xref: /openbmc/linux/drivers/s390/block/dasd.c (revision 8e09f21574ea3028d5629e5de759e0b196c690c5)
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  * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999-2001
9  *
10  */
11 
12 #include <linux/kmod.h>
13 #include <linux/init.h>
14 #include <linux/interrupt.h>
15 #include <linux/ctype.h>
16 #include <linux/major.h>
17 #include <linux/slab.h>
18 #include <linux/buffer_head.h>
19 #include <linux/hdreg.h>
20 
21 #include <asm/ccwdev.h>
22 #include <asm/ebcdic.h>
23 #include <asm/idals.h>
24 #include <asm/todclk.h>
25 
26 /* This is ugly... */
27 #define PRINTK_HEADER "dasd:"
28 
29 #include "dasd_int.h"
30 /*
31  * SECTION: Constant definitions to be used within this file
32  */
33 #define DASD_CHANQ_MAX_SIZE 4
34 
35 /*
36  * SECTION: exported variables of dasd.c
37  */
38 debug_info_t *dasd_debug_area;
39 struct dasd_discipline *dasd_diag_discipline_pointer;
40 void dasd_int_handler(struct ccw_device *, unsigned long, struct irb *);
41 
42 MODULE_AUTHOR("Holger Smolinski <Holger.Smolinski@de.ibm.com>");
43 MODULE_DESCRIPTION("Linux on S/390 DASD device driver,"
44 		   " Copyright 2000 IBM Corporation");
45 MODULE_SUPPORTED_DEVICE("dasd");
46 MODULE_LICENSE("GPL");
47 
48 /*
49  * SECTION: prototypes for static functions of dasd.c
50  */
51 static int  dasd_alloc_queue(struct dasd_block *);
52 static void dasd_setup_queue(struct dasd_block *);
53 static void dasd_free_queue(struct dasd_block *);
54 static void dasd_flush_request_queue(struct dasd_block *);
55 static int dasd_flush_block_queue(struct dasd_block *);
56 static void dasd_device_tasklet(struct dasd_device *);
57 static void dasd_block_tasklet(struct dasd_block *);
58 static void do_kick_device(struct work_struct *);
59 static void dasd_return_cqr_cb(struct dasd_ccw_req *, void *);
60 
61 /*
62  * SECTION: Operations on the device structure.
63  */
64 static wait_queue_head_t dasd_init_waitq;
65 static wait_queue_head_t dasd_flush_wq;
66 
67 /*
68  * Allocate memory for a new device structure.
69  */
70 struct dasd_device *dasd_alloc_device(void)
71 {
72 	struct dasd_device *device;
73 
74 	device = kzalloc(sizeof(struct dasd_device), GFP_ATOMIC);
75 	if (!device)
76 		return ERR_PTR(-ENOMEM);
77 
78 	/* Get two pages for normal block device operations. */
79 	device->ccw_mem = (void *) __get_free_pages(GFP_ATOMIC | GFP_DMA, 1);
80 	if (!device->ccw_mem) {
81 		kfree(device);
82 		return ERR_PTR(-ENOMEM);
83 	}
84 	/* Get one page for error recovery. */
85 	device->erp_mem = (void *) get_zeroed_page(GFP_ATOMIC | GFP_DMA);
86 	if (!device->erp_mem) {
87 		free_pages((unsigned long) device->ccw_mem, 1);
88 		kfree(device);
89 		return ERR_PTR(-ENOMEM);
90 	}
91 
92 	dasd_init_chunklist(&device->ccw_chunks, device->ccw_mem, PAGE_SIZE*2);
93 	dasd_init_chunklist(&device->erp_chunks, device->erp_mem, PAGE_SIZE);
94 	spin_lock_init(&device->mem_lock);
95 	atomic_set(&device->tasklet_scheduled, 0);
96 	tasklet_init(&device->tasklet,
97 		     (void (*)(unsigned long)) dasd_device_tasklet,
98 		     (unsigned long) device);
99 	INIT_LIST_HEAD(&device->ccw_queue);
100 	init_timer(&device->timer);
101 	INIT_WORK(&device->kick_work, do_kick_device);
102 	device->state = DASD_STATE_NEW;
103 	device->target = DASD_STATE_NEW;
104 
105 	return device;
106 }
107 
108 /*
109  * Free memory of a device structure.
110  */
111 void dasd_free_device(struct dasd_device *device)
112 {
113 	kfree(device->private);
114 	free_page((unsigned long) device->erp_mem);
115 	free_pages((unsigned long) device->ccw_mem, 1);
116 	kfree(device);
117 }
118 
119 /*
120  * Allocate memory for a new device structure.
121  */
122 struct dasd_block *dasd_alloc_block(void)
123 {
124 	struct dasd_block *block;
125 
126 	block = kzalloc(sizeof(*block), GFP_ATOMIC);
127 	if (!block)
128 		return ERR_PTR(-ENOMEM);
129 	/* open_count = 0 means device online but not in use */
130 	atomic_set(&block->open_count, -1);
131 
132 	spin_lock_init(&block->request_queue_lock);
133 	atomic_set(&block->tasklet_scheduled, 0);
134 	tasklet_init(&block->tasklet,
135 		     (void (*)(unsigned long)) dasd_block_tasklet,
136 		     (unsigned long) block);
137 	INIT_LIST_HEAD(&block->ccw_queue);
138 	spin_lock_init(&block->queue_lock);
139 	init_timer(&block->timer);
140 
141 	return block;
142 }
143 
144 /*
145  * Free memory of a device structure.
146  */
147 void dasd_free_block(struct dasd_block *block)
148 {
149 	kfree(block);
150 }
151 
152 /*
153  * Make a new device known to the system.
154  */
155 static int dasd_state_new_to_known(struct dasd_device *device)
156 {
157 	int rc;
158 
159 	/*
160 	 * As long as the device is not in state DASD_STATE_NEW we want to
161 	 * keep the reference count > 0.
162 	 */
163 	dasd_get_device(device);
164 
165 	if (device->block) {
166 		rc = dasd_alloc_queue(device->block);
167 		if (rc) {
168 			dasd_put_device(device);
169 			return rc;
170 		}
171 	}
172 	device->state = DASD_STATE_KNOWN;
173 	return 0;
174 }
175 
176 /*
177  * Let the system forget about a device.
178  */
179 static int dasd_state_known_to_new(struct dasd_device *device)
180 {
181 	/* Disable extended error reporting for this device. */
182 	dasd_eer_disable(device);
183 	/* Forget the discipline information. */
184 	if (device->discipline) {
185 		if (device->discipline->uncheck_device)
186 			device->discipline->uncheck_device(device);
187 		module_put(device->discipline->owner);
188 	}
189 	device->discipline = NULL;
190 	if (device->base_discipline)
191 		module_put(device->base_discipline->owner);
192 	device->base_discipline = NULL;
193 	device->state = DASD_STATE_NEW;
194 
195 	if (device->block)
196 		dasd_free_queue(device->block);
197 
198 	/* Give up reference we took in dasd_state_new_to_known. */
199 	dasd_put_device(device);
200 	return 0;
201 }
202 
203 /*
204  * Request the irq line for the device.
205  */
206 static int dasd_state_known_to_basic(struct dasd_device *device)
207 {
208 	int rc;
209 
210 	/* Allocate and register gendisk structure. */
211 	if (device->block) {
212 		rc = dasd_gendisk_alloc(device->block);
213 		if (rc)
214 			return rc;
215 	}
216 	/* register 'device' debug area, used for all DBF_DEV_XXX calls */
217 	device->debug_area = debug_register(device->cdev->dev.bus_id, 1, 2,
218 					    8 * sizeof(long));
219 	debug_register_view(device->debug_area, &debug_sprintf_view);
220 	debug_set_level(device->debug_area, DBF_WARNING);
221 	DBF_DEV_EVENT(DBF_EMERG, device, "%s", "debug area created");
222 
223 	device->state = DASD_STATE_BASIC;
224 	return 0;
225 }
226 
227 /*
228  * Release the irq line for the device. Terminate any running i/o.
229  */
230 static int dasd_state_basic_to_known(struct dasd_device *device)
231 {
232 	int rc;
233 	if (device->block) {
234 		dasd_gendisk_free(device->block);
235 		dasd_block_clear_timer(device->block);
236 	}
237 	rc = dasd_flush_device_queue(device);
238 	if (rc)
239 		return rc;
240 	dasd_device_clear_timer(device);
241 
242 	DBF_DEV_EVENT(DBF_EMERG, device, "%p debug area deleted", device);
243 	if (device->debug_area != NULL) {
244 		debug_unregister(device->debug_area);
245 		device->debug_area = NULL;
246 	}
247 	device->state = DASD_STATE_KNOWN;
248 	return 0;
249 }
250 
251 /*
252  * Do the initial analysis. The do_analysis function may return
253  * -EAGAIN in which case the device keeps the state DASD_STATE_BASIC
254  * until the discipline decides to continue the startup sequence
255  * by calling the function dasd_change_state. The eckd disciplines
256  * uses this to start a ccw that detects the format. The completion
257  * interrupt for this detection ccw uses the kernel event daemon to
258  * trigger the call to dasd_change_state. All this is done in the
259  * discipline code, see dasd_eckd.c.
260  * After the analysis ccw is done (do_analysis returned 0) the block
261  * device is setup.
262  * In case the analysis returns an error, the device setup is stopped
263  * (a fake disk was already added to allow formatting).
264  */
265 static int dasd_state_basic_to_ready(struct dasd_device *device)
266 {
267 	int rc;
268 	struct dasd_block *block;
269 
270 	rc = 0;
271 	block = device->block;
272 	/* make disk known with correct capacity */
273 	if (block) {
274 		if (block->base->discipline->do_analysis != NULL)
275 			rc = block->base->discipline->do_analysis(block);
276 		if (rc) {
277 			if (rc != -EAGAIN)
278 				device->state = DASD_STATE_UNFMT;
279 			return rc;
280 		}
281 		dasd_setup_queue(block);
282 		set_capacity(block->gdp,
283 			     block->blocks << block->s2b_shift);
284 		device->state = DASD_STATE_READY;
285 		rc = dasd_scan_partitions(block);
286 		if (rc)
287 			device->state = DASD_STATE_BASIC;
288 	} else {
289 		device->state = DASD_STATE_READY;
290 	}
291 	return rc;
292 }
293 
294 /*
295  * Remove device from block device layer. Destroy dirty buffers.
296  * Forget format information. Check if the target level is basic
297  * and if it is create fake disk for formatting.
298  */
299 static int dasd_state_ready_to_basic(struct dasd_device *device)
300 {
301 	int rc;
302 
303 	device->state = DASD_STATE_BASIC;
304 	if (device->block) {
305 		struct dasd_block *block = device->block;
306 		rc = dasd_flush_block_queue(block);
307 		if (rc) {
308 			device->state = DASD_STATE_READY;
309 			return rc;
310 		}
311 		dasd_destroy_partitions(block);
312 		dasd_flush_request_queue(block);
313 		block->blocks = 0;
314 		block->bp_block = 0;
315 		block->s2b_shift = 0;
316 	}
317 	return 0;
318 }
319 
320 /*
321  * Back to basic.
322  */
323 static int dasd_state_unfmt_to_basic(struct dasd_device *device)
324 {
325 	device->state = DASD_STATE_BASIC;
326 	return 0;
327 }
328 
329 /*
330  * Make the device online and schedule the bottom half to start
331  * the requeueing of requests from the linux request queue to the
332  * ccw queue.
333  */
334 static int
335 dasd_state_ready_to_online(struct dasd_device * device)
336 {
337 	int rc;
338 
339 	if (device->discipline->ready_to_online) {
340 		rc = device->discipline->ready_to_online(device);
341 		if (rc)
342 			return rc;
343 	}
344 	device->state = DASD_STATE_ONLINE;
345 	if (device->block)
346 		dasd_schedule_block_bh(device->block);
347 	return 0;
348 }
349 
350 /*
351  * Stop the requeueing of requests again.
352  */
353 static int dasd_state_online_to_ready(struct dasd_device *device)
354 {
355 	int rc;
356 
357 	if (device->discipline->online_to_ready) {
358 		rc = device->discipline->online_to_ready(device);
359 		if (rc)
360 			return rc;
361 	}
362 	device->state = DASD_STATE_READY;
363 	return 0;
364 }
365 
366 /*
367  * Device startup state changes.
368  */
369 static int dasd_increase_state(struct dasd_device *device)
370 {
371 	int rc;
372 
373 	rc = 0;
374 	if (device->state == DASD_STATE_NEW &&
375 	    device->target >= DASD_STATE_KNOWN)
376 		rc = dasd_state_new_to_known(device);
377 
378 	if (!rc &&
379 	    device->state == DASD_STATE_KNOWN &&
380 	    device->target >= DASD_STATE_BASIC)
381 		rc = dasd_state_known_to_basic(device);
382 
383 	if (!rc &&
384 	    device->state == DASD_STATE_BASIC &&
385 	    device->target >= DASD_STATE_READY)
386 		rc = dasd_state_basic_to_ready(device);
387 
388 	if (!rc &&
389 	    device->state == DASD_STATE_UNFMT &&
390 	    device->target > DASD_STATE_UNFMT)
391 		rc = -EPERM;
392 
393 	if (!rc &&
394 	    device->state == DASD_STATE_READY &&
395 	    device->target >= DASD_STATE_ONLINE)
396 		rc = dasd_state_ready_to_online(device);
397 
398 	return rc;
399 }
400 
401 /*
402  * Device shutdown state changes.
403  */
404 static int dasd_decrease_state(struct dasd_device *device)
405 {
406 	int rc;
407 
408 	rc = 0;
409 	if (device->state == DASD_STATE_ONLINE &&
410 	    device->target <= DASD_STATE_READY)
411 		rc = dasd_state_online_to_ready(device);
412 
413 	if (!rc &&
414 	    device->state == DASD_STATE_READY &&
415 	    device->target <= DASD_STATE_BASIC)
416 		rc = dasd_state_ready_to_basic(device);
417 
418 	if (!rc &&
419 	    device->state == DASD_STATE_UNFMT &&
420 	    device->target <= DASD_STATE_BASIC)
421 		rc = dasd_state_unfmt_to_basic(device);
422 
423 	if (!rc &&
424 	    device->state == DASD_STATE_BASIC &&
425 	    device->target <= DASD_STATE_KNOWN)
426 		rc = dasd_state_basic_to_known(device);
427 
428 	if (!rc &&
429 	    device->state == DASD_STATE_KNOWN &&
430 	    device->target <= DASD_STATE_NEW)
431 		rc = dasd_state_known_to_new(device);
432 
433 	return rc;
434 }
435 
436 /*
437  * This is the main startup/shutdown routine.
438  */
439 static void dasd_change_state(struct dasd_device *device)
440 {
441         int rc;
442 
443 	if (device->state == device->target)
444 		/* Already where we want to go today... */
445 		return;
446 	if (device->state < device->target)
447 		rc = dasd_increase_state(device);
448 	else
449 		rc = dasd_decrease_state(device);
450         if (rc && rc != -EAGAIN)
451                 device->target = device->state;
452 
453 	if (device->state == device->target)
454 		wake_up(&dasd_init_waitq);
455 
456 	/* let user-space know that the device status changed */
457 	kobject_uevent(&device->cdev->dev.kobj, KOBJ_CHANGE);
458 }
459 
460 /*
461  * Kick starter for devices that did not complete the startup/shutdown
462  * procedure or were sleeping because of a pending state.
463  * dasd_kick_device will schedule a call do do_kick_device to the kernel
464  * event daemon.
465  */
466 static void do_kick_device(struct work_struct *work)
467 {
468 	struct dasd_device *device = container_of(work, struct dasd_device, kick_work);
469 	dasd_change_state(device);
470 	dasd_schedule_device_bh(device);
471 	dasd_put_device(device);
472 }
473 
474 void dasd_kick_device(struct dasd_device *device)
475 {
476 	dasd_get_device(device);
477 	/* queue call to dasd_kick_device to the kernel event daemon. */
478 	schedule_work(&device->kick_work);
479 }
480 
481 /*
482  * Set the target state for a device and starts the state change.
483  */
484 void dasd_set_target_state(struct dasd_device *device, int target)
485 {
486 	/* If we are in probeonly mode stop at DASD_STATE_READY. */
487 	if (dasd_probeonly && target > DASD_STATE_READY)
488 		target = DASD_STATE_READY;
489 	if (device->target != target) {
490                 if (device->state == target)
491 			wake_up(&dasd_init_waitq);
492 		device->target = target;
493 	}
494 	if (device->state != device->target)
495 		dasd_change_state(device);
496 }
497 
498 /*
499  * Enable devices with device numbers in [from..to].
500  */
501 static inline int _wait_for_device(struct dasd_device *device)
502 {
503 	return (device->state == device->target);
504 }
505 
506 void dasd_enable_device(struct dasd_device *device)
507 {
508 	dasd_set_target_state(device, DASD_STATE_ONLINE);
509 	if (device->state <= DASD_STATE_KNOWN)
510 		/* No discipline for device found. */
511 		dasd_set_target_state(device, DASD_STATE_NEW);
512 	/* Now wait for the devices to come up. */
513 	wait_event(dasd_init_waitq, _wait_for_device(device));
514 }
515 
516 /*
517  * SECTION: device operation (interrupt handler, start i/o, term i/o ...)
518  */
519 #ifdef CONFIG_DASD_PROFILE
520 
521 struct dasd_profile_info_t dasd_global_profile;
522 unsigned int dasd_profile_level = DASD_PROFILE_OFF;
523 
524 /*
525  * Increments counter in global and local profiling structures.
526  */
527 #define dasd_profile_counter(value, counter, block) \
528 { \
529 	int index; \
530 	for (index = 0; index < 31 && value >> (2+index); index++); \
531 	dasd_global_profile.counter[index]++; \
532 	block->profile.counter[index]++; \
533 }
534 
535 /*
536  * Add profiling information for cqr before execution.
537  */
538 static void dasd_profile_start(struct dasd_block *block,
539 			       struct dasd_ccw_req *cqr,
540 			       struct request *req)
541 {
542 	struct list_head *l;
543 	unsigned int counter;
544 
545 	if (dasd_profile_level != DASD_PROFILE_ON)
546 		return;
547 
548 	/* count the length of the chanq for statistics */
549 	counter = 0;
550 	list_for_each(l, &block->ccw_queue)
551 		if (++counter >= 31)
552 			break;
553 	dasd_global_profile.dasd_io_nr_req[counter]++;
554 	block->profile.dasd_io_nr_req[counter]++;
555 }
556 
557 /*
558  * Add profiling information for cqr after execution.
559  */
560 static void dasd_profile_end(struct dasd_block *block,
561 			     struct dasd_ccw_req *cqr,
562 			     struct request *req)
563 {
564 	long strtime, irqtime, endtime, tottime;	/* in microseconds */
565 	long tottimeps, sectors;
566 
567 	if (dasd_profile_level != DASD_PROFILE_ON)
568 		return;
569 
570 	sectors = req->nr_sectors;
571 	if (!cqr->buildclk || !cqr->startclk ||
572 	    !cqr->stopclk || !cqr->endclk ||
573 	    !sectors)
574 		return;
575 
576 	strtime = ((cqr->startclk - cqr->buildclk) >> 12);
577 	irqtime = ((cqr->stopclk - cqr->startclk) >> 12);
578 	endtime = ((cqr->endclk - cqr->stopclk) >> 12);
579 	tottime = ((cqr->endclk - cqr->buildclk) >> 12);
580 	tottimeps = tottime / sectors;
581 
582 	if (!dasd_global_profile.dasd_io_reqs)
583 		memset(&dasd_global_profile, 0,
584 		       sizeof(struct dasd_profile_info_t));
585 	dasd_global_profile.dasd_io_reqs++;
586 	dasd_global_profile.dasd_io_sects += sectors;
587 
588 	if (!block->profile.dasd_io_reqs)
589 		memset(&block->profile, 0,
590 		       sizeof(struct dasd_profile_info_t));
591 	block->profile.dasd_io_reqs++;
592 	block->profile.dasd_io_sects += sectors;
593 
594 	dasd_profile_counter(sectors, dasd_io_secs, block);
595 	dasd_profile_counter(tottime, dasd_io_times, block);
596 	dasd_profile_counter(tottimeps, dasd_io_timps, block);
597 	dasd_profile_counter(strtime, dasd_io_time1, block);
598 	dasd_profile_counter(irqtime, dasd_io_time2, block);
599 	dasd_profile_counter(irqtime / sectors, dasd_io_time2ps, block);
600 	dasd_profile_counter(endtime, dasd_io_time3, block);
601 }
602 #else
603 #define dasd_profile_start(block, cqr, req) do {} while (0)
604 #define dasd_profile_end(block, cqr, req) do {} while (0)
605 #endif				/* CONFIG_DASD_PROFILE */
606 
607 /*
608  * Allocate memory for a channel program with 'cplength' channel
609  * command words and 'datasize' additional space. There are two
610  * variantes: 1) dasd_kmalloc_request uses kmalloc to get the needed
611  * memory and 2) dasd_smalloc_request uses the static ccw memory
612  * that gets allocated for each device.
613  */
614 struct dasd_ccw_req *dasd_kmalloc_request(char *magic, int cplength,
615 					  int datasize,
616 					  struct dasd_device *device)
617 {
618 	struct dasd_ccw_req *cqr;
619 
620 	/* Sanity checks */
621 	BUG_ON( magic == NULL || datasize > PAGE_SIZE ||
622 	     (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
623 
624 	cqr = kzalloc(sizeof(struct dasd_ccw_req), GFP_ATOMIC);
625 	if (cqr == NULL)
626 		return ERR_PTR(-ENOMEM);
627 	cqr->cpaddr = NULL;
628 	if (cplength > 0) {
629 		cqr->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
630 				      GFP_ATOMIC | GFP_DMA);
631 		if (cqr->cpaddr == NULL) {
632 			kfree(cqr);
633 			return ERR_PTR(-ENOMEM);
634 		}
635 	}
636 	cqr->data = NULL;
637 	if (datasize > 0) {
638 		cqr->data = kzalloc(datasize, GFP_ATOMIC | GFP_DMA);
639 		if (cqr->data == NULL) {
640 			kfree(cqr->cpaddr);
641 			kfree(cqr);
642 			return ERR_PTR(-ENOMEM);
643 		}
644 	}
645 	strncpy((char *) &cqr->magic, magic, 4);
646 	ASCEBC((char *) &cqr->magic, 4);
647 	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
648 	dasd_get_device(device);
649 	return cqr;
650 }
651 
652 struct dasd_ccw_req *dasd_smalloc_request(char *magic, int cplength,
653 					  int datasize,
654 					  struct dasd_device *device)
655 {
656 	unsigned long flags;
657 	struct dasd_ccw_req *cqr;
658 	char *data;
659 	int size;
660 
661 	/* Sanity checks */
662 	BUG_ON( magic == NULL || datasize > PAGE_SIZE ||
663 	     (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
664 
665 	size = (sizeof(struct dasd_ccw_req) + 7L) & -8L;
666 	if (cplength > 0)
667 		size += cplength * sizeof(struct ccw1);
668 	if (datasize > 0)
669 		size += datasize;
670 	spin_lock_irqsave(&device->mem_lock, flags);
671 	cqr = (struct dasd_ccw_req *)
672 		dasd_alloc_chunk(&device->ccw_chunks, size);
673 	spin_unlock_irqrestore(&device->mem_lock, flags);
674 	if (cqr == NULL)
675 		return ERR_PTR(-ENOMEM);
676 	memset(cqr, 0, sizeof(struct dasd_ccw_req));
677 	data = (char *) cqr + ((sizeof(struct dasd_ccw_req) + 7L) & -8L);
678 	cqr->cpaddr = NULL;
679 	if (cplength > 0) {
680 		cqr->cpaddr = (struct ccw1 *) data;
681 		data += cplength*sizeof(struct ccw1);
682 		memset(cqr->cpaddr, 0, cplength*sizeof(struct ccw1));
683 	}
684 	cqr->data = NULL;
685 	if (datasize > 0) {
686 		cqr->data = data;
687  		memset(cqr->data, 0, datasize);
688 	}
689 	strncpy((char *) &cqr->magic, magic, 4);
690 	ASCEBC((char *) &cqr->magic, 4);
691 	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
692 	dasd_get_device(device);
693 	return cqr;
694 }
695 
696 /*
697  * Free memory of a channel program. This function needs to free all the
698  * idal lists that might have been created by dasd_set_cda and the
699  * struct dasd_ccw_req itself.
700  */
701 void dasd_kfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
702 {
703 #ifdef CONFIG_64BIT
704 	struct ccw1 *ccw;
705 
706 	/* Clear any idals used for the request. */
707 	ccw = cqr->cpaddr;
708 	do {
709 		clear_normalized_cda(ccw);
710 	} while (ccw++->flags & (CCW_FLAG_CC | CCW_FLAG_DC));
711 #endif
712 	kfree(cqr->cpaddr);
713 	kfree(cqr->data);
714 	kfree(cqr);
715 	dasd_put_device(device);
716 }
717 
718 void dasd_sfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
719 {
720 	unsigned long flags;
721 
722 	spin_lock_irqsave(&device->mem_lock, flags);
723 	dasd_free_chunk(&device->ccw_chunks, cqr);
724 	spin_unlock_irqrestore(&device->mem_lock, flags);
725 	dasd_put_device(device);
726 }
727 
728 /*
729  * Check discipline magic in cqr.
730  */
731 static inline int dasd_check_cqr(struct dasd_ccw_req *cqr)
732 {
733 	struct dasd_device *device;
734 
735 	if (cqr == NULL)
736 		return -EINVAL;
737 	device = cqr->startdev;
738 	if (strncmp((char *) &cqr->magic, device->discipline->ebcname, 4)) {
739 		DEV_MESSAGE(KERN_WARNING, device,
740 			    " dasd_ccw_req 0x%08x magic doesn't match"
741 			    " discipline 0x%08x",
742 			    cqr->magic,
743 			    *(unsigned int *) device->discipline->name);
744 		return -EINVAL;
745 	}
746 	return 0;
747 }
748 
749 /*
750  * Terminate the current i/o and set the request to clear_pending.
751  * Timer keeps device runnig.
752  * ccw_device_clear can fail if the i/o subsystem
753  * is in a bad mood.
754  */
755 int dasd_term_IO(struct dasd_ccw_req *cqr)
756 {
757 	struct dasd_device *device;
758 	int retries, rc;
759 
760 	/* Check the cqr */
761 	rc = dasd_check_cqr(cqr);
762 	if (rc)
763 		return rc;
764 	retries = 0;
765 	device = (struct dasd_device *) cqr->startdev;
766 	while ((retries < 5) && (cqr->status == DASD_CQR_IN_IO)) {
767 		rc = ccw_device_clear(device->cdev, (long) cqr);
768 		switch (rc) {
769 		case 0:	/* termination successful */
770 			cqr->retries--;
771 			cqr->status = DASD_CQR_CLEAR_PENDING;
772 			cqr->stopclk = get_clock();
773 			cqr->starttime = 0;
774 			DBF_DEV_EVENT(DBF_DEBUG, device,
775 				      "terminate cqr %p successful",
776 				      cqr);
777 			break;
778 		case -ENODEV:
779 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
780 				      "device gone, retry");
781 			break;
782 		case -EIO:
783 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
784 				      "I/O error, retry");
785 			break;
786 		case -EINVAL:
787 		case -EBUSY:
788 			DBF_DEV_EVENT(DBF_ERR, device, "%s",
789 				      "device busy, retry later");
790 			break;
791 		default:
792 			DEV_MESSAGE(KERN_ERR, device,
793 				    "line %d unknown RC=%d, please "
794 				    "report to linux390@de.ibm.com",
795 				    __LINE__, rc);
796 			BUG();
797 			break;
798 		}
799 		retries++;
800 	}
801 	dasd_schedule_device_bh(device);
802 	return rc;
803 }
804 
805 /*
806  * Start the i/o. This start_IO can fail if the channel is really busy.
807  * In that case set up a timer to start the request later.
808  */
809 int dasd_start_IO(struct dasd_ccw_req *cqr)
810 {
811 	struct dasd_device *device;
812 	int rc;
813 
814 	/* Check the cqr */
815 	rc = dasd_check_cqr(cqr);
816 	if (rc)
817 		return rc;
818 	device = (struct dasd_device *) cqr->startdev;
819 	if (cqr->retries < 0) {
820 		DEV_MESSAGE(KERN_DEBUG, device,
821 			    "start_IO: request %p (%02x/%i) - no retry left.",
822 			    cqr, cqr->status, cqr->retries);
823 		cqr->status = DASD_CQR_ERROR;
824 		return -EIO;
825 	}
826 	cqr->startclk = get_clock();
827 	cqr->starttime = jiffies;
828 	cqr->retries--;
829 	rc = ccw_device_start(device->cdev, cqr->cpaddr, (long) cqr,
830 			      cqr->lpm, 0);
831 	switch (rc) {
832 	case 0:
833 		cqr->status = DASD_CQR_IN_IO;
834 		DBF_DEV_EVENT(DBF_DEBUG, device,
835 			      "start_IO: request %p started successful",
836 			      cqr);
837 		break;
838 	case -EBUSY:
839 		DBF_DEV_EVENT(DBF_ERR, device, "%s",
840 			      "start_IO: device busy, retry later");
841 		break;
842 	case -ETIMEDOUT:
843 		DBF_DEV_EVENT(DBF_ERR, device, "%s",
844 			      "start_IO: request timeout, retry later");
845 		break;
846 	case -EACCES:
847 		/* -EACCES indicates that the request used only a
848 		 * subset of the available pathes and all these
849 		 * pathes are gone.
850 		 * Do a retry with all available pathes.
851 		 */
852 		cqr->lpm = LPM_ANYPATH;
853 		DBF_DEV_EVENT(DBF_ERR, device, "%s",
854 			      "start_IO: selected pathes gone,"
855 			      " retry on all pathes");
856 		break;
857 	case -ENODEV:
858 	case -EIO:
859 		DBF_DEV_EVENT(DBF_ERR, device, "%s",
860 			      "start_IO: device gone, retry");
861 		break;
862 	default:
863 		DEV_MESSAGE(KERN_ERR, device,
864 			    "line %d unknown RC=%d, please report"
865 			    " to linux390@de.ibm.com", __LINE__, rc);
866 		BUG();
867 		break;
868 	}
869 	return rc;
870 }
871 
872 /*
873  * Timeout function for dasd devices. This is used for different purposes
874  *  1) missing interrupt handler for normal operation
875  *  2) delayed start of request where start_IO failed with -EBUSY
876  *  3) timeout for missing state change interrupts
877  * The head of the ccw queue will have status DASD_CQR_IN_IO for 1),
878  * DASD_CQR_QUEUED for 2) and 3).
879  */
880 static void dasd_device_timeout(unsigned long ptr)
881 {
882 	unsigned long flags;
883 	struct dasd_device *device;
884 
885 	device = (struct dasd_device *) ptr;
886 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
887 	/* re-activate request queue */
888         device->stopped &= ~DASD_STOPPED_PENDING;
889 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
890 	dasd_schedule_device_bh(device);
891 }
892 
893 /*
894  * Setup timeout for a device in jiffies.
895  */
896 void dasd_device_set_timer(struct dasd_device *device, int expires)
897 {
898 	if (expires == 0) {
899 		if (timer_pending(&device->timer))
900 			del_timer(&device->timer);
901 		return;
902 	}
903 	if (timer_pending(&device->timer)) {
904 		if (mod_timer(&device->timer, jiffies + expires))
905 			return;
906 	}
907 	device->timer.function = dasd_device_timeout;
908 	device->timer.data = (unsigned long) device;
909 	device->timer.expires = jiffies + expires;
910 	add_timer(&device->timer);
911 }
912 
913 /*
914  * Clear timeout for a device.
915  */
916 void dasd_device_clear_timer(struct dasd_device *device)
917 {
918 	if (timer_pending(&device->timer))
919 		del_timer(&device->timer);
920 }
921 
922 static void dasd_handle_killed_request(struct ccw_device *cdev,
923 				       unsigned long intparm)
924 {
925 	struct dasd_ccw_req *cqr;
926 	struct dasd_device *device;
927 
928 	cqr = (struct dasd_ccw_req *) intparm;
929 	if (cqr->status != DASD_CQR_IN_IO) {
930 		MESSAGE(KERN_DEBUG,
931 			"invalid status in handle_killed_request: "
932 			"bus_id %s, status %02x",
933 			cdev->dev.bus_id, cqr->status);
934 		return;
935 	}
936 
937 	device = (struct dasd_device *) cqr->startdev;
938 	if (device == NULL ||
939 	    device != dasd_device_from_cdev_locked(cdev) ||
940 	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
941 		MESSAGE(KERN_DEBUG, "invalid device in request: bus_id %s",
942 			cdev->dev.bus_id);
943 		return;
944 	}
945 
946 	/* Schedule request to be retried. */
947 	cqr->status = DASD_CQR_QUEUED;
948 
949 	dasd_device_clear_timer(device);
950 	dasd_schedule_device_bh(device);
951 	dasd_put_device(device);
952 }
953 
954 void dasd_generic_handle_state_change(struct dasd_device *device)
955 {
956 	/* First of all start sense subsystem status request. */
957 	dasd_eer_snss(device);
958 
959 	device->stopped &= ~DASD_STOPPED_PENDING;
960 	dasd_schedule_device_bh(device);
961 	if (device->block)
962 		dasd_schedule_block_bh(device->block);
963 }
964 
965 /*
966  * Interrupt handler for "normal" ssch-io based dasd devices.
967  */
968 void dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
969 		      struct irb *irb)
970 {
971 	struct dasd_ccw_req *cqr, *next;
972 	struct dasd_device *device;
973 	unsigned long long now;
974 	int expires;
975 
976 	if (IS_ERR(irb)) {
977 		switch (PTR_ERR(irb)) {
978 		case -EIO:
979 			dasd_handle_killed_request(cdev, intparm);
980 			break;
981 		case -ETIMEDOUT:
982 			printk(KERN_WARNING"%s(%s): request timed out\n",
983 			       __FUNCTION__, cdev->dev.bus_id);
984 			//FIXME - dasd uses own timeout interface...
985 			break;
986 		default:
987 			printk(KERN_WARNING"%s(%s): unknown error %ld\n",
988 			       __FUNCTION__, cdev->dev.bus_id, PTR_ERR(irb));
989 		}
990 		return;
991 	}
992 
993 	now = get_clock();
994 
995 	DBF_EVENT(DBF_ERR, "Interrupt: bus_id %s CS/DS %04x ip %08x",
996 		  cdev->dev.bus_id, ((irb->scsw.cstat<<8)|irb->scsw.dstat),
997 		  (unsigned int) intparm);
998 
999 	/* check for unsolicited interrupts */
1000 	cqr = (struct dasd_ccw_req *) intparm;
1001 	if (!cqr || ((irb->scsw.cc == 1) &&
1002 		     (irb->scsw.fctl & SCSW_FCTL_START_FUNC) &&
1003 		     (irb->scsw.stctl & SCSW_STCTL_STATUS_PEND)) ) {
1004 		if (cqr && cqr->status == DASD_CQR_IN_IO)
1005 			cqr->status = DASD_CQR_QUEUED;
1006 		device = dasd_device_from_cdev_locked(cdev);
1007 		if (!IS_ERR(device)) {
1008 			dasd_device_clear_timer(device);
1009 			device->discipline->handle_unsolicited_interrupt(device,
1010 									 irb);
1011 			dasd_put_device(device);
1012 		}
1013 		return;
1014 	}
1015 
1016 	device = (struct dasd_device *) cqr->startdev;
1017 	if (!device ||
1018 	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
1019 		MESSAGE(KERN_DEBUG, "invalid device in request: bus_id %s",
1020 			cdev->dev.bus_id);
1021 		return;
1022 	}
1023 
1024 	/* Check for clear pending */
1025 	if (cqr->status == DASD_CQR_CLEAR_PENDING &&
1026 	    irb->scsw.fctl & SCSW_FCTL_CLEAR_FUNC) {
1027 		cqr->status = DASD_CQR_CLEARED;
1028 		dasd_device_clear_timer(device);
1029 		wake_up(&dasd_flush_wq);
1030 		dasd_schedule_device_bh(device);
1031 		return;
1032 	}
1033 
1034  	/* check status - the request might have been killed by dyn detach */
1035 	if (cqr->status != DASD_CQR_IN_IO) {
1036 		MESSAGE(KERN_DEBUG,
1037 			"invalid status: bus_id %s, status %02x",
1038 			cdev->dev.bus_id, cqr->status);
1039 		return;
1040 	}
1041 	DBF_DEV_EVENT(DBF_DEBUG, device, "Int: CS/DS 0x%04x for cqr %p",
1042 		      ((irb->scsw.cstat << 8) | irb->scsw.dstat), cqr);
1043 	next = NULL;
1044 	expires = 0;
1045 	if (irb->scsw.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
1046 	    irb->scsw.cstat == 0 && !irb->esw.esw0.erw.cons) {
1047 		/* request was completed successfully */
1048 		cqr->status = DASD_CQR_SUCCESS;
1049 		cqr->stopclk = now;
1050 		/* Start first request on queue if possible -> fast_io. */
1051 		if (cqr->devlist.next != &device->ccw_queue) {
1052 			next = list_entry(cqr->devlist.next,
1053 					  struct dasd_ccw_req, devlist);
1054 		}
1055 	} else {  /* error */
1056 		memcpy(&cqr->irb, irb, sizeof(struct irb));
1057 		if (device->features & DASD_FEATURE_ERPLOG) {
1058 			dasd_log_sense(cqr, irb);
1059 		}
1060 		/* If we have no sense data, or we just don't want complex ERP
1061 		 * for this request, but if we have retries left, then just
1062 		 * reset this request and retry it in the fastpath
1063 		 */
1064 		if (!(cqr->irb.esw.esw0.erw.cons &&
1065 		      test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) &&
1066 		    cqr->retries > 0) {
1067 			DEV_MESSAGE(KERN_DEBUG, device,
1068 				    "default ERP in fastpath (%i retries left)",
1069 				    cqr->retries);
1070 			cqr->lpm    = LPM_ANYPATH;
1071 			cqr->status = DASD_CQR_QUEUED;
1072 			next = cqr;
1073 		} else
1074 			cqr->status = DASD_CQR_ERROR;
1075 	}
1076 	if (next && (next->status == DASD_CQR_QUEUED) &&
1077 	    (!device->stopped)) {
1078 		if (device->discipline->start_IO(next) == 0)
1079 			expires = next->expires;
1080 		else
1081 			DEV_MESSAGE(KERN_DEBUG, device, "%s",
1082 				    "Interrupt fastpath "
1083 				    "failed!");
1084 	}
1085 	if (expires != 0)
1086 		dasd_device_set_timer(device, expires);
1087 	else
1088 		dasd_device_clear_timer(device);
1089 	dasd_schedule_device_bh(device);
1090 }
1091 
1092 /*
1093  * If we have an error on a dasd_block layer request then we cancel
1094  * and return all further requests from the same dasd_block as well.
1095  */
1096 static void __dasd_device_recovery(struct dasd_device *device,
1097 				   struct dasd_ccw_req *ref_cqr)
1098 {
1099 	struct list_head *l, *n;
1100 	struct dasd_ccw_req *cqr;
1101 
1102 	/*
1103 	 * only requeue request that came from the dasd_block layer
1104 	 */
1105 	if (!ref_cqr->block)
1106 		return;
1107 
1108 	list_for_each_safe(l, n, &device->ccw_queue) {
1109 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1110 		if (cqr->status == DASD_CQR_QUEUED &&
1111 		    ref_cqr->block == cqr->block) {
1112 			cqr->status = DASD_CQR_CLEARED;
1113 		}
1114 	}
1115 };
1116 
1117 /*
1118  * Remove those ccw requests from the queue that need to be returned
1119  * to the upper layer.
1120  */
1121 static void __dasd_device_process_ccw_queue(struct dasd_device *device,
1122 					    struct list_head *final_queue)
1123 {
1124 	struct list_head *l, *n;
1125 	struct dasd_ccw_req *cqr;
1126 
1127 	/* Process request with final status. */
1128 	list_for_each_safe(l, n, &device->ccw_queue) {
1129 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1130 
1131 		/* Stop list processing at the first non-final request. */
1132 		if (cqr->status == DASD_CQR_QUEUED ||
1133 		    cqr->status == DASD_CQR_IN_IO ||
1134 		    cqr->status == DASD_CQR_CLEAR_PENDING)
1135 			break;
1136 		if (cqr->status == DASD_CQR_ERROR) {
1137 			__dasd_device_recovery(device, cqr);
1138 		}
1139 		/* Rechain finished requests to final queue */
1140 		list_move_tail(&cqr->devlist, final_queue);
1141 	}
1142 }
1143 
1144 /*
1145  * the cqrs from the final queue are returned to the upper layer
1146  * by setting a dasd_block state and calling the callback function
1147  */
1148 static void __dasd_device_process_final_queue(struct dasd_device *device,
1149 					      struct list_head *final_queue)
1150 {
1151 	struct list_head *l, *n;
1152 	struct dasd_ccw_req *cqr;
1153 
1154 	list_for_each_safe(l, n, final_queue) {
1155 		cqr = list_entry(l, struct dasd_ccw_req, devlist);
1156 		list_del_init(&cqr->devlist);
1157 		if (cqr->block)
1158 			spin_lock_bh(&cqr->block->queue_lock);
1159 		switch (cqr->status) {
1160 		case DASD_CQR_SUCCESS:
1161 			cqr->status = DASD_CQR_DONE;
1162 			break;
1163 		case DASD_CQR_ERROR:
1164 			cqr->status = DASD_CQR_NEED_ERP;
1165 			break;
1166 		case DASD_CQR_CLEARED:
1167 			cqr->status = DASD_CQR_TERMINATED;
1168 			break;
1169 		default:
1170 			DEV_MESSAGE(KERN_ERR, device,
1171 				    "wrong cqr status in __dasd_process_final_queue "
1172 				    "for cqr %p, status %x",
1173 				    cqr, cqr->status);
1174 			BUG();
1175 		}
1176 		if (cqr->block)
1177 			spin_unlock_bh(&cqr->block->queue_lock);
1178 		if (cqr->callback != NULL)
1179 			(cqr->callback)(cqr, cqr->callback_data);
1180 	}
1181 }
1182 
1183 
1184 
1185 /*
1186  * Take a look at the first request on the ccw queue and check
1187  * if it reached its expire time. If so, terminate the IO.
1188  */
1189 static void __dasd_device_check_expire(struct dasd_device *device)
1190 {
1191 	struct dasd_ccw_req *cqr;
1192 
1193 	if (list_empty(&device->ccw_queue))
1194 		return;
1195 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1196 	if ((cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) &&
1197 	    (time_after_eq(jiffies, cqr->expires + cqr->starttime))) {
1198 		if (device->discipline->term_IO(cqr) != 0) {
1199 			/* Hmpf, try again in 5 sec */
1200 			dasd_device_set_timer(device, 5*HZ);
1201 			DEV_MESSAGE(KERN_ERR, device,
1202 				    "internal error - timeout (%is) expired "
1203 				    "for cqr %p, termination failed, "
1204 				    "retrying in 5s",
1205 				    (cqr->expires/HZ), cqr);
1206 		} else {
1207 			DEV_MESSAGE(KERN_ERR, device,
1208 				    "internal error - timeout (%is) expired "
1209 				    "for cqr %p (%i retries left)",
1210 				    (cqr->expires/HZ), cqr, cqr->retries);
1211 		}
1212 	}
1213 }
1214 
1215 /*
1216  * Take a look at the first request on the ccw queue and check
1217  * if it needs to be started.
1218  */
1219 static void __dasd_device_start_head(struct dasd_device *device)
1220 {
1221 	struct dasd_ccw_req *cqr;
1222 	int rc;
1223 
1224 	if (list_empty(&device->ccw_queue))
1225 		return;
1226 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1227 	if (cqr->status != DASD_CQR_QUEUED)
1228 		return;
1229 	/* when device is stopped, return request to previous layer */
1230 	if (device->stopped) {
1231 		cqr->status = DASD_CQR_CLEARED;
1232 		dasd_schedule_device_bh(device);
1233 		return;
1234 	}
1235 
1236 	rc = device->discipline->start_IO(cqr);
1237 	if (rc == 0)
1238 		dasd_device_set_timer(device, cqr->expires);
1239 	else if (rc == -EACCES) {
1240 		dasd_schedule_device_bh(device);
1241 	} else
1242 		/* Hmpf, try again in 1/2 sec */
1243 		dasd_device_set_timer(device, 50);
1244 }
1245 
1246 /*
1247  * Go through all request on the dasd_device request queue,
1248  * terminate them on the cdev if necessary, and return them to the
1249  * submitting layer via callback.
1250  * Note:
1251  * Make sure that all 'submitting layers' still exist when
1252  * this function is called!. In other words, when 'device' is a base
1253  * device then all block layer requests must have been removed before
1254  * via dasd_flush_block_queue.
1255  */
1256 int dasd_flush_device_queue(struct dasd_device *device)
1257 {
1258 	struct dasd_ccw_req *cqr, *n;
1259 	int rc;
1260 	struct list_head flush_queue;
1261 
1262 	INIT_LIST_HEAD(&flush_queue);
1263 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1264 	rc = 0;
1265 	list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
1266 		/* Check status and move request to flush_queue */
1267 		switch (cqr->status) {
1268 		case DASD_CQR_IN_IO:
1269 			rc = device->discipline->term_IO(cqr);
1270 			if (rc) {
1271 				/* unable to terminate requeust */
1272 				DEV_MESSAGE(KERN_ERR, device,
1273 					    "dasd flush ccw_queue is unable "
1274 					    " to terminate request %p",
1275 					    cqr);
1276 				/* stop flush processing */
1277 				goto finished;
1278 			}
1279 			break;
1280 		case DASD_CQR_QUEUED:
1281 			cqr->stopclk = get_clock();
1282 			cqr->status = DASD_CQR_CLEARED;
1283 			break;
1284 		default: /* no need to modify the others */
1285 			break;
1286 		}
1287 		list_move_tail(&cqr->devlist, &flush_queue);
1288 	}
1289 finished:
1290 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1291 	/*
1292 	 * After this point all requests must be in state CLEAR_PENDING,
1293 	 * CLEARED, SUCCESS or ERROR. Now wait for CLEAR_PENDING to become
1294 	 * one of the others.
1295 	 */
1296 	list_for_each_entry_safe(cqr, n, &flush_queue, devlist)
1297 		wait_event(dasd_flush_wq,
1298 			   (cqr->status != DASD_CQR_CLEAR_PENDING));
1299 	/*
1300 	 * Now set each request back to TERMINATED, DONE or NEED_ERP
1301 	 * and call the callback function of flushed requests
1302 	 */
1303 	__dasd_device_process_final_queue(device, &flush_queue);
1304 	return rc;
1305 }
1306 
1307 /*
1308  * Acquire the device lock and process queues for the device.
1309  */
1310 static void dasd_device_tasklet(struct dasd_device *device)
1311 {
1312 	struct list_head final_queue;
1313 
1314 	atomic_set (&device->tasklet_scheduled, 0);
1315 	INIT_LIST_HEAD(&final_queue);
1316 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1317 	/* Check expire time of first request on the ccw queue. */
1318 	__dasd_device_check_expire(device);
1319 	/* find final requests on ccw queue */
1320 	__dasd_device_process_ccw_queue(device, &final_queue);
1321 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1322 	/* Now call the callback function of requests with final status */
1323 	__dasd_device_process_final_queue(device, &final_queue);
1324 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1325 	/* Now check if the head of the ccw queue needs to be started. */
1326 	__dasd_device_start_head(device);
1327 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1328 	dasd_put_device(device);
1329 }
1330 
1331 /*
1332  * Schedules a call to dasd_tasklet over the device tasklet.
1333  */
1334 void dasd_schedule_device_bh(struct dasd_device *device)
1335 {
1336 	/* Protect against rescheduling. */
1337 	if (atomic_cmpxchg (&device->tasklet_scheduled, 0, 1) != 0)
1338 		return;
1339 	dasd_get_device(device);
1340 	tasklet_hi_schedule(&device->tasklet);
1341 }
1342 
1343 /*
1344  * Queue a request to the head of the device ccw_queue.
1345  * Start the I/O if possible.
1346  */
1347 void dasd_add_request_head(struct dasd_ccw_req *cqr)
1348 {
1349 	struct dasd_device *device;
1350 	unsigned long flags;
1351 
1352 	device = cqr->startdev;
1353 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
1354 	cqr->status = DASD_CQR_QUEUED;
1355 	list_add(&cqr->devlist, &device->ccw_queue);
1356 	/* let the bh start the request to keep them in order */
1357 	dasd_schedule_device_bh(device);
1358 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
1359 }
1360 
1361 /*
1362  * Queue a request to the tail of the device ccw_queue.
1363  * Start the I/O if possible.
1364  */
1365 void dasd_add_request_tail(struct dasd_ccw_req *cqr)
1366 {
1367 	struct dasd_device *device;
1368 	unsigned long flags;
1369 
1370 	device = cqr->startdev;
1371 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
1372 	cqr->status = DASD_CQR_QUEUED;
1373 	list_add_tail(&cqr->devlist, &device->ccw_queue);
1374 	/* let the bh start the request to keep them in order */
1375 	dasd_schedule_device_bh(device);
1376 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
1377 }
1378 
1379 /*
1380  * Wakeup helper for the 'sleep_on' functions.
1381  */
1382 static void dasd_wakeup_cb(struct dasd_ccw_req *cqr, void *data)
1383 {
1384 	wake_up((wait_queue_head_t *) data);
1385 }
1386 
1387 static inline int _wait_for_wakeup(struct dasd_ccw_req *cqr)
1388 {
1389 	struct dasd_device *device;
1390 	int rc;
1391 
1392 	device = cqr->startdev;
1393 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1394 	rc = ((cqr->status == DASD_CQR_DONE ||
1395 	       cqr->status == DASD_CQR_NEED_ERP ||
1396 	       cqr->status == DASD_CQR_TERMINATED) &&
1397 	      list_empty(&cqr->devlist));
1398 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1399 	return rc;
1400 }
1401 
1402 /*
1403  * Queue a request to the tail of the device ccw_queue and wait for
1404  * it's completion.
1405  */
1406 int dasd_sleep_on(struct dasd_ccw_req *cqr)
1407 {
1408 	wait_queue_head_t wait_q;
1409 	struct dasd_device *device;
1410 	int rc;
1411 
1412 	device = cqr->startdev;
1413 
1414 	init_waitqueue_head (&wait_q);
1415 	cqr->callback = dasd_wakeup_cb;
1416 	cqr->callback_data = (void *) &wait_q;
1417 	dasd_add_request_tail(cqr);
1418 	wait_event(wait_q, _wait_for_wakeup(cqr));
1419 
1420 	/* Request status is either done or failed. */
1421 	rc = (cqr->status == DASD_CQR_DONE) ? 0 : -EIO;
1422 	return rc;
1423 }
1424 
1425 /*
1426  * Queue a request to the tail of the device ccw_queue and wait
1427  * interruptible for it's completion.
1428  */
1429 int dasd_sleep_on_interruptible(struct dasd_ccw_req *cqr)
1430 {
1431 	wait_queue_head_t wait_q;
1432 	struct dasd_device *device;
1433 	int rc;
1434 
1435 	device = cqr->startdev;
1436 	init_waitqueue_head (&wait_q);
1437 	cqr->callback = dasd_wakeup_cb;
1438 	cqr->callback_data = (void *) &wait_q;
1439 	dasd_add_request_tail(cqr);
1440 	rc = wait_event_interruptible(wait_q, _wait_for_wakeup(cqr));
1441 	if (rc == -ERESTARTSYS) {
1442 		dasd_cancel_req(cqr);
1443 		/* wait (non-interruptible) for final status */
1444 		wait_event(wait_q, _wait_for_wakeup(cqr));
1445 	}
1446 	rc = (cqr->status == DASD_CQR_DONE) ? 0 : -EIO;
1447 	return rc;
1448 }
1449 
1450 /*
1451  * Whoa nelly now it gets really hairy. For some functions (e.g. steal lock
1452  * for eckd devices) the currently running request has to be terminated
1453  * and be put back to status queued, before the special request is added
1454  * to the head of the queue. Then the special request is waited on normally.
1455  */
1456 static inline int _dasd_term_running_cqr(struct dasd_device *device)
1457 {
1458 	struct dasd_ccw_req *cqr;
1459 
1460 	if (list_empty(&device->ccw_queue))
1461 		return 0;
1462 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
1463 	return device->discipline->term_IO(cqr);
1464 }
1465 
1466 int dasd_sleep_on_immediatly(struct dasd_ccw_req *cqr)
1467 {
1468 	wait_queue_head_t wait_q;
1469 	struct dasd_device *device;
1470 	int rc;
1471 
1472 	device = cqr->startdev;
1473 	spin_lock_irq(get_ccwdev_lock(device->cdev));
1474 	rc = _dasd_term_running_cqr(device);
1475 	if (rc) {
1476 		spin_unlock_irq(get_ccwdev_lock(device->cdev));
1477 		return rc;
1478 	}
1479 
1480 	init_waitqueue_head (&wait_q);
1481 	cqr->callback = dasd_wakeup_cb;
1482 	cqr->callback_data = (void *) &wait_q;
1483 	cqr->status = DASD_CQR_QUEUED;
1484 	list_add(&cqr->devlist, &device->ccw_queue);
1485 
1486 	/* let the bh start the request to keep them in order */
1487 	dasd_schedule_device_bh(device);
1488 
1489 	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1490 
1491 	wait_event(wait_q, _wait_for_wakeup(cqr));
1492 
1493 	/* Request status is either done or failed. */
1494 	rc = (cqr->status == DASD_CQR_DONE) ? 0 : -EIO;
1495 	return rc;
1496 }
1497 
1498 /*
1499  * Cancels a request that was started with dasd_sleep_on_req.
1500  * This is useful to timeout requests. The request will be
1501  * terminated if it is currently in i/o.
1502  * Returns 1 if the request has been terminated.
1503  *	   0 if there was no need to terminate the request (not started yet)
1504  *	   negative error code if termination failed
1505  * Cancellation of a request is an asynchronous operation! The calling
1506  * function has to wait until the request is properly returned via callback.
1507  */
1508 int dasd_cancel_req(struct dasd_ccw_req *cqr)
1509 {
1510 	struct dasd_device *device = cqr->startdev;
1511 	unsigned long flags;
1512 	int rc;
1513 
1514 	rc = 0;
1515 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
1516 	switch (cqr->status) {
1517 	case DASD_CQR_QUEUED:
1518 		/* request was not started - just set to cleared */
1519 		cqr->status = DASD_CQR_CLEARED;
1520 		break;
1521 	case DASD_CQR_IN_IO:
1522 		/* request in IO - terminate IO and release again */
1523 		rc = device->discipline->term_IO(cqr);
1524 		if (rc) {
1525 			DEV_MESSAGE(KERN_ERR, device,
1526 				    "dasd_cancel_req is unable "
1527 				    " to terminate request %p, rc = %d",
1528 				    cqr, rc);
1529 		} else {
1530 			cqr->stopclk = get_clock();
1531 			rc = 1;
1532 		}
1533 		break;
1534 	default: /* already finished or clear pending - do nothing */
1535 		break;
1536 	}
1537 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
1538 	dasd_schedule_device_bh(device);
1539 	return rc;
1540 }
1541 
1542 
1543 /*
1544  * SECTION: Operations of the dasd_block layer.
1545  */
1546 
1547 /*
1548  * Timeout function for dasd_block. This is used when the block layer
1549  * is waiting for something that may not come reliably, (e.g. a state
1550  * change interrupt)
1551  */
1552 static void dasd_block_timeout(unsigned long ptr)
1553 {
1554 	unsigned long flags;
1555 	struct dasd_block *block;
1556 
1557 	block = (struct dasd_block *) ptr;
1558 	spin_lock_irqsave(get_ccwdev_lock(block->base->cdev), flags);
1559 	/* re-activate request queue */
1560 	block->base->stopped &= ~DASD_STOPPED_PENDING;
1561 	spin_unlock_irqrestore(get_ccwdev_lock(block->base->cdev), flags);
1562 	dasd_schedule_block_bh(block);
1563 }
1564 
1565 /*
1566  * Setup timeout for a dasd_block in jiffies.
1567  */
1568 void dasd_block_set_timer(struct dasd_block *block, int expires)
1569 {
1570 	if (expires == 0) {
1571 		if (timer_pending(&block->timer))
1572 			del_timer(&block->timer);
1573 		return;
1574 	}
1575 	if (timer_pending(&block->timer)) {
1576 		if (mod_timer(&block->timer, jiffies + expires))
1577 			return;
1578 	}
1579 	block->timer.function = dasd_block_timeout;
1580 	block->timer.data = (unsigned long) block;
1581 	block->timer.expires = jiffies + expires;
1582 	add_timer(&block->timer);
1583 }
1584 
1585 /*
1586  * Clear timeout for a dasd_block.
1587  */
1588 void dasd_block_clear_timer(struct dasd_block *block)
1589 {
1590 	if (timer_pending(&block->timer))
1591 		del_timer(&block->timer);
1592 }
1593 
1594 /*
1595  * posts the buffer_cache about a finalized request
1596  */
1597 static inline void dasd_end_request(struct request *req, int uptodate)
1598 {
1599 	if (end_that_request_first(req, uptodate, req->hard_nr_sectors))
1600 		BUG();
1601 	add_disk_randomness(req->rq_disk);
1602 	end_that_request_last(req, uptodate);
1603 }
1604 
1605 /*
1606  * Process finished error recovery ccw.
1607  */
1608 static inline void __dasd_block_process_erp(struct dasd_block *block,
1609 					    struct dasd_ccw_req *cqr)
1610 {
1611 	dasd_erp_fn_t erp_fn;
1612 	struct dasd_device *device = block->base;
1613 
1614 	if (cqr->status == DASD_CQR_DONE)
1615 		DBF_DEV_EVENT(DBF_NOTICE, device, "%s", "ERP successful");
1616 	else
1617 		DEV_MESSAGE(KERN_ERR, device, "%s", "ERP unsuccessful");
1618 	erp_fn = device->discipline->erp_postaction(cqr);
1619 	erp_fn(cqr);
1620 }
1621 
1622 /*
1623  * Fetch requests from the block device queue.
1624  */
1625 static void __dasd_process_request_queue(struct dasd_block *block)
1626 {
1627 	struct request_queue *queue;
1628 	struct request *req;
1629 	struct dasd_ccw_req *cqr;
1630 	struct dasd_device *basedev;
1631 	unsigned long flags;
1632 	queue = block->request_queue;
1633 	basedev = block->base;
1634 	/* No queue ? Then there is nothing to do. */
1635 	if (queue == NULL)
1636 		return;
1637 
1638 	/*
1639 	 * We requeue request from the block device queue to the ccw
1640 	 * queue only in two states. In state DASD_STATE_READY the
1641 	 * partition detection is done and we need to requeue requests
1642 	 * for that. State DASD_STATE_ONLINE is normal block device
1643 	 * operation.
1644 	 */
1645 	if (basedev->state < DASD_STATE_READY)
1646 		return;
1647 	/* Now we try to fetch requests from the request queue */
1648 	while (!blk_queue_plugged(queue) &&
1649 	       elv_next_request(queue)) {
1650 
1651 		req = elv_next_request(queue);
1652 
1653 		if (basedev->features & DASD_FEATURE_READONLY &&
1654 		    rq_data_dir(req) == WRITE) {
1655 			DBF_DEV_EVENT(DBF_ERR, basedev,
1656 				      "Rejecting write request %p",
1657 				      req);
1658 			blkdev_dequeue_request(req);
1659 			dasd_end_request(req, 0);
1660 			continue;
1661 		}
1662 		cqr = basedev->discipline->build_cp(basedev, block, req);
1663 		if (IS_ERR(cqr)) {
1664 			if (PTR_ERR(cqr) == -EBUSY)
1665 				break;	/* normal end condition */
1666 			if (PTR_ERR(cqr) == -ENOMEM)
1667 				break;	/* terminate request queue loop */
1668 			if (PTR_ERR(cqr) == -EAGAIN) {
1669 				/*
1670 				 * The current request cannot be build right
1671 				 * now, we have to try later. If this request
1672 				 * is the head-of-queue we stop the device
1673 				 * for 1/2 second.
1674 				 */
1675 				if (!list_empty(&block->ccw_queue))
1676 					break;
1677 				spin_lock_irqsave(get_ccwdev_lock(basedev->cdev), flags);
1678 				basedev->stopped |= DASD_STOPPED_PENDING;
1679 				spin_unlock_irqrestore(get_ccwdev_lock(basedev->cdev), flags);
1680 				dasd_block_set_timer(block, HZ/2);
1681 				break;
1682 			}
1683 			DBF_DEV_EVENT(DBF_ERR, basedev,
1684 				      "CCW creation failed (rc=%ld) "
1685 				      "on request %p",
1686 				      PTR_ERR(cqr), req);
1687 			blkdev_dequeue_request(req);
1688 			dasd_end_request(req, 0);
1689 			continue;
1690 		}
1691 		/*
1692 		 *  Note: callback is set to dasd_return_cqr_cb in
1693 		 * __dasd_block_start_head to cover erp requests as well
1694 		 */
1695 		cqr->callback_data = (void *) req;
1696 		cqr->status = DASD_CQR_FILLED;
1697 		blkdev_dequeue_request(req);
1698 		list_add_tail(&cqr->blocklist, &block->ccw_queue);
1699 		dasd_profile_start(block, cqr, req);
1700 	}
1701 }
1702 
1703 static void __dasd_cleanup_cqr(struct dasd_ccw_req *cqr)
1704 {
1705 	struct request *req;
1706 	int status;
1707 
1708 	req = (struct request *) cqr->callback_data;
1709 	dasd_profile_end(cqr->block, cqr, req);
1710 	status = cqr->memdev->discipline->free_cp(cqr, req);
1711 	dasd_end_request(req, status);
1712 }
1713 
1714 /*
1715  * Process ccw request queue.
1716  */
1717 static void __dasd_process_block_ccw_queue(struct dasd_block *block,
1718 					   struct list_head *final_queue)
1719 {
1720 	struct list_head *l, *n;
1721 	struct dasd_ccw_req *cqr;
1722 	dasd_erp_fn_t erp_fn;
1723 	unsigned long flags;
1724 	struct dasd_device *base = block->base;
1725 
1726 restart:
1727 	/* Process request with final status. */
1728 	list_for_each_safe(l, n, &block->ccw_queue) {
1729 		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
1730 		if (cqr->status != DASD_CQR_DONE &&
1731 		    cqr->status != DASD_CQR_FAILED &&
1732 		    cqr->status != DASD_CQR_NEED_ERP &&
1733 		    cqr->status != DASD_CQR_TERMINATED)
1734 			continue;
1735 
1736 		if (cqr->status == DASD_CQR_TERMINATED) {
1737 			base->discipline->handle_terminated_request(cqr);
1738 			goto restart;
1739 		}
1740 
1741 		/*  Process requests that may be recovered */
1742 		if (cqr->status == DASD_CQR_NEED_ERP) {
1743 			if (cqr->irb.esw.esw0.erw.cons &&
1744 			    test_bit(DASD_CQR_FLAGS_USE_ERP,
1745 				     &cqr->flags)) {
1746 				erp_fn = base->discipline->erp_action(cqr);
1747 				erp_fn(cqr);
1748 			}
1749 			goto restart;
1750 		}
1751 
1752 		/* First of all call extended error reporting. */
1753 		if (dasd_eer_enabled(base) &&
1754 		    cqr->status == DASD_CQR_FAILED) {
1755 			dasd_eer_write(base, cqr, DASD_EER_FATALERROR);
1756 
1757 			/* restart request  */
1758 			cqr->status = DASD_CQR_FILLED;
1759 			cqr->retries = 255;
1760 			spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
1761 			base->stopped |= DASD_STOPPED_QUIESCE;
1762 			spin_unlock_irqrestore(get_ccwdev_lock(base->cdev),
1763 					       flags);
1764 			goto restart;
1765 		}
1766 
1767 		/* Process finished ERP request. */
1768 		if (cqr->refers) {
1769 			__dasd_block_process_erp(block, cqr);
1770 			goto restart;
1771 		}
1772 
1773 		/* Rechain finished requests to final queue */
1774 		cqr->endclk = get_clock();
1775 		list_move_tail(&cqr->blocklist, final_queue);
1776 	}
1777 }
1778 
1779 static void dasd_return_cqr_cb(struct dasd_ccw_req *cqr, void *data)
1780 {
1781 	dasd_schedule_block_bh(cqr->block);
1782 }
1783 
1784 static void __dasd_block_start_head(struct dasd_block *block)
1785 {
1786 	struct dasd_ccw_req *cqr;
1787 
1788 	if (list_empty(&block->ccw_queue))
1789 		return;
1790 	/* We allways begin with the first requests on the queue, as some
1791 	 * of previously started requests have to be enqueued on a
1792 	 * dasd_device again for error recovery.
1793 	 */
1794 	list_for_each_entry(cqr, &block->ccw_queue, blocklist) {
1795 		if (cqr->status != DASD_CQR_FILLED)
1796 			continue;
1797 		/* Non-temporary stop condition will trigger fail fast */
1798 		if (block->base->stopped & ~DASD_STOPPED_PENDING &&
1799 		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
1800 		    (!dasd_eer_enabled(block->base))) {
1801 			cqr->status = DASD_CQR_FAILED;
1802 			dasd_schedule_block_bh(block);
1803 			continue;
1804 		}
1805 		/* Don't try to start requests if device is stopped */
1806 		if (block->base->stopped)
1807 			return;
1808 
1809 		/* just a fail safe check, should not happen */
1810 		if (!cqr->startdev)
1811 			cqr->startdev = block->base;
1812 
1813 		/* make sure that the requests we submit find their way back */
1814 		cqr->callback = dasd_return_cqr_cb;
1815 
1816 		dasd_add_request_tail(cqr);
1817 	}
1818 }
1819 
1820 /*
1821  * Central dasd_block layer routine. Takes requests from the generic
1822  * block layer request queue, creates ccw requests, enqueues them on
1823  * a dasd_device and processes ccw requests that have been returned.
1824  */
1825 static void dasd_block_tasklet(struct dasd_block *block)
1826 {
1827 	struct list_head final_queue;
1828 	struct list_head *l, *n;
1829 	struct dasd_ccw_req *cqr;
1830 
1831 	atomic_set(&block->tasklet_scheduled, 0);
1832 	INIT_LIST_HEAD(&final_queue);
1833 	spin_lock(&block->queue_lock);
1834 	/* Finish off requests on ccw queue */
1835 	__dasd_process_block_ccw_queue(block, &final_queue);
1836 	spin_unlock(&block->queue_lock);
1837 	/* Now call the callback function of requests with final status */
1838 	spin_lock_irq(&block->request_queue_lock);
1839 	list_for_each_safe(l, n, &final_queue) {
1840 		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
1841 		list_del_init(&cqr->blocklist);
1842 		__dasd_cleanup_cqr(cqr);
1843 	}
1844 	spin_lock(&block->queue_lock);
1845 	/* Get new request from the block device request queue */
1846 	__dasd_process_request_queue(block);
1847 	/* Now check if the head of the ccw queue needs to be started. */
1848 	__dasd_block_start_head(block);
1849 	spin_unlock(&block->queue_lock);
1850 	spin_unlock_irq(&block->request_queue_lock);
1851 	dasd_put_device(block->base);
1852 }
1853 
1854 static void _dasd_wake_block_flush_cb(struct dasd_ccw_req *cqr, void *data)
1855 {
1856 	wake_up(&dasd_flush_wq);
1857 }
1858 
1859 /*
1860  * Go through all request on the dasd_block request queue, cancel them
1861  * on the respective dasd_device, and return them to the generic
1862  * block layer.
1863  */
1864 static int dasd_flush_block_queue(struct dasd_block *block)
1865 {
1866 	struct dasd_ccw_req *cqr, *n;
1867 	int rc, i;
1868 	struct list_head flush_queue;
1869 
1870 	INIT_LIST_HEAD(&flush_queue);
1871 	spin_lock_bh(&block->queue_lock);
1872 	rc = 0;
1873 restart:
1874 	list_for_each_entry_safe(cqr, n, &block->ccw_queue, blocklist) {
1875 		/* if this request currently owned by a dasd_device cancel it */
1876 		if (cqr->status >= DASD_CQR_QUEUED)
1877 			rc = dasd_cancel_req(cqr);
1878 		if (rc < 0)
1879 			break;
1880 		/* Rechain request (including erp chain) so it won't be
1881 		 * touched by the dasd_block_tasklet anymore.
1882 		 * Replace the callback so we notice when the request
1883 		 * is returned from the dasd_device layer.
1884 		 */
1885 		cqr->callback = _dasd_wake_block_flush_cb;
1886 		for (i = 0; cqr != NULL; cqr = cqr->refers, i++)
1887 			list_move_tail(&cqr->blocklist, &flush_queue);
1888 		if (i > 1)
1889 			/* moved more than one request - need to restart */
1890 			goto restart;
1891 	}
1892 	spin_unlock_bh(&block->queue_lock);
1893 	/* Now call the callback function of flushed requests */
1894 restart_cb:
1895 	list_for_each_entry_safe(cqr, n, &flush_queue, blocklist) {
1896 		wait_event(dasd_flush_wq, (cqr->status < DASD_CQR_QUEUED));
1897 		/* Process finished ERP request. */
1898 		if (cqr->refers) {
1899 			__dasd_block_process_erp(block, cqr);
1900 			/* restart list_for_xx loop since dasd_process_erp
1901 			 * might remove multiple elements */
1902 			goto restart_cb;
1903 		}
1904 		/* call the callback function */
1905 		cqr->endclk = get_clock();
1906 		list_del_init(&cqr->blocklist);
1907 		__dasd_cleanup_cqr(cqr);
1908 	}
1909 	return rc;
1910 }
1911 
1912 /*
1913  * Schedules a call to dasd_tasklet over the device tasklet.
1914  */
1915 void dasd_schedule_block_bh(struct dasd_block *block)
1916 {
1917 	/* Protect against rescheduling. */
1918 	if (atomic_cmpxchg(&block->tasklet_scheduled, 0, 1) != 0)
1919 		return;
1920 	/* life cycle of block is bound to it's base device */
1921 	dasd_get_device(block->base);
1922 	tasklet_hi_schedule(&block->tasklet);
1923 }
1924 
1925 
1926 /*
1927  * SECTION: external block device operations
1928  * (request queue handling, open, release, etc.)
1929  */
1930 
1931 /*
1932  * Dasd request queue function. Called from ll_rw_blk.c
1933  */
1934 static void do_dasd_request(struct request_queue *queue)
1935 {
1936 	struct dasd_block *block;
1937 
1938 	block = queue->queuedata;
1939 	spin_lock(&block->queue_lock);
1940 	/* Get new request from the block device request queue */
1941 	__dasd_process_request_queue(block);
1942 	/* Now check if the head of the ccw queue needs to be started. */
1943 	__dasd_block_start_head(block);
1944 	spin_unlock(&block->queue_lock);
1945 }
1946 
1947 /*
1948  * Allocate and initialize request queue and default I/O scheduler.
1949  */
1950 static int dasd_alloc_queue(struct dasd_block *block)
1951 {
1952 	int rc;
1953 
1954 	block->request_queue = blk_init_queue(do_dasd_request,
1955 					       &block->request_queue_lock);
1956 	if (block->request_queue == NULL)
1957 		return -ENOMEM;
1958 
1959 	block->request_queue->queuedata = block;
1960 
1961 	elevator_exit(block->request_queue->elevator);
1962 	rc = elevator_init(block->request_queue, "deadline");
1963 	if (rc) {
1964 		blk_cleanup_queue(block->request_queue);
1965 		return rc;
1966 	}
1967 	return 0;
1968 }
1969 
1970 /*
1971  * Allocate and initialize request queue.
1972  */
1973 static void dasd_setup_queue(struct dasd_block *block)
1974 {
1975 	int max;
1976 
1977 	blk_queue_hardsect_size(block->request_queue, block->bp_block);
1978 	max = block->base->discipline->max_blocks << block->s2b_shift;
1979 	blk_queue_max_sectors(block->request_queue, max);
1980 	blk_queue_max_phys_segments(block->request_queue, -1L);
1981 	blk_queue_max_hw_segments(block->request_queue, -1L);
1982 	blk_queue_max_segment_size(block->request_queue, -1L);
1983 	blk_queue_segment_boundary(block->request_queue, -1L);
1984 	blk_queue_ordered(block->request_queue, QUEUE_ORDERED_DRAIN, NULL);
1985 }
1986 
1987 /*
1988  * Deactivate and free request queue.
1989  */
1990 static void dasd_free_queue(struct dasd_block *block)
1991 {
1992 	if (block->request_queue) {
1993 		blk_cleanup_queue(block->request_queue);
1994 		block->request_queue = NULL;
1995 	}
1996 }
1997 
1998 /*
1999  * Flush request on the request queue.
2000  */
2001 static void dasd_flush_request_queue(struct dasd_block *block)
2002 {
2003 	struct request *req;
2004 
2005 	if (!block->request_queue)
2006 		return;
2007 
2008 	spin_lock_irq(&block->request_queue_lock);
2009 	while ((req = elv_next_request(block->request_queue))) {
2010 		blkdev_dequeue_request(req);
2011 		dasd_end_request(req, 0);
2012 	}
2013 	spin_unlock_irq(&block->request_queue_lock);
2014 }
2015 
2016 static int dasd_open(struct inode *inp, struct file *filp)
2017 {
2018 	struct gendisk *disk = inp->i_bdev->bd_disk;
2019 	struct dasd_block *block = disk->private_data;
2020 	struct dasd_device *base = block->base;
2021 	int rc;
2022 
2023 	atomic_inc(&block->open_count);
2024 	if (test_bit(DASD_FLAG_OFFLINE, &base->flags)) {
2025 		rc = -ENODEV;
2026 		goto unlock;
2027 	}
2028 
2029 	if (!try_module_get(base->discipline->owner)) {
2030 		rc = -EINVAL;
2031 		goto unlock;
2032 	}
2033 
2034 	if (dasd_probeonly) {
2035 		DEV_MESSAGE(KERN_INFO, base, "%s",
2036 			    "No access to device due to probeonly mode");
2037 		rc = -EPERM;
2038 		goto out;
2039 	}
2040 
2041 	if (base->state <= DASD_STATE_BASIC) {
2042 		DBF_DEV_EVENT(DBF_ERR, base, " %s",
2043 			      " Cannot open unrecognized device");
2044 		rc = -ENODEV;
2045 		goto out;
2046 	}
2047 
2048 	return 0;
2049 
2050 out:
2051 	module_put(base->discipline->owner);
2052 unlock:
2053 	atomic_dec(&block->open_count);
2054 	return rc;
2055 }
2056 
2057 static int dasd_release(struct inode *inp, struct file *filp)
2058 {
2059 	struct gendisk *disk = inp->i_bdev->bd_disk;
2060 	struct dasd_block *block = disk->private_data;
2061 
2062 	atomic_dec(&block->open_count);
2063 	module_put(block->base->discipline->owner);
2064 	return 0;
2065 }
2066 
2067 /*
2068  * Return disk geometry.
2069  */
2070 static int dasd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
2071 {
2072 	struct dasd_block *block;
2073 	struct dasd_device *base;
2074 
2075 	block = bdev->bd_disk->private_data;
2076 	base = block->base;
2077 	if (!block)
2078 		return -ENODEV;
2079 
2080 	if (!base->discipline ||
2081 	    !base->discipline->fill_geometry)
2082 		return -EINVAL;
2083 
2084 	base->discipline->fill_geometry(block, geo);
2085 	geo->start = get_start_sect(bdev) >> block->s2b_shift;
2086 	return 0;
2087 }
2088 
2089 struct block_device_operations
2090 dasd_device_operations = {
2091 	.owner		= THIS_MODULE,
2092 	.open		= dasd_open,
2093 	.release	= dasd_release,
2094 	.ioctl		= dasd_ioctl,
2095 	.compat_ioctl	= dasd_compat_ioctl,
2096 	.getgeo		= dasd_getgeo,
2097 };
2098 
2099 /*******************************************************************************
2100  * end of block device operations
2101  */
2102 
2103 static void
2104 dasd_exit(void)
2105 {
2106 #ifdef CONFIG_PROC_FS
2107 	dasd_proc_exit();
2108 #endif
2109 	dasd_eer_exit();
2110         if (dasd_page_cache != NULL) {
2111 		kmem_cache_destroy(dasd_page_cache);
2112 		dasd_page_cache = NULL;
2113 	}
2114 	dasd_gendisk_exit();
2115 	dasd_devmap_exit();
2116 	if (dasd_debug_area != NULL) {
2117 		debug_unregister(dasd_debug_area);
2118 		dasd_debug_area = NULL;
2119 	}
2120 }
2121 
2122 /*
2123  * SECTION: common functions for ccw_driver use
2124  */
2125 
2126 /*
2127  * Initial attempt at a probe function. this can be simplified once
2128  * the other detection code is gone.
2129  */
2130 int dasd_generic_probe(struct ccw_device *cdev,
2131 		       struct dasd_discipline *discipline)
2132 {
2133 	int ret;
2134 
2135 	ret = ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP);
2136 	if (ret) {
2137 		printk(KERN_WARNING
2138 		       "dasd_generic_probe: could not set ccw-device options "
2139 		       "for %s\n", cdev->dev.bus_id);
2140 		return ret;
2141 	}
2142 	ret = dasd_add_sysfs_files(cdev);
2143 	if (ret) {
2144 		printk(KERN_WARNING
2145 		       "dasd_generic_probe: could not add sysfs entries "
2146 		       "for %s\n", cdev->dev.bus_id);
2147 		return ret;
2148 	}
2149 	cdev->handler = &dasd_int_handler;
2150 
2151 	/*
2152 	 * Automatically online either all dasd devices (dasd_autodetect)
2153 	 * or all devices specified with dasd= parameters during
2154 	 * initial probe.
2155 	 */
2156 	if ((dasd_get_feature(cdev, DASD_FEATURE_INITIAL_ONLINE) > 0 ) ||
2157 	    (dasd_autodetect && dasd_busid_known(cdev->dev.bus_id) != 0))
2158 		ret = ccw_device_set_online(cdev);
2159 	if (ret)
2160 		printk(KERN_WARNING
2161 		       "dasd_generic_probe: could not initially "
2162 		       "online ccw-device %s; return code: %d\n",
2163 		       cdev->dev.bus_id, ret);
2164 	return 0;
2165 }
2166 
2167 /*
2168  * This will one day be called from a global not_oper handler.
2169  * It is also used by driver_unregister during module unload.
2170  */
2171 void dasd_generic_remove(struct ccw_device *cdev)
2172 {
2173 	struct dasd_device *device;
2174 	struct dasd_block *block;
2175 
2176 	cdev->handler = NULL;
2177 
2178 	dasd_remove_sysfs_files(cdev);
2179 	device = dasd_device_from_cdev(cdev);
2180 	if (IS_ERR(device))
2181 		return;
2182 	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
2183 		/* Already doing offline processing */
2184 		dasd_put_device(device);
2185 		return;
2186 	}
2187 	/*
2188 	 * This device is removed unconditionally. Set offline
2189 	 * flag to prevent dasd_open from opening it while it is
2190 	 * no quite down yet.
2191 	 */
2192 	dasd_set_target_state(device, DASD_STATE_NEW);
2193 	/* dasd_delete_device destroys the device reference. */
2194 	block = device->block;
2195 	device->block = NULL;
2196 	dasd_delete_device(device);
2197 	/*
2198 	 * life cycle of block is bound to device, so delete it after
2199 	 * device was safely removed
2200 	 */
2201 	if (block)
2202 		dasd_free_block(block);
2203 }
2204 
2205 /*
2206  * Activate a device. This is called from dasd_{eckd,fba}_probe() when either
2207  * the device is detected for the first time and is supposed to be used
2208  * or the user has started activation through sysfs.
2209  */
2210 int dasd_generic_set_online(struct ccw_device *cdev,
2211 			    struct dasd_discipline *base_discipline)
2212 {
2213 	struct dasd_discipline *discipline;
2214 	struct dasd_device *device;
2215 	int rc;
2216 
2217 	/* first online clears initial online feature flag */
2218 	dasd_set_feature(cdev, DASD_FEATURE_INITIAL_ONLINE, 0);
2219 	device = dasd_create_device(cdev);
2220 	if (IS_ERR(device))
2221 		return PTR_ERR(device);
2222 
2223 	discipline = base_discipline;
2224 	if (device->features & DASD_FEATURE_USEDIAG) {
2225 	  	if (!dasd_diag_discipline_pointer) {
2226 		        printk (KERN_WARNING
2227 				"dasd_generic couldn't online device %s "
2228 				"- discipline DIAG not available\n",
2229 				cdev->dev.bus_id);
2230 			dasd_delete_device(device);
2231 			return -ENODEV;
2232 		}
2233 		discipline = dasd_diag_discipline_pointer;
2234 	}
2235 	if (!try_module_get(base_discipline->owner)) {
2236 		dasd_delete_device(device);
2237 		return -EINVAL;
2238 	}
2239 	if (!try_module_get(discipline->owner)) {
2240 		module_put(base_discipline->owner);
2241 		dasd_delete_device(device);
2242 		return -EINVAL;
2243 	}
2244 	device->base_discipline = base_discipline;
2245 	device->discipline = discipline;
2246 
2247 	/* check_device will allocate block device if necessary */
2248 	rc = discipline->check_device(device);
2249 	if (rc) {
2250 		printk (KERN_WARNING
2251 			"dasd_generic couldn't online device %s "
2252 			"with discipline %s rc=%i\n",
2253 			cdev->dev.bus_id, discipline->name, rc);
2254 		module_put(discipline->owner);
2255 		module_put(base_discipline->owner);
2256 		dasd_delete_device(device);
2257 		return rc;
2258 	}
2259 
2260 	dasd_set_target_state(device, DASD_STATE_ONLINE);
2261 	if (device->state <= DASD_STATE_KNOWN) {
2262 		printk (KERN_WARNING
2263 			"dasd_generic discipline not found for %s\n",
2264 			cdev->dev.bus_id);
2265 		rc = -ENODEV;
2266 		dasd_set_target_state(device, DASD_STATE_NEW);
2267 		if (device->block)
2268 			dasd_free_block(device->block);
2269 		dasd_delete_device(device);
2270 	} else
2271 		pr_debug("dasd_generic device %s found\n",
2272 				cdev->dev.bus_id);
2273 
2274 	/* FIXME: we have to wait for the root device but we don't want
2275 	 * to wait for each single device but for all at once. */
2276 	wait_event(dasd_init_waitq, _wait_for_device(device));
2277 
2278 	dasd_put_device(device);
2279 
2280 	return rc;
2281 }
2282 
2283 int dasd_generic_set_offline(struct ccw_device *cdev)
2284 {
2285 	struct dasd_device *device;
2286 	struct dasd_block *block;
2287 	int max_count, open_count;
2288 
2289 	device = dasd_device_from_cdev(cdev);
2290 	if (IS_ERR(device))
2291 		return PTR_ERR(device);
2292 	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
2293 		/* Already doing offline processing */
2294 		dasd_put_device(device);
2295 		return 0;
2296 	}
2297 	/*
2298 	 * We must make sure that this device is currently not in use.
2299 	 * The open_count is increased for every opener, that includes
2300 	 * the blkdev_get in dasd_scan_partitions. We are only interested
2301 	 * in the other openers.
2302 	 */
2303 	if (device->block) {
2304 		struct dasd_block *block = device->block;
2305 		max_count = block->bdev ? 0 : -1;
2306 		open_count = (int) atomic_read(&block->open_count);
2307 		if (open_count > max_count) {
2308 			if (open_count > 0)
2309 				printk(KERN_WARNING "Can't offline dasd "
2310 				       "device with open count = %i.\n",
2311 				       open_count);
2312 			else
2313 				printk(KERN_WARNING "%s",
2314 				       "Can't offline dasd device due "
2315 				       "to internal use\n");
2316 			clear_bit(DASD_FLAG_OFFLINE, &device->flags);
2317 			dasd_put_device(device);
2318 			return -EBUSY;
2319 		}
2320 	}
2321 	dasd_set_target_state(device, DASD_STATE_NEW);
2322 	/* dasd_delete_device destroys the device reference. */
2323 	block = device->block;
2324 	device->block = NULL;
2325 	dasd_delete_device(device);
2326 	/*
2327 	 * life cycle of block is bound to device, so delete it after
2328 	 * device was safely removed
2329 	 */
2330 	if (block)
2331 		dasd_free_block(block);
2332 	return 0;
2333 }
2334 
2335 int dasd_generic_notify(struct ccw_device *cdev, int event)
2336 {
2337 	struct dasd_device *device;
2338 	struct dasd_ccw_req *cqr;
2339 	unsigned long flags;
2340 	int ret;
2341 
2342 	device = dasd_device_from_cdev(cdev);
2343 	if (IS_ERR(device))
2344 		return 0;
2345 	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
2346 	ret = 0;
2347 	switch (event) {
2348 	case CIO_GONE:
2349 	case CIO_NO_PATH:
2350 		/* First of all call extended error reporting. */
2351 		dasd_eer_write(device, NULL, DASD_EER_NOPATH);
2352 
2353 		if (device->state < DASD_STATE_BASIC)
2354 			break;
2355 		/* Device is active. We want to keep it. */
2356 		list_for_each_entry(cqr, &device->ccw_queue, devlist)
2357 			if (cqr->status == DASD_CQR_IN_IO) {
2358 				cqr->status = DASD_CQR_QUEUED;
2359 				cqr->retries++;
2360 			}
2361 		device->stopped |= DASD_STOPPED_DC_WAIT;
2362 		dasd_device_clear_timer(device);
2363 		dasd_schedule_device_bh(device);
2364 		ret = 1;
2365 		break;
2366 	case CIO_OPER:
2367 		/* FIXME: add a sanity check. */
2368 		device->stopped &= ~DASD_STOPPED_DC_WAIT;
2369 		dasd_schedule_device_bh(device);
2370 		if (device->block)
2371 			dasd_schedule_block_bh(device->block);
2372 		ret = 1;
2373 		break;
2374 	}
2375 	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
2376 	dasd_put_device(device);
2377 	return ret;
2378 }
2379 
2380 static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
2381 						   void *rdc_buffer,
2382 						   int rdc_buffer_size,
2383 						   char *magic)
2384 {
2385 	struct dasd_ccw_req *cqr;
2386 	struct ccw1 *ccw;
2387 
2388 	cqr = dasd_smalloc_request(magic, 1 /* RDC */, rdc_buffer_size, device);
2389 
2390 	if (IS_ERR(cqr)) {
2391 		DEV_MESSAGE(KERN_WARNING, device, "%s",
2392 			    "Could not allocate RDC request");
2393 		return cqr;
2394 	}
2395 
2396 	ccw = cqr->cpaddr;
2397 	ccw->cmd_code = CCW_CMD_RDC;
2398 	ccw->cda = (__u32)(addr_t)rdc_buffer;
2399 	ccw->count = rdc_buffer_size;
2400 
2401 	cqr->startdev = device;
2402 	cqr->memdev = device;
2403 	cqr->expires = 10*HZ;
2404 	clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
2405 	cqr->retries = 2;
2406 	cqr->buildclk = get_clock();
2407 	cqr->status = DASD_CQR_FILLED;
2408 	return cqr;
2409 }
2410 
2411 
2412 int dasd_generic_read_dev_chars(struct dasd_device *device, char *magic,
2413 				void **rdc_buffer, int rdc_buffer_size)
2414 {
2415 	int ret;
2416 	struct dasd_ccw_req *cqr;
2417 
2418 	cqr = dasd_generic_build_rdc(device, *rdc_buffer, rdc_buffer_size,
2419 				     magic);
2420 	if (IS_ERR(cqr))
2421 		return PTR_ERR(cqr);
2422 
2423 	ret = dasd_sleep_on(cqr);
2424 	dasd_sfree_request(cqr, cqr->memdev);
2425 	return ret;
2426 }
2427 EXPORT_SYMBOL_GPL(dasd_generic_read_dev_chars);
2428 
2429 static int __init dasd_init(void)
2430 {
2431 	int rc;
2432 
2433 	init_waitqueue_head(&dasd_init_waitq);
2434 	init_waitqueue_head(&dasd_flush_wq);
2435 
2436 	/* register 'common' DASD debug area, used for all DBF_XXX calls */
2437 	dasd_debug_area = debug_register("dasd", 1, 2, 8 * sizeof(long));
2438 	if (dasd_debug_area == NULL) {
2439 		rc = -ENOMEM;
2440 		goto failed;
2441 	}
2442 	debug_register_view(dasd_debug_area, &debug_sprintf_view);
2443 	debug_set_level(dasd_debug_area, DBF_WARNING);
2444 
2445 	DBF_EVENT(DBF_EMERG, "%s", "debug area created");
2446 
2447 	dasd_diag_discipline_pointer = NULL;
2448 
2449 	rc = dasd_devmap_init();
2450 	if (rc)
2451 		goto failed;
2452 	rc = dasd_gendisk_init();
2453 	if (rc)
2454 		goto failed;
2455 	rc = dasd_parse();
2456 	if (rc)
2457 		goto failed;
2458 	rc = dasd_eer_init();
2459 	if (rc)
2460 		goto failed;
2461 #ifdef CONFIG_PROC_FS
2462 	rc = dasd_proc_init();
2463 	if (rc)
2464 		goto failed;
2465 #endif
2466 
2467 	return 0;
2468 failed:
2469 	MESSAGE(KERN_INFO, "%s", "initialization not performed due to errors");
2470 	dasd_exit();
2471 	return rc;
2472 }
2473 
2474 module_init(dasd_init);
2475 module_exit(dasd_exit);
2476 
2477 EXPORT_SYMBOL(dasd_debug_area);
2478 EXPORT_SYMBOL(dasd_diag_discipline_pointer);
2479 
2480 EXPORT_SYMBOL(dasd_add_request_head);
2481 EXPORT_SYMBOL(dasd_add_request_tail);
2482 EXPORT_SYMBOL(dasd_cancel_req);
2483 EXPORT_SYMBOL(dasd_device_clear_timer);
2484 EXPORT_SYMBOL(dasd_block_clear_timer);
2485 EXPORT_SYMBOL(dasd_enable_device);
2486 EXPORT_SYMBOL(dasd_int_handler);
2487 EXPORT_SYMBOL(dasd_kfree_request);
2488 EXPORT_SYMBOL(dasd_kick_device);
2489 EXPORT_SYMBOL(dasd_kmalloc_request);
2490 EXPORT_SYMBOL(dasd_schedule_device_bh);
2491 EXPORT_SYMBOL(dasd_schedule_block_bh);
2492 EXPORT_SYMBOL(dasd_set_target_state);
2493 EXPORT_SYMBOL(dasd_device_set_timer);
2494 EXPORT_SYMBOL(dasd_block_set_timer);
2495 EXPORT_SYMBOL(dasd_sfree_request);
2496 EXPORT_SYMBOL(dasd_sleep_on);
2497 EXPORT_SYMBOL(dasd_sleep_on_immediatly);
2498 EXPORT_SYMBOL(dasd_sleep_on_interruptible);
2499 EXPORT_SYMBOL(dasd_smalloc_request);
2500 EXPORT_SYMBOL(dasd_start_IO);
2501 EXPORT_SYMBOL(dasd_term_IO);
2502 
2503 EXPORT_SYMBOL_GPL(dasd_generic_probe);
2504 EXPORT_SYMBOL_GPL(dasd_generic_remove);
2505 EXPORT_SYMBOL_GPL(dasd_generic_notify);
2506 EXPORT_SYMBOL_GPL(dasd_generic_set_online);
2507 EXPORT_SYMBOL_GPL(dasd_generic_set_offline);
2508 EXPORT_SYMBOL_GPL(dasd_generic_handle_state_change);
2509 EXPORT_SYMBOL_GPL(dasd_flush_device_queue);
2510 EXPORT_SYMBOL_GPL(dasd_alloc_block);
2511 EXPORT_SYMBOL_GPL(dasd_free_block);
2512