *cdev)
3349 {
3350 	struct dasd_device *device = dasd_device_from_cdev(cdev);
3351 	int rc = 0;
3352 
3353 	if (IS_ERR(device))
3354 		return PTR_ERR(device);
3355 
3356 	/* allow new IO again */
3357 	dasd_device_remove_stop_bits(device,
3358 				     (DASD_STOPPED_PM | DASD_UNRESUMED_PM));
3359 
3360 	dasd_schedule_device_bh(device);
3361 
3362 	/*
3363 	 * call discipline restore function
3364 	 * if device is stopped do nothing e.g. for disconnected devices
3365 	 */
3366 	if (device->discipline->restore && !(device->stopped))
3367 		rc = device->discipline->restore(device);
3368 	if (rc || device->stopped)
3369 		/*
3370 		 * if the resume failed for the DASD we put it in
3371 		 * an UNRESUMED stop state
3372 		 */
3373 		device->stopped |= DASD_UNRESUMED_PM;
3374 
3375 	if (device->block)
3376 		dasd_schedule_block_bh(device->block);
3377 
3378 	clear_bit(DASD_FLAG_SUSPENDED, &device->flags);
3379 	dasd_put_device(device);
3380 	return 0;
3381 }
3382 EXPORT_SYMBOL_GPL(dasd_generic_restore_device);
3383 
3384 static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
3385 						   void *rdc_buffer,
3386 						   int rdc_buffer_size,
3387 						   int magic)
3388 {
3389 	struct dasd_ccw_req *cqr;
3390 	struct ccw1 *ccw;
3391 	unsigned long *idaw;
3392 
3393 	cqr = dasd_smalloc_request(magic, 1 /* RDC */, rdc_buffer_size, device);
3394 
3395 	if (IS_ERR(cqr)) {
3396 		/* internal error 13 - Allocating the RDC request failed*/
3397 		dev_err(&device->cdev->dev,
3398 			 "An error occurred in the DASD device driver, "
3399 			 "reason=%s\n", "13");
3400 		return cqr;
3401 	}
3402 
3403 	ccw = cqr->cpaddr;
3404 	ccw->cmd_code = CCW_CMD_RDC;
3405 	if (idal_is_needed(rdc_buffer, rdc_buffer_size)) {
3406 		idaw = (unsigned long *) (cqr->data);
3407 		ccw->cda = (__u32)(addr_t) idaw;
3408 		ccw->flags = CCW_FLAG_IDA;
3409 		idaw = idal_create_words(idaw, rdc_buffer, rdc_buffer_size);
3410 	} else {
3411 		ccw->cda = (__u32)(addr_t) rdc_buffer;
3412 		ccw->flags = 0;
3413 	}
3414 
3415 	ccw->count = rdc_buffer_size;
3416 	cqr->startdev = device;
3417 	cqr->memdev = device;
3418 	cqr->expires = 10*HZ;
3419 	cqr->retries = 256;
3420 	cqr->buildclk = get_clock();
3421 	cqr->status = DASD_CQR_FILLED;
3422 	return cqr;
3423 }
3424 
3425 
3426 int dasd_generic_read_dev_chars(struct dasd_device *device, int magic,
3427 				void *rdc_buffer, int rdc_buffer_size)
3428 {
3429 	int ret;
3430 	struct dasd_ccw_req *cqr;
3431 
3432 	cqr = dasd_generic_build_rdc(device, rdc_buffer, rdc_buffer_size,
3433 				     magic);
3434 	if (IS_ERR(cqr))
3435 		return PTR_ERR(cqr);
3436 
3437 	ret = dasd_sleep_on(cqr);
3438 	dasd_sfree_request(cqr, cqr->memdev);
3439 	return ret;
3440 }
3441 EXPORT_SYMBOL_GPL(dasd_generic_read_dev_chars);
3442 
3443 /*
3444  *   In command mode and transport mode we need to look for sense
3445  *   data in different places. The sense data itself is allways
3446  *   an array of 32 bytes, so we can unify the sense data access
3447  *   for both modes.
3448  */
3449 char *dasd_get_sense(struct irb *irb)
3450 {
3451 	struct tsb *tsb = NULL;
3452 	char *sense = NULL;
3453 
3454 	if (scsw_is_tm(&irb->scsw) && (irb->scsw.tm.fcxs == 0x01)) {
3455 		if (irb->scsw.tm.tcw)
3456 			tsb = tcw_get_tsb((struct tcw *)(unsigned long)
3457 					  irb->scsw.tm.tcw);
3458 		if (tsb && tsb->length == 64 && tsb->flags)
3459 			switch (tsb->flags & 0x07) {
3460 			case 1:	/* tsa_iostat */
3461 				sense = tsb->tsa.iostat.sense;
3462 				break;
3463 			case 2: /* tsa_ddpc */
3464 				sense = tsb->tsa.ddpc.sense;
3465 				break;
3466 			default:
3467 				/* currently we don't use interrogate data */
3468 				break;
3469 			}
3470 	} else if (irb->esw.esw0.erw.cons) {
3471 		sense = irb->ecw;
3472 	}
3473 	return sense;
3474 }
3475 EXPORT_SYMBOL_GPL(dasd_get_sense);
3476 
3477 static int __init dasd_init(void)
3478 {
3479 	int rc;
3480 
3481 	init_waitqueue_head(&dasd_init_waitq);
3482 	init_waitqueue_head(&dasd_flush_wq);
3483 	init_waitqueue_head(&generic_waitq);
3484 
3485 	/* register 'common' DASD debug area, used for all DBF_XXX calls */
3486 	dasd_debug_area = debug_register("dasd", 1, 1, 8 * sizeof(long));
3487 	if (dasd_debug_area == NULL) {
3488 		rc = -ENOMEM;
3489 		goto failed;
3490 	}
3491 	debug_register_view(dasd_debug_area, &debug_sprintf_view);
3492 	debug_set_level(dasd_debug_area, DBF_WARNING);
3493 
3494 	DBF_EVENT(DBF_EMERG, "%s", "debug area created");
3495 
3496 	dasd_diag_discipline_pointer = NULL;
3497 
3498 	dasd_statistics_createroot();
3499 
3500 	rc = dasd_devmap_init();
3501 	if (rc)
3502 		goto failed;
3503 	rc = dasd_gendisk_init();
3504 	if (rc)
3505 		goto failed;
3506 	rc = dasd_parse();
3507 	if (rc)
3508 		goto failed;
3509 	rc = dasd_eer_init();
3510 	if (rc)
3511 		goto failed;
3512 #ifdef CONFIG_PROC_FS
3513 	rc = dasd_proc_init();
3514 	if (rc)
3515 		goto failed;
3516 #endif
3517 
3518 	return 0;
3519 failed:
3520 	pr_info("The DASD device driver could not be initialized\n");
3521 	dasd_exit();
3522 	return rc;
3523 }
3524 
3525 module_init(dasd_init);
3526 module_exit(dasd_exit);
3527 
3528 EXPORT_SYMBOL(dasd_debug_area);
3529 EXPORT_SYMBOL(dasd_diag_discipline_pointer);
3530 
3531 EXPORT_SYMBOL(dasd_add_request_head);
3532 EXPORT_SYMBOL(dasd_add_request_tail);
3533 EXPORT_SYMBOL(dasd_cancel_req);
3534 EXPORT_SYMBOL(dasd_device_clear_timer);
3535 EXPORT_SYMBOL(dasd_block_clear_timer);
3536 EXPORT_SYMBOL(dasd_enable_device);
3537 EXPORT_SYMBOL(dasd_int_handler);
3538 EXPORT_SYMBOL(dasd_kfree_request);
3539 EXPORT_SYMBOL(dasd_kick_device);
3540 EXPORT_SYMBOL(dasd_kmalloc_request);
3541 EXPORT_SYMBOL(dasd_schedule_device_bh);
3542 EXPORT_SYMBOL(dasd_schedule_block_bh);
3543 EXPORT_SYMBOL(dasd_set_target_state);
3544 EXPORT_SYMBOL(dasd_device_set_timer);
3545 EXPORT_SYMBOL(dasd_block_set_timer);
3546 EXPORT_SYMBOL(dasd_sfree_request);
3547 EXPORT_SYMBOL(dasd_sleep_on);
3548 EXPORT_SYMBOL(dasd_sleep_on_immediatly);
3549 EXPORT_SYMBOL(dasd_sleep_on_interruptible);
3550 EXPORT_SYMBOL(dasd_smalloc_request);
3551 EXPORT_SYMBOL(dasd_start_IO);
3552 EXPORT_SYMBOL(dasd_term_IO);
3553 
3554 EXPORT_SYMBOL_GPL(dasd_generic_probe);
3555 EXPORT_SYMBOL_GPL(dasd_generic_remove);
3556 EXPORT_SYMBOL_GPL(dasd_generic_notify);
3557 EXPORT_SYMBOL_GPL(dasd_generic_set_online);
3558 EXPORT_SYMBOL_GPL(dasd_generic_set_offline);
3559 EXPORT_SYMBOL_GPL(dasd_generic_handle_state_change);
3560 EXPORT_SYMBOL_GPL(dasd_flush_device_queue);
3561 EXPORT_SYMBOL_GPL(dasd_alloc_block);
3562 EXPORT_SYMBOL_GPL(dasd_free_block);
3563