xref: /openbmc/linux/drivers/s390/block/dasd.c (revision f4ae40a6)
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/buffer_head.h>
21 #include <linux/hdreg.h>
22 #include <linux/async.h>
23 #include <linux/mutex.h>
24 #include <linux/debugfs.h>
25 #include <linux/seq_file.h>
26 #include <linux/vmalloc.h>
27 
28 #include <asm/ccwdev.h>
29 #include <asm/ebcdic.h>
30 #include <asm/idals.h>
31 #include <asm/itcw.h>
32 #include <asm/diag.h>
33 
34 /* This is ugly... */
35 #define PRINTK_HEADER "dasd:"
36 
37 #include "dasd_int.h"
38 /*
39  * SECTION: Constant definitions to be used within this file
40  */
41 #define DASD_CHANQ_MAX_SIZE 4
42 
43 #define DASD_SLEEPON_START_TAG	(void *) 1
44 #define DASD_SLEEPON_END_TAG	(void *) 2
45 
46 /*
47  * SECTION: exported variables of dasd.c
48  */
49 debug_info_t *dasd_debug_area;
50 static struct dentry *dasd_debugfs_root_entry;
51 struct dasd_discipline *dasd_diag_discipline_pointer;
52 void dasd_int_handler(struct ccw_device *, unsigned long, struct irb *);
53 
54 MODULE_AUTHOR("Holger Smolinski <Holger.Smolinski@de.ibm.com>");
55 MODULE_DESCRIPTION("Linux on S/390 DASD device driver,"
56 		   " Copyright 2000 IBM Corporation");
57 MODULE_SUPPORTED_DEVICE("dasd");
58 MODULE_LICENSE("GPL");
59 
60 /*
61  * SECTION: prototypes for static functions of dasd.c
62  */
63 static int  dasd_alloc_queue(struct dasd_block *);
64 static void dasd_setup_queue(struct dasd_block *);
65 static void dasd_free_queue(struct dasd_block *);
66 static void dasd_flush_request_queue(struct dasd_block *);
67 static int dasd_flush_block_queue(struct dasd_block *);
68 static void dasd_device_tasklet(struct dasd_device *);
69 static void dasd_block_tasklet(struct dasd_block *);
70 static void do_kick_device(struct work_struct *);
71 static void do_restore_device(struct work_struct *);
72 static void do_reload_device(struct work_struct *);
73 static void dasd_return_cqr_cb(struct dasd_ccw_req *, void *);
74 static void dasd_device_timeout(unsigned long);
75 static void dasd_block_timeout(unsigned long);
76 static void __dasd_process_erp(struct dasd_device *, struct dasd_ccw_req *);
77 static void dasd_profile_init(struct dasd_profile *, struct dentry *);
78 static void dasd_profile_exit(struct dasd_profile *);
79 
80 /*
81  * SECTION: Operations on the device structure.
82  */
83 static wait_queue_head_t dasd_init_waitq;
84 static wait_queue_head_t dasd_flush_wq;
85 static wait_queue_head_t generic_waitq;
86 
87 /*
88  * Allocate memory for a new device structure.
89  */
90 struct dasd_device *dasd_alloc_device(void)
91 {
92 	struct dasd_device *device;
93 
94 	device = kzalloc(sizeof(struct dasd_device), GFP_ATOMIC);
95 	if (!device)
96 		return ERR_PTR(-ENOMEM);
97 
98 	/* Get two pages for normal block device operations. */
99 	device->ccw_mem = (void *) __get_free_pages(GFP_ATOMIC | GFP_DMA, 1);
100 	if (!device->ccw_mem) {
101 		kfree(device);
102 		return ERR_PTR(-ENOMEM);
103 	}
104 	/* Get one page for error recovery. */
105 	device->erp_mem = (void *) get_zeroed_page(GFP_ATOMIC | GFP_DMA);
106 	if (!device->erp_mem) {
107 		free_pages((unsigned long) device->ccw_mem, 1);
108 		kfree(device);
109 		return ERR_PTR(-ENOMEM);
110 	}
111 
112 	dasd_init_chunklist(&device->ccw_chunks, device->ccw_mem, PAGE_SIZE*2);
113 	dasd_init_chunklist(&device->erp_chunks, device->erp_mem, PAGE_SIZE);
114 	spin_lock_init(&device->mem_lock);
115 	atomic_set(&device->tasklet_scheduled, 0);
116 	tasklet_init(&device->tasklet,
117 		     (void (*)(unsigned long)) dasd_device_tasklet,
118 		     (unsigned long) device);
119 	INIT_LIST_HEAD(&device->ccw_queue);
120 	init_timer(&device->timer);
121 	device->timer.function = dasd_device_timeout;
122 	device->timer.data = (unsigned long) device;
123 	INIT_WORK(&device->kick_work, do_kick_device);
124 	INIT_WORK(&device->restore_device, do_restore_device);
125 	INIT_WORK(&device->reload_device, do_reload_device);
126 	device->state = DASD_STATE_NEW;
127 	device->target = DASD_STATE_NEW;
128 	mutex_init(&device->state_mutex);
129 	spin_lock_init(&device->profile.lock);
130 	return device;
131 }
132 
133 /*
134  * Free memory of a device structure.
135  */
136 void dasd_free_device(struct dasd_device *device)
137 {
138 	kfree(device->private);
139 	free_page((unsigned long) device->erp_mem);
140 	free_pages((unsigned long) device->ccw_mem, 1);
141 	kfree(device);
142 }
143 
144 /*
145  * Allocate memory for a new device structure.
146  */
147 struct dasd_block *dasd_alloc_block(void)
148 {
149 	struct dasd_block *block;
150 
151 	block = kzalloc(sizeof(*block), GFP_ATOMIC);
152 	if (!block)
153 		return ERR_PTR(-ENOMEM);
154 	/* open_count = 0 means device online but not in use */
155 	atomic_set(&block->open_count, -1);
156 
157 	spin_lock_init(&block->request_queue_lock);
158 	atomic_set(&block->tasklet_scheduled, 0);
159 	tasklet_init(&block->tasklet,
160 		     (void (*)(unsigned long)) dasd_block_tasklet,
161 		     (unsigned long) block);
162 	INIT_LIST_HEAD(&block->ccw_queue);
163 	spin_lock_init(&block->queue_lock);
164 	init_timer(&block->timer);
165 	block->timer.function = dasd_block_timeout;
166 	block->timer.data = (unsigned long) block;
167 	spin_lock_init(&block->profile.lock);
168 
169 	return block;
170 }
171 
172 /*
173  * Free memory of a device structure.
174  */
175 void dasd_free_block(struct dasd_block *block)
176 {
177 	kfree(block);
178 }
179 
180 /*
181  * Make a new device known to the system.
182  */
183 static int dasd_state_new_to_known(struct dasd_device *device)
184 {
185 	int rc;
186 
187 	/*
188 	 * As long as the device is not in state DASD_STATE_NEW we want to
189 	 * keep the reference count > 0.
190 	 */
191 	dasd_get_device(device);
192 
193 	if (device->block) {
194 		rc = dasd_alloc_queue(device->block);
195 		if (rc) {
196 			dasd_put_device(device);
197 			return rc;
198 		}
199 	}
200 	device->state = DASD_STATE_KNOWN;
201 	return 0;
202 }
203 
204 /*
205  * Let the system forget about a device.
206  */
207 static int dasd_state_known_to_new(struct dasd_device *device)
208 {
209 	/* Disable extended error reporting for this device. */
210 	dasd_eer_disable(device);
211 	/* Forget the discipline information. */
212 	if (device->discipline) {
213 		if (device->discipline->uncheck_device)
214 			device->discipline->uncheck_device(device);
215 		module_put(device->discipline->owner);
216 	}
217 	device->discipline = NULL;
218 	if (device->base_discipline)
219 		module_put(device->base_discipline->owner);
220 	device->base_discipline = NULL;
221 	device->state = DASD_STATE_NEW;
222 
223 	if (device->block)
224 		dasd_free_queue(device->block);
225 
226 	/* Give up reference we took in dasd_state_new_to_known. */
227 	dasd_put_device(device);
228 	return 0;
229 }
230 
231 static struct dentry *dasd_debugfs_setup(const char *name,
232 					 struct dentry *base_dentry)
233 {
234 	struct dentry *pde;
235 
236 	if (!base_dentry)
237 		return NULL;
238 	pde = debugfs_create_dir(name, base_dentry);
239 	if (!pde || IS_ERR(pde))
240 		return NULL;
241 	return pde;
242 }
243 
244 /*
245  * Request the irq line for the device.
246  */
247 static int dasd_state_known_to_basic(struct dasd_device *device)
248 {
249 	struct dasd_block *block = device->block;
250 	int rc;
251 
252 	/* Allocate and register gendisk structure. */
253 	if (block) {
254 		rc = dasd_gendisk_alloc(block);
255 		if (rc)
256 			return rc;
257 		block->debugfs_dentry =
258 			dasd_debugfs_setup(block->gdp->disk_name,
259 					   dasd_debugfs_root_entry);
260 		dasd_profile_init(&block->profile, block->debugfs_dentry);
261 		if (dasd_global_profile_level == DASD_PROFILE_ON)
262 			dasd_profile_on(&device->block->profile);
263 	}
264 	device->debugfs_dentry =
265 		dasd_debugfs_setup(dev_name(&device->cdev->dev),
266 				   dasd_debugfs_root_entry);
267 	dasd_profile_init(&device->profile, device->debugfs_dentry);
268 
269 	/* register 'device' debug area, used for all DBF_DEV_XXX calls */
270 	device->debug_area = debug_register(dev_name(&device->cdev->dev), 4, 1,
271 					    8 * sizeof(long));
272 	debug_register_view(device->debug_area, &debug_sprintf_view);
273 	debug_set_level(device->debug_area, DBF_WARNING);
274 	DBF_DEV_EVENT(DBF_EMERG, device, "%s", "debug area created");
275 
276 	device->state = DASD_STATE_BASIC;
277 	return 0;
278 }
279 
280 /*
281  * Release the irq line for the device. Terminate any running i/o.
282  */
283 static int dasd_state_basic_to_known(struct dasd_device *device)
284 {
285 	int rc;
286 	if (device->block) {
287 		dasd_profile_exit(&device->block->profile);
288 		if (device->block->debugfs_dentry)
289 			debugfs_remove(device->block->debugfs_dentry);
290 		dasd_gendisk_free(device->block);
291 		dasd_block_clear_timer(device->block);
292 	}
293 	rc = dasd_flush_device_queue(device);
294 	if (rc)
295 		return rc;
296 	dasd_device_clear_timer(device);
297 	dasd_profile_exit(&device->profile);
298 	if (device->debugfs_dentry)
299 		debugfs_remove(device->debugfs_dentry);
300 
301 	DBF_DEV_EVENT(DBF_EMERG, device, "%p debug area deleted", device);
302 	if (device->debug_area != NULL) {
303 		debug_unregister(device->debug_area);
304 		device->debug_area = NULL;
305 	}
306 	device->state = DASD_STATE_KNOWN;
307 	return 0;
308 }
309 
310 /*
311  * Do the initial analysis. The do_analysis function may return
312  * -EAGAIN in which case the device keeps the state DASD_STATE_BASIC
313  * until the discipline decides to continue the startup sequence
314  * by calling the function dasd_change_state. The eckd disciplines
315  * uses this to start a ccw that detects the format. The completion
316  * interrupt for this detection ccw uses the kernel event daemon to
317  * trigger the call to dasd_change_state. All this is done in the
318  * discipline code, see dasd_eckd.c.
319  * After the analysis ccw is done (do_analysis returned 0) the block
320  * device is setup.
321  * In case the analysis returns an error, the device setup is stopped
322  * (a fake disk was already added to allow formatting).
323  */
324 static int dasd_state_basic_to_ready(struct dasd_device *device)
325 {
326 	int rc;
327 	struct dasd_block *block;
328 
329 	rc = 0;
330 	block = device->block;
331 	/* make disk known with correct capacity */
332 	if (block) {
333 		if (block->base->discipline->do_analysis != NULL)
334 			rc = block->base->discipline->do_analysis(block);
335 		if (rc) {
336 			if (rc != -EAGAIN)
337 				device->state = DASD_STATE_UNFMT;
338 			return rc;
339 		}
340 		dasd_setup_queue(block);
341 		set_capacity(block->gdp,
342 			     block->blocks << block->s2b_shift);
343 		device->state = DASD_STATE_READY;
344 		rc = dasd_scan_partitions(block);
345 		if (rc)
346 			device->state = DASD_STATE_BASIC;
347 	} else {
348 		device->state = DASD_STATE_READY;
349 	}
350 	return rc;
351 }
352 
353 /*
354  * Remove device from block device layer. Destroy dirty buffers.
355  * Forget format information. Check if the target level is basic
356  * and if it is create fake disk for formatting.
357  */
358 static int dasd_state_ready_to_basic(struct dasd_device *device)
359 {
360 	int rc;
361 
362 	device->state = DASD_STATE_BASIC;
363 	if (device->block) {
364 		struct dasd_block *block = device->block;
365 		rc = dasd_flush_block_queue(block);
366 		if (rc) {
367 			device->state = DASD_STATE_READY;
368 			return rc;
369 		}
370 		dasd_flush_request_queue(block);
371 		dasd_destroy_partitions(block);
372 		block->blocks = 0;
373 		block->bp_block = 0;
374 		block->s2b_shift = 0;
375 	}
376 	return 0;
377 }
378 
379 /*
380  * Back to basic.
381  */
382 static int dasd_state_unfmt_to_basic(struct dasd_device *device)
383 {
384 	device->state = DASD_STATE_BASIC;
385 	return 0;
386 }
387 
388 /*
389  * Make the device online and schedule the bottom half to start
390  * the requeueing of requests from the linux request queue to the
391  * ccw queue.
392  */
393 static int
394 dasd_state_ready_to_online(struct dasd_device * device)
395 {
396 	int rc;
397 	struct gendisk *disk;
398 	struct disk_part_iter piter;
399 	struct hd_struct *part;
400 
401 	if (device->discipline->ready_to_online) {
402 		rc = device->discipline->ready_to_online(device);
403 		if (rc)
404 			return rc;
405 	}
406 	device->state = DASD_STATE_ONLINE;
407 	if (device->block) {
408 		dasd_schedule_block_bh(device->block);
409 		if ((device->features & DASD_FEATURE_USERAW)) {
410 			disk = device->block->gdp;
411 			kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
412 			return 0;
413 		}
414 		disk = device->block->bdev->bd_disk;
415 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
416 		while ((part = disk_part_iter_next(&piter)))
417 			kobject_uevent(&part_to_dev(part)->kobj, KOBJ_CHANGE);
418 		disk_part_iter_exit(&piter);
419 	}
420 	return 0;
421 }
422 
423 /*
424  * Stop the requeueing of requests again.
425  */
426 static int dasd_state_online_to_ready(struct dasd_device *device)
427 {
428 	int rc;
429 	struct gendisk *disk;
430 	struct disk_part_iter piter;
431 	struct hd_struct *part;
432 
433 	if (device->discipline->online_to_ready) {
434 		rc = device->discipline->online_to_ready(device);
435 		if (rc)
436 			return rc;
437 	}
438 	device->state = DASD_STATE_READY;
439 	if (device->block && !(device->features & DASD_FEATURE_USERAW)) {
440 		disk = device->block->bdev->bd_disk;
441 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
442 		while ((part = disk_part_iter_next(&piter)))
443 			kobject_uevent(&part_to_dev(part)->kobj, KOBJ_CHANGE);
444 		disk_part_iter_exit(&piter);
445 	}
446 	return 0;
447 }
448 
449 /*
450  * Device startup state changes.
451  */
452 static int dasd_increase_state(struct dasd_device *device)
453 {
454 	int rc;
455 
456 	rc = 0;
457 	if (device->state == DASD_STATE_NEW &&
458 	    device->target >= DASD_STATE_KNOWN)
459 		rc = dasd_state_new_to_known(device);
460 
461 	if (!rc &&
462 	    device->state == DASD_STATE_KNOWN &&
463 	    device->target >= DASD_STATE_BASIC)
464 		rc = dasd_state_known_to_basic(device);
465 
466 	if (!rc &&
467 	    device->state == DASD_STATE_BASIC &&
468 	    device->target >= DASD_STATE_READY)
469 		rc = dasd_state_basic_to_ready(device);
470 
471 	if (!rc &&
472 	    device->state == DASD_STATE_UNFMT &&
473 	    device->target > DASD_STATE_UNFMT)
474 		rc = -EPERM;
475 
476 	if (!rc &&
477 	    device->state == DASD_STATE_READY &&
478 	    device->target >= DASD_STATE_ONLINE)
479 		rc = dasd_state_ready_to_online(device);
480 
481 	return rc;
482 }
483 
484 /*
485  * Device shutdown state changes.
486  */
487 static int dasd_decrease_state(struct dasd_device *device)
488 {
489 	int rc;
490 
491 	rc = 0;
492 	if (device->state == DASD_STATE_ONLINE &&
493 	    device->target <= DASD_STATE_READY)
494 		rc = dasd_state_online_to_ready(device);
495 
496 	if (!rc &&
497 	    device->state == DASD_STATE_READY &&
498 	    device->target <= DASD_STATE_BASIC)
499 		rc = dasd_state_ready_to_basic(device);
500 
501 	if (!rc &&
502 	    device->state == DASD_STATE_UNFMT &&
503 	    device->target <= DASD_STATE_BASIC)
504 		rc = dasd_state_unfmt_to_basic(device);
505 
506 	if (!rc &&
507 	    device->state == DASD_STATE_BASIC &&
508 	    device->target <= DASD_STATE_KNOWN)
509 		rc = dasd_state_basic_to_known(device);
510 
511 	if (!rc &&
512 	    device->state == DASD_STATE_KNOWN &&
513 	    device->target <= DASD_STATE_NEW)
514 		rc = dasd_state_known_to_new(device);
515 
516 	return rc;
517 }
518 
519 /*
520  * This is the main startup/shutdown routine.
521  */
522 static void dasd_change_state(struct dasd_device *device)
523 {
524 	int rc;
525 
526 	if (device->state == device->target)
527 		/* Already where we want to go today... */
528 		return;
529 	if (device->state < device->target)
530 		rc = dasd_increase_state(device);
531 	else
532 		rc = dasd_decrease_state(device);
533 	if (rc == -EAGAIN)
534 		return;
535 	if (rc)
536 		device->target = device->state;
537 
538 	if (device->state == device->target)
539 		wake_up(&dasd_init_waitq);
540 
541 	/* let user-space know that the device status changed */
542 	kobject_uevent(&device->cdev->dev.kobj, KOBJ_CHANGE);
543 }
544 
545 /*
546  * Kick starter for devices that did not complete the startup/shutdown
547  * procedure or were sleeping because of a pending state.
548  * dasd_kick_device will schedule a call do do_kick_device to the kernel
549  * event daemon.
550  */
551 static void do_kick_device(struct work_struct *work)
552 {
553 	struct dasd_device *device = container_of(work, struct dasd_device, kick_work);
554 	mutex_lock(&device->state_mutex);
555 	dasd_change_state(device);
556 	mutex_unlock(&device->state_mutex);
557 	dasd_schedule_device_bh(device);
558 	dasd_put_device(device);
559 }
560 
561 void dasd_kick_device(struct dasd_device *device)
562 {
563 	dasd_get_device(device);
564 	/* queue call to dasd_kick_device to the kernel event daemon. */
565 	schedule_work(&device->kick_work);
566 }
567 
568 /*
569  * dasd_reload_device will schedule a call do do_reload_device to the kernel
570  * event daemon.
571  */
572 static void do_reload_device(struct work_struct *work)
573 {
574 	struct dasd_device *device = container_of(work, struct dasd_device,
575 						  reload_device);
576 	device->discipline->reload(device);
577 	dasd_put_device(device);
578 }
579 
580 void dasd_reload_device(struct dasd_device *device)
581 {
582 	dasd_get_device(device);
583 	/* queue call to dasd_reload_device to the kernel event daemon. */
584 	schedule_work(&device->reload_device);
585 }
586 EXPORT_SYMBOL(dasd_reload_device);
587 
588 /*
589  * dasd_restore_device will schedule a call do do_restore_device to the kernel
590  * event daemon.
591  */
592 static void do_restore_device(struct work_struct *work)
593 {
594 	struct dasd_device *device = container_of(work, struct dasd_device,
595 						  restore_device);
596 	device->cdev->drv->restore(device->cdev);
597 	dasd_put_device(device);
598 }
599 
600 void dasd_restore_device(struct dasd_device *device)
601 {
602 	dasd_get_device(device);
603 	/* queue call to dasd_restore_device to the kernel event daemon. */
604 	schedule_work(&device->restore_device);
605 }
606 
607 /*
608  * Set the target state for a device and starts the state change.
609  */
610 void dasd_set_target_state(struct dasd_device *device, int target)
611 {
612 	dasd_get_device(device);
613 	mutex_lock(&device->state_mutex);
614 	/* If we are in probeonly mode stop at DASD_STATE_READY. */
615 	if (dasd_probeonly && target > DASD_STATE_READY)
616 		target = DASD_STATE_READY;
617 	if (device->target != target) {
618 		if (device->state == target)
619 			wake_up(&dasd_init_waitq);
620 		device->target = target;
621 	}
622 	if (device->state != device->target)
623 		dasd_change_state(device);
624 	mutex_unlock(&device->state_mutex);
625 	dasd_put_device(device);
626 }
627 
628 /*
629  * Enable devices with device numbers in [from..to].
630  */
631 static inline int _wait_for_device(struct dasd_device *device)
632 {
633 	return (device->state == device->target);
634 }
635 
636 void dasd_enable_device(struct dasd_device *device)
637 {
638 	dasd_set_target_state(device, DASD_STATE_ONLINE);
639 	if (device->state <= DASD_STATE_KNOWN)
640 		/* No discipline for device found. */
641 		dasd_set_target_state(device, DASD_STATE_NEW);
642 	/* Now wait for the devices to come up. */
643 	wait_event(dasd_init_waitq, _wait_for_device(device));
644 }
645 
646 /*
647  * SECTION: device operation (interrupt handler, start i/o, term i/o ...)
648  */
649 
650 unsigned int dasd_global_profile_level = DASD_PROFILE_OFF;
651 
652 #ifdef CONFIG_DASD_PROFILE
653 struct dasd_profile_info dasd_global_profile_data;
654 static struct dentry *dasd_global_profile_dentry;
655 static struct dentry *dasd_debugfs_global_entry;
656 
657 /*
658  * Add profiling information for cqr before execution.
659  */
660 static void dasd_profile_start(struct dasd_block *block,
661 			       struct dasd_ccw_req *cqr,
662 			       struct request *req)
663 {
664 	struct list_head *l;
665 	unsigned int counter;
666 	struct dasd_device *device;
667 
668 	/* count the length of the chanq for statistics */
669 	counter = 0;
670 	if (dasd_global_profile_level || block->profile.data)
671 		list_for_each(l, &block->ccw_queue)
672 			if (++counter >= 31)
673 				break;
674 
675 	if (dasd_global_profile_level) {
676 		dasd_global_profile_data.dasd_io_nr_req[counter]++;
677 		if (rq_data_dir(req) == READ)
678 			dasd_global_profile_data.dasd_read_nr_req[counter]++;
679 	}
680 
681 	spin_lock(&block->profile.lock);
682 	if (block->profile.data)
683 		block->profile.data->dasd_io_nr_req[counter]++;
684 		if (rq_data_dir(req) == READ)
685 			block->profile.data->dasd_read_nr_req[counter]++;
686 	spin_unlock(&block->profile.lock);
687 
688 	/*
689 	 * We count the request for the start device, even though it may run on
690 	 * some other device due to error recovery. This way we make sure that
691 	 * we count each request only once.
692 	 */
693 	device = cqr->startdev;
694 	if (device->profile.data) {
695 		counter = 1; /* request is not yet queued on the start device */
696 		list_for_each(l, &device->ccw_queue)
697 			if (++counter >= 31)
698 				break;
699 	}
700 	spin_lock(&device->profile.lock);
701 	if (device->profile.data) {
702 		device->profile.data->dasd_io_nr_req[counter]++;
703 		if (rq_data_dir(req) == READ)
704 			device->profile.data->dasd_read_nr_req[counter]++;
705 	}
706 	spin_unlock(&device->profile.lock);
707 }
708 
709 /*
710  * Add profiling information for cqr after execution.
711  */
712 
713 #define dasd_profile_counter(value, index)			   \
714 {								   \
715 	for (index = 0; index < 31 && value >> (2+index); index++) \
716 		;						   \
717 }
718 
719 static void dasd_profile_end_add_data(struct dasd_profile_info *data,
720 				      int is_alias,
721 				      int is_tpm,
722 				      int is_read,
723 				      long sectors,
724 				      int sectors_ind,
725 				      int tottime_ind,
726 				      int tottimeps_ind,
727 				      int strtime_ind,
728 				      int irqtime_ind,
729 				      int irqtimeps_ind,
730 				      int endtime_ind)
731 {
732 	/* in case of an overflow, reset the whole profile */
733 	if (data->dasd_io_reqs == UINT_MAX) {
734 			memset(data, 0, sizeof(*data));
735 			getnstimeofday(&data->starttod);
736 	}
737 	data->dasd_io_reqs++;
738 	data->dasd_io_sects += sectors;
739 	if (is_alias)
740 		data->dasd_io_alias++;
741 	if (is_tpm)
742 		data->dasd_io_tpm++;
743 
744 	data->dasd_io_secs[sectors_ind]++;
745 	data->dasd_io_times[tottime_ind]++;
746 	data->dasd_io_timps[tottimeps_ind]++;
747 	data->dasd_io_time1[strtime_ind]++;
748 	data->dasd_io_time2[irqtime_ind]++;
749 	data->dasd_io_time2ps[irqtimeps_ind]++;
750 	data->dasd_io_time3[endtime_ind]++;
751 
752 	if (is_read) {
753 		data->dasd_read_reqs++;
754 		data->dasd_read_sects += sectors;
755 		if (is_alias)
756 			data->dasd_read_alias++;
757 		if (is_tpm)
758 			data->dasd_read_tpm++;
759 		data->dasd_read_secs[sectors_ind]++;
760 		data->dasd_read_times[tottime_ind]++;
761 		data->dasd_read_time1[strtime_ind]++;
762 		data->dasd_read_time2[irqtime_ind]++;
763 		data->dasd_read_time3[endtime_ind]++;
764 	}
765 }
766 
767 static void dasd_profile_end(struct dasd_block *block,
768 			     struct dasd_ccw_req *cqr,
769 			     struct request *req)
770 {
771 	long strtime, irqtime, endtime, tottime;	/* in microseconds */
772 	long tottimeps, sectors;
773 	struct dasd_device *device;
774 	int sectors_ind, tottime_ind, tottimeps_ind, strtime_ind;
775 	int irqtime_ind, irqtimeps_ind, endtime_ind;
776 
777 	device = cqr->startdev;
778 	if (!(dasd_global_profile_level ||
779 	      block->profile.data ||
780 	      device->profile.data))
781 		return;
782 
783 	sectors = blk_rq_sectors(req);
784 	if (!cqr->buildclk || !cqr->startclk ||
785 	    !cqr->stopclk || !cqr->endclk ||
786 	    !sectors)
787 		return;
788 
789 	strtime = ((cqr->startclk - cqr->buildclk) >> 12);
790 	irqtime = ((cqr->stopclk - cqr->startclk) >> 12);
791 	endtime = ((cqr->endclk - cqr->stopclk) >> 12);
792 	tottime = ((cqr->endclk - cqr->buildclk) >> 12);
793 	tottimeps = tottime / sectors;
794 
795 	dasd_profile_counter(sectors, sectors_ind);
796 	dasd_profile_counter(tottime, tottime_ind);
797 	dasd_profile_counter(tottimeps, tottimeps_ind);
798 	dasd_profile_counter(strtime, strtime_ind);
799 	dasd_profile_counter(irqtime, irqtime_ind);
800 	dasd_profile_counter(irqtime / sectors, irqtimeps_ind);
801 	dasd_profile_counter(endtime, endtime_ind);
802 
803 	if (dasd_global_profile_level) {
804 		dasd_profile_end_add_data(&dasd_global_profile_data,
805 					  cqr->startdev != block->base,
806 					  cqr->cpmode == 1,
807 					  rq_data_dir(req) == READ,
808 					  sectors, sectors_ind, tottime_ind,
809 					  tottimeps_ind, strtime_ind,
810 					  irqtime_ind, irqtimeps_ind,
811 					  endtime_ind);
812 	}
813 
814 	spin_lock(&block->profile.lock);
815 	if (block->profile.data)
816 		dasd_profile_end_add_data(block->profile.data,
817 					  cqr->startdev != block->base,
818 					  cqr->cpmode == 1,
819 					  rq_data_dir(req) == READ,
820 					  sectors, sectors_ind, tottime_ind,
821 					  tottimeps_ind, strtime_ind,
822 					  irqtime_ind, irqtimeps_ind,
823 					  endtime_ind);
824 	spin_unlock(&block->profile.lock);
825 
826 	spin_lock(&device->profile.lock);
827 	if (device->profile.data)
828 		dasd_profile_end_add_data(device->profile.data,
829 					  cqr->startdev != block->base,
830 					  cqr->cpmode == 1,
831 					  rq_data_dir(req) == READ,
832 					  sectors, sectors_ind, tottime_ind,
833 					  tottimeps_ind, strtime_ind,
834 					  irqtime_ind, irqtimeps_ind,
835 					  endtime_ind);
836 	spin_unlock(&device->profile.lock);
837 }
838 
839 void dasd_profile_reset(struct dasd_profile *profile)
840 {
841 	struct dasd_profile_info *data;
842 
843 	spin_lock_bh(&profile->lock);
844 	data = profile->data;
845 	if (!data) {
846 		spin_unlock_bh(&profile->lock);
847 		return;
848 	}
849 	memset(data, 0, sizeof(*data));
850 	getnstimeofday(&data->starttod);
851 	spin_unlock_bh(&profile->lock);
852 }
853 
854 void dasd_global_profile_reset(void)
855 {
856 	memset(&dasd_global_profile_data, 0, sizeof(dasd_global_profile_data));
857 	getnstimeofday(&dasd_global_profile_data.starttod);
858 }
859 
860 int dasd_profile_on(struct dasd_profile *profile)
861 {
862 	struct dasd_profile_info *data;
863 
864 	data = kzalloc(sizeof(*data), GFP_KERNEL);
865 	if (!data)
866 		return -ENOMEM;
867 	spin_lock_bh(&profile->lock);
868 	if (profile->data) {
869 		spin_unlock_bh(&profile->lock);
870 		kfree(data);
871 		return 0;
872 	}
873 	getnstimeofday(&data->starttod);
874 	profile->data = data;
875 	spin_unlock_bh(&profile->lock);
876 	return 0;
877 }
878 
879 void dasd_profile_off(struct dasd_profile *profile)
880 {
881 	spin_lock_bh(&profile->lock);
882 	kfree(profile->data);
883 	profile->data = NULL;
884 	spin_unlock_bh(&profile->lock);
885 }
886 
887 char *dasd_get_user_string(const char __user *user_buf, size_t user_len)
888 {
889 	char *buffer;
890 
891 	buffer = vmalloc(user_len + 1);
892 	if (buffer == NULL)
893 		return ERR_PTR(-ENOMEM);
894 	if (copy_from_user(buffer, user_buf, user_len) != 0) {
895 		vfree(buffer);
896 		return ERR_PTR(-EFAULT);
897 	}
898 	/* got the string, now strip linefeed. */
899 	if (buffer[user_len - 1] == '\n')
900 		buffer[user_len - 1] = 0;
901 	else
902 		buffer[user_len] = 0;
903 	return buffer;
904 }
905 
906 static ssize_t dasd_stats_write(struct file *file,
907 				const char __user *user_buf,
908 				size_t user_len, loff_t *pos)
909 {
910 	char *buffer, *str;
911 	int rc;
912 	struct seq_file *m = (struct seq_file *)file->private_data;
913 	struct dasd_profile *prof = m->private;
914 
915 	if (user_len > 65536)
916 		user_len = 65536;
917 	buffer = dasd_get_user_string(user_buf, user_len);
918 	if (IS_ERR(buffer))
919 		return PTR_ERR(buffer);
920 
921 	str = skip_spaces(buffer);
922 	rc = user_len;
923 	if (strncmp(str, "reset", 5) == 0) {
924 		dasd_profile_reset(prof);
925 	} else if (strncmp(str, "on", 2) == 0) {
926 		rc = dasd_profile_on(prof);
927 		if (!rc)
928 			rc = user_len;
929 	} else if (strncmp(str, "off", 3) == 0) {
930 		dasd_profile_off(prof);
931 	} else
932 		rc = -EINVAL;
933 	vfree(buffer);
934 	return rc;
935 }
936 
937 static void dasd_stats_array(struct seq_file *m, unsigned int *array)
938 {
939 	int i;
940 
941 	for (i = 0; i < 32; i++)
942 		seq_printf(m, "%u ", array[i]);
943 	seq_putc(m, '\n');
944 }
945 
946 static void dasd_stats_seq_print(struct seq_file *m,
947 				 struct dasd_profile_info *data)
948 {
949 	seq_printf(m, "start_time %ld.%09ld\n",
950 		   data->starttod.tv_sec, data->starttod.tv_nsec);
951 	seq_printf(m, "total_requests %u\n", data->dasd_io_reqs);
952 	seq_printf(m, "total_sectors %u\n", data->dasd_io_sects);
953 	seq_printf(m, "total_pav %u\n", data->dasd_io_alias);
954 	seq_printf(m, "total_hpf %u\n", data->dasd_io_tpm);
955 	seq_printf(m, "histogram_sectors ");
956 	dasd_stats_array(m, data->dasd_io_secs);
957 	seq_printf(m, "histogram_io_times ");
958 	dasd_stats_array(m, data->dasd_io_times);
959 	seq_printf(m, "histogram_io_times_weighted ");
960 	dasd_stats_array(m, data->dasd_io_timps);
961 	seq_printf(m, "histogram_time_build_to_ssch ");
962 	dasd_stats_array(m, data->dasd_io_time1);
963 	seq_printf(m, "histogram_time_ssch_to_irq ");
964 	dasd_stats_array(m, data->dasd_io_time2);
965 	seq_printf(m, "histogram_time_ssch_to_irq_weighted ");
966 	dasd_stats_array(m, data->dasd_io_time2ps);
967 	seq_printf(m, "histogram_time_irq_to_end ");
968 	dasd_stats_array(m, data->dasd_io_time3);
969 	seq_printf(m, "histogram_ccw_queue_length ");
970 	dasd_stats_array(m, data->dasd_io_nr_req);
971 	seq_printf(m, "total_read_requests %u\n", data->dasd_read_reqs);
972 	seq_printf(m, "total_read_sectors %u\n", data->dasd_read_sects);
973 	seq_printf(m, "total_read_pav %u\n", data->dasd_read_alias);
974 	seq_printf(m, "total_read_hpf %u\n", data->dasd_read_tpm);
975 	seq_printf(m, "histogram_read_sectors ");
976 	dasd_stats_array(m, data->dasd_read_secs);
977 	seq_printf(m, "histogram_read_times ");
978 	dasd_stats_array(m, data->dasd_read_times);
979 	seq_printf(m, "histogram_read_time_build_to_ssch ");
980 	dasd_stats_array(m, data->dasd_read_time1);
981 	seq_printf(m, "histogram_read_time_ssch_to_irq ");
982 	dasd_stats_array(m, data->dasd_read_time2);
983 	seq_printf(m, "histogram_read_time_irq_to_end ");
984 	dasd_stats_array(m, data->dasd_read_time3);
985 	seq_printf(m, "histogram_read_ccw_queue_length ");
986 	dasd_stats_array(m, data->dasd_read_nr_req);
987 }
988 
989 static int dasd_stats_show(struct seq_file *m, void *v)
990 {
991 	struct dasd_profile *profile;
992 	struct dasd_profile_info *data;
993 
994 	profile = m->private;
995 	spin_lock_bh(&profile->lock);
996 	data = profile->data;
997 	if (!data) {
998 		spin_unlock_bh(&profile->lock);
999 		seq_printf(m, "disabled\n");
1000 		return 0;
1001 	}
1002 	dasd_stats_seq_print(m, data);
1003 	spin_unlock_bh(&profile->lock);
1004 	return 0;
1005 }
1006 
1007 static int dasd_stats_open(struct inode *inode, struct file *file)
1008 {
1009 	struct dasd_profile *profile = inode->i_private;
1010 	return single_open(file, dasd_stats_show, profile);
1011 }
1012 
1013 static const struct file_operations dasd_stats_raw_fops = {
1014 	.owner		= THIS_MODULE,
1015 	.open		= dasd_stats_open,
1016 	.read		= seq_read,
1017 	.llseek		= seq_lseek,
1018 	.release	= single_release,
1019 	.write		= dasd_stats_write,
1020 };
1021 
1022 static ssize_t dasd_stats_global_write(struct file *file,
1023 				       const char __user *user_buf,
1024 				       size_t user_len, loff_t *pos)
1025 {
1026 	char *buffer, *str;
1027 	ssize_t rc;
1028 
1029 	if (user_len > 65536)
1030 		user_len = 65536;
1031 	buffer = dasd_get_user_string(user_buf, user_len);
1032 	if (IS_ERR(buffer))
1033 		return PTR_ERR(buffer);
1034 	str = skip_spaces(buffer);
1035 	rc = user_len;
1036 	if (strncmp(str, "reset", 5) == 0) {
1037 		dasd_global_profile_reset();
1038 	} else if (strncmp(str, "on", 2) == 0) {
1039 		dasd_global_profile_reset();
1040 		dasd_global_profile_level = DASD_PROFILE_GLOBAL_ONLY;
1041 	} else if (strncmp(str, "off", 3) == 0) {
1042 		dasd_global_profile_level = DASD_PROFILE_OFF;
1043 	} else
1044 		rc = -EINVAL;
1045 	vfree(buffer);
1046 	return rc;
1047 }
1048 
1049 static int dasd_stats_global_show(struct seq_file *m, void *v)
1050 {
1051 	if (!dasd_global_profile_level) {
1052 		seq_printf(m, "disabled\n");
1053 		return 0;
1054 	}
1055 	dasd_stats_seq_print(m, &dasd_global_profile_data);
1056 	return 0;
1057 }
1058 
1059 static int dasd_stats_global_open(struct inode *inode, struct file *file)
1060 {
1061 	return single_open(file, dasd_stats_global_show, NULL);
1062 }
1063 
1064 static const struct file_operations dasd_stats_global_fops = {
1065 	.owner		= THIS_MODULE,
1066 	.open		= dasd_stats_global_open,
1067 	.read		= seq_read,
1068 	.llseek		= seq_lseek,
1069 	.release	= single_release,
1070 	.write		= dasd_stats_global_write,
1071 };
1072 
1073 static void dasd_profile_init(struct dasd_profile *profile,
1074 			      struct dentry *base_dentry)
1075 {
1076 	umode_t mode;
1077 	struct dentry *pde;
1078 
1079 	if (!base_dentry)
1080 		return;
1081 	profile->dentry = NULL;
1082 	profile->data = NULL;
1083 	mode = (S_IRUSR | S_IWUSR | S_IFREG);
1084 	pde = debugfs_create_file("statistics", mode, base_dentry,
1085 				  profile, &dasd_stats_raw_fops);
1086 	if (pde && !IS_ERR(pde))
1087 		profile->dentry = pde;
1088 	return;
1089 }
1090 
1091 static void dasd_profile_exit(struct dasd_profile *profile)
1092 {
1093 	dasd_profile_off(profile);
1094 	if (profile->dentry) {
1095 		debugfs_remove(profile->dentry);
1096 		profile->dentry = NULL;
1097 	}
1098 }
1099 
1100 static void dasd_statistics_removeroot(void)
1101 {
1102 	dasd_global_profile_level = DASD_PROFILE_OFF;
1103 	if (dasd_global_profile_dentry) {
1104 		debugfs_remove(dasd_global_profile_dentry);
1105 		dasd_global_profile_dentry = NULL;
1106 	}
1107 	if (dasd_debugfs_global_entry)
1108 		debugfs_remove(dasd_debugfs_global_entry);
1109 	if (dasd_debugfs_root_entry)
1110 		debugfs_remove(dasd_debugfs_root_entry);
1111 }
1112 
1113 static void dasd_statistics_createroot(void)
1114 {
1115 	umode_t mode;
1116 	struct dentry *pde;
1117 
1118 	dasd_debugfs_root_entry = NULL;
1119 	dasd_debugfs_global_entry = NULL;
1120 	dasd_global_profile_dentry = NULL;
1121 	pde = debugfs_create_dir("dasd", NULL);
1122 	if (!pde || IS_ERR(pde))
1123 		goto error;
1124 	dasd_debugfs_root_entry = pde;
1125 	pde = debugfs_create_dir("global", dasd_debugfs_root_entry);
1126 	if (!pde || IS_ERR(pde))
1127 		goto error;
1128 	dasd_debugfs_global_entry = pde;
1129 
1130 	mode = (S_IRUSR | S_IWUSR | S_IFREG);
1131 	pde = debugfs_create_file("statistics", mode, dasd_debugfs_global_entry,
1132 				  NULL, &dasd_stats_global_fops);
1133 	if (!pde || IS_ERR(pde))
1134 		goto error;
1135 	dasd_global_profile_dentry = pde;
1136 	return;
1137 
1138 error:
1139 	DBF_EVENT(DBF_ERR, "%s",
1140 		  "Creation of the dasd debugfs interface failed");
1141 	dasd_statistics_removeroot();
1142 	return;
1143 }
1144 
1145 #else
1146 #define dasd_profile_start(block, cqr, req) do {} while (0)
1147 #define dasd_profile_end(block, cqr, req) do {} while (0)
1148 
1149 static void dasd_statistics_createroot(void)
1150 {
1151 	return;
1152 }
1153 
1154 static void dasd_statistics_removeroot(void)
1155 {
1156 	return;
1157 }
1158 
1159 int dasd_stats_generic_show(struct seq_file *m, void *v)
1160 {
1161 	seq_printf(m, "Statistics are not activated in this kernel\n");
1162 	return 0;
1163 }
1164 
1165 static void dasd_profile_init(struct dasd_profile *profile,
1166 			      struct dentry *base_dentry)
1167 {
1168 	return;
1169 }
1170 
1171 static void dasd_profile_exit(struct dasd_profile *profile)
1172 {
1173 	return;
1174 }
1175 
1176 int dasd_profile_on(struct dasd_profile *profile)
1177 {
1178 	return 0;
1179 }
1180 
1181 #endif				/* CONFIG_DASD_PROFILE */
1182 
1183 /*
1184  * Allocate memory for a channel program with 'cplength' channel
1185  * command words and 'datasize' additional space. There are two
1186  * variantes: 1) dasd_kmalloc_request uses kmalloc to get the needed
1187  * memory and 2) dasd_smalloc_request uses the static ccw memory
1188  * that gets allocated for each device.
1189  */
1190 struct dasd_ccw_req *dasd_kmalloc_request(int magic, int cplength,
1191 					  int datasize,
1192 					  struct dasd_device *device)
1193 {
1194 	struct dasd_ccw_req *cqr;
1195 
1196 	/* Sanity checks */
1197 	BUG_ON(datasize > PAGE_SIZE ||
1198 	     (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
1199 
1200 	cqr = kzalloc(sizeof(struct dasd_ccw_req), GFP_ATOMIC);
1201 	if (cqr == NULL)
1202 		return ERR_PTR(-ENOMEM);
1203 	cqr->cpaddr = NULL;
1204 	if (cplength > 0) {
1205 		cqr->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
1206 				      GFP_ATOMIC | GFP_DMA);
1207 		if (cqr->cpaddr == NULL) {
1208 			kfree(cqr);
1209 			return ERR_PTR(-ENOMEM);
1210 		}
1211 	}
1212 	cqr->data = NULL;
1213 	if (datasize > 0) {
1214 		cqr->data = kzalloc(datasize, GFP_ATOMIC | GFP_DMA);
1215 		if (cqr->data == NULL) {
1216 			kfree(cqr->cpaddr);
1217 			kfree(cqr);
1218 			return ERR_PTR(-ENOMEM);
1219 		}
1220 	}
1221 	cqr->magic =  magic;
1222 	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
1223 	dasd_get_device(device);
1224 	return cqr;
1225 }
1226 
1227 struct dasd_ccw_req *dasd_smalloc_request(int magic, int cplength,
1228 					  int datasize,
1229 					  struct dasd_device *device)
1230 {
1231 	unsigned long flags;
1232 	struct dasd_ccw_req *cqr;
1233 	char *data;
1234 	int size;
1235 
1236 	size = (sizeof(struct dasd_ccw_req) + 7L) & -8L;
1237 	if (cplength > 0)
1238 		size += cplength * sizeof(struct ccw1);
1239 	if (datasize > 0)
1240 		size += datasize;
1241 	spin_lock_irqsave(&device->mem_lock, flags);
1242 	cqr = (struct dasd_ccw_req *)
1243 		dasd_alloc_chunk(&device->ccw_chunks, size);
1244 	spin_unlock_irqrestore(&device->mem_lock, flags);
1245 	if (cqr == NULL)
1246 		return ERR_PTR(-ENOMEM);
1247 	memset(cqr, 0, sizeof(struct dasd_ccw_req));
1248 	data = (char *) cqr + ((sizeof(struct dasd_ccw_req) + 7L) & -8L);
1249 	cqr->cpaddr = NULL;
1250 	if (cplength > 0) {
1251 		cqr->cpaddr = (struct ccw1 *) data;
1252 		data += cplength*sizeof(struct ccw1);
1253 		memset(cqr->cpaddr, 0, cplength*sizeof(struct ccw1));
1254 	}
1255 	cqr->data = NULL;
1256 	if (datasize > 0) {
1257 		cqr->data = data;
1258  		memset(cqr->data, 0, datasize);
1259 	}
1260 	cqr->magic = magic;
1261 	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
1262 	dasd_get_device(device);
1263 	return cqr;
1264 }
1265 
1266 /*
1267  * Free memory of a channel program. This function needs to free all the
1268  * idal lists that might have been created by dasd_set_cda and the
1269  * struct dasd_ccw_req itself.
1270  */
1271 void dasd_kfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
1272 {
1273 #ifdef CONFIG_64BIT
1274 	struct ccw1 *ccw;
1275 
1276 	/* Clear any idals used for the request. */
1277 	ccw = cqr->cpaddr;
1278 	do {
1279 		clear_normalized_cda(ccw);
1280 	} while (ccw++->flags & (CCW_FLAG_CC | CCW_FLAG_DC));
1281 #endif
1282 	kfree(cqr->cpaddr);
1283 	kfree(cqr->data);
1284 	kfree(cqr);
1285 	dasd_put_device(device);
1286 }
1287 
1288 void dasd_sfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
1289 {
1290 	unsigned long flags;
1291 
1292 	spin_lock_irqsave(&device->mem_lock, flags);
1293 	dasd_free_chunk(&device->ccw_chunks, cqr);
1294 	spin_unlock_irqrestore(&device->mem_lock, flags);
1295 	dasd_put_device(device);
1296 }
1297 
1298 /*
1299  * Check discipline magic in cqr.
1300  */
1301 static inline int dasd_check_cqr(struct dasd_ccw_req *cqr)
1302 {
1303 	struct dasd_device *device;
1304 
1305 	if (cqr == NULL)
1306 		return -EINVAL;
1307 	device = cqr->startdev;
1308 	if (strncmp((char *) &cqr->magic, device->discipline->ebcname, 4)) {
1309 		DBF_DEV_EVENT(DBF_WARNING, device,
1310 			    " dasd_ccw_req 0x%08x magic doesn't match"
1311 			    " discipline 0x%08x",
1312 			    cqr->magic,
1313 			    *(unsigned int *) device->discipline->name);
1314 		return -EINVAL;
1315 	}
1316 	return 0;
1317 }
1318 
1319 /*
1320  * Terminate the current i/o and set the request to clear_pending.
1321  * Timer keeps device runnig.
1322  * ccw_device_clear can fail if the i/o subsystem
1323  * is in a bad mood.
1324  */
1325 int dasd_term_IO(struct dasd_ccw_req *cqr)
1326 {
1327 	struct dasd_device *device;
1328 	int retries, rc;
1329 	char errorstring[ERRORLENGTH];
1330 
1331 	/* Check the cqr */
1332 	rc = dasd_check_cqr(cqr);
1333 	if (rc)
1334 		return rc;
1335 	retries = 0;
1336 	device = (struct dasd_device *) cqr->startdev;
1337 	while ((retries < 5) && (cqr->status == DASD_CQR_IN_IO)) {
1338 		rc = ccw_device_clear(device->cdev, (long) cqr);
1339 		switch (rc) {
1340 		case 0:	/* termination successful */
1341 			cqr->status = DASD_CQR_CLEAR_PENDING;
1342 			cqr->stopclk = get_clock();
1343 			cqr->starttime = 0;
1344 			DBF_DEV_EVENT(DBF_DEBUG, device,
1345 				      "terminate cqr %p successful",
1346 				      cqr);
1347 			break;
1348 		case -ENODEV:
1349 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
1350 				      "device gone, retry");
1351 			break;
1352 		case -EIO:
1353 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
1354 				      "I/O error, retry");
1355 			break;
1356 		case -EINVAL:
1357 		case -EBUSY:
1358 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
1359 				      "device busy, retry later");
1360 			break;
1361 		default:
1362 			/* internal error 10 - unknown rc*/
1363 			snprintf(errorstring, ERRORLENGTH, "10 %d", rc);
1364 			dev_err(&device->cdev->dev, "An error occurred in the "
1365 				"DASD device driver, reason=%s\n", errorstring);
1366 			BUG();
1367 			break;
1368 		}
1369 		retries++;
1370 	}
1371 	dasd_schedule_device_bh(device);
1372 	return rc;
1373 }
1374 
1375 /*
1376  * Start the i/o. This start_IO can fail if the channel is really busy.
1377  * In that case set up a timer to start the request later.
1378  */
1379 int dasd_start_IO(struct dasd_ccw_req *cqr)
1380 {
1381 	struct dasd_device *device;
1382 	int rc;
1383 	char errorstring[ERRORLENGTH];
1384 
1385 	/* Check the cqr */
1386 	rc = dasd_check_cqr(cqr);
1387 	if (rc) {
1388 		cqr->intrc = rc;
1389 		return rc;
1390 	}
1391 	device = (struct dasd_device *) cqr->startdev;
1392 	if (((cqr->block &&
1393 	      test_bit(DASD_FLAG_LOCK_STOLEN, &cqr->block->base->flags)) ||
1394 	     test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags)) &&
1395 	    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
1396 		DBF_DEV_EVENT(DBF_DEBUG, device, "start_IO: return request %p "
1397 			      "because of stolen lock", cqr);
1398 		cqr->status = DASD_CQR_ERROR;
1399 		cqr->intrc = -EPERM;
1400 		return -EPERM;
1401 	}
1402 	if (cqr->retries < 0) {
1403 		/* internal error 14 - start_IO run out of retries */
1404 		sprintf(errorstring, "14 %p", cqr);
1405 		dev_err(&device->cdev->dev, "An error occurred in the DASD "
1406 			"device driver, reason=%s\n", errorstring);
1407 		cqr->status = DASD_CQR_ERROR;
1408 		return -EIO;
1409 	}
1410 	cqr->startclk = get_clock();
1411 	cqr->starttime = jiffies;
1412 	cqr->retries--;
1413 	if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
1414 		cqr->lpm &= device->path_data.opm;
1415 		if (!cqr->lpm)
1416 			cqr->lpm = device->path_data.opm;
1417 	}
1418 	if (cqr->cpmode == 1) {
1419 		rc = ccw_device_tm_start(device->cdev, cqr->cpaddr,
1420 					 (long) cqr, cqr->lpm);
1421 	} else {
1422 		rc = ccw_device_start(device->cdev, cqr->cpaddr,
1423 				      (long) cqr, cqr->lpm, 0);
1424 	}
1425 	switch (rc) {
1426 	case 0:
1427 		cqr->status = DASD_CQR_IN_IO;
1428 		break;
1429 	case -EBUSY:
1430 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1431 			      "start_IO: device busy, retry later");
1432 		break;
1433 	case -ETIMEDOUT:
1434 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1435 			      "start_IO: request timeout, retry later");
1436 		break;
1437 	case -EACCES:
1438 		/* -EACCES indicates that the request used only a subset of the
1439 		 * available paths and all these paths are gone. If the lpm of
1440 		 * this request was only a subset of the opm (e.g. the ppm) then
1441 		 * we just do a retry with all available paths.
1442 		 * If we already use the full opm, something is amiss, and we
1443 		 * need a full path verification.
1444 		 */
1445 		if (test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
1446 			DBF_DEV_EVENT(DBF_WARNING, device,
1447 				      "start_IO: selected paths gone (%x)",
1448 				      cqr->lpm);
1449 		} else if (cqr->lpm != device->path_data.opm) {
1450 			cqr->lpm = device->path_data.opm;
1451 			DBF_DEV_EVENT(DBF_DEBUG, device, "%s",
1452 				      "start_IO: selected paths gone,"
1453 				      " retry on all paths");
1454 		} else {
1455 			DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1456 				      "start_IO: all paths in opm gone,"
1457 				      " do path verification");
1458 			dasd_generic_last_path_gone(device);
1459 			device->path_data.opm = 0;
1460 			device->path_data.ppm = 0;
1461 			device->path_data.npm = 0;
1462 			device->path_data.tbvpm =
1463 				ccw_device_get_path_mask(device->cdev);
1464 		}
1465 		break;
1466 	case -ENODEV:
1467 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1468 			      "start_IO: -ENODEV device gone, retry");
1469 		break;
1470 	case -EIO:
1471 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1472 			      "start_IO: -EIO device gone, retry");
1473 		break;
1474 	case -EINVAL:
1475 		/* most likely caused in power management context */
1476 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1477 			      "start_IO: -EINVAL device currently "
1478 			      "not accessible");
1479 		break;
1480 	default:
1481 		/* internal error 11 - unknown rc */
1482 		snprintf(errorstring, ERRORLENGTH, "11 %d", rc);
1483 		dev_err(&device->cdev->dev,
1484 			"An error occurred in the DASD device driver, "
1485 			"reason=%s\n", errorstring);
1486 		BUG();
1487 		break;
1488 	}
1489 	cqr->intrc = rc;
1490 	return rc;
1491 }
1492 
1493 /*
1494  * Timeout function for dasd devices. This is used for different purposes
1495  *  1) missing interrupt handler for normal operation
1496  *  2) delayed start of request where start_IO failed with -EBUSY
1497  *  3) timeout for missing state change interrupts
1498  * The head of the ccw queue will have status DASD_CQR_IN_IO for 1),
1499  * DASD_CQR_QUEUED for 2) and 3).
1500  */
1501 static void dasd_device_timeout(unsigned long ptr)
1502 {
1503 	unsigned long flags;
1504 	struct dasd_device *device;
1505 
1506 	device = (struct dasd_device *) ptr;
1507 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
1508 	/* re-activate request queue */
1509 	dasd_device_remove_stop_bits(device, DASD_STOPPED_PENDING);
1510 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
1511 	dasd_schedule_device_bh(device);
1512 }
1513 
1514 /*
1515  * Setup timeout for a device in jiffies.
1516  */
1517 void dasd_device_set_timer(struct dasd_device *device, int expires)
1518 {
1519 	if (expires == 0)
1520 		del_timer(&device->timer);
1521 	else
1522 		mod_timer(&device->timer, jiffies + expires);
1523 }
1524 
1525 /*
1526  * Clear timeout for a device.
1527  */
1528 void dasd_device_clear_timer(struct dasd_device *device)
1529 {
1530 	del_timer(&device->timer);
1531 }
1532 
1533 static void dasd_handle_killed_request(struct ccw_device *cdev,
1534 				       unsigned long intparm)
1535 {
1536 	struct dasd_ccw_req *cqr;
1537 	struct dasd_device *device;
1538 
1539 	if (!intparm)
1540 		return;
1541 	cqr = (struct dasd_ccw_req *) intparm;
1542 	if (cqr->status != DASD_CQR_IN_IO) {
1543 		DBF_EVENT_DEVID(DBF_DEBUG, cdev,
1544 				"invalid status in handle_killed_request: "
1545 				"%02x", cqr->status);
1546 		return;
1547 	}
1548 
1549 	device = dasd_device_from_cdev_locked(cdev);
1550 	if (IS_ERR(device)) {
1551 		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
1552 				"unable to get device from cdev");
1553 		return;
1554 	}
1555 
1556 	if (!cqr->startdev ||
1557 	    device != cqr->startdev ||
1558 	    strncmp(cqr->startdev->discipline->ebcname,
1559 		    (char *) &cqr->magic, 4)) {
1560 		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
1561 				"invalid device in request");
1562 		dasd_put_device(device);
1563 		return;
1564 	}
1565 
1566 	/* Schedule request to be retried. */
1567 	cqr->status = DASD_CQR_QUEUED;
1568 
1569 	dasd_device_clear_timer(device);
1570 	dasd_schedule_device_bh(device);
1571 	dasd_put_device(device);
1572 }
1573 
1574 void dasd_generic_handle_state_change(struct dasd_device *device)
1575 {
1576 	/* First of all start sense subsystem status request. */
1577 	dasd_eer_snss(device);
1578 
1579 	dasd_device_remove_stop_bits(device, DASD_STOPPED_PENDING);
1580 	dasd_schedule_device_bh(device);
1581 	if (device->block)
1582 		dasd_schedule_block_bh(device->block);
1583 }
1584 
1585 /*
1586  * Interrupt handler for "normal" ssch-io based dasd devices.
1587  */
1588 void dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
1589 		      struct irb *irb)
1590 {
1591 	struct dasd_ccw_req *cqr, *next;
1592 	struct dasd_device *device;
1593 	unsigned long long now;
1594 	int expires;
1595 
1596 	if (IS_ERR(irb)) {
1597 		switch (PTR_ERR(irb)) {
1598 		case -EIO:
1599 			break;
1600 		case -ETIMEDOUT:
1601 			DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
1602 					"request timed out\n", __func__);
1603 			break;
1604 		default:
1605 			DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
1606 					"unknown error %ld\n", __func__,
1607 					PTR_ERR(irb));
1608 		}
1609 		dasd_handle_killed_request(cdev, intparm);
1610 		return;
1611 	}
1612 
1613 	now = get_clock();
1614 	cqr = (struct dasd_ccw_req *) intparm;
1615 	/* check for conditions that should be handled immediately */
1616 	if (!cqr ||
1617 	    !(scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
1618 	      scsw_cstat(&irb->scsw) == 0)) {
1619 		if (cqr)
1620 			memcpy(&cqr->irb, irb, sizeof(*irb));
1621 		device = dasd_device_from_cdev_locked(cdev);
1622 		if (IS_ERR(device))
1623 			return;
1624 		/* ignore unsolicited interrupts for DIAG discipline */
1625 		if (device->discipline == dasd_diag_discipline_pointer) {
1626 			dasd_put_device(device);
1627 			return;
1628 		}
1629 		device->discipline->dump_sense_dbf(device, irb, "int");
1630 		if (device->features & DASD_FEATURE_ERPLOG)
1631 			device->discipline->dump_sense(device, cqr, irb);
1632 		device->discipline->check_for_device_change(device, cqr, irb);
1633 		dasd_put_device(device);
1634 	}
1635 	if (!cqr)
1636 		return;
1637 
1638 	device = (struct dasd_device *) cqr->startdev;
1639 	if (!device ||
1640 	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
1641 		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
1642 				"invalid device in request");
1643 		return;
1644 	}
1645 
1646 	/* Check for clear pending */
1647 	if (cqr->status == DASD_CQR_CLEAR_PENDING &&
1648 	    scsw_fctl(&irb->scsw) & SCSW_FCTL_CLEAR_FUNC) {
1649 		cqr->status = DASD_CQR_CLEARED;
1650 		dasd_device_clear_timer(device);
1651 		wake_up(&dasd_flush_wq);
1652 		dasd_schedule_device_bh(device);
1653 		return;
1654 	}
1655 
1656 	/* check status - the request might have been killed by dyn detach */
1657 	if (cqr->status != DASD_CQR_IN_IO) {
1658 		DBF_DEV_EVENT(DBF_DEBUG, device, "invalid status: bus_id %s, "
1659 			      "status %02x", dev_name(&cdev->dev), cqr->status);
1660 		return;
1661 	}
1662 
1663 	next = NULL;
1664 	expires = 0;
1665 	if (scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
1666 	    scsw_cstat(&irb->scsw) == 0) {
1667 		/* request was completed successfully */
1668 		cqr->status = DASD_CQR_SUCCESS;
1669 		cqr->stopclk = now;
1670 		/* Start first request on queue if possible -> fast_io. */
1671 		if (cqr->devlist.next != &device->ccw_queue) {
1672 			next = list_entry(cqr->devlist.next,
1673 					  struct dasd_ccw_req, devlist);
1674 		}
1675 	} else {  /* error */
1676 		/*
1677 		 * If we don't want complex ERP for this request, then just
1678 		 * reset this and retry it in the fastpath
1679 		 */
1680 		if (!test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags) &&
1681 		    cqr->retries > 0) {
1682 			if (cqr->lpm == device->path_data.opm)
1683 				DBF_DEV_EVENT(DBF_DEBUG, device,
1684 					      "default ERP in fastpath "
1685 					      "(%i retries left)",
1686 					      cqr->retries);
1687 			if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags))
1688 				cqr->lpm = device->path_data.opm;
1689 			cqr->status = DASD_CQR_QUEUED;
1690 			next = cqr;
1691 		} else
1692 			cqr->status = DASD_CQR_ERROR;
1693 	}
1694 	if (next && (next->status == DASD_CQR_QUEUED) &&
1695 	    (!device->stopped)) {
1696 		if (device->discipline->start_IO(next) == 0)
1697 			expires = next->expires;
1698 	}
1699 	if (expires != 0)
1700 		dasd_device_set_timer(device, expires);
1701 	else
1702 		dasd_device_clear_timer(device);
1703 	dasd_schedule_device_bh(device);
1704 }
1705 
1706 enum uc_todo dasd_generic_uc_handler(struct ccw_device *cdev, struct irb *irb)
1707 {
1708 	struct dasd_device *device;
1709 
1710 	device = dasd_device_from_cdev_locked(cdev);
1711 
1712 	if (IS_ERR(device))
1713 		goto out;
1714 	if (test_bit(DASD_FLAG_OFFLINE, &device->flags) ||
1715 	   device->state != device->target ||
1716 	   !device->discipline->check_for_device_change){
1717 		dasd_put_device(device);
1718 		goto out;
1719 	}
1720 	if (device->discipline->dump_sense_dbf)
1721 		device->discipline->dump_sense_dbf(device, irb, "uc");
1722 	device->discipline->check_for_device_change(device, NULL, irb);
1723 	dasd_put_device(device);
1724 out:
1725 	return UC_TODO_RETRY;
1726 }
1727 EXPORT_SYMBOL_GPL(dasd_generic_uc_handler);
1728 
1729 /*
1730  * If we have an error on a dasd_block layer request then we cancel
1731  * and return all further requests from the same dasd_block as well.
1732  */
1733 static void __dasd_device_recovery(struct dasd_device *device,
1734 				   struct dasd_ccw_req *ref_cqr)
1735 {
1736 	struct list_head *l, *n;
1737 	struct dasd_ccw_req *cqr;
1738 
1739 	/*
1740 	 * only requeue request that came from the dasd_block layer
1741 	 */
1742 	if (!ref_cqr->block)
1743 		return;
1744 
1745 	list_for_each_safe(l, n, &device->ccw_queue) {
1746 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1747 		if (cqr->status == DASD_CQR_QUEUED &&
1748 		    ref_cqr->block == cqr->block) {
1749 			cqr->status = DASD_CQR_CLEARED;
1750 		}
1751 	}
1752 };
1753 
1754 /*
1755  * Remove those ccw requests from the queue that need to be returned
1756  * to the upper layer.
1757  */
1758 static void __dasd_device_process_ccw_queue(struct dasd_device *device,
1759 					    struct list_head *final_queue)
1760 {
1761 	struct list_head *l, *n;
1762 	struct dasd_ccw_req *cqr;
1763 
1764 	/* Process request with final status. */
1765 	list_for_each_safe(l, n, &device->ccw_queue) {
1766 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1767 
1768 		/* Stop list processing at the first non-final request. */
1769 		if (cqr->status == DASD_CQR_QUEUED ||
1770 		    cqr->status == DASD_CQR_IN_IO ||
1771 		    cqr->status == DASD_CQR_CLEAR_PENDING)
1772 			break;
1773 		if (cqr->status == DASD_CQR_ERROR) {
1774 			__dasd_device_recovery(device, cqr);
1775 		}
1776 		/* Rechain finished requests to final queue */
1777 		list_move_tail(&cqr->devlist, final_queue);
1778 	}
1779 }
1780 
1781 /*
1782  * the cqrs from the final queue are returned to the upper layer
1783  * by setting a dasd_block state and calling the callback function
1784  */
1785 static void __dasd_device_process_final_queue(struct dasd_device *device,
1786 					      struct list_head *final_queue)
1787 {
1788 	struct list_head *l, *n;
1789 	struct dasd_ccw_req *cqr;
1790 	struct dasd_block *block;
1791 	void (*callback)(struct dasd_ccw_req *, void *data);
1792 	void *callback_data;
1793 	char errorstring[ERRORLENGTH];
1794 
1795 	list_for_each_safe(l, n, final_queue) {
1796 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1797 		list_del_init(&cqr->devlist);
1798 		block = cqr->block;
1799 		callback = cqr->callback;
1800 		callback_data = cqr->callback_data;
1801 		if (block)
1802 			spin_lock_bh(&block->queue_lock);
1803 		switch (cqr->status) {
1804 		case DASD_CQR_SUCCESS:
1805 			cqr->status = DASD_CQR_DONE;
1806 			break;
1807 		case DASD_CQR_ERROR:
1808 			cqr->status = DASD_CQR_NEED_ERP;
1809 			break;
1810 		case DASD_CQR_CLEARED:
1811 			cqr->status = DASD_CQR_TERMINATED;
1812 			break;
1813 		default:
1814 			/* internal error 12 - wrong cqr status*/
1815 			snprintf(errorstring, ERRORLENGTH, "12 %p %x02", cqr, cqr->status);
1816 			dev_err(&device->cdev->dev,
1817 				"An error occurred in the DASD device driver, "
1818 				"reason=%s\n", errorstring);
1819 			BUG();
1820 		}
1821 		if (cqr->callback != NULL)
1822 			(callback)(cqr, callback_data);
1823 		if (block)
1824 			spin_unlock_bh(&block->queue_lock);
1825 	}
1826 }
1827 
1828 /*
1829  * Take a look at the first request on the ccw queue and check
1830  * if it reached its expire time. If so, terminate the IO.
1831  */
1832 static void __dasd_device_check_expire(struct dasd_device *device)
1833 {
1834 	struct dasd_ccw_req *cqr;
1835 
1836 	if (list_empty(&device->ccw_queue))
1837 		return;
1838 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1839 	if ((cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) &&
1840 	    (time_after_eq(jiffies, cqr->expires + cqr->starttime))) {
1841 		if (device->discipline->term_IO(cqr) != 0) {
1842 			/* Hmpf, try again in 5 sec */
1843 			dev_err(&device->cdev->dev,
1844 				"cqr %p timed out (%lus) but cannot be "
1845 				"ended, retrying in 5 s\n",
1846 				cqr, (cqr->expires/HZ));
1847 			cqr->expires += 5*HZ;
1848 			dasd_device_set_timer(device, 5*HZ);
1849 		} else {
1850 			dev_err(&device->cdev->dev,
1851 				"cqr %p timed out (%lus), %i retries "
1852 				"remaining\n", cqr, (cqr->expires/HZ),
1853 				cqr->retries);
1854 		}
1855 	}
1856 }
1857 
1858 /*
1859  * Take a look at the first request on the ccw queue and check
1860  * if it needs to be started.
1861  */
1862 static void __dasd_device_start_head(struct dasd_device *device)
1863 {
1864 	struct dasd_ccw_req *cqr;
1865 	int rc;
1866 
1867 	if (list_empty(&device->ccw_queue))
1868 		return;
1869 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1870 	if (cqr->status != DASD_CQR_QUEUED)
1871 		return;
1872 	/* when device is stopped, return request to previous layer
1873 	 * exception: only the disconnect or unresumed bits are set and the
1874 	 * cqr is a path verification request
1875 	 */
1876 	if (device->stopped &&
1877 	    !(!(device->stopped & ~(DASD_STOPPED_DC_WAIT | DASD_UNRESUMED_PM))
1878 	      && test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags))) {
1879 		cqr->intrc = -EAGAIN;
1880 		cqr->status = DASD_CQR_CLEARED;
1881 		dasd_schedule_device_bh(device);
1882 		return;
1883 	}
1884 
1885 	rc = device->discipline->start_IO(cqr);
1886 	if (rc == 0)
1887 		dasd_device_set_timer(device, cqr->expires);
1888 	else if (rc == -EACCES) {
1889 		dasd_schedule_device_bh(device);
1890 	} else
1891 		/* Hmpf, try again in 1/2 sec */
1892 		dasd_device_set_timer(device, 50);
1893 }
1894 
1895 static void __dasd_device_check_path_events(struct dasd_device *device)
1896 {
1897 	int rc;
1898 
1899 	if (device->path_data.tbvpm) {
1900 		if (device->stopped & ~(DASD_STOPPED_DC_WAIT |
1901 					DASD_UNRESUMED_PM))
1902 			return;
1903 		rc = device->discipline->verify_path(
1904 			device, device->path_data.tbvpm);
1905 		if (rc)
1906 			dasd_device_set_timer(device, 50);
1907 		else
1908 			device->path_data.tbvpm = 0;
1909 	}
1910 };
1911 
1912 /*
1913  * Go through all request on the dasd_device request queue,
1914  * terminate them on the cdev if necessary, and return them to the
1915  * submitting layer via callback.
1916  * Note:
1917  * Make sure that all 'submitting layers' still exist when
1918  * this function is called!. In other words, when 'device' is a base
1919  * device then all block layer requests must have been removed before
1920  * via dasd_flush_block_queue.
1921  */
1922 int dasd_flush_device_queue(struct dasd_device *device)
1923 {
1924 	struct dasd_ccw_req *cqr, *n;
1925 	int rc;
1926 	struct list_head flush_queue;
1927 
1928 	INIT_LIST_HEAD(&flush_queue);
1929 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1930 	rc = 0;
1931 	list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
1932 		/* Check status and move request to flush_queue */
1933 		switch (cqr->status) {
1934 		case DASD_CQR_IN_IO:
1935 			rc = device->discipline->term_IO(cqr);
1936 			if (rc) {
1937 				/* unable to terminate requeust */
1938 				dev_err(&device->cdev->dev,
1939 					"Flushing the DASD request queue "
1940 					"failed for request %p\n", cqr);
1941 				/* stop flush processing */
1942 				goto finished;
1943 			}
1944 			break;
1945 		case DASD_CQR_QUEUED:
1946 			cqr->stopclk = get_clock();
1947 			cqr->status = DASD_CQR_CLEARED;
1948 			break;
1949 		default: /* no need to modify the others */
1950 			break;
1951 		}
1952 		list_move_tail(&cqr->devlist, &flush_queue);
1953 	}
1954 finished:
1955 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1956 	/*
1957 	 * After this point all requests must be in state CLEAR_PENDING,
1958 	 * CLEARED, SUCCESS or ERROR. Now wait for CLEAR_PENDING to become
1959 	 * one of the others.
1960 	 */
1961 	list_for_each_entry_safe(cqr, n, &flush_queue, devlist)
1962 		wait_event(dasd_flush_wq,
1963 			   (cqr->status != DASD_CQR_CLEAR_PENDING));
1964 	/*
1965 	 * Now set each request back to TERMINATED, DONE or NEED_ERP
1966 	 * and call the callback function of flushed requests
1967 	 */
1968 	__dasd_device_process_final_queue(device, &flush_queue);
1969 	return rc;
1970 }
1971 
1972 /*
1973  * Acquire the device lock and process queues for the device.
1974  */
1975 static void dasd_device_tasklet(struct dasd_device *device)
1976 {
1977 	struct list_head final_queue;
1978 
1979 	atomic_set (&device->tasklet_scheduled, 0);
1980 	INIT_LIST_HEAD(&final_queue);
1981 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1982 	/* Check expire time of first request on the ccw queue. */
1983 	__dasd_device_check_expire(device);
1984 	/* find final requests on ccw queue */
1985 	__dasd_device_process_ccw_queue(device, &final_queue);
1986 	__dasd_device_check_path_events(device);
1987 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1988 	/* Now call the callback function of requests with final status */
1989 	__dasd_device_process_final_queue(device, &final_queue);
1990 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1991 	/* Now check if the head of the ccw queue needs to be started. */
1992 	__dasd_device_start_head(device);
1993 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1994 	dasd_put_device(device);
1995 }
1996 
1997 /*
1998  * Schedules a call to dasd_tasklet over the device tasklet.
1999  */
2000 void dasd_schedule_device_bh(struct dasd_device *device)
2001 {
2002 	/* Protect against rescheduling. */
2003 	if (atomic_cmpxchg (&device->tasklet_scheduled, 0, 1) != 0)
2004 		return;
2005 	dasd_get_device(device);
2006 	tasklet_hi_schedule(&device->tasklet);
2007 }
2008 
2009 void dasd_device_set_stop_bits(struct dasd_device *device, int bits)
2010 {
2011 	device->stopped |= bits;
2012 }
2013 EXPORT_SYMBOL_GPL(dasd_device_set_stop_bits);
2014 
2015 void dasd_device_remove_stop_bits(struct dasd_device *device, int bits)
2016 {
2017 	device->stopped &= ~bits;
2018 	if (!device->stopped)
2019 		wake_up(&generic_waitq);
2020 }
2021 EXPORT_SYMBOL_GPL(dasd_device_remove_stop_bits);
2022 
2023 /*
2024  * Queue a request to the head of the device ccw_queue.
2025  * Start the I/O if possible.
2026  */
2027 void dasd_add_request_head(struct dasd_ccw_req *cqr)
2028 {
2029 	struct dasd_device *device;
2030 	unsigned long flags;
2031 
2032 	device = cqr->startdev;
2033 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
2034 	cqr->status = DASD_CQR_QUEUED;
2035 	list_add(&cqr->devlist, &device->ccw_queue);
2036 	/* let the bh start the request to keep them in order */
2037 	dasd_schedule_device_bh(device);
2038 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
2039 }
2040 
2041 /*
2042  * Queue a request to the tail of the device ccw_queue.
2043  * Start the I/O if possible.
2044  */
2045 void dasd_add_request_tail(struct dasd_ccw_req *cqr)
2046 {
2047 	struct dasd_device *device;
2048 	unsigned long flags;
2049 
2050 	device = cqr->startdev;
2051 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
2052 	cqr->status = DASD_CQR_QUEUED;
2053 	list_add_tail(&cqr->devlist, &device->ccw_queue);
2054 	/* let the bh start the request to keep them in order */
2055 	dasd_schedule_device_bh(device);
2056 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
2057 }
2058 
2059 /*
2060  * Wakeup helper for the 'sleep_on' functions.
2061  */
2062 void dasd_wakeup_cb(struct dasd_ccw_req *cqr, void *data)
2063 {
2064 	spin_lock_irq(get_ccwdev_lock(cqr->startdev->cdev));
2065 	cqr->callback_data = DASD_SLEEPON_END_TAG;
2066 	spin_unlock_irq(get_ccwdev_lock(cqr->startdev->cdev));
2067 	wake_up(&generic_waitq);
2068 }
2069 EXPORT_SYMBOL_GPL(dasd_wakeup_cb);
2070 
2071 static inline int _wait_for_wakeup(struct dasd_ccw_req *cqr)
2072 {
2073 	struct dasd_device *device;
2074 	int rc;
2075 
2076 	device = cqr->startdev;
2077 	spin_lock_irq(get_ccwdev_lock(device->cdev));
2078 	rc = (cqr->callback_data == DASD_SLEEPON_END_TAG);
2079 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
2080 	return rc;
2081 }
2082 
2083 /*
2084  * checks if error recovery is necessary, returns 1 if yes, 0 otherwise.
2085  */
2086 static int __dasd_sleep_on_erp(struct dasd_ccw_req *cqr)
2087 {
2088 	struct dasd_device *device;
2089 	dasd_erp_fn_t erp_fn;
2090 
2091 	if (cqr->status == DASD_CQR_FILLED)
2092 		return 0;
2093 	device = cqr->startdev;
2094 	if (test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) {
2095 		if (cqr->status == DASD_CQR_TERMINATED) {
2096 			device->discipline->handle_terminated_request(cqr);
2097 			return 1;
2098 		}
2099 		if (cqr->status == DASD_CQR_NEED_ERP) {
2100 			erp_fn = device->discipline->erp_action(cqr);
2101 			erp_fn(cqr);
2102 			return 1;
2103 		}
2104 		if (cqr->status == DASD_CQR_FAILED)
2105 			dasd_log_sense(cqr, &cqr->irb);
2106 		if (cqr->refers) {
2107 			__dasd_process_erp(device, cqr);
2108 			return 1;
2109 		}
2110 	}
2111 	return 0;
2112 }
2113 
2114 static int __dasd_sleep_on_loop_condition(struct dasd_ccw_req *cqr)
2115 {
2116 	if (test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) {
2117 		if (cqr->refers) /* erp is not done yet */
2118 			return 1;
2119 		return ((cqr->status != DASD_CQR_DONE) &&
2120 			(cqr->status != DASD_CQR_FAILED));
2121 	} else
2122 		return (cqr->status == DASD_CQR_FILLED);
2123 }
2124 
2125 static int _dasd_sleep_on(struct dasd_ccw_req *maincqr, int interruptible)
2126 {
2127 	struct dasd_device *device;
2128 	int rc;
2129 	struct list_head ccw_queue;
2130 	struct dasd_ccw_req *cqr;
2131 
2132 	INIT_LIST_HEAD(&ccw_queue);
2133 	maincqr->status = DASD_CQR_FILLED;
2134 	device = maincqr->startdev;
2135 	list_add(&maincqr->blocklist, &ccw_queue);
2136 	for (cqr = maincqr;  __dasd_sleep_on_loop_condition(cqr);
2137 	     cqr = list_first_entry(&ccw_queue,
2138 				    struct dasd_ccw_req, blocklist)) {
2139 
2140 		if (__dasd_sleep_on_erp(cqr))
2141 			continue;
2142 		if (cqr->status != DASD_CQR_FILLED) /* could be failed */
2143 			continue;
2144 		if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
2145 		    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
2146 			cqr->status = DASD_CQR_FAILED;
2147 			cqr->intrc = -EPERM;
2148 			continue;
2149 		}
2150 		/* Non-temporary stop condition will trigger fail fast */
2151 		if (device->stopped & ~DASD_STOPPED_PENDING &&
2152 		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
2153 		    (!dasd_eer_enabled(device))) {
2154 			cqr->status = DASD_CQR_FAILED;
2155 			continue;
2156 		}
2157 		/* Don't try to start requests if device is stopped */
2158 		if (interruptible) {
2159 			rc = wait_event_interruptible(
2160 				generic_waitq, !(device->stopped));
2161 			if (rc == -ERESTARTSYS) {
2162 				cqr->status = DASD_CQR_FAILED;
2163 				maincqr->intrc = rc;
2164 				continue;
2165 			}
2166 		} else
2167 			wait_event(generic_waitq, !(device->stopped));
2168 
2169 		if (!cqr->callback)
2170 			cqr->callback = dasd_wakeup_cb;
2171 
2172 		cqr->callback_data = DASD_SLEEPON_START_TAG;
2173 		dasd_add_request_tail(cqr);
2174 		if (interruptible) {
2175 			rc = wait_event_interruptible(
2176 				generic_waitq, _wait_for_wakeup(cqr));
2177 			if (rc == -ERESTARTSYS) {
2178 				dasd_cancel_req(cqr);
2179 				/* wait (non-interruptible) for final status */
2180 				wait_event(generic_waitq,
2181 					   _wait_for_wakeup(cqr));
2182 				cqr->status = DASD_CQR_FAILED;
2183 				maincqr->intrc = rc;
2184 				continue;
2185 			}
2186 		} else
2187 			wait_event(generic_waitq, _wait_for_wakeup(cqr));
2188 	}
2189 
2190 	maincqr->endclk = get_clock();
2191 	if ((maincqr->status != DASD_CQR_DONE) &&
2192 	    (maincqr->intrc != -ERESTARTSYS))
2193 		dasd_log_sense(maincqr, &maincqr->irb);
2194 	if (maincqr->status == DASD_CQR_DONE)
2195 		rc = 0;
2196 	else if (maincqr->intrc)
2197 		rc = maincqr->intrc;
2198 	else
2199 		rc = -EIO;
2200 	return rc;
2201 }
2202 
2203 /*
2204  * Queue a request to the tail of the device ccw_queue and wait for
2205  * it's completion.
2206  */
2207 int dasd_sleep_on(struct dasd_ccw_req *cqr)
2208 {
2209 	return _dasd_sleep_on(cqr, 0);
2210 }
2211 
2212 /*
2213  * Queue a request to the tail of the device ccw_queue and wait
2214  * interruptible for it's completion.
2215  */
2216 int dasd_sleep_on_interruptible(struct dasd_ccw_req *cqr)
2217 {
2218 	return _dasd_sleep_on(cqr, 1);
2219 }
2220 
2221 /*
2222  * Whoa nelly now it gets really hairy. For some functions (e.g. steal lock
2223  * for eckd devices) the currently running request has to be terminated
2224  * and be put back to status queued, before the special request is added
2225  * to the head of the queue. Then the special request is waited on normally.
2226  */
2227 static inline int _dasd_term_running_cqr(struct dasd_device *device)
2228 {
2229 	struct dasd_ccw_req *cqr;
2230 	int rc;
2231 
2232 	if (list_empty(&device->ccw_queue))
2233 		return 0;
2234 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
2235 	rc = device->discipline->term_IO(cqr);
2236 	if (!rc)
2237 		/*
2238 		 * CQR terminated because a more important request is pending.
2239 		 * Undo decreasing of retry counter because this is
2240 		 * not an error case.
2241 		 */
2242 		cqr->retries++;
2243 	return rc;
2244 }
2245 
2246 int dasd_sleep_on_immediatly(struct dasd_ccw_req *cqr)
2247 {
2248 	struct dasd_device *device;
2249 	int rc;
2250 
2251 	device = cqr->startdev;
2252 	if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
2253 	    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
2254 		cqr->status = DASD_CQR_FAILED;
2255 		cqr->intrc = -EPERM;
2256 		return -EIO;
2257 	}
2258 	spin_lock_irq(get_ccwdev_lock(device->cdev));
2259 	rc = _dasd_term_running_cqr(device);
2260 	if (rc) {
2261 		spin_unlock_irq(get_ccwdev_lock(device->cdev));
2262 		return rc;
2263 	}
2264 	cqr->callback = dasd_wakeup_cb;
2265 	cqr->callback_data = DASD_SLEEPON_START_TAG;
2266 	cqr->status = DASD_CQR_QUEUED;
2267 	/*
2268 	 * add new request as second
2269 	 * first the terminated cqr needs to be finished
2270 	 */
2271 	list_add(&cqr->devlist, device->ccw_queue.next);
2272 
2273 	/* let the bh start the request to keep them in order */
2274 	dasd_schedule_device_bh(device);
2275 
2276 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
2277 
2278 	wait_event(generic_waitq, _wait_for_wakeup(cqr));
2279 
2280 	if (cqr->status == DASD_CQR_DONE)
2281 		rc = 0;
2282 	else if (cqr->intrc)
2283 		rc = cqr->intrc;
2284 	else
2285 		rc = -EIO;
2286 	return rc;
2287 }
2288 
2289 /*
2290  * Cancels a request that was started with dasd_sleep_on_req.
2291  * This is useful to timeout requests. The request will be
2292  * terminated if it is currently in i/o.
2293  * Returns 1 if the request has been terminated.
2294  *	   0 if there was no need to terminate the request (not started yet)
2295  *	   negative error code if termination failed
2296  * Cancellation of a request is an asynchronous operation! The calling
2297  * function has to wait until the request is properly returned via callback.
2298  */
2299 int dasd_cancel_req(struct dasd_ccw_req *cqr)
2300 {
2301 	struct dasd_device *device = cqr->startdev;
2302 	unsigned long flags;
2303 	int rc;
2304 
2305 	rc = 0;
2306 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
2307 	switch (cqr->status) {
2308 	case DASD_CQR_QUEUED:
2309 		/* request was not started - just set to cleared */
2310 		cqr->status = DASD_CQR_CLEARED;
2311 		break;
2312 	case DASD_CQR_IN_IO:
2313 		/* request in IO - terminate IO and release again */
2314 		rc = device->discipline->term_IO(cqr);
2315 		if (rc) {
2316 			dev_err(&device->cdev->dev,
2317 				"Cancelling request %p failed with rc=%d\n",
2318 				cqr, rc);
2319 		} else {
2320 			cqr->stopclk = get_clock();
2321 		}
2322 		break;
2323 	default: /* already finished or clear pending - do nothing */
2324 		break;
2325 	}
2326 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
2327 	dasd_schedule_device_bh(device);
2328 	return rc;
2329 }
2330 
2331 
2332 /*
2333  * SECTION: Operations of the dasd_block layer.
2334  */
2335 
2336 /*
2337  * Timeout function for dasd_block. This is used when the block layer
2338  * is waiting for something that may not come reliably, (e.g. a state
2339  * change interrupt)
2340  */
2341 static void dasd_block_timeout(unsigned long ptr)
2342 {
2343 	unsigned long flags;
2344 	struct dasd_block *block;
2345 
2346 	block = (struct dasd_block *) ptr;
2347 	spin_lock_irqsave(get_ccwdev_lock(block->base->cdev), flags);
2348 	/* re-activate request queue */
2349 	dasd_device_remove_stop_bits(block->base, DASD_STOPPED_PENDING);
2350 	spin_unlock_irqrestore(get_ccwdev_lock(block->base->cdev), flags);
2351 	dasd_schedule_block_bh(block);
2352 }
2353 
2354 /*
2355  * Setup timeout for a dasd_block in jiffies.
2356  */
2357 void dasd_block_set_timer(struct dasd_block *block, int expires)
2358 {
2359 	if (expires == 0)
2360 		del_timer(&block->timer);
2361 	else
2362 		mod_timer(&block->timer, jiffies + expires);
2363 }
2364 
2365 /*
2366  * Clear timeout for a dasd_block.
2367  */
2368 void dasd_block_clear_timer(struct dasd_block *block)
2369 {
2370 	del_timer(&block->timer);
2371 }
2372 
2373 /*
2374  * Process finished error recovery ccw.
2375  */
2376 static void __dasd_process_erp(struct dasd_device *device,
2377 			       struct dasd_ccw_req *cqr)
2378 {
2379 	dasd_erp_fn_t erp_fn;
2380 
2381 	if (cqr->status == DASD_CQR_DONE)
2382 		DBF_DEV_EVENT(DBF_NOTICE, device, "%s", "ERP successful");
2383 	else
2384 		dev_err(&device->cdev->dev, "ERP failed for the DASD\n");
2385 	erp_fn = device->discipline->erp_postaction(cqr);
2386 	erp_fn(cqr);
2387 }
2388 
2389 /*
2390  * Fetch requests from the block device queue.
2391  */
2392 static void __dasd_process_request_queue(struct dasd_block *block)
2393 {
2394 	struct request_queue *queue;
2395 	struct request *req;
2396 	struct dasd_ccw_req *cqr;
2397 	struct dasd_device *basedev;
2398 	unsigned long flags;
2399 	queue = block->request_queue;
2400 	basedev = block->base;
2401 	/* No queue ? Then there is nothing to do. */
2402 	if (queue == NULL)
2403 		return;
2404 
2405 	/*
2406 	 * We requeue request from the block device queue to the ccw
2407 	 * queue only in two states. In state DASD_STATE_READY the
2408 	 * partition detection is done and we need to requeue requests
2409 	 * for that. State DASD_STATE_ONLINE is normal block device
2410 	 * operation.
2411 	 */
2412 	if (basedev->state < DASD_STATE_READY) {
2413 		while ((req = blk_fetch_request(block->request_queue)))
2414 			__blk_end_request_all(req, -EIO);
2415 		return;
2416 	}
2417 	/* Now we try to fetch requests from the request queue */
2418 	while ((req = blk_peek_request(queue))) {
2419 		if (basedev->features & DASD_FEATURE_READONLY &&
2420 		    rq_data_dir(req) == WRITE) {
2421 			DBF_DEV_EVENT(DBF_ERR, basedev,
2422 				      "Rejecting write request %p",
2423 				      req);
2424 			blk_start_request(req);
2425 			__blk_end_request_all(req, -EIO);
2426 			continue;
2427 		}
2428 		cqr = basedev->discipline->build_cp(basedev, block, req);
2429 		if (IS_ERR(cqr)) {
2430 			if (PTR_ERR(cqr) == -EBUSY)
2431 				break;	/* normal end condition */
2432 			if (PTR_ERR(cqr) == -ENOMEM)
2433 				break;	/* terminate request queue loop */
2434 			if (PTR_ERR(cqr) == -EAGAIN) {
2435 				/*
2436 				 * The current request cannot be build right
2437 				 * now, we have to try later. If this request
2438 				 * is the head-of-queue we stop the device
2439 				 * for 1/2 second.
2440 				 */
2441 				if (!list_empty(&block->ccw_queue))
2442 					break;
2443 				spin_lock_irqsave(
2444 					get_ccwdev_lock(basedev->cdev), flags);
2445 				dasd_device_set_stop_bits(basedev,
2446 							  DASD_STOPPED_PENDING);
2447 				spin_unlock_irqrestore(
2448 					get_ccwdev_lock(basedev->cdev), flags);
2449 				dasd_block_set_timer(block, HZ/2);
2450 				break;
2451 			}
2452 			DBF_DEV_EVENT(DBF_ERR, basedev,
2453 				      "CCW creation failed (rc=%ld) "
2454 				      "on request %p",
2455 				      PTR_ERR(cqr), req);
2456 			blk_start_request(req);
2457 			__blk_end_request_all(req, -EIO);
2458 			continue;
2459 		}
2460 		/*
2461 		 *  Note: callback is set to dasd_return_cqr_cb in
2462 		 * __dasd_block_start_head to cover erp requests as well
2463 		 */
2464 		cqr->callback_data = (void *) req;
2465 		cqr->status = DASD_CQR_FILLED;
2466 		blk_start_request(req);
2467 		list_add_tail(&cqr->blocklist, &block->ccw_queue);
2468 		dasd_profile_start(block, cqr, req);
2469 	}
2470 }
2471 
2472 static void __dasd_cleanup_cqr(struct dasd_ccw_req *cqr)
2473 {
2474 	struct request *req;
2475 	int status;
2476 	int error = 0;
2477 
2478 	req = (struct request *) cqr->callback_data;
2479 	dasd_profile_end(cqr->block, cqr, req);
2480 	status = cqr->block->base->discipline->free_cp(cqr, req);
2481 	if (status <= 0)
2482 		error = status ? status : -EIO;
2483 	__blk_end_request_all(req, error);
2484 }
2485 
2486 /*
2487  * Process ccw request queue.
2488  */
2489 static void __dasd_process_block_ccw_queue(struct dasd_block *block,
2490 					   struct list_head *final_queue)
2491 {
2492 	struct list_head *l, *n;
2493 	struct dasd_ccw_req *cqr;
2494 	dasd_erp_fn_t erp_fn;
2495 	unsigned long flags;
2496 	struct dasd_device *base = block->base;
2497 
2498 restart:
2499 	/* Process request with final status. */
2500 	list_for_each_safe(l, n, &block->ccw_queue) {
2501 		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
2502 		if (cqr->status != DASD_CQR_DONE &&
2503 		    cqr->status != DASD_CQR_FAILED &&
2504 		    cqr->status != DASD_CQR_NEED_ERP &&
2505 		    cqr->status != DASD_CQR_TERMINATED)
2506 			continue;
2507 
2508 		if (cqr->status == DASD_CQR_TERMINATED) {
2509 			base->discipline->handle_terminated_request(cqr);
2510 			goto restart;
2511 		}
2512 
2513 		/*  Process requests that may be recovered */
2514 		if (cqr->status == DASD_CQR_NEED_ERP) {
2515 			erp_fn = base->discipline->erp_action(cqr);
2516 			if (IS_ERR(erp_fn(cqr)))
2517 				continue;
2518 			goto restart;
2519 		}
2520 
2521 		/* log sense for fatal error */
2522 		if (cqr->status == DASD_CQR_FAILED) {
2523 			dasd_log_sense(cqr, &cqr->irb);
2524 		}
2525 
2526 		/* First of all call extended error reporting. */
2527 		if (dasd_eer_enabled(base) &&
2528 		    cqr->status == DASD_CQR_FAILED) {
2529 			dasd_eer_write(base, cqr, DASD_EER_FATALERROR);
2530 
2531 			/* restart request  */
2532 			cqr->status = DASD_CQR_FILLED;
2533 			cqr->retries = 255;
2534 			spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
2535 			dasd_device_set_stop_bits(base, DASD_STOPPED_QUIESCE);
2536 			spin_unlock_irqrestore(get_ccwdev_lock(base->cdev),
2537 					       flags);
2538 			goto restart;
2539 		}
2540 
2541 		/* Process finished ERP request. */
2542 		if (cqr->refers) {
2543 			__dasd_process_erp(base, cqr);
2544 			goto restart;
2545 		}
2546 
2547 		/* Rechain finished requests to final queue */
2548 		cqr->endclk = get_clock();
2549 		list_move_tail(&cqr->blocklist, final_queue);
2550 	}
2551 }
2552 
2553 static void dasd_return_cqr_cb(struct dasd_ccw_req *cqr, void *data)
2554 {
2555 	dasd_schedule_block_bh(cqr->block);
2556 }
2557 
2558 static void __dasd_block_start_head(struct dasd_block *block)
2559 {
2560 	struct dasd_ccw_req *cqr;
2561 
2562 	if (list_empty(&block->ccw_queue))
2563 		return;
2564 	/* We allways begin with the first requests on the queue, as some
2565 	 * of previously started requests have to be enqueued on a
2566 	 * dasd_device again for error recovery.
2567 	 */
2568 	list_for_each_entry(cqr, &block->ccw_queue, blocklist) {
2569 		if (cqr->status != DASD_CQR_FILLED)
2570 			continue;
2571 		if (test_bit(DASD_FLAG_LOCK_STOLEN, &block->base->flags) &&
2572 		    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
2573 			cqr->status = DASD_CQR_FAILED;
2574 			cqr->intrc = -EPERM;
2575 			dasd_schedule_block_bh(block);
2576 			continue;
2577 		}
2578 		/* Non-temporary stop condition will trigger fail fast */
2579 		if (block->base->stopped & ~DASD_STOPPED_PENDING &&
2580 		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
2581 		    (!dasd_eer_enabled(block->base))) {
2582 			cqr->status = DASD_CQR_FAILED;
2583 			dasd_schedule_block_bh(block);
2584 			continue;
2585 		}
2586 		/* Don't try to start requests if device is stopped */
2587 		if (block->base->stopped)
2588 			return;
2589 
2590 		/* just a fail safe check, should not happen */
2591 		if (!cqr->startdev)
2592 			cqr->startdev = block->base;
2593 
2594 		/* make sure that the requests we submit find their way back */
2595 		cqr->callback = dasd_return_cqr_cb;
2596 
2597 		dasd_add_request_tail(cqr);
2598 	}
2599 }
2600 
2601 /*
2602  * Central dasd_block layer routine. Takes requests from the generic
2603  * block layer request queue, creates ccw requests, enqueues them on
2604  * a dasd_device and processes ccw requests that have been returned.
2605  */
2606 static void dasd_block_tasklet(struct dasd_block *block)
2607 {
2608 	struct list_head final_queue;
2609 	struct list_head *l, *n;
2610 	struct dasd_ccw_req *cqr;
2611 
2612 	atomic_set(&block->tasklet_scheduled, 0);
2613 	INIT_LIST_HEAD(&final_queue);
2614 	spin_lock(&block->queue_lock);
2615 	/* Finish off requests on ccw queue */
2616 	__dasd_process_block_ccw_queue(block, &final_queue);
2617 	spin_unlock(&block->queue_lock);
2618 	/* Now call the callback function of requests with final status */
2619 	spin_lock_irq(&block->request_queue_lock);
2620 	list_for_each_safe(l, n, &final_queue) {
2621 		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
2622 		list_del_init(&cqr->blocklist);
2623 		__dasd_cleanup_cqr(cqr);
2624 	}
2625 	spin_lock(&block->queue_lock);
2626 	/* Get new request from the block device request queue */
2627 	__dasd_process_request_queue(block);
2628 	/* Now check if the head of the ccw queue needs to be started. */
2629 	__dasd_block_start_head(block);
2630 	spin_unlock(&block->queue_lock);
2631 	spin_unlock_irq(&block->request_queue_lock);
2632 	dasd_put_device(block->base);
2633 }
2634 
2635 static void _dasd_wake_block_flush_cb(struct dasd_ccw_req *cqr, void *data)
2636 {
2637 	wake_up(&dasd_flush_wq);
2638 }
2639 
2640 /*
2641  * Go through all request on the dasd_block request queue, cancel them
2642  * on the respective dasd_device, and return them to the generic
2643  * block layer.
2644  */
2645 static int dasd_flush_block_queue(struct dasd_block *block)
2646 {
2647 	struct dasd_ccw_req *cqr, *n;
2648 	int rc, i;
2649 	struct list_head flush_queue;
2650 
2651 	INIT_LIST_HEAD(&flush_queue);
2652 	spin_lock_bh(&block->queue_lock);
2653 	rc = 0;
2654 restart:
2655 	list_for_each_entry_safe(cqr, n, &block->ccw_queue, blocklist) {
2656 		/* if this request currently owned by a dasd_device cancel it */
2657 		if (cqr->status >= DASD_CQR_QUEUED)
2658 			rc = dasd_cancel_req(cqr);
2659 		if (rc < 0)
2660 			break;
2661 		/* Rechain request (including erp chain) so it won't be
2662 		 * touched by the dasd_block_tasklet anymore.
2663 		 * Replace the callback so we notice when the request
2664 		 * is returned from the dasd_device layer.
2665 		 */
2666 		cqr->callback = _dasd_wake_block_flush_cb;
2667 		for (i = 0; cqr != NULL; cqr = cqr->refers, i++)
2668 			list_move_tail(&cqr->blocklist, &flush_queue);
2669 		if (i > 1)
2670 			/* moved more than one request - need to restart */
2671 			goto restart;
2672 	}
2673 	spin_unlock_bh(&block->queue_lock);
2674 	/* Now call the callback function of flushed requests */
2675 restart_cb:
2676 	list_for_each_entry_safe(cqr, n, &flush_queue, blocklist) {
2677 		wait_event(dasd_flush_wq, (cqr->status < DASD_CQR_QUEUED));
2678 		/* Process finished ERP request. */
2679 		if (cqr->refers) {
2680 			spin_lock_bh(&block->queue_lock);
2681 			__dasd_process_erp(block->base, cqr);
2682 			spin_unlock_bh(&block->queue_lock);
2683 			/* restart list_for_xx loop since dasd_process_erp
2684 			 * might remove multiple elements */
2685 			goto restart_cb;
2686 		}
2687 		/* call the callback function */
2688 		spin_lock_irq(&block->request_queue_lock);
2689 		cqr->endclk = get_clock();
2690 		list_del_init(&cqr->blocklist);
2691 		__dasd_cleanup_cqr(cqr);
2692 		spin_unlock_irq(&block->request_queue_lock);
2693 	}
2694 	return rc;
2695 }
2696 
2697 /*
2698  * Schedules a call to dasd_tasklet over the device tasklet.
2699  */
2700 void dasd_schedule_block_bh(struct dasd_block *block)
2701 {
2702 	/* Protect against rescheduling. */
2703 	if (atomic_cmpxchg(&block->tasklet_scheduled, 0, 1) != 0)
2704 		return;
2705 	/* life cycle of block is bound to it's base device */
2706 	dasd_get_device(block->base);
2707 	tasklet_hi_schedule(&block->tasklet);
2708 }
2709 
2710 
2711 /*
2712  * SECTION: external block device operations
2713  * (request queue handling, open, release, etc.)
2714  */
2715 
2716 /*
2717  * Dasd request queue function. Called from ll_rw_blk.c
2718  */
2719 static void do_dasd_request(struct request_queue *queue)
2720 {
2721 	struct dasd_block *block;
2722 
2723 	block = queue->queuedata;
2724 	spin_lock(&block->queue_lock);
2725 	/* Get new request from the block device request queue */
2726 	__dasd_process_request_queue(block);
2727 	/* Now check if the head of the ccw queue needs to be started. */
2728 	__dasd_block_start_head(block);
2729 	spin_unlock(&block->queue_lock);
2730 }
2731 
2732 /*
2733  * Allocate and initialize request queue and default I/O scheduler.
2734  */
2735 static int dasd_alloc_queue(struct dasd_block *block)
2736 {
2737 	int rc;
2738 
2739 	block->request_queue = blk_init_queue(do_dasd_request,
2740 					       &block->request_queue_lock);
2741 	if (block->request_queue == NULL)
2742 		return -ENOMEM;
2743 
2744 	block->request_queue->queuedata = block;
2745 
2746 	elevator_exit(block->request_queue->elevator);
2747 	block->request_queue->elevator = NULL;
2748 	rc = elevator_init(block->request_queue, "deadline");
2749 	if (rc) {
2750 		blk_cleanup_queue(block->request_queue);
2751 		return rc;
2752 	}
2753 	return 0;
2754 }
2755 
2756 /*
2757  * Allocate and initialize request queue.
2758  */
2759 static void dasd_setup_queue(struct dasd_block *block)
2760 {
2761 	int max;
2762 
2763 	if (block->base->features & DASD_FEATURE_USERAW) {
2764 		/*
2765 		 * the max_blocks value for raw_track access is 256
2766 		 * it is higher than the native ECKD value because we
2767 		 * only need one ccw per track
2768 		 * so the max_hw_sectors are
2769 		 * 2048 x 512B = 1024kB = 16 tracks
2770 		 */
2771 		max = 2048;
2772 	} else {
2773 		max = block->base->discipline->max_blocks << block->s2b_shift;
2774 	}
2775 	blk_queue_logical_block_size(block->request_queue,
2776 				     block->bp_block);
2777 	blk_queue_max_hw_sectors(block->request_queue, max);
2778 	blk_queue_max_segments(block->request_queue, -1L);
2779 	/* with page sized segments we can translate each segement into
2780 	 * one idaw/tidaw
2781 	 */
2782 	blk_queue_max_segment_size(block->request_queue, PAGE_SIZE);
2783 	blk_queue_segment_boundary(block->request_queue, PAGE_SIZE - 1);
2784 }
2785 
2786 /*
2787  * Deactivate and free request queue.
2788  */
2789 static void dasd_free_queue(struct dasd_block *block)
2790 {
2791 	if (block->request_queue) {
2792 		blk_cleanup_queue(block->request_queue);
2793 		block->request_queue = NULL;
2794 	}
2795 }
2796 
2797 /*
2798  * Flush request on the request queue.
2799  */
2800 static void dasd_flush_request_queue(struct dasd_block *block)
2801 {
2802 	struct request *req;
2803 
2804 	if (!block->request_queue)
2805 		return;
2806 
2807 	spin_lock_irq(&block->request_queue_lock);
2808 	while ((req = blk_fetch_request(block->request_queue)))
2809 		__blk_end_request_all(req, -EIO);
2810 	spin_unlock_irq(&block->request_queue_lock);
2811 }
2812 
2813 static int dasd_open(struct block_device *bdev, fmode_t mode)
2814 {
2815 	struct dasd_device *base;
2816 	int rc;
2817 
2818 	base = dasd_device_from_gendisk(bdev->bd_disk);
2819 	if (!base)
2820 		return -ENODEV;
2821 
2822 	atomic_inc(&base->block->open_count);
2823 	if (test_bit(DASD_FLAG_OFFLINE, &base->flags)) {
2824 		rc = -ENODEV;
2825 		goto unlock;
2826 	}
2827 
2828 	if (!try_module_get(base->discipline->owner)) {
2829 		rc = -EINVAL;
2830 		goto unlock;
2831 	}
2832 
2833 	if (dasd_probeonly) {
2834 		dev_info(&base->cdev->dev,
2835 			 "Accessing the DASD failed because it is in "
2836 			 "probeonly mode\n");
2837 		rc = -EPERM;
2838 		goto out;
2839 	}
2840 
2841 	if (base->state <= DASD_STATE_BASIC) {
2842 		DBF_DEV_EVENT(DBF_ERR, base, " %s",
2843 			      " Cannot open unrecognized device");
2844 		rc = -ENODEV;
2845 		goto out;
2846 	}
2847 
2848 	if ((mode & FMODE_WRITE) &&
2849 	    (test_bit(DASD_FLAG_DEVICE_RO, &base->flags) ||
2850 	     (base->features & DASD_FEATURE_READONLY))) {
2851 		rc = -EROFS;
2852 		goto out;
2853 	}
2854 
2855 	dasd_put_device(base);
2856 	return 0;
2857 
2858 out:
2859 	module_put(base->discipline->owner);
2860 unlock:
2861 	atomic_dec(&base->block->open_count);
2862 	dasd_put_device(base);
2863 	return rc;
2864 }
2865 
2866 static int dasd_release(struct gendisk *disk, fmode_t mode)
2867 {
2868 	struct dasd_device *base;
2869 
2870 	base = dasd_device_from_gendisk(disk);
2871 	if (!base)
2872 		return -ENODEV;
2873 
2874 	atomic_dec(&base->block->open_count);
2875 	module_put(base->discipline->owner);
2876 	dasd_put_device(base);
2877 	return 0;
2878 }
2879 
2880 /*
2881  * Return disk geometry.
2882  */
2883 static int dasd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
2884 {
2885 	struct dasd_device *base;
2886 
2887 	base = dasd_device_from_gendisk(bdev->bd_disk);
2888 	if (!base)
2889 		return -ENODEV;
2890 
2891 	if (!base->discipline ||
2892 	    !base->discipline->fill_geometry) {
2893 		dasd_put_device(base);
2894 		return -EINVAL;
2895 	}
2896 	base->discipline->fill_geometry(base->block, geo);
2897 	geo->start = get_start_sect(bdev) >> base->block->s2b_shift;
2898 	dasd_put_device(base);
2899 	return 0;
2900 }
2901 
2902 const struct block_device_operations
2903 dasd_device_operations = {
2904 	.owner		= THIS_MODULE,
2905 	.open		= dasd_open,
2906 	.release	= dasd_release,
2907 	.ioctl		= dasd_ioctl,
2908 	.compat_ioctl	= dasd_ioctl,
2909 	.getgeo		= dasd_getgeo,
2910 };
2911 
2912 /*******************************************************************************
2913  * end of block device operations
2914  */
2915 
2916 static void
2917 dasd_exit(void)
2918 {
2919 #ifdef CONFIG_PROC_FS
2920 	dasd_proc_exit();
2921 #endif
2922 	dasd_eer_exit();
2923         if (dasd_page_cache != NULL) {
2924 		kmem_cache_destroy(dasd_page_cache);
2925 		dasd_page_cache = NULL;
2926 	}
2927 	dasd_gendisk_exit();
2928 	dasd_devmap_exit();
2929 	if (dasd_debug_area != NULL) {
2930 		debug_unregister(dasd_debug_area);
2931 		dasd_debug_area = NULL;
2932 	}
2933 	dasd_statistics_removeroot();
2934 }
2935 
2936 /*
2937  * SECTION: common functions for ccw_driver use
2938  */
2939 
2940 /*
2941  * Is the device read-only?
2942  * Note that this function does not report the setting of the
2943  * readonly device attribute, but how it is configured in z/VM.
2944  */
2945 int dasd_device_is_ro(struct dasd_device *device)
2946 {
2947 	struct ccw_dev_id dev_id;
2948 	struct diag210 diag_data;
2949 	int rc;
2950 
2951 	if (!MACHINE_IS_VM)
2952 		return 0;
2953 	ccw_device_get_id(device->cdev, &dev_id);
2954 	memset(&diag_data, 0, sizeof(diag_data));
2955 	diag_data.vrdcdvno = dev_id.devno;
2956 	diag_data.vrdclen = sizeof(diag_data);
2957 	rc = diag210(&diag_data);
2958 	if (rc == 0 || rc == 2) {
2959 		return diag_data.vrdcvfla & 0x80;
2960 	} else {
2961 		DBF_EVENT(DBF_WARNING, "diag210 failed for dev=%04x with rc=%d",
2962 			  dev_id.devno, rc);
2963 		return 0;
2964 	}
2965 }
2966 EXPORT_SYMBOL_GPL(dasd_device_is_ro);
2967 
2968 static void dasd_generic_auto_online(void *data, async_cookie_t cookie)
2969 {
2970 	struct ccw_device *cdev = data;
2971 	int ret;
2972 
2973 	ret = ccw_device_set_online(cdev);
2974 	if (ret)
2975 		pr_warning("%s: Setting the DASD online failed with rc=%d\n",
2976 			   dev_name(&cdev->dev), ret);
2977 }
2978 
2979 /*
2980  * Initial attempt at a probe function. this can be simplified once
2981  * the other detection code is gone.
2982  */
2983 int dasd_generic_probe(struct ccw_device *cdev,
2984 		       struct dasd_discipline *discipline)
2985 {
2986 	int ret;
2987 
2988 	ret = dasd_add_sysfs_files(cdev);
2989 	if (ret) {
2990 		DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s",
2991 				"dasd_generic_probe: could not add "
2992 				"sysfs entries");
2993 		return ret;
2994 	}
2995 	cdev->handler = &dasd_int_handler;
2996 
2997 	/*
2998 	 * Automatically online either all dasd devices (dasd_autodetect)
2999 	 * or all devices specified with dasd= parameters during
3000 	 * initial probe.
3001 	 */
3002 	if ((dasd_get_feature(cdev, DASD_FEATURE_INITIAL_ONLINE) > 0 ) ||
3003 	    (dasd_autodetect && dasd_busid_known(dev_name(&cdev->dev)) != 0))
3004 		async_schedule(dasd_generic_auto_online, cdev);
3005 	return 0;
3006 }
3007 
3008 /*
3009  * This will one day be called from a global not_oper handler.
3010  * It is also used by driver_unregister during module unload.
3011  */
3012 void dasd_generic_remove(struct ccw_device *cdev)
3013 {
3014 	struct dasd_device *device;
3015 	struct dasd_block *block;
3016 
3017 	cdev->handler = NULL;
3018 
3019 	dasd_remove_sysfs_files(cdev);
3020 	device = dasd_device_from_cdev(cdev);
3021 	if (IS_ERR(device))
3022 		return;
3023 	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
3024 		/* Already doing offline processing */
3025 		dasd_put_device(device);
3026 		return;
3027 	}
3028 	/*
3029 	 * This device is removed unconditionally. Set offline
3030 	 * flag to prevent dasd_open from opening it while it is
3031 	 * no quite down yet.
3032 	 */
3033 	dasd_set_target_state(device, DASD_STATE_NEW);
3034 	/* dasd_delete_device destroys the device reference. */
3035 	block = device->block;
3036 	dasd_delete_device(device);
3037 	/*
3038 	 * life cycle of block is bound to device, so delete it after
3039 	 * device was safely removed
3040 	 */
3041 	if (block)
3042 		dasd_free_block(block);
3043 }
3044 
3045 /*
3046  * Activate a device. This is called from dasd_{eckd,fba}_probe() when either
3047  * the device is detected for the first time and is supposed to be used
3048  * or the user has started activation through sysfs.
3049  */
3050 int dasd_generic_set_online(struct ccw_device *cdev,
3051 			    struct dasd_discipline *base_discipline)
3052 {
3053 	struct dasd_discipline *discipline;
3054 	struct dasd_device *device;
3055 	int rc;
3056 
3057 	/* first online clears initial online feature flag */
3058 	dasd_set_feature(cdev, DASD_FEATURE_INITIAL_ONLINE, 0);
3059 	device = dasd_create_device(cdev);
3060 	if (IS_ERR(device))
3061 		return PTR_ERR(device);
3062 
3063 	discipline = base_discipline;
3064 	if (device->features & DASD_FEATURE_USEDIAG) {
3065 	  	if (!dasd_diag_discipline_pointer) {
3066 			pr_warning("%s Setting the DASD online failed because "
3067 				   "of missing DIAG discipline\n",
3068 				   dev_name(&cdev->dev));
3069 			dasd_delete_device(device);
3070 			return -ENODEV;
3071 		}
3072 		discipline = dasd_diag_discipline_pointer;
3073 	}
3074 	if (!try_module_get(base_discipline->owner)) {
3075 		dasd_delete_device(device);
3076 		return -EINVAL;
3077 	}
3078 	if (!try_module_get(discipline->owner)) {
3079 		module_put(base_discipline->owner);
3080 		dasd_delete_device(device);
3081 		return -EINVAL;
3082 	}
3083 	device->base_discipline = base_discipline;
3084 	device->discipline = discipline;
3085 
3086 	/* check_device will allocate block device if necessary */
3087 	rc = discipline->check_device(device);
3088 	if (rc) {
3089 		pr_warning("%s Setting the DASD online with discipline %s "
3090 			   "failed with rc=%i\n",
3091 			   dev_name(&cdev->dev), discipline->name, rc);
3092 		module_put(discipline->owner);
3093 		module_put(base_discipline->owner);
3094 		dasd_delete_device(device);
3095 		return rc;
3096 	}
3097 
3098 	dasd_set_target_state(device, DASD_STATE_ONLINE);
3099 	if (device->state <= DASD_STATE_KNOWN) {
3100 		pr_warning("%s Setting the DASD online failed because of a "
3101 			   "missing discipline\n", dev_name(&cdev->dev));
3102 		rc = -ENODEV;
3103 		dasd_set_target_state(device, DASD_STATE_NEW);
3104 		if (device->block)
3105 			dasd_free_block(device->block);
3106 		dasd_delete_device(device);
3107 	} else
3108 		pr_debug("dasd_generic device %s found\n",
3109 				dev_name(&cdev->dev));
3110 
3111 	wait_event(dasd_init_waitq, _wait_for_device(device));
3112 
3113 	dasd_put_device(device);
3114 	return rc;
3115 }
3116 
3117 int dasd_generic_set_offline(struct ccw_device *cdev)
3118 {
3119 	struct dasd_device *device;
3120 	struct dasd_block *block;
3121 	int max_count, open_count;
3122 
3123 	device = dasd_device_from_cdev(cdev);
3124 	if (IS_ERR(device))
3125 		return PTR_ERR(device);
3126 	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
3127 		/* Already doing offline processing */
3128 		dasd_put_device(device);
3129 		return 0;
3130 	}
3131 	/*
3132 	 * We must make sure that this device is currently not in use.
3133 	 * The open_count is increased for every opener, that includes
3134 	 * the blkdev_get in dasd_scan_partitions. We are only interested
3135 	 * in the other openers.
3136 	 */
3137 	if (device->block) {
3138 		max_count = device->block->bdev ? 0 : -1;
3139 		open_count = atomic_read(&device->block->open_count);
3140 		if (open_count > max_count) {
3141 			if (open_count > 0)
3142 				pr_warning("%s: The DASD cannot be set offline "
3143 					   "with open count %i\n",
3144 					   dev_name(&cdev->dev), open_count);
3145 			else
3146 				pr_warning("%s: The DASD cannot be set offline "
3147 					   "while it is in use\n",
3148 					   dev_name(&cdev->dev));
3149 			clear_bit(DASD_FLAG_OFFLINE, &device->flags);
3150 			dasd_put_device(device);
3151 			return -EBUSY;
3152 		}
3153 	}
3154 	dasd_set_target_state(device, DASD_STATE_NEW);
3155 	/* dasd_delete_device destroys the device reference. */
3156 	block = device->block;
3157 	dasd_delete_device(device);
3158 	/*
3159 	 * life cycle of block is bound to device, so delete it after
3160 	 * device was safely removed
3161 	 */
3162 	if (block)
3163 		dasd_free_block(block);
3164 	return 0;
3165 }
3166 
3167 int dasd_generic_last_path_gone(struct dasd_device *device)
3168 {
3169 	struct dasd_ccw_req *cqr;
3170 
3171 	dev_warn(&device->cdev->dev, "No operational channel path is left "
3172 		 "for the device\n");
3173 	DBF_DEV_EVENT(DBF_WARNING, device, "%s", "last path gone");
3174 	/* First of all call extended error reporting. */
3175 	dasd_eer_write(device, NULL, DASD_EER_NOPATH);
3176 
3177 	if (device->state < DASD_STATE_BASIC)
3178 		return 0;
3179 	/* Device is active. We want to keep it. */
3180 	list_for_each_entry(cqr, &device->ccw_queue, devlist)
3181 		if ((cqr->status == DASD_CQR_IN_IO) ||
3182 		    (cqr->status == DASD_CQR_CLEAR_PENDING)) {
3183 			cqr->status = DASD_CQR_QUEUED;
3184 			cqr->retries++;
3185 		}
3186 	dasd_device_set_stop_bits(device, DASD_STOPPED_DC_WAIT);
3187 	dasd_device_clear_timer(device);
3188 	dasd_schedule_device_bh(device);
3189 	return 1;
3190 }
3191 EXPORT_SYMBOL_GPL(dasd_generic_last_path_gone);
3192 
3193 int dasd_generic_path_operational(struct dasd_device *device)
3194 {
3195 	dev_info(&device->cdev->dev, "A channel path to the device has become "
3196 		 "operational\n");
3197 	DBF_DEV_EVENT(DBF_WARNING, device, "%s", "path operational");
3198 	dasd_device_remove_stop_bits(device, DASD_STOPPED_DC_WAIT);
3199 	if (device->stopped & DASD_UNRESUMED_PM) {
3200 		dasd_device_remove_stop_bits(device, DASD_UNRESUMED_PM);
3201 		dasd_restore_device(device);
3202 		return 1;
3203 	}
3204 	dasd_schedule_device_bh(device);
3205 	if (device->block)
3206 		dasd_schedule_block_bh(device->block);
3207 	return 1;
3208 }
3209 EXPORT_SYMBOL_GPL(dasd_generic_path_operational);
3210 
3211 int dasd_generic_notify(struct ccw_device *cdev, int event)
3212 {
3213 	struct dasd_device *device;
3214 	int ret;
3215 
3216 	device = dasd_device_from_cdev_locked(cdev);
3217 	if (IS_ERR(device))
3218 		return 0;
3219 	ret = 0;
3220 	switch (event) {
3221 	case CIO_GONE:
3222 	case CIO_BOXED:
3223 	case CIO_NO_PATH:
3224 		device->path_data.opm = 0;
3225 		device->path_data.ppm = 0;
3226 		device->path_data.npm = 0;
3227 		ret = dasd_generic_last_path_gone(device);
3228 		break;
3229 	case CIO_OPER:
3230 		ret = 1;
3231 		if (device->path_data.opm)
3232 			ret = dasd_generic_path_operational(device);
3233 		break;
3234 	}
3235 	dasd_put_device(device);
3236 	return ret;
3237 }
3238 
3239 void dasd_generic_path_event(struct ccw_device *cdev, int *path_event)
3240 {
3241 	int chp;
3242 	__u8 oldopm, eventlpm;
3243 	struct dasd_device *device;
3244 
3245 	device = dasd_device_from_cdev_locked(cdev);
3246 	if (IS_ERR(device))
3247 		return;
3248 	for (chp = 0; chp < 8; chp++) {
3249 		eventlpm = 0x80 >> chp;
3250 		if (path_event[chp] & PE_PATH_GONE) {
3251 			oldopm = device->path_data.opm;
3252 			device->path_data.opm &= ~eventlpm;
3253 			device->path_data.ppm &= ~eventlpm;
3254 			device->path_data.npm &= ~eventlpm;
3255 			if (oldopm && !device->path_data.opm)
3256 				dasd_generic_last_path_gone(device);
3257 		}
3258 		if (path_event[chp] & PE_PATH_AVAILABLE) {
3259 			device->path_data.opm &= ~eventlpm;
3260 			device->path_data.ppm &= ~eventlpm;
3261 			device->path_data.npm &= ~eventlpm;
3262 			device->path_data.tbvpm |= eventlpm;
3263 			dasd_schedule_device_bh(device);
3264 		}
3265 	}
3266 	dasd_put_device(device);
3267 }
3268 EXPORT_SYMBOL_GPL(dasd_generic_path_event);
3269 
3270 int dasd_generic_verify_path(struct dasd_device *device, __u8 lpm)
3271 {
3272 	if (!device->path_data.opm && lpm) {
3273 		device->path_data.opm = lpm;
3274 		dasd_generic_path_operational(device);
3275 	} else
3276 		device->path_data.opm |= lpm;
3277 	return 0;
3278 }
3279 EXPORT_SYMBOL_GPL(dasd_generic_verify_path);
3280 
3281 
3282 int dasd_generic_pm_freeze(struct ccw_device *cdev)
3283 {
3284 	struct dasd_ccw_req *cqr, *n;
3285 	int rc;
3286 	struct list_head freeze_queue;
3287 	struct dasd_device *device = dasd_device_from_cdev(cdev);
3288 
3289 	if (IS_ERR(device))
3290 		return PTR_ERR(device);
3291 
3292 	/* mark device as suspended */
3293 	set_bit(DASD_FLAG_SUSPENDED, &device->flags);
3294 
3295 	if (device->discipline->freeze)
3296 		rc = device->discipline->freeze(device);
3297 
3298 	/* disallow new I/O  */
3299 	dasd_device_set_stop_bits(device, DASD_STOPPED_PM);
3300 	/* clear active requests */
3301 	INIT_LIST_HEAD(&freeze_queue);
3302 	spin_lock_irq(get_ccwdev_lock(cdev));
3303 	rc = 0;
3304 	list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
3305 		/* Check status and move request to flush_queue */
3306 		if (cqr->status == DASD_CQR_IN_IO) {
3307 			rc = device->discipline->term_IO(cqr);
3308 			if (rc) {
3309 				/* unable to terminate requeust */
3310 				dev_err(&device->cdev->dev,
3311 					"Unable to terminate request %p "
3312 					"on suspend\n", cqr);
3313 				spin_unlock_irq(get_ccwdev_lock(cdev));
3314 				dasd_put_device(device);
3315 				return rc;
3316 			}
3317 		}
3318 		list_move_tail(&cqr->devlist, &freeze_queue);
3319 	}
3320 
3321 	spin_unlock_irq(get_ccwdev_lock(cdev));
3322 
3323 	list_for_each_entry_safe(cqr, n, &freeze_queue, devlist) {
3324 		wait_event(dasd_flush_wq,
3325 			   (cqr->status != DASD_CQR_CLEAR_PENDING));
3326 		if (cqr->status == DASD_CQR_CLEARED)
3327 			cqr->status = DASD_CQR_QUEUED;
3328 	}
3329 	/* move freeze_queue to start of the ccw_queue */
3330 	spin_lock_irq(get_ccwdev_lock(cdev));
3331 	list_splice_tail(&freeze_queue, &device->ccw_queue);
3332 	spin_unlock_irq(get_ccwdev_lock(cdev));
3333 
3334 	dasd_put_device(device);
3335 	return rc;
3336 }
3337 EXPORT_SYMBOL_GPL(dasd_generic_pm_freeze);
3338 
3339 int dasd_generic_restore_device(struct ccw_device *cdev)
3340 {
3341 	struct dasd_device *device = dasd_device_from_cdev(cdev);
3342 	int rc = 0;
3343 
3344 	if (IS_ERR(device))
3345 		return PTR_ERR(device);
3346 
3347 	/* allow new IO again */
3348 	dasd_device_remove_stop_bits(device,
3349 				     (DASD_STOPPED_PM | DASD_UNRESUMED_PM));
3350 
3351 	dasd_schedule_device_bh(device);
3352 
3353 	/*
3354 	 * call discipline restore function
3355 	 * if device is stopped do nothing e.g. for disconnected devices
3356 	 */
3357 	if (device->discipline->restore && !(device->stopped))
3358 		rc = device->discipline->restore(device);
3359 	if (rc || device->stopped)
3360 		/*
3361 		 * if the resume failed for the DASD we put it in
3362 		 * an UNRESUMED stop state
3363 		 */
3364 		device->stopped |= DASD_UNRESUMED_PM;
3365 
3366 	if (device->block)
3367 		dasd_schedule_block_bh(device->block);
3368 
3369 	clear_bit(DASD_FLAG_SUSPENDED, &device->flags);
3370 	dasd_put_device(device);
3371 	return 0;
3372 }
3373 EXPORT_SYMBOL_GPL(dasd_generic_restore_device);
3374 
3375 static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
3376 						   void *rdc_buffer,
3377 						   int rdc_buffer_size,
3378 						   int magic)
3379 {
3380 	struct dasd_ccw_req *cqr;
3381 	struct ccw1 *ccw;
3382 	unsigned long *idaw;
3383 
3384 	cqr = dasd_smalloc_request(magic, 1 /* RDC */, rdc_buffer_size, device);
3385 
3386 	if (IS_ERR(cqr)) {
3387 		/* internal error 13 - Allocating the RDC request failed*/
3388 		dev_err(&device->cdev->dev,
3389 			 "An error occurred in the DASD device driver, "
3390 			 "reason=%s\n", "13");
3391 		return cqr;
3392 	}
3393 
3394 	ccw = cqr->cpaddr;
3395 	ccw->cmd_code = CCW_CMD_RDC;
3396 	if (idal_is_needed(rdc_buffer, rdc_buffer_size)) {
3397 		idaw = (unsigned long *) (cqr->data);
3398 		ccw->cda = (__u32)(addr_t) idaw;
3399 		ccw->flags = CCW_FLAG_IDA;
3400 		idaw = idal_create_words(idaw, rdc_buffer, rdc_buffer_size);
3401 	} else {
3402 		ccw->cda = (__u32)(addr_t) rdc_buffer;
3403 		ccw->flags = 0;
3404 	}
3405 
3406 	ccw->count = rdc_buffer_size;
3407 	cqr->startdev = device;
3408 	cqr->memdev = device;
3409 	cqr->expires = 10*HZ;
3410 	cqr->retries = 256;
3411 	cqr->buildclk = get_clock();
3412 	cqr->status = DASD_CQR_FILLED;
3413 	return cqr;
3414 }
3415 
3416 
3417 int dasd_generic_read_dev_chars(struct dasd_device *device, int magic,
3418 				void *rdc_buffer, int rdc_buffer_size)
3419 {
3420 	int ret;
3421 	struct dasd_ccw_req *cqr;
3422 
3423 	cqr = dasd_generic_build_rdc(device, rdc_buffer, rdc_buffer_size,
3424 				     magic);
3425 	if (IS_ERR(cqr))
3426 		return PTR_ERR(cqr);
3427 
3428 	ret = dasd_sleep_on(cqr);
3429 	dasd_sfree_request(cqr, cqr->memdev);
3430 	return ret;
3431 }
3432 EXPORT_SYMBOL_GPL(dasd_generic_read_dev_chars);
3433 
3434 /*
3435  *   In command mode and transport mode we need to look for sense
3436  *   data in different places. The sense data itself is allways
3437  *   an array of 32 bytes, so we can unify the sense data access
3438  *   for both modes.
3439  */
3440 char *dasd_get_sense(struct irb *irb)
3441 {
3442 	struct tsb *tsb = NULL;
3443 	char *sense = NULL;
3444 
3445 	if (scsw_is_tm(&irb->scsw) && (irb->scsw.tm.fcxs == 0x01)) {
3446 		if (irb->scsw.tm.tcw)
3447 			tsb = tcw_get_tsb((struct tcw *)(unsigned long)
3448 					  irb->scsw.tm.tcw);
3449 		if (tsb && tsb->length == 64 && tsb->flags)
3450 			switch (tsb->flags & 0x07) {
3451 			case 1:	/* tsa_iostat */
3452 				sense = tsb->tsa.iostat.sense;
3453 				break;
3454 			case 2: /* tsa_ddpc */
3455 				sense = tsb->tsa.ddpc.sense;
3456 				break;
3457 			default:
3458 				/* currently we don't use interrogate data */
3459 				break;
3460 			}
3461 	} else if (irb->esw.esw0.erw.cons) {
3462 		sense = irb->ecw;
3463 	}
3464 	return sense;
3465 }
3466 EXPORT_SYMBOL_GPL(dasd_get_sense);
3467 
3468 static int __init dasd_init(void)
3469 {
3470 	int rc;
3471 
3472 	init_waitqueue_head(&dasd_init_waitq);
3473 	init_waitqueue_head(&dasd_flush_wq);
3474 	init_waitqueue_head(&generic_waitq);
3475 
3476 	/* register 'common' DASD debug area, used for all DBF_XXX calls */
3477 	dasd_debug_area = debug_register("dasd", 1, 1, 8 * sizeof(long));
3478 	if (dasd_debug_area == NULL) {
3479 		rc = -ENOMEM;
3480 		goto failed;
3481 	}
3482 	debug_register_view(dasd_debug_area, &debug_sprintf_view);
3483 	debug_set_level(dasd_debug_area, DBF_WARNING);
3484 
3485 	DBF_EVENT(DBF_EMERG, "%s", "debug area created");
3486 
3487 	dasd_diag_discipline_pointer = NULL;
3488 
3489 	dasd_statistics_createroot();
3490 
3491 	rc = dasd_devmap_init();
3492 	if (rc)
3493 		goto failed;
3494 	rc = dasd_gendisk_init();
3495 	if (rc)
3496 		goto failed;
3497 	rc = dasd_parse();
3498 	if (rc)
3499 		goto failed;
3500 	rc = dasd_eer_init();
3501 	if (rc)
3502 		goto failed;
3503 #ifdef CONFIG_PROC_FS
3504 	rc = dasd_proc_init();
3505 	if (rc)
3506 		goto failed;
3507 #endif
3508 
3509 	return 0;
3510 failed:
3511 	pr_info("The DASD device driver could not be initialized\n");
3512 	dasd_exit();
3513 	return rc;
3514 }
3515 
3516 module_init(dasd_init);
3517 module_exit(dasd_exit);
3518 
3519 EXPORT_SYMBOL(dasd_debug_area);
3520 EXPORT_SYMBOL(dasd_diag_discipline_pointer);
3521 
3522 EXPORT_SYMBOL(dasd_add_request_head);
3523 EXPORT_SYMBOL(dasd_add_request_tail);
3524 EXPORT_SYMBOL(dasd_cancel_req);
3525 EXPORT_SYMBOL(dasd_device_clear_timer);
3526 EXPORT_SYMBOL(dasd_block_clear_timer);
3527 EXPORT_SYMBOL(dasd_enable_device);
3528 EXPORT_SYMBOL(dasd_int_handler);
3529 EXPORT_SYMBOL(dasd_kfree_request);
3530 EXPORT_SYMBOL(dasd_kick_device);
3531 EXPORT_SYMBOL(dasd_kmalloc_request);
3532 EXPORT_SYMBOL(dasd_schedule_device_bh);
3533 EXPORT_SYMBOL(dasd_schedule_block_bh);
3534 EXPORT_SYMBOL(dasd_set_target_state);
3535 EXPORT_SYMBOL(dasd_device_set_timer);
3536 EXPORT_SYMBOL(dasd_block_set_timer);
3537 EXPORT_SYMBOL(dasd_sfree_request);
3538 EXPORT_SYMBOL(dasd_sleep_on);
3539 EXPORT_SYMBOL(dasd_sleep_on_immediatly);
3540 EXPORT_SYMBOL(dasd_sleep_on_interruptible);
3541 EXPORT_SYMBOL(dasd_smalloc_request);
3542 EXPORT_SYMBOL(dasd_start_IO);
3543 EXPORT_SYMBOL(dasd_term_IO);
3544 
3545 EXPORT_SYMBOL_GPL(dasd_generic_probe);
3546 EXPORT_SYMBOL_GPL(dasd_generic_remove);
3547 EXPORT_SYMBOL_GPL(dasd_generic_notify);
3548 EXPORT_SYMBOL_GPL(dasd_generic_set_online);
3549 EXPORT_SYMBOL_GPL(dasd_generic_set_offline);
3550 EXPORT_SYMBOL_GPL(dasd_generic_handle_state_change);
3551 EXPORT_SYMBOL_GPL(dasd_flush_device_queue);
3552 EXPORT_SYMBOL_GPL(dasd_alloc_block);
3553 EXPORT_SYMBOL_GPL(dasd_free_block);
3554