xref: /openbmc/linux/drivers/s390/block/dasd.c (revision 4fa52aa7)
1 /*
2  * File...........: linux/drivers/s390/block/dasd.c
3  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
4  *		    Horst Hummel <Horst.Hummel@de.ibm.com>
5  *		    Carsten Otte <Cotte@de.ibm.com>
6  *		    Martin Schwidefsky <schwidefsky@de.ibm.com>
7  * Bugreports.to..: <Linux390@de.ibm.com>
8  * Copyright IBM Corp. 1999, 2009
9  */
10 
11 #define KMSG_COMPONENT "dasd"
12 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
13 
14 #include <linux/kernel_stat.h>
15 #include <linux/kmod.h>
16 #include <linux/init.h>
17 #include <linux/interrupt.h>
18 #include <linux/ctype.h>
19 #include <linux/major.h>
20 #include <linux/slab.h>
21 #include <linux/buffer_head.h>
22 #include <linux/hdreg.h>
23 #include <linux/async.h>
24 #include <linux/mutex.h>
25 #include <linux/debugfs.h>
26 #include <linux/seq_file.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 = kmalloc(user_len + 1, GFP_KERNEL);
892 	if (buffer == NULL)
893 		return ERR_PTR(-ENOMEM);
894 	if (copy_from_user(buffer, user_buf, user_len) != 0) {
895 		kfree(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 	kfree(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 	kfree(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 	mode_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 	mode_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 	kstat_cpu(smp_processor_id()).irqs[IOINT_DAS]++;
1597 	if (IS_ERR(irb)) {
1598 		switch (PTR_ERR(irb)) {
1599 		case -EIO:
1600 			break;
1601 		case -ETIMEDOUT:
1602 			DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
1603 					"request timed out\n", __func__);
1604 			break;
1605 		default:
1606 			DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
1607 					"unknown error %ld\n", __func__,
1608 					PTR_ERR(irb));
1609 		}
1610 		dasd_handle_killed_request(cdev, intparm);
1611 		return;
1612 	}
1613 
1614 	now = get_clock();
1615 	cqr = (struct dasd_ccw_req *) intparm;
1616 	/* check for conditions that should be handled immediately */
1617 	if (!cqr ||
1618 	    !(scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
1619 	      scsw_cstat(&irb->scsw) == 0)) {
1620 		if (cqr)
1621 			memcpy(&cqr->irb, irb, sizeof(*irb));
1622 		device = dasd_device_from_cdev_locked(cdev);
1623 		if (IS_ERR(device))
1624 			return;
1625 		/* ignore unsolicited interrupts for DIAG discipline */
1626 		if (device->discipline == dasd_diag_discipline_pointer) {
1627 			dasd_put_device(device);
1628 			return;
1629 		}
1630 		device->discipline->dump_sense_dbf(device, irb, "int");
1631 		if (device->features & DASD_FEATURE_ERPLOG)
1632 			device->discipline->dump_sense(device, cqr, irb);
1633 		device->discipline->check_for_device_change(device, cqr, irb);
1634 		dasd_put_device(device);
1635 	}
1636 	if (!cqr)
1637 		return;
1638 
1639 	device = (struct dasd_device *) cqr->startdev;
1640 	if (!device ||
1641 	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
1642 		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
1643 				"invalid device in request");
1644 		return;
1645 	}
1646 
1647 	/* Check for clear pending */
1648 	if (cqr->status == DASD_CQR_CLEAR_PENDING &&
1649 	    scsw_fctl(&irb->scsw) & SCSW_FCTL_CLEAR_FUNC) {
1650 		cqr->status = DASD_CQR_CLEARED;
1651 		dasd_device_clear_timer(device);
1652 		wake_up(&dasd_flush_wq);
1653 		dasd_schedule_device_bh(device);
1654 		return;
1655 	}
1656 
1657 	/* check status - the request might have been killed by dyn detach */
1658 	if (cqr->status != DASD_CQR_IN_IO) {
1659 		DBF_DEV_EVENT(DBF_DEBUG, device, "invalid status: bus_id %s, "
1660 			      "status %02x", dev_name(&cdev->dev), cqr->status);
1661 		return;
1662 	}
1663 
1664 	next = NULL;
1665 	expires = 0;
1666 	if (scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
1667 	    scsw_cstat(&irb->scsw) == 0) {
1668 		/* request was completed successfully */
1669 		cqr->status = DASD_CQR_SUCCESS;
1670 		cqr->stopclk = now;
1671 		/* Start first request on queue if possible -> fast_io. */
1672 		if (cqr->devlist.next != &device->ccw_queue) {
1673 			next = list_entry(cqr->devlist.next,
1674 					  struct dasd_ccw_req, devlist);
1675 		}
1676 	} else {  /* error */
1677 		/*
1678 		 * If we don't want complex ERP for this request, then just
1679 		 * reset this and retry it in the fastpath
1680 		 */
1681 		if (!test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags) &&
1682 		    cqr->retries > 0) {
1683 			if (cqr->lpm == device->path_data.opm)
1684 				DBF_DEV_EVENT(DBF_DEBUG, device,
1685 					      "default ERP in fastpath "
1686 					      "(%i retries left)",
1687 					      cqr->retries);
1688 			if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags))
1689 				cqr->lpm = device->path_data.opm;
1690 			cqr->status = DASD_CQR_QUEUED;
1691 			next = cqr;
1692 		} else
1693 			cqr->status = DASD_CQR_ERROR;
1694 	}
1695 	if (next && (next->status == DASD_CQR_QUEUED) &&
1696 	    (!device->stopped)) {
1697 		if (device->discipline->start_IO(next) == 0)
1698 			expires = next->expires;
1699 	}
1700 	if (expires != 0)
1701 		dasd_device_set_timer(device, expires);
1702 	else
1703 		dasd_device_clear_timer(device);
1704 	dasd_schedule_device_bh(device);
1705 }
1706 
1707 enum uc_todo dasd_generic_uc_handler(struct ccw_device *cdev, struct irb *irb)
1708 {
1709 	struct dasd_device *device;
1710 
1711 	device = dasd_device_from_cdev_locked(cdev);
1712 
1713 	if (IS_ERR(device))
1714 		goto out;
1715 	if (test_bit(DASD_FLAG_OFFLINE, &device->flags) ||
1716 	   device->state != device->target ||
1717 	   !device->discipline->check_for_device_change){
1718 		dasd_put_device(device);
1719 		goto out;
1720 	}
1721 	if (device->discipline->dump_sense_dbf)
1722 		device->discipline->dump_sense_dbf(device, irb, "uc");
1723 	device->discipline->check_for_device_change(device, NULL, irb);
1724 	dasd_put_device(device);
1725 out:
1726 	return UC_TODO_RETRY;
1727 }
1728 EXPORT_SYMBOL_GPL(dasd_generic_uc_handler);
1729 
1730 /*
1731  * If we have an error on a dasd_block layer request then we cancel
1732  * and return all further requests from the same dasd_block as well.
1733  */
1734 static void __dasd_device_recovery(struct dasd_device *device,
1735 				   struct dasd_ccw_req *ref_cqr)
1736 {
1737 	struct list_head *l, *n;
1738 	struct dasd_ccw_req *cqr;
1739 
1740 	/*
1741 	 * only requeue request that came from the dasd_block layer
1742 	 */
1743 	if (!ref_cqr->block)
1744 		return;
1745 
1746 	list_for_each_safe(l, n, &device->ccw_queue) {
1747 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1748 		if (cqr->status == DASD_CQR_QUEUED &&
1749 		    ref_cqr->block == cqr->block) {
1750 			cqr->status = DASD_CQR_CLEARED;
1751 		}
1752 	}
1753 };
1754 
1755 /*
1756  * Remove those ccw requests from the queue that need to be returned
1757  * to the upper layer.
1758  */
1759 static void __dasd_device_process_ccw_queue(struct dasd_device *device,
1760 					    struct list_head *final_queue)
1761 {
1762 	struct list_head *l, *n;
1763 	struct dasd_ccw_req *cqr;
1764 
1765 	/* Process request with final status. */
1766 	list_for_each_safe(l, n, &device->ccw_queue) {
1767 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1768 
1769 		/* Stop list processing at the first non-final request. */
1770 		if (cqr->status == DASD_CQR_QUEUED ||
1771 		    cqr->status == DASD_CQR_IN_IO ||
1772 		    cqr->status == DASD_CQR_CLEAR_PENDING)
1773 			break;
1774 		if (cqr->status == DASD_CQR_ERROR) {
1775 			__dasd_device_recovery(device, cqr);
1776 		}
1777 		/* Rechain finished requests to final queue */
1778 		list_move_tail(&cqr->devlist, final_queue);
1779 	}
1780 }
1781 
1782 /*
1783  * the cqrs from the final queue are returned to the upper layer
1784  * by setting a dasd_block state and calling the callback function
1785  */
1786 static void __dasd_device_process_final_queue(struct dasd_device *device,
1787 					      struct list_head *final_queue)
1788 {
1789 	struct list_head *l, *n;
1790 	struct dasd_ccw_req *cqr;
1791 	struct dasd_block *block;
1792 	void (*callback)(struct dasd_ccw_req *, void *data);
1793 	void *callback_data;
1794 	char errorstring[ERRORLENGTH];
1795 
1796 	list_for_each_safe(l, n, final_queue) {
1797 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1798 		list_del_init(&cqr->devlist);
1799 		block = cqr->block;
1800 		callback = cqr->callback;
1801 		callback_data = cqr->callback_data;
1802 		if (block)
1803 			spin_lock_bh(&block->queue_lock);
1804 		switch (cqr->status) {
1805 		case DASD_CQR_SUCCESS:
1806 			cqr->status = DASD_CQR_DONE;
1807 			break;
1808 		case DASD_CQR_ERROR:
1809 			cqr->status = DASD_CQR_NEED_ERP;
1810 			break;
1811 		case DASD_CQR_CLEARED:
1812 			cqr->status = DASD_CQR_TERMINATED;
1813 			break;
1814 		default:
1815 			/* internal error 12 - wrong cqr status*/
1816 			snprintf(errorstring, ERRORLENGTH, "12 %p %x02", cqr, cqr->status);
1817 			dev_err(&device->cdev->dev,
1818 				"An error occurred in the DASD device driver, "
1819 				"reason=%s\n", errorstring);
1820 			BUG();
1821 		}
1822 		if (cqr->callback != NULL)
1823 			(callback)(cqr, callback_data);
1824 		if (block)
1825 			spin_unlock_bh(&block->queue_lock);
1826 	}
1827 }
1828 
1829 /*
1830  * Take a look at the first request on the ccw queue and check
1831  * if it reached its expire time. If so, terminate the IO.
1832  */
1833 static void __dasd_device_check_expire(struct dasd_device *device)
1834 {
1835 	struct dasd_ccw_req *cqr;
1836 
1837 	if (list_empty(&device->ccw_queue))
1838 		return;
1839 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1840 	if ((cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) &&
1841 	    (time_after_eq(jiffies, cqr->expires + cqr->starttime))) {
1842 		if (device->discipline->term_IO(cqr) != 0) {
1843 			/* Hmpf, try again in 5 sec */
1844 			dev_err(&device->cdev->dev,
1845 				"cqr %p timed out (%lus) but cannot be "
1846 				"ended, retrying in 5 s\n",
1847 				cqr, (cqr->expires/HZ));
1848 			cqr->expires += 5*HZ;
1849 			dasd_device_set_timer(device, 5*HZ);
1850 		} else {
1851 			dev_err(&device->cdev->dev,
1852 				"cqr %p timed out (%lus), %i retries "
1853 				"remaining\n", cqr, (cqr->expires/HZ),
1854 				cqr->retries);
1855 		}
1856 	}
1857 }
1858 
1859 /*
1860  * Take a look at the first request on the ccw queue and check
1861  * if it needs to be started.
1862  */
1863 static void __dasd_device_start_head(struct dasd_device *device)
1864 {
1865 	struct dasd_ccw_req *cqr;
1866 	int rc;
1867 
1868 	if (list_empty(&device->ccw_queue))
1869 		return;
1870 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1871 	if (cqr->status != DASD_CQR_QUEUED)
1872 		return;
1873 	/* when device is stopped, return request to previous layer
1874 	 * exception: only the disconnect or unresumed bits are set and the
1875 	 * cqr is a path verification request
1876 	 */
1877 	if (device->stopped &&
1878 	    !(!(device->stopped & ~(DASD_STOPPED_DC_WAIT | DASD_UNRESUMED_PM))
1879 	      && test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags))) {
1880 		cqr->intrc = -EAGAIN;
1881 		cqr->status = DASD_CQR_CLEARED;
1882 		dasd_schedule_device_bh(device);
1883 		return;
1884 	}
1885 
1886 	rc = device->discipline->start_IO(cqr);
1887 	if (rc == 0)
1888 		dasd_device_set_timer(device, cqr->expires);
1889 	else if (rc == -EACCES) {
1890 		dasd_schedule_device_bh(device);
1891 	} else
1892 		/* Hmpf, try again in 1/2 sec */
1893 		dasd_device_set_timer(device, 50);
1894 }
1895 
1896 static void __dasd_device_check_path_events(struct dasd_device *device)
1897 {
1898 	int rc;
1899 
1900 	if (device->path_data.tbvpm) {
1901 		if (device->stopped & ~(DASD_STOPPED_DC_WAIT |
1902 					DASD_UNRESUMED_PM))
1903 			return;
1904 		rc = device->discipline->verify_path(
1905 			device, device->path_data.tbvpm);
1906 		if (rc)
1907 			dasd_device_set_timer(device, 50);
1908 		else
1909 			device->path_data.tbvpm = 0;
1910 	}
1911 };
1912 
1913 /*
1914  * Go through all request on the dasd_device request queue,
1915  * terminate them on the cdev if necessary, and return them to the
1916  * submitting layer via callback.
1917  * Note:
1918  * Make sure that all 'submitting layers' still exist when
1919  * this function is called!. In other words, when 'device' is a base
1920  * device then all block layer requests must have been removed before
1921  * via dasd_flush_block_queue.
1922  */
1923 int dasd_flush_device_queue(struct dasd_device *device)
1924 {
1925 	struct dasd_ccw_req *cqr, *n;
1926 	int rc;
1927 	struct list_head flush_queue;
1928 
1929 	INIT_LIST_HEAD(&flush_queue);
1930 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1931 	rc = 0;
1932 	list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
1933 		/* Check status and move request to flush_queue */
1934 		switch (cqr->status) {
1935 		case DASD_CQR_IN_IO:
1936 			rc = device->discipline->term_IO(cqr);
1937 			if (rc) {
1938 				/* unable to terminate requeust */
1939 				dev_err(&device->cdev->dev,
1940 					"Flushing the DASD request queue "
1941 					"failed for request %p\n", cqr);
1942 				/* stop flush processing */
1943 				goto finished;
1944 			}
1945 			break;
1946 		case DASD_CQR_QUEUED:
1947 			cqr->stopclk = get_clock();
1948 			cqr->status = DASD_CQR_CLEARED;
1949 			break;
1950 		default: /* no need to modify the others */
1951 			break;
1952 		}
1953 		list_move_tail(&cqr->devlist, &flush_queue);
1954 	}
1955 finished:
1956 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1957 	/*
1958 	 * After this point all requests must be in state CLEAR_PENDING,
1959 	 * CLEARED, SUCCESS or ERROR. Now wait for CLEAR_PENDING to become
1960 	 * one of the others.
1961 	 */
1962 	list_for_each_entry_safe(cqr, n, &flush_queue, devlist)
1963 		wait_event(dasd_flush_wq,
1964 			   (cqr->status != DASD_CQR_CLEAR_PENDING));
1965 	/*
1966 	 * Now set each request back to TERMINATED, DONE or NEED_ERP
1967 	 * and call the callback function of flushed requests
1968 	 */
1969 	__dasd_device_process_final_queue(device, &flush_queue);
1970 	return rc;
1971 }
1972 
1973 /*
1974  * Acquire the device lock and process queues for the device.
1975  */
1976 static void dasd_device_tasklet(struct dasd_device *device)
1977 {
1978 	struct list_head final_queue;
1979 
1980 	atomic_set (&device->tasklet_scheduled, 0);
1981 	INIT_LIST_HEAD(&final_queue);
1982 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1983 	/* Check expire time of first request on the ccw queue. */
1984 	__dasd_device_check_expire(device);
1985 	/* find final requests on ccw queue */
1986 	__dasd_device_process_ccw_queue(device, &final_queue);
1987 	__dasd_device_check_path_events(device);
1988 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1989 	/* Now call the callback function of requests with final status */
1990 	__dasd_device_process_final_queue(device, &final_queue);
1991 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1992 	/* Now check if the head of the ccw queue needs to be started. */
1993 	__dasd_device_start_head(device);
1994 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1995 	dasd_put_device(device);
1996 }
1997 
1998 /*
1999  * Schedules a call to dasd_tasklet over the device tasklet.
2000  */
2001 void dasd_schedule_device_bh(struct dasd_device *device)
2002 {
2003 	/* Protect against rescheduling. */
2004 	if (atomic_cmpxchg (&device->tasklet_scheduled, 0, 1) != 0)
2005 		return;
2006 	dasd_get_device(device);
2007 	tasklet_hi_schedule(&device->tasklet);
2008 }
2009 
2010 void dasd_device_set_stop_bits(struct dasd_device *device, int bits)
2011 {
2012 	device->stopped |= bits;
2013 }
2014 EXPORT_SYMBOL_GPL(dasd_device_set_stop_bits);
2015 
2016 void dasd_device_remove_stop_bits(struct dasd_device *device, int bits)
2017 {
2018 	device->stopped &= ~bits;
2019 	if (!device->stopped)
2020 		wake_up(&generic_waitq);
2021 }
2022 EXPORT_SYMBOL_GPL(dasd_device_remove_stop_bits);
2023 
2024 /*
2025  * Queue a request to the head of the device ccw_queue.
2026  * Start the I/O if possible.
2027  */
2028 void dasd_add_request_head(struct dasd_ccw_req *cqr)
2029 {
2030 	struct dasd_device *device;
2031 	unsigned long flags;
2032 
2033 	device = cqr->startdev;
2034 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
2035 	cqr->status = DASD_CQR_QUEUED;
2036 	list_add(&cqr->devlist, &device->ccw_queue);
2037 	/* let the bh start the request to keep them in order */
2038 	dasd_schedule_device_bh(device);
2039 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
2040 }
2041 
2042 /*
2043  * Queue a request to the tail of the device ccw_queue.
2044  * Start the I/O if possible.
2045  */
2046 void dasd_add_request_tail(struct dasd_ccw_req *cqr)
2047 {
2048 	struct dasd_device *device;
2049 	unsigned long flags;
2050 
2051 	device = cqr->startdev;
2052 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
2053 	cqr->status = DASD_CQR_QUEUED;
2054 	list_add_tail(&cqr->devlist, &device->ccw_queue);
2055 	/* let the bh start the request to keep them in order */
2056 	dasd_schedule_device_bh(device);
2057 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
2058 }
2059 
2060 /*
2061  * Wakeup helper for the 'sleep_on' functions.
2062  */
2063 static void dasd_wakeup_cb(struct dasd_ccw_req *cqr, void *data)
2064 {
2065 	spin_lock_irq(get_ccwdev_lock(cqr->startdev->cdev));
2066 	cqr->callback_data = DASD_SLEEPON_END_TAG;
2067 	spin_unlock_irq(get_ccwdev_lock(cqr->startdev->cdev));
2068 	wake_up(&generic_waitq);
2069 }
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 		cqr->callback = dasd_wakeup_cb;
2170 		cqr->callback_data = DASD_SLEEPON_START_TAG;
2171 		dasd_add_request_tail(cqr);
2172 		if (interruptible) {
2173 			rc = wait_event_interruptible(
2174 				generic_waitq, _wait_for_wakeup(cqr));
2175 			if (rc == -ERESTARTSYS) {
2176 				dasd_cancel_req(cqr);
2177 				/* wait (non-interruptible) for final status */
2178 				wait_event(generic_waitq,
2179 					   _wait_for_wakeup(cqr));
2180 				cqr->status = DASD_CQR_FAILED;
2181 				maincqr->intrc = rc;
2182 				continue;
2183 			}
2184 		} else
2185 			wait_event(generic_waitq, _wait_for_wakeup(cqr));
2186 	}
2187 
2188 	maincqr->endclk = get_clock();
2189 	if ((maincqr->status != DASD_CQR_DONE) &&
2190 	    (maincqr->intrc != -ERESTARTSYS))
2191 		dasd_log_sense(maincqr, &maincqr->irb);
2192 	if (maincqr->status == DASD_CQR_DONE)
2193 		rc = 0;
2194 	else if (maincqr->intrc)
2195 		rc = maincqr->intrc;
2196 	else
2197 		rc = -EIO;
2198 	return rc;
2199 }
2200 
2201 /*
2202  * Queue a request to the tail of the device ccw_queue and wait for
2203  * it's completion.
2204  */
2205 int dasd_sleep_on(struct dasd_ccw_req *cqr)
2206 {
2207 	return _dasd_sleep_on(cqr, 0);
2208 }
2209 
2210 /*
2211  * Queue a request to the tail of the device ccw_queue and wait
2212  * interruptible for it's completion.
2213  */
2214 int dasd_sleep_on_interruptible(struct dasd_ccw_req *cqr)
2215 {
2216 	return _dasd_sleep_on(cqr, 1);
2217 }
2218 
2219 /*
2220  * Whoa nelly now it gets really hairy. For some functions (e.g. steal lock
2221  * for eckd devices) the currently running request has to be terminated
2222  * and be put back to status queued, before the special request is added
2223  * to the head of the queue. Then the special request is waited on normally.
2224  */
2225 static inline int _dasd_term_running_cqr(struct dasd_device *device)
2226 {
2227 	struct dasd_ccw_req *cqr;
2228 	int rc;
2229 
2230 	if (list_empty(&device->ccw_queue))
2231 		return 0;
2232 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
2233 	rc = device->discipline->term_IO(cqr);
2234 	if (!rc)
2235 		/*
2236 		 * CQR terminated because a more important request is pending.
2237 		 * Undo decreasing of retry counter because this is
2238 		 * not an error case.
2239 		 */
2240 		cqr->retries++;
2241 	return rc;
2242 }
2243 
2244 int dasd_sleep_on_immediatly(struct dasd_ccw_req *cqr)
2245 {
2246 	struct dasd_device *device;
2247 	int rc;
2248 
2249 	device = cqr->startdev;
2250 	if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
2251 	    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
2252 		cqr->status = DASD_CQR_FAILED;
2253 		cqr->intrc = -EPERM;
2254 		return -EIO;
2255 	}
2256 	spin_lock_irq(get_ccwdev_lock(device->cdev));
2257 	rc = _dasd_term_running_cqr(device);
2258 	if (rc) {
2259 		spin_unlock_irq(get_ccwdev_lock(device->cdev));
2260 		return rc;
2261 	}
2262 	cqr->callback = dasd_wakeup_cb;
2263 	cqr->callback_data = DASD_SLEEPON_START_TAG;
2264 	cqr->status = DASD_CQR_QUEUED;
2265 	list_add(&cqr->devlist, &device->ccw_queue);
2266 
2267 	/* let the bh start the request to keep them in order */
2268 	dasd_schedule_device_bh(device);
2269 
2270 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
2271 
2272 	wait_event(generic_waitq, _wait_for_wakeup(cqr));
2273 
2274 	if (cqr->status == DASD_CQR_DONE)
2275 		rc = 0;
2276 	else if (cqr->intrc)
2277 		rc = cqr->intrc;
2278 	else
2279 		rc = -EIO;
2280 	return rc;
2281 }
2282 
2283 /*
2284  * Cancels a request that was started with dasd_sleep_on_req.
2285  * This is useful to timeout requests. The request will be
2286  * terminated if it is currently in i/o.
2287  * Returns 1 if the request has been terminated.
2288  *	   0 if there was no need to terminate the request (not started yet)
2289  *	   negative error code if termination failed
2290  * Cancellation of a request is an asynchronous operation! The calling
2291  * function has to wait until the request is properly returned via callback.
2292  */
2293 int dasd_cancel_req(struct dasd_ccw_req *cqr)
2294 {
2295 	struct dasd_device *device = cqr->startdev;
2296 	unsigned long flags;
2297 	int rc;
2298 
2299 	rc = 0;
2300 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
2301 	switch (cqr->status) {
2302 	case DASD_CQR_QUEUED:
2303 		/* request was not started - just set to cleared */
2304 		cqr->status = DASD_CQR_CLEARED;
2305 		break;
2306 	case DASD_CQR_IN_IO:
2307 		/* request in IO - terminate IO and release again */
2308 		rc = device->discipline->term_IO(cqr);
2309 		if (rc) {
2310 			dev_err(&device->cdev->dev,
2311 				"Cancelling request %p failed with rc=%d\n",
2312 				cqr, rc);
2313 		} else {
2314 			cqr->stopclk = get_clock();
2315 		}
2316 		break;
2317 	default: /* already finished or clear pending - do nothing */
2318 		break;
2319 	}
2320 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
2321 	dasd_schedule_device_bh(device);
2322 	return rc;
2323 }
2324 
2325 
2326 /*
2327  * SECTION: Operations of the dasd_block layer.
2328  */
2329 
2330 /*
2331  * Timeout function for dasd_block. This is used when the block layer
2332  * is waiting for something that may not come reliably, (e.g. a state
2333  * change interrupt)
2334  */
2335 static void dasd_block_timeout(unsigned long ptr)
2336 {
2337 	unsigned long flags;
2338 	struct dasd_block *block;
2339 
2340 	block = (struct dasd_block *) ptr;
2341 	spin_lock_irqsave(get_ccwdev_lock(block->base->cdev), flags);
2342 	/* re-activate request queue */
2343 	dasd_device_remove_stop_bits(block->base, DASD_STOPPED_PENDING);
2344 	spin_unlock_irqrestore(get_ccwdev_lock(block->base->cdev), flags);
2345 	dasd_schedule_block_bh(block);
2346 }
2347 
2348 /*
2349  * Setup timeout for a dasd_block in jiffies.
2350  */
2351 void dasd_block_set_timer(struct dasd_block *block, int expires)
2352 {
2353 	if (expires == 0)
2354 		del_timer(&block->timer);
2355 	else
2356 		mod_timer(&block->timer, jiffies + expires);
2357 }
2358 
2359 /*
2360  * Clear timeout for a dasd_block.
2361  */
2362 void dasd_block_clear_timer(struct dasd_block *block)
2363 {
2364 	del_timer(&block->timer);
2365 }
2366 
2367 /*
2368  * Process finished error recovery ccw.
2369  */
2370 static void __dasd_process_erp(struct dasd_device *device,
2371 			       struct dasd_ccw_req *cqr)
2372 {
2373 	dasd_erp_fn_t erp_fn;
2374 
2375 	if (cqr->status == DASD_CQR_DONE)
2376 		DBF_DEV_EVENT(DBF_NOTICE, device, "%s", "ERP successful");
2377 	else
2378 		dev_err(&device->cdev->dev, "ERP failed for the DASD\n");
2379 	erp_fn = device->discipline->erp_postaction(cqr);
2380 	erp_fn(cqr);
2381 }
2382 
2383 /*
2384  * Fetch requests from the block device queue.
2385  */
2386 static void __dasd_process_request_queue(struct dasd_block *block)
2387 {
2388 	struct request_queue *queue;
2389 	struct request *req;
2390 	struct dasd_ccw_req *cqr;
2391 	struct dasd_device *basedev;
2392 	unsigned long flags;
2393 	queue = block->request_queue;
2394 	basedev = block->base;
2395 	/* No queue ? Then there is nothing to do. */
2396 	if (queue == NULL)
2397 		return;
2398 
2399 	/*
2400 	 * We requeue request from the block device queue to the ccw
2401 	 * queue only in two states. In state DASD_STATE_READY the
2402 	 * partition detection is done and we need to requeue requests
2403 	 * for that. State DASD_STATE_ONLINE is normal block device
2404 	 * operation.
2405 	 */
2406 	if (basedev->state < DASD_STATE_READY) {
2407 		while ((req = blk_fetch_request(block->request_queue)))
2408 			__blk_end_request_all(req, -EIO);
2409 		return;
2410 	}
2411 	/* Now we try to fetch requests from the request queue */
2412 	while ((req = blk_peek_request(queue))) {
2413 		if (basedev->features & DASD_FEATURE_READONLY &&
2414 		    rq_data_dir(req) == WRITE) {
2415 			DBF_DEV_EVENT(DBF_ERR, basedev,
2416 				      "Rejecting write request %p",
2417 				      req);
2418 			blk_start_request(req);
2419 			__blk_end_request_all(req, -EIO);
2420 			continue;
2421 		}
2422 		cqr = basedev->discipline->build_cp(basedev, block, req);
2423 		if (IS_ERR(cqr)) {
2424 			if (PTR_ERR(cqr) == -EBUSY)
2425 				break;	/* normal end condition */
2426 			if (PTR_ERR(cqr) == -ENOMEM)
2427 				break;	/* terminate request queue loop */
2428 			if (PTR_ERR(cqr) == -EAGAIN) {
2429 				/*
2430 				 * The current request cannot be build right
2431 				 * now, we have to try later. If this request
2432 				 * is the head-of-queue we stop the device
2433 				 * for 1/2 second.
2434 				 */
2435 				if (!list_empty(&block->ccw_queue))
2436 					break;
2437 				spin_lock_irqsave(
2438 					get_ccwdev_lock(basedev->cdev), flags);
2439 				dasd_device_set_stop_bits(basedev,
2440 							  DASD_STOPPED_PENDING);
2441 				spin_unlock_irqrestore(
2442 					get_ccwdev_lock(basedev->cdev), flags);
2443 				dasd_block_set_timer(block, HZ/2);
2444 				break;
2445 			}
2446 			DBF_DEV_EVENT(DBF_ERR, basedev,
2447 				      "CCW creation failed (rc=%ld) "
2448 				      "on request %p",
2449 				      PTR_ERR(cqr), req);
2450 			blk_start_request(req);
2451 			__blk_end_request_all(req, -EIO);
2452 			continue;
2453 		}
2454 		/*
2455 		 *  Note: callback is set to dasd_return_cqr_cb in
2456 		 * __dasd_block_start_head to cover erp requests as well
2457 		 */
2458 		cqr->callback_data = (void *) req;
2459 		cqr->status = DASD_CQR_FILLED;
2460 		blk_start_request(req);
2461 		list_add_tail(&cqr->blocklist, &block->ccw_queue);
2462 		dasd_profile_start(block, cqr, req);
2463 	}
2464 }
2465 
2466 static void __dasd_cleanup_cqr(struct dasd_ccw_req *cqr)
2467 {
2468 	struct request *req;
2469 	int status;
2470 	int error = 0;
2471 
2472 	req = (struct request *) cqr->callback_data;
2473 	dasd_profile_end(cqr->block, cqr, req);
2474 	status = cqr->block->base->discipline->free_cp(cqr, req);
2475 	if (status <= 0)
2476 		error = status ? status : -EIO;
2477 	__blk_end_request_all(req, error);
2478 }
2479 
2480 /*
2481  * Process ccw request queue.
2482  */
2483 static void __dasd_process_block_ccw_queue(struct dasd_block *block,
2484 					   struct list_head *final_queue)
2485 {
2486 	struct list_head *l, *n;
2487 	struct dasd_ccw_req *cqr;
2488 	dasd_erp_fn_t erp_fn;
2489 	unsigned long flags;
2490 	struct dasd_device *base = block->base;
2491 
2492 restart:
2493 	/* Process request with final status. */
2494 	list_for_each_safe(l, n, &block->ccw_queue) {
2495 		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
2496 		if (cqr->status != DASD_CQR_DONE &&
2497 		    cqr->status != DASD_CQR_FAILED &&
2498 		    cqr->status != DASD_CQR_NEED_ERP &&
2499 		    cqr->status != DASD_CQR_TERMINATED)
2500 			continue;
2501 
2502 		if (cqr->status == DASD_CQR_TERMINATED) {
2503 			base->discipline->handle_terminated_request(cqr);
2504 			goto restart;
2505 		}
2506 
2507 		/*  Process requests that may be recovered */
2508 		if (cqr->status == DASD_CQR_NEED_ERP) {
2509 			erp_fn = base->discipline->erp_action(cqr);
2510 			if (IS_ERR(erp_fn(cqr)))
2511 				continue;
2512 			goto restart;
2513 		}
2514 
2515 		/* log sense for fatal error */
2516 		if (cqr->status == DASD_CQR_FAILED) {
2517 			dasd_log_sense(cqr, &cqr->irb);
2518 		}
2519 
2520 		/* First of all call extended error reporting. */
2521 		if (dasd_eer_enabled(base) &&
2522 		    cqr->status == DASD_CQR_FAILED) {
2523 			dasd_eer_write(base, cqr, DASD_EER_FATALERROR);
2524 
2525 			/* restart request  */
2526 			cqr->status = DASD_CQR_FILLED;
2527 			cqr->retries = 255;
2528 			spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
2529 			dasd_device_set_stop_bits(base, DASD_STOPPED_QUIESCE);
2530 			spin_unlock_irqrestore(get_ccwdev_lock(base->cdev),
2531 					       flags);
2532 			goto restart;
2533 		}
2534 
2535 		/* Process finished ERP request. */
2536 		if (cqr->refers) {
2537 			__dasd_process_erp(base, cqr);
2538 			goto restart;
2539 		}
2540 
2541 		/* Rechain finished requests to final queue */
2542 		cqr->endclk = get_clock();
2543 		list_move_tail(&cqr->blocklist, final_queue);
2544 	}
2545 }
2546 
2547 static void dasd_return_cqr_cb(struct dasd_ccw_req *cqr, void *data)
2548 {
2549 	dasd_schedule_block_bh(cqr->block);
2550 }
2551 
2552 static void __dasd_block_start_head(struct dasd_block *block)
2553 {
2554 	struct dasd_ccw_req *cqr;
2555 
2556 	if (list_empty(&block->ccw_queue))
2557 		return;
2558 	/* We allways begin with the first requests on the queue, as some
2559 	 * of previously started requests have to be enqueued on a
2560 	 * dasd_device again for error recovery.
2561 	 */
2562 	list_for_each_entry(cqr, &block->ccw_queue, blocklist) {
2563 		if (cqr->status != DASD_CQR_FILLED)
2564 			continue;
2565 		if (test_bit(DASD_FLAG_LOCK_STOLEN, &block->base->flags) &&
2566 		    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
2567 			cqr->status = DASD_CQR_FAILED;
2568 			cqr->intrc = -EPERM;
2569 			dasd_schedule_block_bh(block);
2570 			continue;
2571 		}
2572 		/* Non-temporary stop condition will trigger fail fast */
2573 		if (block->base->stopped & ~DASD_STOPPED_PENDING &&
2574 		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
2575 		    (!dasd_eer_enabled(block->base))) {
2576 			cqr->status = DASD_CQR_FAILED;
2577 			dasd_schedule_block_bh(block);
2578 			continue;
2579 		}
2580 		/* Don't try to start requests if device is stopped */
2581 		if (block->base->stopped)
2582 			return;
2583 
2584 		/* just a fail safe check, should not happen */
2585 		if (!cqr->startdev)
2586 			cqr->startdev = block->base;
2587 
2588 		/* make sure that the requests we submit find their way back */
2589 		cqr->callback = dasd_return_cqr_cb;
2590 
2591 		dasd_add_request_tail(cqr);
2592 	}
2593 }
2594 
2595 /*
2596  * Central dasd_block layer routine. Takes requests from the generic
2597  * block layer request queue, creates ccw requests, enqueues them on
2598  * a dasd_device and processes ccw requests that have been returned.
2599  */
2600 static void dasd_block_tasklet(struct dasd_block *block)
2601 {
2602 	struct list_head final_queue;
2603 	struct list_head *l, *n;
2604 	struct dasd_ccw_req *cqr;
2605 
2606 	atomic_set(&block->tasklet_scheduled, 0);
2607 	INIT_LIST_HEAD(&final_queue);
2608 	spin_lock(&block->queue_lock);
2609 	/* Finish off requests on ccw queue */
2610 	__dasd_process_block_ccw_queue(block, &final_queue);
2611 	spin_unlock(&block->queue_lock);
2612 	/* Now call the callback function of requests with final status */
2613 	spin_lock_irq(&block->request_queue_lock);
2614 	list_for_each_safe(l, n, &final_queue) {
2615 		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
2616 		list_del_init(&cqr->blocklist);
2617 		__dasd_cleanup_cqr(cqr);
2618 	}
2619 	spin_lock(&block->queue_lock);
2620 	/* Get new request from the block device request queue */
2621 	__dasd_process_request_queue(block);
2622 	/* Now check if the head of the ccw queue needs to be started. */
2623 	__dasd_block_start_head(block);
2624 	spin_unlock(&block->queue_lock);
2625 	spin_unlock_irq(&block->request_queue_lock);
2626 	dasd_put_device(block->base);
2627 }
2628 
2629 static void _dasd_wake_block_flush_cb(struct dasd_ccw_req *cqr, void *data)
2630 {
2631 	wake_up(&dasd_flush_wq);
2632 }
2633 
2634 /*
2635  * Go through all request on the dasd_block request queue, cancel them
2636  * on the respective dasd_device, and return them to the generic
2637  * block layer.
2638  */
2639 static int dasd_flush_block_queue(struct dasd_block *block)
2640 {
2641 	struct dasd_ccw_req *cqr, *n;
2642 	int rc, i;
2643 	struct list_head flush_queue;
2644 
2645 	INIT_LIST_HEAD(&flush_queue);
2646 	spin_lock_bh(&block->queue_lock);
2647 	rc = 0;
2648 restart:
2649 	list_for_each_entry_safe(cqr, n, &block->ccw_queue, blocklist) {
2650 		/* if this request currently owned by a dasd_device cancel it */
2651 		if (cqr->status >= DASD_CQR_QUEUED)
2652 			rc = dasd_cancel_req(cqr);
2653 		if (rc < 0)
2654 			break;
2655 		/* Rechain request (including erp chain) so it won't be
2656 		 * touched by the dasd_block_tasklet anymore.
2657 		 * Replace the callback so we notice when the request
2658 		 * is returned from the dasd_device layer.
2659 		 */
2660 		cqr->callback = _dasd_wake_block_flush_cb;
2661 		for (i = 0; cqr != NULL; cqr = cqr->refers, i++)
2662 			list_move_tail(&cqr->blocklist, &flush_queue);
2663 		if (i > 1)
2664 			/* moved more than one request - need to restart */
2665 			goto restart;
2666 	}
2667 	spin_unlock_bh(&block->queue_lock);
2668 	/* Now call the callback function of flushed requests */
2669 restart_cb:
2670 	list_for_each_entry_safe(cqr, n, &flush_queue, blocklist) {
2671 		wait_event(dasd_flush_wq, (cqr->status < DASD_CQR_QUEUED));
2672 		/* Process finished ERP request. */
2673 		if (cqr->refers) {
2674 			spin_lock_bh(&block->queue_lock);
2675 			__dasd_process_erp(block->base, cqr);
2676 			spin_unlock_bh(&block->queue_lock);
2677 			/* restart list_for_xx loop since dasd_process_erp
2678 			 * might remove multiple elements */
2679 			goto restart_cb;
2680 		}
2681 		/* call the callback function */
2682 		spin_lock_irq(&block->request_queue_lock);
2683 		cqr->endclk = get_clock();
2684 		list_del_init(&cqr->blocklist);
2685 		__dasd_cleanup_cqr(cqr);
2686 		spin_unlock_irq(&block->request_queue_lock);
2687 	}
2688 	return rc;
2689 }
2690 
2691 /*
2692  * Schedules a call to dasd_tasklet over the device tasklet.
2693  */
2694 void dasd_schedule_block_bh(struct dasd_block *block)
2695 {
2696 	/* Protect against rescheduling. */
2697 	if (atomic_cmpxchg(&block->tasklet_scheduled, 0, 1) != 0)
2698 		return;
2699 	/* life cycle of block is bound to it's base device */
2700 	dasd_get_device(block->base);
2701 	tasklet_hi_schedule(&block->tasklet);
2702 }
2703 
2704 
2705 /*
2706  * SECTION: external block device operations
2707  * (request queue handling, open, release, etc.)
2708  */
2709 
2710 /*
2711  * Dasd request queue function. Called from ll_rw_blk.c
2712  */
2713 static void do_dasd_request(struct request_queue *queue)
2714 {
2715 	struct dasd_block *block;
2716 
2717 	block = queue->queuedata;
2718 	spin_lock(&block->queue_lock);
2719 	/* Get new request from the block device request queue */
2720 	__dasd_process_request_queue(block);
2721 	/* Now check if the head of the ccw queue needs to be started. */
2722 	__dasd_block_start_head(block);
2723 	spin_unlock(&block->queue_lock);
2724 }
2725 
2726 /*
2727  * Allocate and initialize request queue and default I/O scheduler.
2728  */
2729 static int dasd_alloc_queue(struct dasd_block *block)
2730 {
2731 	int rc;
2732 
2733 	block->request_queue = blk_init_queue(do_dasd_request,
2734 					       &block->request_queue_lock);
2735 	if (block->request_queue == NULL)
2736 		return -ENOMEM;
2737 
2738 	block->request_queue->queuedata = block;
2739 
2740 	elevator_exit(block->request_queue->elevator);
2741 	block->request_queue->elevator = NULL;
2742 	rc = elevator_init(block->request_queue, "deadline");
2743 	if (rc) {
2744 		blk_cleanup_queue(block->request_queue);
2745 		return rc;
2746 	}
2747 	return 0;
2748 }
2749 
2750 /*
2751  * Allocate and initialize request queue.
2752  */
2753 static void dasd_setup_queue(struct dasd_block *block)
2754 {
2755 	int max;
2756 
2757 	if (block->base->features & DASD_FEATURE_USERAW) {
2758 		/*
2759 		 * the max_blocks value for raw_track access is 256
2760 		 * it is higher than the native ECKD value because we
2761 		 * only need one ccw per track
2762 		 * so the max_hw_sectors are
2763 		 * 2048 x 512B = 1024kB = 16 tracks
2764 		 */
2765 		max = 2048;
2766 	} else {
2767 		max = block->base->discipline->max_blocks << block->s2b_shift;
2768 	}
2769 	blk_queue_logical_block_size(block->request_queue,
2770 				     block->bp_block);
2771 	blk_queue_max_hw_sectors(block->request_queue, max);
2772 	blk_queue_max_segments(block->request_queue, -1L);
2773 	/* with page sized segments we can translate each segement into
2774 	 * one idaw/tidaw
2775 	 */
2776 	blk_queue_max_segment_size(block->request_queue, PAGE_SIZE);
2777 	blk_queue_segment_boundary(block->request_queue, PAGE_SIZE - 1);
2778 }
2779 
2780 /*
2781  * Deactivate and free request queue.
2782  */
2783 static void dasd_free_queue(struct dasd_block *block)
2784 {
2785 	if (block->request_queue) {
2786 		blk_cleanup_queue(block->request_queue);
2787 		block->request_queue = NULL;
2788 	}
2789 }
2790 
2791 /*
2792  * Flush request on the request queue.
2793  */
2794 static void dasd_flush_request_queue(struct dasd_block *block)
2795 {
2796 	struct request *req;
2797 
2798 	if (!block->request_queue)
2799 		return;
2800 
2801 	spin_lock_irq(&block->request_queue_lock);
2802 	while ((req = blk_fetch_request(block->request_queue)))
2803 		__blk_end_request_all(req, -EIO);
2804 	spin_unlock_irq(&block->request_queue_lock);
2805 }
2806 
2807 static int dasd_open(struct block_device *bdev, fmode_t mode)
2808 {
2809 	struct dasd_device *base;
2810 	int rc;
2811 
2812 	base = dasd_device_from_gendisk(bdev->bd_disk);
2813 	if (!base)
2814 		return -ENODEV;
2815 
2816 	atomic_inc(&base->block->open_count);
2817 	if (test_bit(DASD_FLAG_OFFLINE, &base->flags)) {
2818 		rc = -ENODEV;
2819 		goto unlock;
2820 	}
2821 
2822 	if (!try_module_get(base->discipline->owner)) {
2823 		rc = -EINVAL;
2824 		goto unlock;
2825 	}
2826 
2827 	if (dasd_probeonly) {
2828 		dev_info(&base->cdev->dev,
2829 			 "Accessing the DASD failed because it is in "
2830 			 "probeonly mode\n");
2831 		rc = -EPERM;
2832 		goto out;
2833 	}
2834 
2835 	if (base->state <= DASD_STATE_BASIC) {
2836 		DBF_DEV_EVENT(DBF_ERR, base, " %s",
2837 			      " Cannot open unrecognized device");
2838 		rc = -ENODEV;
2839 		goto out;
2840 	}
2841 
2842 	if ((mode & FMODE_WRITE) &&
2843 	    (test_bit(DASD_FLAG_DEVICE_RO, &base->flags) ||
2844 	     (base->features & DASD_FEATURE_READONLY))) {
2845 		rc = -EROFS;
2846 		goto out;
2847 	}
2848 
2849 	dasd_put_device(base);
2850 	return 0;
2851 
2852 out:
2853 	module_put(base->discipline->owner);
2854 unlock:
2855 	atomic_dec(&base->block->open_count);
2856 	dasd_put_device(base);
2857 	return rc;
2858 }
2859 
2860 static int dasd_release(struct gendisk *disk, fmode_t mode)
2861 {
2862 	struct dasd_device *base;
2863 
2864 	base = dasd_device_from_gendisk(disk);
2865 	if (!base)
2866 		return -ENODEV;
2867 
2868 	atomic_dec(&base->block->open_count);
2869 	module_put(base->discipline->owner);
2870 	dasd_put_device(base);
2871 	return 0;
2872 }
2873 
2874 /*
2875  * Return disk geometry.
2876  */
2877 static int dasd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
2878 {
2879 	struct dasd_device *base;
2880 
2881 	base = dasd_device_from_gendisk(bdev->bd_disk);
2882 	if (!base)
2883 		return -ENODEV;
2884 
2885 	if (!base->discipline ||
2886 	    !base->discipline->fill_geometry) {
2887 		dasd_put_device(base);
2888 		return -EINVAL;
2889 	}
2890 	base->discipline->fill_geometry(base->block, geo);
2891 	geo->start = get_start_sect(bdev) >> base->block->s2b_shift;
2892 	dasd_put_device(base);
2893 	return 0;
2894 }
2895 
2896 const struct block_device_operations
2897 dasd_device_operations = {
2898 	.owner		= THIS_MODULE,
2899 	.open		= dasd_open,
2900 	.release	= dasd_release,
2901 	.ioctl		= dasd_ioctl,
2902 	.compat_ioctl	= dasd_ioctl,
2903 	.getgeo		= dasd_getgeo,
2904 };
2905 
2906 /*******************************************************************************
2907  * end of block device operations
2908  */
2909 
2910 static void
2911 dasd_exit(void)
2912 {
2913 #ifdef CONFIG_PROC_FS
2914 	dasd_proc_exit();
2915 #endif
2916 	dasd_eer_exit();
2917         if (dasd_page_cache != NULL) {
2918 		kmem_cache_destroy(dasd_page_cache);
2919 		dasd_page_cache = NULL;
2920 	}
2921 	dasd_gendisk_exit();
2922 	dasd_devmap_exit();
2923 	if (dasd_debug_area != NULL) {
2924 		debug_unregister(dasd_debug_area);
2925 		dasd_debug_area = NULL;
2926 	}
2927 	dasd_statistics_removeroot();
2928 }
2929 
2930 /*
2931  * SECTION: common functions for ccw_driver use
2932  */
2933 
2934 /*
2935  * Is the device read-only?
2936  * Note that this function does not report the setting of the
2937  * readonly device attribute, but how it is configured in z/VM.
2938  */
2939 int dasd_device_is_ro(struct dasd_device *device)
2940 {
2941 	struct ccw_dev_id dev_id;
2942 	struct diag210 diag_data;
2943 	int rc;
2944 
2945 	if (!MACHINE_IS_VM)
2946 		return 0;
2947 	ccw_device_get_id(device->cdev, &dev_id);
2948 	memset(&diag_data, 0, sizeof(diag_data));
2949 	diag_data.vrdcdvno = dev_id.devno;
2950 	diag_data.vrdclen = sizeof(diag_data);
2951 	rc = diag210(&diag_data);
2952 	if (rc == 0 || rc == 2) {
2953 		return diag_data.vrdcvfla & 0x80;
2954 	} else {
2955 		DBF_EVENT(DBF_WARNING, "diag210 failed for dev=%04x with rc=%d",
2956 			  dev_id.devno, rc);
2957 		return 0;
2958 	}
2959 }
2960 EXPORT_SYMBOL_GPL(dasd_device_is_ro);
2961 
2962 static void dasd_generic_auto_online(void *data, async_cookie_t cookie)
2963 {
2964 	struct ccw_device *cdev = data;
2965 	int ret;
2966 
2967 	ret = ccw_device_set_online(cdev);
2968 	if (ret)
2969 		pr_warning("%s: Setting the DASD online failed with rc=%d\n",
2970 			   dev_name(&cdev->dev), ret);
2971 }
2972 
2973 /*
2974  * Initial attempt at a probe function. this can be simplified once
2975  * the other detection code is gone.
2976  */
2977 int dasd_generic_probe(struct ccw_device *cdev,
2978 		       struct dasd_discipline *discipline)
2979 {
2980 	int ret;
2981 
2982 	ret = dasd_add_sysfs_files(cdev);
2983 	if (ret) {
2984 		DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s",
2985 				"dasd_generic_probe: could not add "
2986 				"sysfs entries");
2987 		return ret;
2988 	}
2989 	cdev->handler = &dasd_int_handler;
2990 
2991 	/*
2992 	 * Automatically online either all dasd devices (dasd_autodetect)
2993 	 * or all devices specified with dasd= parameters during
2994 	 * initial probe.
2995 	 */
2996 	if ((dasd_get_feature(cdev, DASD_FEATURE_INITIAL_ONLINE) > 0 ) ||
2997 	    (dasd_autodetect && dasd_busid_known(dev_name(&cdev->dev)) != 0))
2998 		async_schedule(dasd_generic_auto_online, cdev);
2999 	return 0;
3000 }
3001 
3002 /*
3003  * This will one day be called from a global not_oper handler.
3004  * It is also used by driver_unregister during module unload.
3005  */
3006 void dasd_generic_remove(struct ccw_device *cdev)
3007 {
3008 	struct dasd_device *device;
3009 	struct dasd_block *block;
3010 
3011 	cdev->handler = NULL;
3012 
3013 	dasd_remove_sysfs_files(cdev);
3014 	device = dasd_device_from_cdev(cdev);
3015 	if (IS_ERR(device))
3016 		return;
3017 	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
3018 		/* Already doing offline processing */
3019 		dasd_put_device(device);
3020 		return;
3021 	}
3022 	/*
3023 	 * This device is removed unconditionally. Set offline
3024 	 * flag to prevent dasd_open from opening it while it is
3025 	 * no quite down yet.
3026 	 */
3027 	dasd_set_target_state(device, DASD_STATE_NEW);
3028 	/* dasd_delete_device destroys the device reference. */
3029 	block = device->block;
3030 	dasd_delete_device(device);
3031 	/*
3032 	 * life cycle of block is bound to device, so delete it after
3033 	 * device was safely removed
3034 	 */
3035 	if (block)
3036 		dasd_free_block(block);
3037 }
3038 
3039 /*
3040  * Activate a device. This is called from dasd_{eckd,fba}_probe() when either
3041  * the device is detected for the first time and is supposed to be used
3042  * or the user has started activation through sysfs.
3043  */
3044 int dasd_generic_set_online(struct ccw_device *cdev,
3045 			    struct dasd_discipline *base_discipline)
3046 {
3047 	struct dasd_discipline *discipline;
3048 	struct dasd_device *device;
3049 	int rc;
3050 
3051 	/* first online clears initial online feature flag */
3052 	dasd_set_feature(cdev, DASD_FEATURE_INITIAL_ONLINE, 0);
3053 	device = dasd_create_device(cdev);
3054 	if (IS_ERR(device))
3055 		return PTR_ERR(device);
3056 
3057 	discipline = base_discipline;
3058 	if (device->features & DASD_FEATURE_USEDIAG) {
3059 	  	if (!dasd_diag_discipline_pointer) {
3060 			pr_warning("%s Setting the DASD online failed because "
3061 				   "of missing DIAG discipline\n",
3062 				   dev_name(&cdev->dev));
3063 			dasd_delete_device(device);
3064 			return -ENODEV;
3065 		}
3066 		discipline = dasd_diag_discipline_pointer;
3067 	}
3068 	if (!try_module_get(base_discipline->owner)) {
3069 		dasd_delete_device(device);
3070 		return -EINVAL;
3071 	}
3072 	if (!try_module_get(discipline->owner)) {
3073 		module_put(base_discipline->owner);
3074 		dasd_delete_device(device);
3075 		return -EINVAL;
3076 	}
3077 	device->base_discipline = base_discipline;
3078 	device->discipline = discipline;
3079 
3080 	/* check_device will allocate block device if necessary */
3081 	rc = discipline->check_device(device);
3082 	if (rc) {
3083 		pr_warning("%s Setting the DASD online with discipline %s "
3084 			   "failed with rc=%i\n",
3085 			   dev_name(&cdev->dev), discipline->name, rc);
3086 		module_put(discipline->owner);
3087 		module_put(base_discipline->owner);
3088 		dasd_delete_device(device);
3089 		return rc;
3090 	}
3091 
3092 	dasd_set_target_state(device, DASD_STATE_ONLINE);
3093 	if (device->state <= DASD_STATE_KNOWN) {
3094 		pr_warning("%s Setting the DASD online failed because of a "
3095 			   "missing discipline\n", dev_name(&cdev->dev));
3096 		rc = -ENODEV;
3097 		dasd_set_target_state(device, DASD_STATE_NEW);
3098 		if (device->block)
3099 			dasd_free_block(device->block);
3100 		dasd_delete_device(device);
3101 	} else
3102 		pr_debug("dasd_generic device %s found\n",
3103 				dev_name(&cdev->dev));
3104 
3105 	wait_event(dasd_init_waitq, _wait_for_device(device));
3106 
3107 	dasd_put_device(device);
3108 	return rc;
3109 }
3110 
3111 int dasd_generic_set_offline(struct ccw_device *cdev)
3112 {
3113 	struct dasd_device *device;
3114 	struct dasd_block *block;
3115 	int max_count, open_count;
3116 
3117 	device = dasd_device_from_cdev(cdev);
3118 	if (IS_ERR(device))
3119 		return PTR_ERR(device);
3120 	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
3121 		/* Already doing offline processing */
3122 		dasd_put_device(device);
3123 		return 0;
3124 	}
3125 	/*
3126 	 * We must make sure that this device is currently not in use.
3127 	 * The open_count is increased for every opener, that includes
3128 	 * the blkdev_get in dasd_scan_partitions. We are only interested
3129 	 * in the other openers.
3130 	 */
3131 	if (device->block) {
3132 		max_count = device->block->bdev ? 0 : -1;
3133 		open_count = atomic_read(&device->block->open_count);
3134 		if (open_count > max_count) {
3135 			if (open_count > 0)
3136 				pr_warning("%s: The DASD cannot be set offline "
3137 					   "with open count %i\n",
3138 					   dev_name(&cdev->dev), open_count);
3139 			else
3140 				pr_warning("%s: The DASD cannot be set offline "
3141 					   "while it is in use\n",
3142 					   dev_name(&cdev->dev));
3143 			clear_bit(DASD_FLAG_OFFLINE, &device->flags);
3144 			dasd_put_device(device);
3145 			return -EBUSY;
3146 		}
3147 	}
3148 	dasd_set_target_state(device, DASD_STATE_NEW);
3149 	/* dasd_delete_device destroys the device reference. */
3150 	block = device->block;
3151 	dasd_delete_device(device);
3152 	/*
3153 	 * life cycle of block is bound to device, so delete it after
3154 	 * device was safely removed
3155 	 */
3156 	if (block)
3157 		dasd_free_block(block);
3158 	return 0;
3159 }
3160 
3161 int dasd_generic_last_path_gone(struct dasd_device *device)
3162 {
3163 	struct dasd_ccw_req *cqr;
3164 
3165 	dev_warn(&device->cdev->dev, "No operational channel path is left "
3166 		 "for the device\n");
3167 	DBF_DEV_EVENT(DBF_WARNING, device, "%s", "last path gone");
3168 	/* First of all call extended error reporting. */
3169 	dasd_eer_write(device, NULL, DASD_EER_NOPATH);
3170 
3171 	if (device->state < DASD_STATE_BASIC)
3172 		return 0;
3173 	/* Device is active. We want to keep it. */
3174 	list_for_each_entry(cqr, &device->ccw_queue, devlist)
3175 		if ((cqr->status == DASD_CQR_IN_IO) ||
3176 		    (cqr->status == DASD_CQR_CLEAR_PENDING)) {
3177 			cqr->status = DASD_CQR_QUEUED;
3178 			cqr->retries++;
3179 		}
3180 	dasd_device_set_stop_bits(device, DASD_STOPPED_DC_WAIT);
3181 	dasd_device_clear_timer(device);
3182 	dasd_schedule_device_bh(device);
3183 	return 1;
3184 }
3185 EXPORT_SYMBOL_GPL(dasd_generic_last_path_gone);
3186 
3187 int dasd_generic_path_operational(struct dasd_device *device)
3188 {
3189 	dev_info(&device->cdev->dev, "A channel path to the device has become "
3190 		 "operational\n");
3191 	DBF_DEV_EVENT(DBF_WARNING, device, "%s", "path operational");
3192 	dasd_device_remove_stop_bits(device, DASD_STOPPED_DC_WAIT);
3193 	if (device->stopped & DASD_UNRESUMED_PM) {
3194 		dasd_device_remove_stop_bits(device, DASD_UNRESUMED_PM);
3195 		dasd_restore_device(device);
3196 		return 1;
3197 	}
3198 	dasd_schedule_device_bh(device);
3199 	if (device->block)
3200 		dasd_schedule_block_bh(device->block);
3201 	return 1;
3202 }
3203 EXPORT_SYMBOL_GPL(dasd_generic_path_operational);
3204 
3205 int dasd_generic_notify(struct ccw_device *cdev, int event)
3206 {
3207 	struct dasd_device *device;
3208 	int ret;
3209 
3210 	device = dasd_device_from_cdev_locked(cdev);
3211 	if (IS_ERR(device))
3212 		return 0;
3213 	ret = 0;
3214 	switch (event) {
3215 	case CIO_GONE:
3216 	case CIO_BOXED:
3217 	case CIO_NO_PATH:
3218 		device->path_data.opm = 0;
3219 		device->path_data.ppm = 0;
3220 		device->path_data.npm = 0;
3221 		ret = dasd_generic_last_path_gone(device);
3222 		break;
3223 	case CIO_OPER:
3224 		ret = 1;
3225 		if (device->path_data.opm)
3226 			ret = dasd_generic_path_operational(device);
3227 		break;
3228 	}
3229 	dasd_put_device(device);
3230 	return ret;
3231 }
3232 
3233 void dasd_generic_path_event(struct ccw_device *cdev, int *path_event)
3234 {
3235 	int chp;
3236 	__u8 oldopm, eventlpm;
3237 	struct dasd_device *device;
3238 
3239 	device = dasd_device_from_cdev_locked(cdev);
3240 	if (IS_ERR(device))
3241 		return;
3242 	for (chp = 0; chp < 8; chp++) {
3243 		eventlpm = 0x80 >> chp;
3244 		if (path_event[chp] & PE_PATH_GONE) {
3245 			oldopm = device->path_data.opm;
3246 			device->path_data.opm &= ~eventlpm;
3247 			device->path_data.ppm &= ~eventlpm;
3248 			device->path_data.npm &= ~eventlpm;
3249 			if (oldopm && !device->path_data.opm)
3250 				dasd_generic_last_path_gone(device);
3251 		}
3252 		if (path_event[chp] & PE_PATH_AVAILABLE) {
3253 			device->path_data.opm &= ~eventlpm;
3254 			device->path_data.ppm &= ~eventlpm;
3255 			device->path_data.npm &= ~eventlpm;
3256 			device->path_data.tbvpm |= eventlpm;
3257 			dasd_schedule_device_bh(device);
3258 		}
3259 	}
3260 	dasd_put_device(device);
3261 }
3262 EXPORT_SYMBOL_GPL(dasd_generic_path_event);
3263 
3264 int dasd_generic_verify_path(struct dasd_device *device, __u8 lpm)
3265 {
3266 	if (!device->path_data.opm && lpm) {
3267 		device->path_data.opm = lpm;
3268 		dasd_generic_path_operational(device);
3269 	} else
3270 		device->path_data.opm |= lpm;
3271 	return 0;
3272 }
3273 EXPORT_SYMBOL_GPL(dasd_generic_verify_path);
3274 
3275 
3276 int dasd_generic_pm_freeze(struct ccw_device *cdev)
3277 {
3278 	struct dasd_ccw_req *cqr, *n;
3279 	int rc;
3280 	struct list_head freeze_queue;
3281 	struct dasd_device *device = dasd_device_from_cdev(cdev);
3282 
3283 	if (IS_ERR(device))
3284 		return PTR_ERR(device);
3285 
3286 	if (device->discipline->freeze)
3287 		rc = device->discipline->freeze(device);
3288 
3289 	/* disallow new I/O  */
3290 	dasd_device_set_stop_bits(device, DASD_STOPPED_PM);
3291 	/* clear active requests */
3292 	INIT_LIST_HEAD(&freeze_queue);
3293 	spin_lock_irq(get_ccwdev_lock(cdev));
3294 	rc = 0;
3295 	list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
3296 		/* Check status and move request to flush_queue */
3297 		if (cqr->status == DASD_CQR_IN_IO) {
3298 			rc = device->discipline->term_IO(cqr);
3299 			if (rc) {
3300 				/* unable to terminate requeust */
3301 				dev_err(&device->cdev->dev,
3302 					"Unable to terminate request %p "
3303 					"on suspend\n", cqr);
3304 				spin_unlock_irq(get_ccwdev_lock(cdev));
3305 				dasd_put_device(device);
3306 				return rc;
3307 			}
3308 		}
3309 		list_move_tail(&cqr->devlist, &freeze_queue);
3310 	}
3311 
3312 	spin_unlock_irq(get_ccwdev_lock(cdev));
3313 
3314 	list_for_each_entry_safe(cqr, n, &freeze_queue, devlist) {
3315 		wait_event(dasd_flush_wq,
3316 			   (cqr->status != DASD_CQR_CLEAR_PENDING));
3317 		if (cqr->status == DASD_CQR_CLEARED)
3318 			cqr->status = DASD_CQR_QUEUED;
3319 	}
3320 	/* move freeze_queue to start of the ccw_queue */
3321 	spin_lock_irq(get_ccwdev_lock(cdev));
3322 	list_splice_tail(&freeze_queue, &device->ccw_queue);
3323 	spin_unlock_irq(get_ccwdev_lock(cdev));
3324 
3325 	dasd_put_device(device);
3326 	return rc;
3327 }
3328 EXPORT_SYMBOL_GPL(dasd_generic_pm_freeze);
3329 
3330 int dasd_generic_restore_device(struct ccw_device *cdev)
3331 {
3332 	struct dasd_device *device = dasd_device_from_cdev(cdev);
3333 	int rc = 0;
3334 
3335 	if (IS_ERR(device))
3336 		return PTR_ERR(device);
3337 
3338 	/* allow new IO again */
3339 	dasd_device_remove_stop_bits(device,
3340 				     (DASD_STOPPED_PM | DASD_UNRESUMED_PM));
3341 
3342 	dasd_schedule_device_bh(device);
3343 
3344 	/*
3345 	 * call discipline restore function
3346 	 * if device is stopped do nothing e.g. for disconnected devices
3347 	 */
3348 	if (device->discipline->restore && !(device->stopped))
3349 		rc = device->discipline->restore(device);
3350 	if (rc || device->stopped)
3351 		/*
3352 		 * if the resume failed for the DASD we put it in
3353 		 * an UNRESUMED stop state
3354 		 */
3355 		device->stopped |= DASD_UNRESUMED_PM;
3356 
3357 	if (device->block)
3358 		dasd_schedule_block_bh(device->block);
3359 
3360 	dasd_put_device(device);
3361 	return 0;
3362 }
3363 EXPORT_SYMBOL_GPL(dasd_generic_restore_device);
3364 
3365 static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
3366 						   void *rdc_buffer,
3367 						   int rdc_buffer_size,
3368 						   int magic)
3369 {
3370 	struct dasd_ccw_req *cqr;
3371 	struct ccw1 *ccw;
3372 	unsigned long *idaw;
3373 
3374 	cqr = dasd_smalloc_request(magic, 1 /* RDC */, rdc_buffer_size, device);
3375 
3376 	if (IS_ERR(cqr)) {
3377 		/* internal error 13 - Allocating the RDC request failed*/
3378 		dev_err(&device->cdev->dev,
3379 			 "An error occurred in the DASD device driver, "
3380 			 "reason=%s\n", "13");
3381 		return cqr;
3382 	}
3383 
3384 	ccw = cqr->cpaddr;
3385 	ccw->cmd_code = CCW_CMD_RDC;
3386 	if (idal_is_needed(rdc_buffer, rdc_buffer_size)) {
3387 		idaw = (unsigned long *) (cqr->data);
3388 		ccw->cda = (__u32)(addr_t) idaw;
3389 		ccw->flags = CCW_FLAG_IDA;
3390 		idaw = idal_create_words(idaw, rdc_buffer, rdc_buffer_size);
3391 	} else {
3392 		ccw->cda = (__u32)(addr_t) rdc_buffer;
3393 		ccw->flags = 0;
3394 	}
3395 
3396 	ccw->count = rdc_buffer_size;
3397 	cqr->startdev = device;
3398 	cqr->memdev = device;
3399 	cqr->expires = 10*HZ;
3400 	cqr->retries = 256;
3401 	cqr->buildclk = get_clock();
3402 	cqr->status = DASD_CQR_FILLED;
3403 	return cqr;
3404 }
3405 
3406 
3407 int dasd_generic_read_dev_chars(struct dasd_device *device, int magic,
3408 				void *rdc_buffer, int rdc_buffer_size)
3409 {
3410 	int ret;
3411 	struct dasd_ccw_req *cqr;
3412 
3413 	cqr = dasd_generic_build_rdc(device, rdc_buffer, rdc_buffer_size,
3414 				     magic);
3415 	if (IS_ERR(cqr))
3416 		return PTR_ERR(cqr);
3417 
3418 	ret = dasd_sleep_on(cqr);
3419 	dasd_sfree_request(cqr, cqr->memdev);
3420 	return ret;
3421 }
3422 EXPORT_SYMBOL_GPL(dasd_generic_read_dev_chars);
3423 
3424 /*
3425  *   In command mode and transport mode we need to look for sense
3426  *   data in different places. The sense data itself is allways
3427  *   an array of 32 bytes, so we can unify the sense data access
3428  *   for both modes.
3429  */
3430 char *dasd_get_sense(struct irb *irb)
3431 {
3432 	struct tsb *tsb = NULL;
3433 	char *sense = NULL;
3434 
3435 	if (scsw_is_tm(&irb->scsw) && (irb->scsw.tm.fcxs == 0x01)) {
3436 		if (irb->scsw.tm.tcw)
3437 			tsb = tcw_get_tsb((struct tcw *)(unsigned long)
3438 					  irb->scsw.tm.tcw);
3439 		if (tsb && tsb->length == 64 && tsb->flags)
3440 			switch (tsb->flags & 0x07) {
3441 			case 1:	/* tsa_iostat */
3442 				sense = tsb->tsa.iostat.sense;
3443 				break;
3444 			case 2: /* tsa_ddpc */
3445 				sense = tsb->tsa.ddpc.sense;
3446 				break;
3447 			default:
3448 				/* currently we don't use interrogate data */
3449 				break;
3450 			}
3451 	} else if (irb->esw.esw0.erw.cons) {
3452 		sense = irb->ecw;
3453 	}
3454 	return sense;
3455 }
3456 EXPORT_SYMBOL_GPL(dasd_get_sense);
3457 
3458 static int __init dasd_init(void)
3459 {
3460 	int rc;
3461 
3462 	init_waitqueue_head(&dasd_init_waitq);
3463 	init_waitqueue_head(&dasd_flush_wq);
3464 	init_waitqueue_head(&generic_waitq);
3465 
3466 	/* register 'common' DASD debug area, used for all DBF_XXX calls */
3467 	dasd_debug_area = debug_register("dasd", 1, 1, 8 * sizeof(long));
3468 	if (dasd_debug_area == NULL) {
3469 		rc = -ENOMEM;
3470 		goto failed;
3471 	}
3472 	debug_register_view(dasd_debug_area, &debug_sprintf_view);
3473 	debug_set_level(dasd_debug_area, DBF_WARNING);
3474 
3475 	DBF_EVENT(DBF_EMERG, "%s", "debug area created");
3476 
3477 	dasd_diag_discipline_pointer = NULL;
3478 
3479 	dasd_statistics_createroot();
3480 
3481 	rc = dasd_devmap_init();
3482 	if (rc)
3483 		goto failed;
3484 	rc = dasd_gendisk_init();
3485 	if (rc)
3486 		goto failed;
3487 	rc = dasd_parse();
3488 	if (rc)
3489 		goto failed;
3490 	rc = dasd_eer_init();
3491 	if (rc)
3492 		goto failed;
3493 #ifdef CONFIG_PROC_FS
3494 	rc = dasd_proc_init();
3495 	if (rc)
3496 		goto failed;
3497 #endif
3498 
3499 	return 0;
3500 failed:
3501 	pr_info("The DASD device driver could not be initialized\n");
3502 	dasd_exit();
3503 	return rc;
3504 }
3505 
3506 module_init(dasd_init);
3507 module_exit(dasd_exit);
3508 
3509 EXPORT_SYMBOL(dasd_debug_area);
3510 EXPORT_SYMBOL(dasd_diag_discipline_pointer);
3511 
3512 EXPORT_SYMBOL(dasd_add_request_head);
3513 EXPORT_SYMBOL(dasd_add_request_tail);
3514 EXPORT_SYMBOL(dasd_cancel_req);
3515 EXPORT_SYMBOL(dasd_device_clear_timer);
3516 EXPORT_SYMBOL(dasd_block_clear_timer);
3517 EXPORT_SYMBOL(dasd_enable_device);
3518 EXPORT_SYMBOL(dasd_int_handler);
3519 EXPORT_SYMBOL(dasd_kfree_request);
3520 EXPORT_SYMBOL(dasd_kick_device);
3521 EXPORT_SYMBOL(dasd_kmalloc_request);
3522 EXPORT_SYMBOL(dasd_schedule_device_bh);
3523 EXPORT_SYMBOL(dasd_schedule_block_bh);
3524 EXPORT_SYMBOL(dasd_set_target_state);
3525 EXPORT_SYMBOL(dasd_device_set_timer);
3526 EXPORT_SYMBOL(dasd_block_set_timer);
3527 EXPORT_SYMBOL(dasd_sfree_request);
3528 EXPORT_SYMBOL(dasd_sleep_on);
3529 EXPORT_SYMBOL(dasd_sleep_on_immediatly);
3530 EXPORT_SYMBOL(dasd_sleep_on_interruptible);
3531 EXPORT_SYMBOL(dasd_smalloc_request);
3532 EXPORT_SYMBOL(dasd_start_IO);
3533 EXPORT_SYMBOL(dasd_term_IO);
3534 
3535 EXPORT_SYMBOL_GPL(dasd_generic_probe);
3536 EXPORT_SYMBOL_GPL(dasd_generic_remove);
3537 EXPORT_SYMBOL_GPL(dasd_generic_notify);
3538 EXPORT_SYMBOL_GPL(dasd_generic_set_online);
3539 EXPORT_SYMBOL_GPL(dasd_generic_set_offline);
3540 EXPORT_SYMBOL_GPL(dasd_generic_handle_state_change);
3541 EXPORT_SYMBOL_GPL(dasd_flush_device_queue);
3542 EXPORT_SYMBOL_GPL(dasd_alloc_block);
3543 EXPORT_SYMBOL_GPL(dasd_free_block);
3544