xref: /openbmc/linux/drivers/s390/block/dasd.c (revision de3e0da1270bccb046885fbf1baa9140721de7e0)
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_device * device);
52  static void dasd_setup_queue(struct dasd_device * device);
53  static void dasd_free_queue(struct dasd_device * device);
54  static void dasd_flush_request_queue(struct dasd_device *);
55  static int dasd_flush_ccw_queue(struct dasd_device *, int);
56  static void dasd_tasklet(struct dasd_device *);
57  static void do_kick_device(struct work_struct *);
58  
59  /*
60   * SECTION: Operations on the device structure.
61   */
62  static wait_queue_head_t dasd_init_waitq;
63  static wait_queue_head_t dasd_flush_wq;
64  
65  /*
66   * Allocate memory for a new device structure.
67   */
68  struct dasd_device *
69  dasd_alloc_device(void)
70  {
71  	struct dasd_device *device;
72  
73  	device = kzalloc(sizeof (struct dasd_device), GFP_ATOMIC);
74  	if (device == NULL)
75  		return ERR_PTR(-ENOMEM);
76  	/* open_count = 0 means device online but not in use */
77  	atomic_set(&device->open_count, -1);
78  
79  	/* Get two pages for normal block device operations. */
80  	device->ccw_mem = (void *) __get_free_pages(GFP_ATOMIC | GFP_DMA, 1);
81  	if (device->ccw_mem == NULL) {
82  		kfree(device);
83  		return ERR_PTR(-ENOMEM);
84  	}
85  	/* Get one page for error recovery. */
86  	device->erp_mem = (void *) get_zeroed_page(GFP_ATOMIC | GFP_DMA);
87  	if (device->erp_mem == NULL) {
88  		free_pages((unsigned long) device->ccw_mem, 1);
89  		kfree(device);
90  		return ERR_PTR(-ENOMEM);
91  	}
92  
93  	dasd_init_chunklist(&device->ccw_chunks, device->ccw_mem, PAGE_SIZE*2);
94  	dasd_init_chunklist(&device->erp_chunks, device->erp_mem, PAGE_SIZE);
95  	spin_lock_init(&device->mem_lock);
96  	spin_lock_init(&device->request_queue_lock);
97  	atomic_set (&device->tasklet_scheduled, 0);
98  	tasklet_init(&device->tasklet,
99  		     (void (*)(unsigned long)) dasd_tasklet,
100  		     (unsigned long) device);
101  	INIT_LIST_HEAD(&device->ccw_queue);
102  	init_timer(&device->timer);
103  	INIT_WORK(&device->kick_work, do_kick_device);
104  	device->state = DASD_STATE_NEW;
105  	device->target = DASD_STATE_NEW;
106  
107  	return device;
108  }
109  
110  /*
111   * Free memory of a device structure.
112   */
113  void
114  dasd_free_device(struct dasd_device *device)
115  {
116  	kfree(device->private);
117  	free_page((unsigned long) device->erp_mem);
118  	free_pages((unsigned long) device->ccw_mem, 1);
119  	kfree(device);
120  }
121  
122  /*
123   * Make a new device known to the system.
124   */
125  static int
126  dasd_state_new_to_known(struct dasd_device *device)
127  {
128  	int rc;
129  
130  	/*
131  	 * As long as the device is not in state DASD_STATE_NEW we want to
132  	 * keep the reference count > 0.
133  	 */
134  	dasd_get_device(device);
135  
136  	rc = dasd_alloc_queue(device);
137  	if (rc) {
138  		dasd_put_device(device);
139  		return rc;
140  	}
141  
142  	device->state = DASD_STATE_KNOWN;
143  	return 0;
144  }
145  
146  /*
147   * Let the system forget about a device.
148   */
149  static int
150  dasd_state_known_to_new(struct dasd_device * device)
151  {
152  	/* Disable extended error reporting for this device. */
153  	dasd_eer_disable(device);
154  	/* Forget the discipline information. */
155  	if (device->discipline)
156  		module_put(device->discipline->owner);
157  	device->discipline = NULL;
158  	if (device->base_discipline)
159  		module_put(device->base_discipline->owner);
160  	device->base_discipline = NULL;
161  	device->state = DASD_STATE_NEW;
162  
163  	dasd_free_queue(device);
164  
165  	/* Give up reference we took in dasd_state_new_to_known. */
166  	dasd_put_device(device);
167  	return 0;
168  }
169  
170  /*
171   * Request the irq line for the device.
172   */
173  static int
174  dasd_state_known_to_basic(struct dasd_device * device)
175  {
176  	int rc;
177  
178  	/* Allocate and register gendisk structure. */
179  	rc = dasd_gendisk_alloc(device);
180  	if (rc)
181  		return rc;
182  
183  	/* register 'device' debug area, used for all DBF_DEV_XXX calls */
184  	device->debug_area = debug_register(device->cdev->dev.bus_id, 1, 2,
185  					    8 * sizeof (long));
186  	debug_register_view(device->debug_area, &debug_sprintf_view);
187  	debug_set_level(device->debug_area, DBF_WARNING);
188  	DBF_DEV_EVENT(DBF_EMERG, device, "%s", "debug area created");
189  
190  	device->state = DASD_STATE_BASIC;
191  	return 0;
192  }
193  
194  /*
195   * Release the irq line for the device. Terminate any running i/o.
196   */
197  static int
198  dasd_state_basic_to_known(struct dasd_device * device)
199  {
200  	int rc;
201  
202  	dasd_gendisk_free(device);
203  	rc = dasd_flush_ccw_queue(device, 1);
204  	if (rc)
205  		return rc;
206  	dasd_clear_timer(device);
207  
208  	DBF_DEV_EVENT(DBF_EMERG, device, "%p debug area deleted", device);
209  	if (device->debug_area != NULL) {
210  		debug_unregister(device->debug_area);
211  		device->debug_area = NULL;
212  	}
213  	device->state = DASD_STATE_KNOWN;
214  	return 0;
215  }
216  
217  /*
218   * Do the initial analysis. The do_analysis function may return
219   * -EAGAIN in which case the device keeps the state DASD_STATE_BASIC
220   * until the discipline decides to continue the startup sequence
221   * by calling the function dasd_change_state. The eckd disciplines
222   * uses this to start a ccw that detects the format. The completion
223   * interrupt for this detection ccw uses the kernel event daemon to
224   * trigger the call to dasd_change_state. All this is done in the
225   * discipline code, see dasd_eckd.c.
226   * After the analysis ccw is done (do_analysis returned 0) the block
227   * device is setup.
228   * In case the analysis returns an error, the device setup is stopped
229   * (a fake disk was already added to allow formatting).
230   */
231  static int
232  dasd_state_basic_to_ready(struct dasd_device * device)
233  {
234  	int rc;
235  
236  	rc = 0;
237  	if (device->discipline->do_analysis != NULL)
238  		rc = device->discipline->do_analysis(device);
239  	if (rc) {
240  		if (rc != -EAGAIN)
241  			device->state = DASD_STATE_UNFMT;
242  		return rc;
243  	}
244  	/* make disk known with correct capacity */
245  	dasd_setup_queue(device);
246  	set_capacity(device->gdp, device->blocks << device->s2b_shift);
247  	device->state = DASD_STATE_READY;
248  	rc = dasd_scan_partitions(device);
249  	if (rc)
250  		device->state = DASD_STATE_BASIC;
251  	return rc;
252  }
253  
254  /*
255   * Remove device from block device layer. Destroy dirty buffers.
256   * Forget format information. Check if the target level is basic
257   * and if it is create fake disk for formatting.
258   */
259  static int
260  dasd_state_ready_to_basic(struct dasd_device * device)
261  {
262  	int rc;
263  
264  	rc = dasd_flush_ccw_queue(device, 0);
265  	if (rc)
266  		return rc;
267  	dasd_destroy_partitions(device);
268  	dasd_flush_request_queue(device);
269  	device->blocks = 0;
270  	device->bp_block = 0;
271  	device->s2b_shift = 0;
272  	device->state = DASD_STATE_BASIC;
273  	return 0;
274  }
275  
276  /*
277   * Back to basic.
278   */
279  static int
280  dasd_state_unfmt_to_basic(struct dasd_device * device)
281  {
282  	device->state = DASD_STATE_BASIC;
283  	return 0;
284  }
285  
286  /*
287   * Make the device online and schedule the bottom half to start
288   * the requeueing of requests from the linux request queue to the
289   * ccw queue.
290   */
291  static int
292  dasd_state_ready_to_online(struct dasd_device * device)
293  {
294  	device->state = DASD_STATE_ONLINE;
295  	dasd_schedule_bh(device);
296  	return 0;
297  }
298  
299  /*
300   * Stop the requeueing of requests again.
301   */
302  static int
303  dasd_state_online_to_ready(struct dasd_device * device)
304  {
305  	device->state = DASD_STATE_READY;
306  	return 0;
307  }
308  
309  /*
310   * Device startup state changes.
311   */
312  static int
313  dasd_increase_state(struct dasd_device *device)
314  {
315  	int rc;
316  
317  	rc = 0;
318  	if (device->state == DASD_STATE_NEW &&
319  	    device->target >= DASD_STATE_KNOWN)
320  		rc = dasd_state_new_to_known(device);
321  
322  	if (!rc &&
323  	    device->state == DASD_STATE_KNOWN &&
324  	    device->target >= DASD_STATE_BASIC)
325  		rc = dasd_state_known_to_basic(device);
326  
327  	if (!rc &&
328  	    device->state == DASD_STATE_BASIC &&
329  	    device->target >= DASD_STATE_READY)
330  		rc = dasd_state_basic_to_ready(device);
331  
332  	if (!rc &&
333  	    device->state == DASD_STATE_UNFMT &&
334  	    device->target > DASD_STATE_UNFMT)
335  		rc = -EPERM;
336  
337  	if (!rc &&
338  	    device->state == DASD_STATE_READY &&
339  	    device->target >= DASD_STATE_ONLINE)
340  		rc = dasd_state_ready_to_online(device);
341  
342  	return rc;
343  }
344  
345  /*
346   * Device shutdown state changes.
347   */
348  static int
349  dasd_decrease_state(struct dasd_device *device)
350  {
351  	int rc;
352  
353  	rc = 0;
354  	if (device->state == DASD_STATE_ONLINE &&
355  	    device->target <= DASD_STATE_READY)
356  		rc = dasd_state_online_to_ready(device);
357  
358  	if (!rc &&
359  	    device->state == DASD_STATE_READY &&
360  	    device->target <= DASD_STATE_BASIC)
361  		rc = dasd_state_ready_to_basic(device);
362  
363  	if (!rc &&
364  	    device->state == DASD_STATE_UNFMT &&
365  	    device->target <= DASD_STATE_BASIC)
366  		rc = dasd_state_unfmt_to_basic(device);
367  
368  	if (!rc &&
369  	    device->state == DASD_STATE_BASIC &&
370  	    device->target <= DASD_STATE_KNOWN)
371  		rc = dasd_state_basic_to_known(device);
372  
373  	if (!rc &&
374  	    device->state == DASD_STATE_KNOWN &&
375  	    device->target <= DASD_STATE_NEW)
376  		rc = dasd_state_known_to_new(device);
377  
378  	return rc;
379  }
380  
381  /*
382   * This is the main startup/shutdown routine.
383   */
384  static void
385  dasd_change_state(struct dasd_device *device)
386  {
387          int rc;
388  
389  	if (device->state == device->target)
390  		/* Already where we want to go today... */
391  		return;
392  	if (device->state < device->target)
393  		rc = dasd_increase_state(device);
394  	else
395  		rc = dasd_decrease_state(device);
396          if (rc && rc != -EAGAIN)
397                  device->target = device->state;
398  
399  	if (device->state == device->target)
400  		wake_up(&dasd_init_waitq);
401  
402  	/* let user-space know that the device status changed */
403  	kobject_uevent(&device->cdev->dev.kobj, KOBJ_CHANGE);
404  }
405  
406  /*
407   * Kick starter for devices that did not complete the startup/shutdown
408   * procedure or were sleeping because of a pending state.
409   * dasd_kick_device will schedule a call do do_kick_device to the kernel
410   * event daemon.
411   */
412  static void
413  do_kick_device(struct work_struct *work)
414  {
415  	struct dasd_device *device = container_of(work, struct dasd_device, kick_work);
416  	dasd_change_state(device);
417  	dasd_schedule_bh(device);
418  	dasd_put_device(device);
419  }
420  
421  void
422  dasd_kick_device(struct dasd_device *device)
423  {
424  	dasd_get_device(device);
425  	/* queue call to dasd_kick_device to the kernel event daemon. */
426  	schedule_work(&device->kick_work);
427  }
428  
429  /*
430   * Set the target state for a device and starts the state change.
431   */
432  void
433  dasd_set_target_state(struct dasd_device *device, int target)
434  {
435  	/* If we are in probeonly mode stop at DASD_STATE_READY. */
436  	if (dasd_probeonly && target > DASD_STATE_READY)
437  		target = DASD_STATE_READY;
438  	if (device->target != target) {
439                  if (device->state == target)
440  			wake_up(&dasd_init_waitq);
441  		device->target = target;
442  	}
443  	if (device->state != device->target)
444  		dasd_change_state(device);
445  }
446  
447  /*
448   * Enable devices with device numbers in [from..to].
449   */
450  static inline int
451  _wait_for_device(struct dasd_device *device)
452  {
453  	return (device->state == device->target);
454  }
455  
456  void
457  dasd_enable_device(struct dasd_device *device)
458  {
459  	dasd_set_target_state(device, DASD_STATE_ONLINE);
460  	if (device->state <= DASD_STATE_KNOWN)
461  		/* No discipline for device found. */
462  		dasd_set_target_state(device, DASD_STATE_NEW);
463  	/* Now wait for the devices to come up. */
464  	wait_event(dasd_init_waitq, _wait_for_device(device));
465  }
466  
467  /*
468   * SECTION: device operation (interrupt handler, start i/o, term i/o ...)
469   */
470  #ifdef CONFIG_DASD_PROFILE
471  
472  struct dasd_profile_info_t dasd_global_profile;
473  unsigned int dasd_profile_level = DASD_PROFILE_OFF;
474  
475  /*
476   * Increments counter in global and local profiling structures.
477   */
478  #define dasd_profile_counter(value, counter, device) \
479  { \
480  	int index; \
481  	for (index = 0; index < 31 && value >> (2+index); index++); \
482  	dasd_global_profile.counter[index]++; \
483  	device->profile.counter[index]++; \
484  }
485  
486  /*
487   * Add profiling information for cqr before execution.
488   */
489  static void
490  dasd_profile_start(struct dasd_device *device, struct dasd_ccw_req * cqr,
491  		   struct request *req)
492  {
493  	struct list_head *l;
494  	unsigned int counter;
495  
496  	if (dasd_profile_level != DASD_PROFILE_ON)
497  		return;
498  
499  	/* count the length of the chanq for statistics */
500  	counter = 0;
501  	list_for_each(l, &device->ccw_queue)
502  		if (++counter >= 31)
503  			break;
504  	dasd_global_profile.dasd_io_nr_req[counter]++;
505  	device->profile.dasd_io_nr_req[counter]++;
506  }
507  
508  /*
509   * Add profiling information for cqr after execution.
510   */
511  static void
512  dasd_profile_end(struct dasd_device *device, struct dasd_ccw_req * cqr,
513  		 struct request *req)
514  {
515  	long strtime, irqtime, endtime, tottime;	/* in microseconds */
516  	long tottimeps, sectors;
517  
518  	if (dasd_profile_level != DASD_PROFILE_ON)
519  		return;
520  
521  	sectors = req->nr_sectors;
522  	if (!cqr->buildclk || !cqr->startclk ||
523  	    !cqr->stopclk || !cqr->endclk ||
524  	    !sectors)
525  		return;
526  
527  	strtime = ((cqr->startclk - cqr->buildclk) >> 12);
528  	irqtime = ((cqr->stopclk - cqr->startclk) >> 12);
529  	endtime = ((cqr->endclk - cqr->stopclk) >> 12);
530  	tottime = ((cqr->endclk - cqr->buildclk) >> 12);
531  	tottimeps = tottime / sectors;
532  
533  	if (!dasd_global_profile.dasd_io_reqs)
534  		memset(&dasd_global_profile, 0,
535  		       sizeof (struct dasd_profile_info_t));
536  	dasd_global_profile.dasd_io_reqs++;
537  	dasd_global_profile.dasd_io_sects += sectors;
538  
539  	if (!device->profile.dasd_io_reqs)
540  		memset(&device->profile, 0,
541  		       sizeof (struct dasd_profile_info_t));
542  	device->profile.dasd_io_reqs++;
543  	device->profile.dasd_io_sects += sectors;
544  
545  	dasd_profile_counter(sectors, dasd_io_secs, device);
546  	dasd_profile_counter(tottime, dasd_io_times, device);
547  	dasd_profile_counter(tottimeps, dasd_io_timps, device);
548  	dasd_profile_counter(strtime, dasd_io_time1, device);
549  	dasd_profile_counter(irqtime, dasd_io_time2, device);
550  	dasd_profile_counter(irqtime / sectors, dasd_io_time2ps, device);
551  	dasd_profile_counter(endtime, dasd_io_time3, device);
552  }
553  #else
554  #define dasd_profile_start(device, cqr, req) do {} while (0)
555  #define dasd_profile_end(device, cqr, req) do {} while (0)
556  #endif				/* CONFIG_DASD_PROFILE */
557  
558  /*
559   * Allocate memory for a channel program with 'cplength' channel
560   * command words and 'datasize' additional space. There are two
561   * variantes: 1) dasd_kmalloc_request uses kmalloc to get the needed
562   * memory and 2) dasd_smalloc_request uses the static ccw memory
563   * that gets allocated for each device.
564   */
565  struct dasd_ccw_req *
566  dasd_kmalloc_request(char *magic, int cplength, int datasize,
567  		   struct dasd_device * device)
568  {
569  	struct dasd_ccw_req *cqr;
570  
571  	/* Sanity checks */
572  	BUG_ON( magic == NULL || datasize > PAGE_SIZE ||
573  	     (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
574  
575  	cqr = kzalloc(sizeof(struct dasd_ccw_req), GFP_ATOMIC);
576  	if (cqr == NULL)
577  		return ERR_PTR(-ENOMEM);
578  	cqr->cpaddr = NULL;
579  	if (cplength > 0) {
580  		cqr->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
581  				      GFP_ATOMIC | GFP_DMA);
582  		if (cqr->cpaddr == NULL) {
583  			kfree(cqr);
584  			return ERR_PTR(-ENOMEM);
585  		}
586  	}
587  	cqr->data = NULL;
588  	if (datasize > 0) {
589  		cqr->data = kzalloc(datasize, GFP_ATOMIC | GFP_DMA);
590  		if (cqr->data == NULL) {
591  			kfree(cqr->cpaddr);
592  			kfree(cqr);
593  			return ERR_PTR(-ENOMEM);
594  		}
595  	}
596  	strncpy((char *) &cqr->magic, magic, 4);
597  	ASCEBC((char *) &cqr->magic, 4);
598  	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
599  	dasd_get_device(device);
600  	return cqr;
601  }
602  
603  struct dasd_ccw_req *
604  dasd_smalloc_request(char *magic, int cplength, int datasize,
605  		   struct dasd_device * device)
606  {
607  	unsigned long flags;
608  	struct dasd_ccw_req *cqr;
609  	char *data;
610  	int size;
611  
612  	/* Sanity checks */
613  	BUG_ON( magic == NULL || datasize > PAGE_SIZE ||
614  	     (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
615  
616  	size = (sizeof(struct dasd_ccw_req) + 7L) & -8L;
617  	if (cplength > 0)
618  		size += cplength * sizeof(struct ccw1);
619  	if (datasize > 0)
620  		size += datasize;
621  	spin_lock_irqsave(&device->mem_lock, flags);
622  	cqr = (struct dasd_ccw_req *)
623  		dasd_alloc_chunk(&device->ccw_chunks, size);
624  	spin_unlock_irqrestore(&device->mem_lock, flags);
625  	if (cqr == NULL)
626  		return ERR_PTR(-ENOMEM);
627  	memset(cqr, 0, sizeof(struct dasd_ccw_req));
628  	data = (char *) cqr + ((sizeof(struct dasd_ccw_req) + 7L) & -8L);
629  	cqr->cpaddr = NULL;
630  	if (cplength > 0) {
631  		cqr->cpaddr = (struct ccw1 *) data;
632  		data += cplength*sizeof(struct ccw1);
633  		memset(cqr->cpaddr, 0, cplength*sizeof(struct ccw1));
634  	}
635  	cqr->data = NULL;
636  	if (datasize > 0) {
637  		cqr->data = data;
638   		memset(cqr->data, 0, datasize);
639  	}
640  	strncpy((char *) &cqr->magic, magic, 4);
641  	ASCEBC((char *) &cqr->magic, 4);
642  	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
643  	dasd_get_device(device);
644  	return cqr;
645  }
646  
647  /*
648   * Free memory of a channel program. This function needs to free all the
649   * idal lists that might have been created by dasd_set_cda and the
650   * struct dasd_ccw_req itself.
651   */
652  void
653  dasd_kfree_request(struct dasd_ccw_req * cqr, struct dasd_device * device)
654  {
655  #ifdef CONFIG_64BIT
656  	struct ccw1 *ccw;
657  
658  	/* Clear any idals used for the request. */
659  	ccw = cqr->cpaddr;
660  	do {
661  		clear_normalized_cda(ccw);
662  	} while (ccw++->flags & (CCW_FLAG_CC | CCW_FLAG_DC));
663  #endif
664  	kfree(cqr->cpaddr);
665  	kfree(cqr->data);
666  	kfree(cqr);
667  	dasd_put_device(device);
668  }
669  
670  void
671  dasd_sfree_request(struct dasd_ccw_req * cqr, struct dasd_device * device)
672  {
673  	unsigned long flags;
674  
675  	spin_lock_irqsave(&device->mem_lock, flags);
676  	dasd_free_chunk(&device->ccw_chunks, cqr);
677  	spin_unlock_irqrestore(&device->mem_lock, flags);
678  	dasd_put_device(device);
679  }
680  
681  /*
682   * Check discipline magic in cqr.
683   */
684  static inline int
685  dasd_check_cqr(struct dasd_ccw_req *cqr)
686  {
687  	struct dasd_device *device;
688  
689  	if (cqr == NULL)
690  		return -EINVAL;
691  	device = cqr->device;
692  	if (strncmp((char *) &cqr->magic, device->discipline->ebcname, 4)) {
693  		DEV_MESSAGE(KERN_WARNING, device,
694  			    " dasd_ccw_req 0x%08x magic doesn't match"
695  			    " discipline 0x%08x",
696  			    cqr->magic,
697  			    *(unsigned int *) device->discipline->name);
698  		return -EINVAL;
699  	}
700  	return 0;
701  }
702  
703  /*
704   * Terminate the current i/o and set the request to clear_pending.
705   * Timer keeps device runnig.
706   * ccw_device_clear can fail if the i/o subsystem
707   * is in a bad mood.
708   */
709  int
710  dasd_term_IO(struct dasd_ccw_req * cqr)
711  {
712  	struct dasd_device *device;
713  	int retries, rc;
714  
715  	/* Check the cqr */
716  	rc = dasd_check_cqr(cqr);
717  	if (rc)
718  		return rc;
719  	retries = 0;
720  	device = (struct dasd_device *) cqr->device;
721  	while ((retries < 5) && (cqr->status == DASD_CQR_IN_IO)) {
722  		rc = ccw_device_clear(device->cdev, (long) cqr);
723  		switch (rc) {
724  		case 0:	/* termination successful */
725  			cqr->retries--;
726  			cqr->status = DASD_CQR_CLEAR;
727  			cqr->stopclk = get_clock();
728  			cqr->starttime = 0;
729  			DBF_DEV_EVENT(DBF_DEBUG, device,
730  				      "terminate cqr %p successful",
731  				      cqr);
732  			break;
733  		case -ENODEV:
734  			DBF_DEV_EVENT(DBF_ERR, device, "%s",
735  				      "device gone, retry");
736  			break;
737  		case -EIO:
738  			DBF_DEV_EVENT(DBF_ERR, device, "%s",
739  				      "I/O error, retry");
740  			break;
741  		case -EINVAL:
742  		case -EBUSY:
743  			DBF_DEV_EVENT(DBF_ERR, device, "%s",
744  				      "device busy, retry later");
745  			break;
746  		default:
747  			DEV_MESSAGE(KERN_ERR, device,
748  				    "line %d unknown RC=%d, please "
749  				    "report to linux390@de.ibm.com",
750  				    __LINE__, rc);
751  			BUG();
752  			break;
753  		}
754  		retries++;
755  	}
756  	dasd_schedule_bh(device);
757  	return rc;
758  }
759  
760  /*
761   * Start the i/o. This start_IO can fail if the channel is really busy.
762   * In that case set up a timer to start the request later.
763   */
764  int
765  dasd_start_IO(struct dasd_ccw_req * cqr)
766  {
767  	struct dasd_device *device;
768  	int rc;
769  
770  	/* Check the cqr */
771  	rc = dasd_check_cqr(cqr);
772  	if (rc)
773  		return rc;
774  	device = (struct dasd_device *) cqr->device;
775  	if (cqr->retries < 0) {
776  		DEV_MESSAGE(KERN_DEBUG, device,
777  			    "start_IO: request %p (%02x/%i) - no retry left.",
778  			    cqr, cqr->status, cqr->retries);
779  		cqr->status = DASD_CQR_FAILED;
780  		return -EIO;
781  	}
782  	cqr->startclk = get_clock();
783  	cqr->starttime = jiffies;
784  	cqr->retries--;
785  	rc = ccw_device_start(device->cdev, cqr->cpaddr, (long) cqr,
786  			      cqr->lpm, 0);
787  	switch (rc) {
788  	case 0:
789  		cqr->status = DASD_CQR_IN_IO;
790  		DBF_DEV_EVENT(DBF_DEBUG, device,
791  			      "start_IO: request %p started successful",
792  			      cqr);
793  		break;
794  	case -EBUSY:
795  		DBF_DEV_EVENT(DBF_ERR, device, "%s",
796  			      "start_IO: device busy, retry later");
797  		break;
798  	case -ETIMEDOUT:
799  		DBF_DEV_EVENT(DBF_ERR, device, "%s",
800  			      "start_IO: request timeout, retry later");
801  		break;
802  	case -EACCES:
803  		/* -EACCES indicates that the request used only a
804  		 * subset of the available pathes and all these
805  		 * pathes are gone.
806  		 * Do a retry with all available pathes.
807  		 */
808  		cqr->lpm = LPM_ANYPATH;
809  		DBF_DEV_EVENT(DBF_ERR, device, "%s",
810  			      "start_IO: selected pathes gone,"
811  			      " retry on all pathes");
812  		break;
813  	case -ENODEV:
814  	case -EIO:
815  		DBF_DEV_EVENT(DBF_ERR, device, "%s",
816  			      "start_IO: device gone, retry");
817  		break;
818  	default:
819  		DEV_MESSAGE(KERN_ERR, device,
820  			    "line %d unknown RC=%d, please report"
821  			    " to linux390@de.ibm.com", __LINE__, rc);
822  		BUG();
823  		break;
824  	}
825  	return rc;
826  }
827  
828  /*
829   * Timeout function for dasd devices. This is used for different purposes
830   *  1) missing interrupt handler for normal operation
831   *  2) delayed start of request where start_IO failed with -EBUSY
832   *  3) timeout for missing state change interrupts
833   * The head of the ccw queue will have status DASD_CQR_IN_IO for 1),
834   * DASD_CQR_QUEUED for 2) and 3).
835   */
836  static void
837  dasd_timeout_device(unsigned long ptr)
838  {
839  	unsigned long flags;
840  	struct dasd_device *device;
841  
842  	device = (struct dasd_device *) ptr;
843  	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
844  	/* re-activate request queue */
845          device->stopped &= ~DASD_STOPPED_PENDING;
846  	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
847  	dasd_schedule_bh(device);
848  }
849  
850  /*
851   * Setup timeout for a device in jiffies.
852   */
853  void
854  dasd_set_timer(struct dasd_device *device, int expires)
855  {
856  	if (expires == 0) {
857  		if (timer_pending(&device->timer))
858  			del_timer(&device->timer);
859  		return;
860  	}
861  	if (timer_pending(&device->timer)) {
862  		if (mod_timer(&device->timer, jiffies + expires))
863  			return;
864  	}
865  	device->timer.function = dasd_timeout_device;
866  	device->timer.data = (unsigned long) device;
867  	device->timer.expires = jiffies + expires;
868  	add_timer(&device->timer);
869  }
870  
871  /*
872   * Clear timeout for a device.
873   */
874  void
875  dasd_clear_timer(struct dasd_device *device)
876  {
877  	if (timer_pending(&device->timer))
878  		del_timer(&device->timer);
879  }
880  
881  static void
882  dasd_handle_killed_request(struct ccw_device *cdev, unsigned long intparm)
883  {
884  	struct dasd_ccw_req *cqr;
885  	struct dasd_device *device;
886  
887  	cqr = (struct dasd_ccw_req *) intparm;
888  	if (cqr->status != DASD_CQR_IN_IO) {
889  		MESSAGE(KERN_DEBUG,
890  			"invalid status in handle_killed_request: "
891  			"bus_id %s, status %02x",
892  			cdev->dev.bus_id, cqr->status);
893  		return;
894  	}
895  
896  	device = (struct dasd_device *) cqr->device;
897  	if (device == NULL ||
898  	    device != dasd_device_from_cdev_locked(cdev) ||
899  	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
900  		MESSAGE(KERN_DEBUG, "invalid device in request: bus_id %s",
901  			cdev->dev.bus_id);
902  		return;
903  	}
904  
905  	/* Schedule request to be retried. */
906  	cqr->status = DASD_CQR_QUEUED;
907  
908  	dasd_clear_timer(device);
909  	dasd_schedule_bh(device);
910  	dasd_put_device(device);
911  }
912  
913  static void
914  dasd_handle_state_change_pending(struct dasd_device *device)
915  {
916  	struct dasd_ccw_req *cqr;
917  	struct list_head *l, *n;
918  
919  	/* First of all start sense subsystem status request. */
920  	dasd_eer_snss(device);
921  
922  	device->stopped &= ~DASD_STOPPED_PENDING;
923  
924          /* restart all 'running' IO on queue */
925  	list_for_each_safe(l, n, &device->ccw_queue) {
926  		cqr = list_entry(l, struct dasd_ccw_req, list);
927                  if (cqr->status == DASD_CQR_IN_IO) {
928                          cqr->status = DASD_CQR_QUEUED;
929  		}
930          }
931  	dasd_clear_timer(device);
932  	dasd_schedule_bh(device);
933  }
934  
935  /*
936   * Interrupt handler for "normal" ssch-io based dasd devices.
937   */
938  void
939  dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
940  		 struct irb *irb)
941  {
942  	struct dasd_ccw_req *cqr, *next;
943  	struct dasd_device *device;
944  	unsigned long long now;
945  	int expires;
946  	dasd_era_t era;
947  	char mask;
948  
949  	if (IS_ERR(irb)) {
950  		switch (PTR_ERR(irb)) {
951  		case -EIO:
952  			dasd_handle_killed_request(cdev, intparm);
953  			break;
954  		case -ETIMEDOUT:
955  			printk(KERN_WARNING"%s(%s): request timed out\n",
956  			       __FUNCTION__, cdev->dev.bus_id);
957  			//FIXME - dasd uses own timeout interface...
958  			break;
959  		default:
960  			printk(KERN_WARNING"%s(%s): unknown error %ld\n",
961  			       __FUNCTION__, cdev->dev.bus_id, PTR_ERR(irb));
962  		}
963  		return;
964  	}
965  
966  	now = get_clock();
967  
968  	DBF_EVENT(DBF_ERR, "Interrupt: bus_id %s CS/DS %04x ip %08x",
969  		  cdev->dev.bus_id, ((irb->scsw.cstat<<8)|irb->scsw.dstat),
970  		  (unsigned int) intparm);
971  
972  	/* first of all check for state change pending interrupt */
973  	mask = DEV_STAT_ATTENTION | DEV_STAT_DEV_END | DEV_STAT_UNIT_EXCEP;
974  	if ((irb->scsw.dstat & mask) == mask) {
975  		device = dasd_device_from_cdev_locked(cdev);
976  		if (!IS_ERR(device)) {
977  			dasd_handle_state_change_pending(device);
978  			dasd_put_device(device);
979  		}
980  		return;
981  	}
982  
983  	cqr = (struct dasd_ccw_req *) intparm;
984  
985  	/* check for unsolicited interrupts */
986  	if (cqr == NULL) {
987  		MESSAGE(KERN_DEBUG,
988  			"unsolicited interrupt received: bus_id %s",
989  			cdev->dev.bus_id);
990  		return;
991  	}
992  
993  	device = (struct dasd_device *) cqr->device;
994  	if (device == NULL ||
995  	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
996  		MESSAGE(KERN_DEBUG, "invalid device in request: bus_id %s",
997  			cdev->dev.bus_id);
998  		return;
999  	}
1000  
1001  	/* Check for clear pending */
1002  	if (cqr->status == DASD_CQR_CLEAR &&
1003  	    irb->scsw.fctl & SCSW_FCTL_CLEAR_FUNC) {
1004  		cqr->status = DASD_CQR_QUEUED;
1005  		dasd_clear_timer(device);
1006  		wake_up(&dasd_flush_wq);
1007  		dasd_schedule_bh(device);
1008  		return;
1009  	}
1010  
1011   	/* check status - the request might have been killed by dyn detach */
1012  	if (cqr->status != DASD_CQR_IN_IO) {
1013  		MESSAGE(KERN_DEBUG,
1014  			"invalid status: bus_id %s, status %02x",
1015  			cdev->dev.bus_id, cqr->status);
1016  		return;
1017  	}
1018  	DBF_DEV_EVENT(DBF_DEBUG, device, "Int: CS/DS 0x%04x for cqr %p",
1019  		      ((irb->scsw.cstat << 8) | irb->scsw.dstat), cqr);
1020  
1021   	/* Find out the appropriate era_action. */
1022  	if (irb->scsw.fctl & SCSW_FCTL_HALT_FUNC)
1023  		era = dasd_era_fatal;
1024  	else if (irb->scsw.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
1025  		 irb->scsw.cstat == 0 &&
1026  		 !irb->esw.esw0.erw.cons)
1027  		era = dasd_era_none;
1028  	else if (irb->esw.esw0.erw.cons)
1029  		era = device->discipline->examine_error(cqr, irb);
1030  	else
1031  		era = dasd_era_recover;
1032  
1033  	DBF_DEV_EVENT(DBF_DEBUG, device, "era_code %d", era);
1034  	expires = 0;
1035  	if (era == dasd_era_none) {
1036  		cqr->status = DASD_CQR_DONE;
1037  		cqr->stopclk = now;
1038  		/* Start first request on queue if possible -> fast_io. */
1039  		if (cqr->list.next != &device->ccw_queue) {
1040  			next = list_entry(cqr->list.next,
1041  					  struct dasd_ccw_req, list);
1042  			if ((next->status == DASD_CQR_QUEUED) &&
1043  			    (!device->stopped)) {
1044  				if (device->discipline->start_IO(next) == 0)
1045  					expires = next->expires;
1046  				else
1047  					DEV_MESSAGE(KERN_DEBUG, device, "%s",
1048  						    "Interrupt fastpath "
1049  						    "failed!");
1050  			}
1051  		}
1052  	} else {		/* error */
1053  		memcpy(&cqr->irb, irb, sizeof (struct irb));
1054  		if (device->features & DASD_FEATURE_ERPLOG) {
1055  			/* dump sense data */
1056  			dasd_log_sense(cqr, irb);
1057  		}
1058  		switch (era) {
1059  		case dasd_era_fatal:
1060  			cqr->status = DASD_CQR_FAILED;
1061  			cqr->stopclk = now;
1062  			break;
1063  		case dasd_era_recover:
1064  			cqr->status = DASD_CQR_ERROR;
1065  			break;
1066  		default:
1067  			BUG();
1068  		}
1069  	}
1070  	if (expires != 0)
1071  		dasd_set_timer(device, expires);
1072  	else
1073  		dasd_clear_timer(device);
1074  	dasd_schedule_bh(device);
1075  }
1076  
1077  /*
1078   * posts the buffer_cache about a finalized request
1079   */
1080  static inline void
1081  dasd_end_request(struct request *req, int uptodate)
1082  {
1083  	if (end_that_request_first(req, uptodate, req->hard_nr_sectors))
1084  		BUG();
1085  	add_disk_randomness(req->rq_disk);
1086  	end_that_request_last(req, uptodate);
1087  }
1088  
1089  /*
1090   * Process finished error recovery ccw.
1091   */
1092  static inline void
1093  __dasd_process_erp(struct dasd_device *device, struct dasd_ccw_req *cqr)
1094  {
1095  	dasd_erp_fn_t erp_fn;
1096  
1097  	if (cqr->status == DASD_CQR_DONE)
1098  		DBF_DEV_EVENT(DBF_NOTICE, device, "%s", "ERP successful");
1099  	else
1100  		DEV_MESSAGE(KERN_ERR, device, "%s", "ERP unsuccessful");
1101  	erp_fn = device->discipline->erp_postaction(cqr);
1102  	erp_fn(cqr);
1103  }
1104  
1105  /*
1106   * Process ccw request queue.
1107   */
1108  static void
1109  __dasd_process_ccw_queue(struct dasd_device * device,
1110  			 struct list_head *final_queue)
1111  {
1112  	struct list_head *l, *n;
1113  	struct dasd_ccw_req *cqr;
1114  	dasd_erp_fn_t erp_fn;
1115  
1116  restart:
1117  	/* Process request with final status. */
1118  	list_for_each_safe(l, n, &device->ccw_queue) {
1119  		cqr = list_entry(l, struct dasd_ccw_req, list);
1120  		/* Stop list processing at the first non-final request. */
1121  		if (cqr->status != DASD_CQR_DONE &&
1122  		    cqr->status != DASD_CQR_FAILED &&
1123  		    cqr->status != DASD_CQR_ERROR)
1124  			break;
1125  		/*  Process requests with DASD_CQR_ERROR */
1126  		if (cqr->status == DASD_CQR_ERROR) {
1127  			if (cqr->irb.scsw.fctl & SCSW_FCTL_HALT_FUNC) {
1128  				cqr->status = DASD_CQR_FAILED;
1129  				cqr->stopclk = get_clock();
1130  			} else {
1131  				if (cqr->irb.esw.esw0.erw.cons &&
1132  				    test_bit(DASD_CQR_FLAGS_USE_ERP,
1133  					     &cqr->flags)) {
1134  					erp_fn = device->discipline->
1135  						erp_action(cqr);
1136  					erp_fn(cqr);
1137  				} else
1138  					dasd_default_erp_action(cqr);
1139  			}
1140  			goto restart;
1141  		}
1142  
1143  		/* First of all call extended error reporting. */
1144  		if (dasd_eer_enabled(device) &&
1145  		    cqr->status == DASD_CQR_FAILED) {
1146  			dasd_eer_write(device, cqr, DASD_EER_FATALERROR);
1147  
1148  			/* restart request  */
1149  			cqr->status = DASD_CQR_QUEUED;
1150  			cqr->retries = 255;
1151  			device->stopped |= DASD_STOPPED_QUIESCE;
1152  			goto restart;
1153  		}
1154  
1155  		/* Process finished ERP request. */
1156  		if (cqr->refers) {
1157  			__dasd_process_erp(device, cqr);
1158  			goto restart;
1159  		}
1160  
1161  		/* Rechain finished requests to final queue */
1162  		cqr->endclk = get_clock();
1163  		list_move_tail(&cqr->list, final_queue);
1164  	}
1165  }
1166  
1167  static void
1168  dasd_end_request_cb(struct dasd_ccw_req * cqr, void *data)
1169  {
1170  	struct request *req;
1171  	struct dasd_device *device;
1172  	int status;
1173  
1174  	req = (struct request *) data;
1175  	device = cqr->device;
1176  	dasd_profile_end(device, cqr, req);
1177  	status = cqr->device->discipline->free_cp(cqr,req);
1178  	spin_lock_irq(&device->request_queue_lock);
1179  	dasd_end_request(req, status);
1180  	spin_unlock_irq(&device->request_queue_lock);
1181  }
1182  
1183  
1184  /*
1185   * Fetch requests from the block device queue.
1186   */
1187  static void
1188  __dasd_process_blk_queue(struct dasd_device * device)
1189  {
1190  	struct request_queue *queue;
1191  	struct request *req;
1192  	struct dasd_ccw_req *cqr;
1193  	int nr_queued;
1194  
1195  	queue = device->request_queue;
1196  	/* No queue ? Then there is nothing to do. */
1197  	if (queue == NULL)
1198  		return;
1199  
1200  	/*
1201  	 * We requeue request from the block device queue to the ccw
1202  	 * queue only in two states. In state DASD_STATE_READY the
1203  	 * partition detection is done and we need to requeue requests
1204  	 * for that. State DASD_STATE_ONLINE is normal block device
1205  	 * operation.
1206  	 */
1207  	if (device->state != DASD_STATE_READY &&
1208  	    device->state != DASD_STATE_ONLINE)
1209  		return;
1210  	nr_queued = 0;
1211  	/* Now we try to fetch requests from the request queue */
1212  	list_for_each_entry(cqr, &device->ccw_queue, list)
1213  		if (cqr->status == DASD_CQR_QUEUED)
1214  			nr_queued++;
1215  	while (!blk_queue_plugged(queue) &&
1216  	       elv_next_request(queue) &&
1217  		nr_queued < DASD_CHANQ_MAX_SIZE) {
1218  		req = elv_next_request(queue);
1219  
1220  		if (device->features & DASD_FEATURE_READONLY &&
1221  		    rq_data_dir(req) == WRITE) {
1222  			DBF_DEV_EVENT(DBF_ERR, device,
1223  				      "Rejecting write request %p",
1224  				      req);
1225  			blkdev_dequeue_request(req);
1226  			dasd_end_request(req, 0);
1227  			continue;
1228  		}
1229  		if (device->stopped & DASD_STOPPED_DC_EIO) {
1230  			blkdev_dequeue_request(req);
1231  			dasd_end_request(req, 0);
1232  			continue;
1233  		}
1234  		cqr = device->discipline->build_cp(device, req);
1235  		if (IS_ERR(cqr)) {
1236  			if (PTR_ERR(cqr) == -ENOMEM)
1237  				break;	/* terminate request queue loop */
1238  			if (PTR_ERR(cqr) == -EAGAIN) {
1239  				/*
1240  				 * The current request cannot be build right
1241  				 * now, we have to try later. If this request
1242  				 * is the head-of-queue we stop the device
1243  				 * for 1/2 second.
1244  				 */
1245  				if (!list_empty(&device->ccw_queue))
1246  					break;
1247  				device->stopped |= DASD_STOPPED_PENDING;
1248  				dasd_set_timer(device, HZ/2);
1249  				break;
1250  			}
1251  			DBF_DEV_EVENT(DBF_ERR, device,
1252  				      "CCW creation failed (rc=%ld) "
1253  				      "on request %p",
1254  				      PTR_ERR(cqr), req);
1255  			blkdev_dequeue_request(req);
1256  			dasd_end_request(req, 0);
1257  			continue;
1258  		}
1259  		cqr->callback = dasd_end_request_cb;
1260  		cqr->callback_data = (void *) req;
1261  		cqr->status = DASD_CQR_QUEUED;
1262  		blkdev_dequeue_request(req);
1263  		list_add_tail(&cqr->list, &device->ccw_queue);
1264  		dasd_profile_start(device, cqr, req);
1265  		nr_queued++;
1266  	}
1267  }
1268  
1269  /*
1270   * Take a look at the first request on the ccw queue and check
1271   * if it reached its expire time. If so, terminate the IO.
1272   */
1273  static void
1274  __dasd_check_expire(struct dasd_device * device)
1275  {
1276  	struct dasd_ccw_req *cqr;
1277  
1278  	if (list_empty(&device->ccw_queue))
1279  		return;
1280  	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, list);
1281  	if ((cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) &&
1282  	    (time_after_eq(jiffies, cqr->expires + cqr->starttime))) {
1283  		if (device->discipline->term_IO(cqr) != 0) {
1284  			/* Hmpf, try again in 5 sec */
1285  			dasd_set_timer(device, 5*HZ);
1286  			DEV_MESSAGE(KERN_ERR, device,
1287  				    "internal error - timeout (%is) expired "
1288  				    "for cqr %p, termination failed, "
1289  				    "retrying in 5s",
1290  				    (cqr->expires/HZ), cqr);
1291  		} else {
1292  			DEV_MESSAGE(KERN_ERR, device,
1293  				    "internal error - timeout (%is) expired "
1294  				    "for cqr %p (%i retries left)",
1295  				    (cqr->expires/HZ), cqr, cqr->retries);
1296  		}
1297  	}
1298  }
1299  
1300  /*
1301   * Take a look at the first request on the ccw queue and check
1302   * if it needs to be started.
1303   */
1304  static void
1305  __dasd_start_head(struct dasd_device * device)
1306  {
1307  	struct dasd_ccw_req *cqr;
1308  	int rc;
1309  
1310  	if (list_empty(&device->ccw_queue))
1311  		return;
1312  	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, list);
1313  	if (cqr->status != DASD_CQR_QUEUED)
1314  		return;
1315  	/* Non-temporary stop condition will trigger fail fast */
1316  	if (device->stopped & ~DASD_STOPPED_PENDING &&
1317  	    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
1318  	    (!dasd_eer_enabled(device))) {
1319  		cqr->status = DASD_CQR_FAILED;
1320  		dasd_schedule_bh(device);
1321  		return;
1322  	}
1323  	/* Don't try to start requests if device is stopped */
1324  	if (device->stopped)
1325  		return;
1326  
1327  	rc = device->discipline->start_IO(cqr);
1328  	if (rc == 0)
1329  		dasd_set_timer(device, cqr->expires);
1330  	else if (rc == -EACCES) {
1331  		dasd_schedule_bh(device);
1332  	} else
1333  		/* Hmpf, try again in 1/2 sec */
1334  		dasd_set_timer(device, 50);
1335  }
1336  
1337  static inline int
1338  _wait_for_clear(struct dasd_ccw_req *cqr)
1339  {
1340  	return (cqr->status == DASD_CQR_QUEUED);
1341  }
1342  
1343  /*
1344   * Remove all requests from the ccw queue (all = '1') or only block device
1345   * requests in case all = '0'.
1346   * Take care of the erp-chain (chained via cqr->refers) and remove either
1347   * the whole erp-chain or none of the erp-requests.
1348   * If a request is currently running, term_IO is called and the request
1349   * is re-queued. Prior to removing the terminated request we need to wait
1350   * for the clear-interrupt.
1351   * In case termination is not possible we stop processing and just finishing
1352   * the already moved requests.
1353   */
1354  static int
1355  dasd_flush_ccw_queue(struct dasd_device * device, int all)
1356  {
1357  	struct dasd_ccw_req *cqr, *orig, *n;
1358  	int rc, i;
1359  
1360  	struct list_head flush_queue;
1361  
1362  	INIT_LIST_HEAD(&flush_queue);
1363  	spin_lock_irq(get_ccwdev_lock(device->cdev));
1364  	rc = 0;
1365  restart:
1366  	list_for_each_entry_safe(cqr, n, &device->ccw_queue, list) {
1367  		/* get original request of erp request-chain */
1368  		for (orig = cqr; orig->refers != NULL; orig = orig->refers);
1369  
1370  		/* Flush all request or only block device requests? */
1371  		if (all == 0 && cqr->callback != dasd_end_request_cb &&
1372  		    orig->callback != dasd_end_request_cb) {
1373  			continue;
1374  		}
1375  		/* Check status and move request to flush_queue */
1376  		switch (cqr->status) {
1377  		case DASD_CQR_IN_IO:
1378  			rc = device->discipline->term_IO(cqr);
1379  			if (rc) {
1380  				/* unable to terminate requeust */
1381  				DEV_MESSAGE(KERN_ERR, device,
1382  					    "dasd flush ccw_queue is unable "
1383  					    " to terminate request %p",
1384  					    cqr);
1385  				/* stop flush processing */
1386  				goto finished;
1387  			}
1388  			break;
1389  		case DASD_CQR_QUEUED:
1390  		case DASD_CQR_ERROR:
1391  			/* set request to FAILED */
1392  			cqr->stopclk = get_clock();
1393  			cqr->status = DASD_CQR_FAILED;
1394  			break;
1395  		default: /* do not touch the others */
1396  			break;
1397  		}
1398  		/* Rechain request (including erp chain) */
1399  		for (i = 0; cqr != NULL; cqr = cqr->refers, i++) {
1400  			cqr->endclk = get_clock();
1401  			list_move_tail(&cqr->list, &flush_queue);
1402  		}
1403  		if (i > 1)
1404  			/* moved more than one request - need to restart */
1405  			goto restart;
1406  	}
1407  
1408  finished:
1409  	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1410  	/* Now call the callback function of flushed requests */
1411  restart_cb:
1412  	list_for_each_entry_safe(cqr, n, &flush_queue, list) {
1413  		if (cqr->status == DASD_CQR_CLEAR) {
1414  			/* wait for clear interrupt! */
1415  			wait_event(dasd_flush_wq, _wait_for_clear(cqr));
1416  			cqr->status = DASD_CQR_FAILED;
1417  		}
1418  		/* Process finished ERP request. */
1419  		if (cqr->refers) {
1420  			__dasd_process_erp(device, cqr);
1421  			/* restart list_for_xx loop since dasd_process_erp
1422  			 * might remove multiple elements */
1423  			goto restart_cb;
1424  		}
1425  		/* call the callback function */
1426  		cqr->endclk = get_clock();
1427  		if (cqr->callback != NULL)
1428  			(cqr->callback)(cqr, cqr->callback_data);
1429  	}
1430  	return rc;
1431  }
1432  
1433  /*
1434   * Acquire the device lock and process queues for the device.
1435   */
1436  static void
1437  dasd_tasklet(struct dasd_device * device)
1438  {
1439  	struct list_head final_queue;
1440  	struct list_head *l, *n;
1441  	struct dasd_ccw_req *cqr;
1442  
1443  	atomic_set (&device->tasklet_scheduled, 0);
1444  	INIT_LIST_HEAD(&final_queue);
1445  	spin_lock_irq(get_ccwdev_lock(device->cdev));
1446  	/* Check expire time of first request on the ccw queue. */
1447  	__dasd_check_expire(device);
1448  	/* Finish off requests on ccw queue */
1449  	__dasd_process_ccw_queue(device, &final_queue);
1450  	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1451  	/* Now call the callback function of requests with final status */
1452  	list_for_each_safe(l, n, &final_queue) {
1453  		cqr = list_entry(l, struct dasd_ccw_req, list);
1454  		list_del_init(&cqr->list);
1455  		if (cqr->callback != NULL)
1456  			(cqr->callback)(cqr, cqr->callback_data);
1457  	}
1458  	spin_lock_irq(&device->request_queue_lock);
1459  	spin_lock(get_ccwdev_lock(device->cdev));
1460  	/* Get new request from the block device request queue */
1461  	__dasd_process_blk_queue(device);
1462  	/* Now check if the head of the ccw queue needs to be started. */
1463  	__dasd_start_head(device);
1464  	spin_unlock(get_ccwdev_lock(device->cdev));
1465  	spin_unlock_irq(&device->request_queue_lock);
1466  	dasd_put_device(device);
1467  }
1468  
1469  /*
1470   * Schedules a call to dasd_tasklet over the device tasklet.
1471   */
1472  void
1473  dasd_schedule_bh(struct dasd_device * device)
1474  {
1475  	/* Protect against rescheduling. */
1476  	if (atomic_cmpxchg (&device->tasklet_scheduled, 0, 1) != 0)
1477  		return;
1478  	dasd_get_device(device);
1479  	tasklet_hi_schedule(&device->tasklet);
1480  }
1481  
1482  /*
1483   * Queue a request to the head of the ccw_queue. Start the I/O if
1484   * possible.
1485   */
1486  void
1487  dasd_add_request_head(struct dasd_ccw_req *req)
1488  {
1489  	struct dasd_device *device;
1490  	unsigned long flags;
1491  
1492  	device = req->device;
1493  	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
1494  	req->status = DASD_CQR_QUEUED;
1495  	req->device = device;
1496  	list_add(&req->list, &device->ccw_queue);
1497  	/* let the bh start the request to keep them in order */
1498  	dasd_schedule_bh(device);
1499  	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
1500  }
1501  
1502  /*
1503   * Queue a request to the tail of the ccw_queue. Start the I/O if
1504   * possible.
1505   */
1506  void
1507  dasd_add_request_tail(struct dasd_ccw_req *req)
1508  {
1509  	struct dasd_device *device;
1510  	unsigned long flags;
1511  
1512  	device = req->device;
1513  	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
1514  	req->status = DASD_CQR_QUEUED;
1515  	req->device = device;
1516  	list_add_tail(&req->list, &device->ccw_queue);
1517  	/* let the bh start the request to keep them in order */
1518  	dasd_schedule_bh(device);
1519  	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
1520  }
1521  
1522  /*
1523   * Wakeup callback.
1524   */
1525  static void
1526  dasd_wakeup_cb(struct dasd_ccw_req *cqr, void *data)
1527  {
1528  	wake_up((wait_queue_head_t *) data);
1529  }
1530  
1531  static inline int
1532  _wait_for_wakeup(struct dasd_ccw_req *cqr)
1533  {
1534  	struct dasd_device *device;
1535  	int rc;
1536  
1537  	device = cqr->device;
1538  	spin_lock_irq(get_ccwdev_lock(device->cdev));
1539  	rc = ((cqr->status == DASD_CQR_DONE ||
1540  	       cqr->status == DASD_CQR_FAILED) &&
1541  	      list_empty(&cqr->list));
1542  	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1543  	return rc;
1544  }
1545  
1546  /*
1547   * Attempts to start a special ccw queue and waits for its completion.
1548   */
1549  int
1550  dasd_sleep_on(struct dasd_ccw_req * cqr)
1551  {
1552  	wait_queue_head_t wait_q;
1553  	struct dasd_device *device;
1554  	int rc;
1555  
1556  	device = cqr->device;
1557  	spin_lock_irq(get_ccwdev_lock(device->cdev));
1558  
1559  	init_waitqueue_head (&wait_q);
1560  	cqr->callback = dasd_wakeup_cb;
1561  	cqr->callback_data = (void *) &wait_q;
1562  	cqr->status = DASD_CQR_QUEUED;
1563  	list_add_tail(&cqr->list, &device->ccw_queue);
1564  
1565  	/* let the bh start the request to keep them in order */
1566  	dasd_schedule_bh(device);
1567  
1568  	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1569  
1570  	wait_event(wait_q, _wait_for_wakeup(cqr));
1571  
1572  	/* Request status is either done or failed. */
1573  	rc = (cqr->status == DASD_CQR_FAILED) ? -EIO : 0;
1574  	return rc;
1575  }
1576  
1577  /*
1578   * Attempts to start a special ccw queue and wait interruptible
1579   * for its completion.
1580   */
1581  int
1582  dasd_sleep_on_interruptible(struct dasd_ccw_req * cqr)
1583  {
1584  	wait_queue_head_t wait_q;
1585  	struct dasd_device *device;
1586  	int rc, finished;
1587  
1588  	device = cqr->device;
1589  	spin_lock_irq(get_ccwdev_lock(device->cdev));
1590  
1591  	init_waitqueue_head (&wait_q);
1592  	cqr->callback = dasd_wakeup_cb;
1593  	cqr->callback_data = (void *) &wait_q;
1594  	cqr->status = DASD_CQR_QUEUED;
1595  	list_add_tail(&cqr->list, &device->ccw_queue);
1596  
1597  	/* let the bh start the request to keep them in order */
1598  	dasd_schedule_bh(device);
1599  	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1600  
1601  	finished = 0;
1602  	while (!finished) {
1603  		rc = wait_event_interruptible(wait_q, _wait_for_wakeup(cqr));
1604  		if (rc != -ERESTARTSYS) {
1605  			/* Request is final (done or failed) */
1606  			rc = (cqr->status == DASD_CQR_DONE) ? 0 : -EIO;
1607  			break;
1608  		}
1609  		spin_lock_irq(get_ccwdev_lock(device->cdev));
1610  		switch (cqr->status) {
1611  		case DASD_CQR_IN_IO:
1612                          /* terminate runnig cqr */
1613  			if (device->discipline->term_IO) {
1614  				cqr->retries = -1;
1615  				device->discipline->term_IO(cqr);
1616  				/* wait (non-interruptible) for final status
1617  				 * because signal ist still pending */
1618  				spin_unlock_irq(get_ccwdev_lock(device->cdev));
1619  				wait_event(wait_q, _wait_for_wakeup(cqr));
1620  				spin_lock_irq(get_ccwdev_lock(device->cdev));
1621  				rc = (cqr->status == DASD_CQR_DONE) ? 0 : -EIO;
1622  				finished = 1;
1623  			}
1624  			break;
1625  		case DASD_CQR_QUEUED:
1626  			/* request  */
1627  			list_del_init(&cqr->list);
1628  			rc = -EIO;
1629  			finished = 1;
1630  			break;
1631  		default:
1632  			/* cqr with 'non-interruptable' status - just wait */
1633  			break;
1634  		}
1635  		spin_unlock_irq(get_ccwdev_lock(device->cdev));
1636  	}
1637  	return rc;
1638  }
1639  
1640  /*
1641   * Whoa nelly now it gets really hairy. For some functions (e.g. steal lock
1642   * for eckd devices) the currently running request has to be terminated
1643   * and be put back to status queued, before the special request is added
1644   * to the head of the queue. Then the special request is waited on normally.
1645   */
1646  static inline int
1647  _dasd_term_running_cqr(struct dasd_device *device)
1648  {
1649  	struct dasd_ccw_req *cqr;
1650  
1651  	if (list_empty(&device->ccw_queue))
1652  		return 0;
1653  	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, list);
1654  	return device->discipline->term_IO(cqr);
1655  }
1656  
1657  int
1658  dasd_sleep_on_immediatly(struct dasd_ccw_req * cqr)
1659  {
1660  	wait_queue_head_t wait_q;
1661  	struct dasd_device *device;
1662  	int rc;
1663  
1664  	device = cqr->device;
1665  	spin_lock_irq(get_ccwdev_lock(device->cdev));
1666  	rc = _dasd_term_running_cqr(device);
1667  	if (rc) {
1668  		spin_unlock_irq(get_ccwdev_lock(device->cdev));
1669  		return rc;
1670  	}
1671  
1672  	init_waitqueue_head (&wait_q);
1673  	cqr->callback = dasd_wakeup_cb;
1674  	cqr->callback_data = (void *) &wait_q;
1675  	cqr->status = DASD_CQR_QUEUED;
1676  	list_add(&cqr->list, &device->ccw_queue);
1677  
1678  	/* let the bh start the request to keep them in order */
1679  	dasd_schedule_bh(device);
1680  
1681  	spin_unlock_irq(get_ccwdev_lock(device->cdev));
1682  
1683  	wait_event(wait_q, _wait_for_wakeup(cqr));
1684  
1685  	/* Request status is either done or failed. */
1686  	rc = (cqr->status == DASD_CQR_FAILED) ? -EIO : 0;
1687  	return rc;
1688  }
1689  
1690  /*
1691   * Cancels a request that was started with dasd_sleep_on_req.
1692   * This is useful to timeout requests. The request will be
1693   * terminated if it is currently in i/o.
1694   * Returns 1 if the request has been terminated.
1695   */
1696  int
1697  dasd_cancel_req(struct dasd_ccw_req *cqr)
1698  {
1699  	struct dasd_device *device = cqr->device;
1700  	unsigned long flags;
1701  	int rc;
1702  
1703  	rc = 0;
1704  	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
1705  	switch (cqr->status) {
1706  	case DASD_CQR_QUEUED:
1707  		/* request was not started - just set to failed */
1708  		cqr->status = DASD_CQR_FAILED;
1709  		break;
1710  	case DASD_CQR_IN_IO:
1711  		/* request in IO - terminate IO and release again */
1712  		if (device->discipline->term_IO(cqr) != 0)
1713  			/* what to do if unable to terminate ??????
1714  			   e.g. not _IN_IO */
1715  			cqr->status = DASD_CQR_FAILED;
1716  		cqr->stopclk = get_clock();
1717  		rc = 1;
1718  		break;
1719  	case DASD_CQR_DONE:
1720  	case DASD_CQR_FAILED:
1721  		/* already finished - do nothing */
1722  		break;
1723  	default:
1724  		DEV_MESSAGE(KERN_ALERT, device,
1725  			    "invalid status %02x in request",
1726  			    cqr->status);
1727  		BUG();
1728  
1729  	}
1730  	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
1731  	dasd_schedule_bh(device);
1732  	return rc;
1733  }
1734  
1735  /*
1736   * SECTION: Block device operations (request queue, partitions, open, release).
1737   */
1738  
1739  /*
1740   * Dasd request queue function. Called from ll_rw_blk.c
1741   */
1742  static void
1743  do_dasd_request(struct request_queue * queue)
1744  {
1745  	struct dasd_device *device;
1746  
1747  	device = (struct dasd_device *) queue->queuedata;
1748  	spin_lock(get_ccwdev_lock(device->cdev));
1749  	/* Get new request from the block device request queue */
1750  	__dasd_process_blk_queue(device);
1751  	/* Now check if the head of the ccw queue needs to be started. */
1752  	__dasd_start_head(device);
1753  	spin_unlock(get_ccwdev_lock(device->cdev));
1754  }
1755  
1756  /*
1757   * Allocate and initialize request queue and default I/O scheduler.
1758   */
1759  static int
1760  dasd_alloc_queue(struct dasd_device * device)
1761  {
1762  	int rc;
1763  
1764  	device->request_queue = blk_init_queue(do_dasd_request,
1765  					       &device->request_queue_lock);
1766  	if (device->request_queue == NULL)
1767  		return -ENOMEM;
1768  
1769  	device->request_queue->queuedata = device;
1770  
1771  	elevator_exit(device->request_queue->elevator);
1772  	rc = elevator_init(device->request_queue, "deadline");
1773  	if (rc) {
1774  		blk_cleanup_queue(device->request_queue);
1775  		return rc;
1776  	}
1777  	return 0;
1778  }
1779  
1780  /*
1781   * Allocate and initialize request queue.
1782   */
1783  static void
1784  dasd_setup_queue(struct dasd_device * device)
1785  {
1786  	int max;
1787  
1788  	blk_queue_hardsect_size(device->request_queue, device->bp_block);
1789  	max = device->discipline->max_blocks << device->s2b_shift;
1790  	blk_queue_max_sectors(device->request_queue, max);
1791  	blk_queue_max_phys_segments(device->request_queue, -1L);
1792  	blk_queue_max_hw_segments(device->request_queue, -1L);
1793  	blk_queue_max_segment_size(device->request_queue, -1L);
1794  	blk_queue_segment_boundary(device->request_queue, -1L);
1795  	blk_queue_ordered(device->request_queue, QUEUE_ORDERED_TAG, NULL);
1796  }
1797  
1798  /*
1799   * Deactivate and free request queue.
1800   */
1801  static void
1802  dasd_free_queue(struct dasd_device * device)
1803  {
1804  	if (device->request_queue) {
1805  		blk_cleanup_queue(device->request_queue);
1806  		device->request_queue = NULL;
1807  	}
1808  }
1809  
1810  /*
1811   * Flush request on the request queue.
1812   */
1813  static void
1814  dasd_flush_request_queue(struct dasd_device * device)
1815  {
1816  	struct request *req;
1817  
1818  	if (!device->request_queue)
1819  		return;
1820  
1821  	spin_lock_irq(&device->request_queue_lock);
1822  	while ((req = elv_next_request(device->request_queue))) {
1823  		blkdev_dequeue_request(req);
1824  		dasd_end_request(req, 0);
1825  	}
1826  	spin_unlock_irq(&device->request_queue_lock);
1827  }
1828  
1829  static int
1830  dasd_open(struct inode *inp, struct file *filp)
1831  {
1832  	struct gendisk *disk = inp->i_bdev->bd_disk;
1833  	struct dasd_device *device = disk->private_data;
1834  	int rc;
1835  
1836          atomic_inc(&device->open_count);
1837  	if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
1838  		rc = -ENODEV;
1839  		goto unlock;
1840  	}
1841  
1842  	if (!try_module_get(device->discipline->owner)) {
1843  		rc = -EINVAL;
1844  		goto unlock;
1845  	}
1846  
1847  	if (dasd_probeonly) {
1848  		DEV_MESSAGE(KERN_INFO, device, "%s",
1849  			    "No access to device due to probeonly mode");
1850  		rc = -EPERM;
1851  		goto out;
1852  	}
1853  
1854  	if (device->state <= DASD_STATE_BASIC) {
1855  		DBF_DEV_EVENT(DBF_ERR, device, " %s",
1856  			      " Cannot open unrecognized device");
1857  		rc = -ENODEV;
1858  		goto out;
1859  	}
1860  
1861  	return 0;
1862  
1863  out:
1864  	module_put(device->discipline->owner);
1865  unlock:
1866  	atomic_dec(&device->open_count);
1867  	return rc;
1868  }
1869  
1870  static int
1871  dasd_release(struct inode *inp, struct file *filp)
1872  {
1873  	struct gendisk *disk = inp->i_bdev->bd_disk;
1874  	struct dasd_device *device = disk->private_data;
1875  
1876  	atomic_dec(&device->open_count);
1877  	module_put(device->discipline->owner);
1878  	return 0;
1879  }
1880  
1881  /*
1882   * Return disk geometry.
1883   */
1884  static int
1885  dasd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1886  {
1887  	struct dasd_device *device;
1888  
1889  	device = bdev->bd_disk->private_data;
1890  	if (!device)
1891  		return -ENODEV;
1892  
1893  	if (!device->discipline ||
1894  	    !device->discipline->fill_geometry)
1895  		return -EINVAL;
1896  
1897  	device->discipline->fill_geometry(device, geo);
1898  	geo->start = get_start_sect(bdev) >> device->s2b_shift;
1899  	return 0;
1900  }
1901  
1902  struct block_device_operations
1903  dasd_device_operations = {
1904  	.owner		= THIS_MODULE,
1905  	.open		= dasd_open,
1906  	.release	= dasd_release,
1907  	.ioctl		= dasd_ioctl,
1908  	.compat_ioctl	= dasd_compat_ioctl,
1909  	.getgeo		= dasd_getgeo,
1910  };
1911  
1912  
1913  static void
1914  dasd_exit(void)
1915  {
1916  #ifdef CONFIG_PROC_FS
1917  	dasd_proc_exit();
1918  #endif
1919  	dasd_eer_exit();
1920          if (dasd_page_cache != NULL) {
1921  		kmem_cache_destroy(dasd_page_cache);
1922  		dasd_page_cache = NULL;
1923  	}
1924  	dasd_gendisk_exit();
1925  	dasd_devmap_exit();
1926  	if (dasd_debug_area != NULL) {
1927  		debug_unregister(dasd_debug_area);
1928  		dasd_debug_area = NULL;
1929  	}
1930  }
1931  
1932  /*
1933   * SECTION: common functions for ccw_driver use
1934   */
1935  
1936  /*
1937   * Initial attempt at a probe function. this can be simplified once
1938   * the other detection code is gone.
1939   */
1940  int
1941  dasd_generic_probe (struct ccw_device *cdev,
1942  		    struct dasd_discipline *discipline)
1943  {
1944  	int ret;
1945  
1946  	ret = ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP);
1947  	if (ret) {
1948  		printk(KERN_WARNING
1949  		       "dasd_generic_probe: could not set ccw-device options "
1950  		       "for %s\n", cdev->dev.bus_id);
1951  		return ret;
1952  	}
1953  	ret = dasd_add_sysfs_files(cdev);
1954  	if (ret) {
1955  		printk(KERN_WARNING
1956  		       "dasd_generic_probe: could not add sysfs entries "
1957  		       "for %s\n", cdev->dev.bus_id);
1958  		return ret;
1959  	}
1960  	cdev->handler = &dasd_int_handler;
1961  
1962  	/*
1963  	 * Automatically online either all dasd devices (dasd_autodetect)
1964  	 * or all devices specified with dasd= parameters during
1965  	 * initial probe.
1966  	 */
1967  	if ((dasd_get_feature(cdev, DASD_FEATURE_INITIAL_ONLINE) > 0 ) ||
1968  	    (dasd_autodetect && dasd_busid_known(cdev->dev.bus_id) != 0))
1969  		ret = ccw_device_set_online(cdev);
1970  	if (ret)
1971  		printk(KERN_WARNING
1972  		       "dasd_generic_probe: could not initially "
1973  		       "online ccw-device %s; return code: %d\n",
1974  		       cdev->dev.bus_id, ret);
1975  	return 0;
1976  }
1977  
1978  /*
1979   * This will one day be called from a global not_oper handler.
1980   * It is also used by driver_unregister during module unload.
1981   */
1982  void
1983  dasd_generic_remove (struct ccw_device *cdev)
1984  {
1985  	struct dasd_device *device;
1986  
1987  	cdev->handler = NULL;
1988  
1989  	dasd_remove_sysfs_files(cdev);
1990  	device = dasd_device_from_cdev(cdev);
1991  	if (IS_ERR(device))
1992  		return;
1993  	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
1994  		/* Already doing offline processing */
1995  		dasd_put_device(device);
1996  		return;
1997  	}
1998  	/*
1999  	 * This device is removed unconditionally. Set offline
2000  	 * flag to prevent dasd_open from opening it while it is
2001  	 * no quite down yet.
2002  	 */
2003  	dasd_set_target_state(device, DASD_STATE_NEW);
2004  	/* dasd_delete_device destroys the device reference. */
2005  	dasd_delete_device(device);
2006  }
2007  
2008  /*
2009   * Activate a device. This is called from dasd_{eckd,fba}_probe() when either
2010   * the device is detected for the first time and is supposed to be used
2011   * or the user has started activation through sysfs.
2012   */
2013  int
2014  dasd_generic_set_online (struct ccw_device *cdev,
2015  			 struct dasd_discipline *base_discipline)
2016  
2017  {
2018  	struct dasd_discipline *discipline;
2019  	struct dasd_device *device;
2020  	int rc;
2021  
2022  	/* first online clears initial online feature flag */
2023  	dasd_set_feature(cdev, DASD_FEATURE_INITIAL_ONLINE, 0);
2024  	device = dasd_create_device(cdev);
2025  	if (IS_ERR(device))
2026  		return PTR_ERR(device);
2027  
2028  	discipline = base_discipline;
2029  	if (device->features & DASD_FEATURE_USEDIAG) {
2030  	  	if (!dasd_diag_discipline_pointer) {
2031  		        printk (KERN_WARNING
2032  				"dasd_generic couldn't online device %s "
2033  				"- discipline DIAG not available\n",
2034  				cdev->dev.bus_id);
2035  			dasd_delete_device(device);
2036  			return -ENODEV;
2037  		}
2038  		discipline = dasd_diag_discipline_pointer;
2039  	}
2040  	if (!try_module_get(base_discipline->owner)) {
2041  		dasd_delete_device(device);
2042  		return -EINVAL;
2043  	}
2044  	if (!try_module_get(discipline->owner)) {
2045  		module_put(base_discipline->owner);
2046  		dasd_delete_device(device);
2047  		return -EINVAL;
2048  	}
2049  	device->base_discipline = base_discipline;
2050  	device->discipline = discipline;
2051  
2052  	rc = discipline->check_device(device);
2053  	if (rc) {
2054  		printk (KERN_WARNING
2055  			"dasd_generic couldn't online device %s "
2056  			"with discipline %s rc=%i\n",
2057  			cdev->dev.bus_id, discipline->name, rc);
2058  		module_put(discipline->owner);
2059  		module_put(base_discipline->owner);
2060  		dasd_delete_device(device);
2061  		return rc;
2062  	}
2063  
2064  	dasd_set_target_state(device, DASD_STATE_ONLINE);
2065  	if (device->state <= DASD_STATE_KNOWN) {
2066  		printk (KERN_WARNING
2067  			"dasd_generic discipline not found for %s\n",
2068  			cdev->dev.bus_id);
2069  		rc = -ENODEV;
2070  		dasd_set_target_state(device, DASD_STATE_NEW);
2071  		dasd_delete_device(device);
2072  	} else
2073  		pr_debug("dasd_generic device %s found\n",
2074  				cdev->dev.bus_id);
2075  
2076  	/* FIXME: we have to wait for the root device but we don't want
2077  	 * to wait for each single device but for all at once. */
2078  	wait_event(dasd_init_waitq, _wait_for_device(device));
2079  
2080  	dasd_put_device(device);
2081  
2082  	return rc;
2083  }
2084  
2085  int
2086  dasd_generic_set_offline (struct ccw_device *cdev)
2087  {
2088  	struct dasd_device *device;
2089  	int max_count, open_count;
2090  
2091  	device = dasd_device_from_cdev(cdev);
2092  	if (IS_ERR(device))
2093  		return PTR_ERR(device);
2094  	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
2095  		/* Already doing offline processing */
2096  		dasd_put_device(device);
2097  		return 0;
2098  	}
2099  	/*
2100  	 * We must make sure that this device is currently not in use.
2101  	 * The open_count is increased for every opener, that includes
2102  	 * the blkdev_get in dasd_scan_partitions. We are only interested
2103  	 * in the other openers.
2104  	 */
2105  	max_count = device->bdev ? 0 : -1;
2106  	open_count = (int) atomic_read(&device->open_count);
2107  	if (open_count > max_count) {
2108  		if (open_count > 0)
2109  			printk (KERN_WARNING "Can't offline dasd device with "
2110  				"open count = %i.\n",
2111  				open_count);
2112  		else
2113  			printk (KERN_WARNING "%s",
2114  				"Can't offline dasd device due to internal "
2115  				"use\n");
2116  		clear_bit(DASD_FLAG_OFFLINE, &device->flags);
2117  		dasd_put_device(device);
2118  		return -EBUSY;
2119  	}
2120  	dasd_set_target_state(device, DASD_STATE_NEW);
2121  	/* dasd_delete_device destroys the device reference. */
2122  	dasd_delete_device(device);
2123  
2124  	return 0;
2125  }
2126  
2127  int
2128  dasd_generic_notify(struct ccw_device *cdev, int event)
2129  {
2130  	struct dasd_device *device;
2131  	struct dasd_ccw_req *cqr;
2132  	unsigned long flags;
2133  	int ret;
2134  
2135  	device = dasd_device_from_cdev(cdev);
2136  	if (IS_ERR(device))
2137  		return 0;
2138  	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
2139  	ret = 0;
2140  	switch (event) {
2141  	case CIO_GONE:
2142  	case CIO_NO_PATH:
2143  		/* First of all call extended error reporting. */
2144  		dasd_eer_write(device, NULL, DASD_EER_NOPATH);
2145  
2146  		if (device->state < DASD_STATE_BASIC)
2147  			break;
2148  		/* Device is active. We want to keep it. */
2149  		if (test_bit(DASD_FLAG_DSC_ERROR, &device->flags)) {
2150  			list_for_each_entry(cqr, &device->ccw_queue, list)
2151  				if (cqr->status == DASD_CQR_IN_IO)
2152  					cqr->status = DASD_CQR_FAILED;
2153  			device->stopped |= DASD_STOPPED_DC_EIO;
2154  		} else {
2155  			list_for_each_entry(cqr, &device->ccw_queue, list)
2156  				if (cqr->status == DASD_CQR_IN_IO) {
2157  					cqr->status = DASD_CQR_QUEUED;
2158  					cqr->retries++;
2159  				}
2160  			device->stopped |= DASD_STOPPED_DC_WAIT;
2161  			dasd_set_timer(device, 0);
2162  		}
2163  		dasd_schedule_bh(device);
2164  		ret = 1;
2165  		break;
2166  	case CIO_OPER:
2167  		/* FIXME: add a sanity check. */
2168  		device->stopped &= ~(DASD_STOPPED_DC_WAIT|DASD_STOPPED_DC_EIO);
2169  		dasd_schedule_bh(device);
2170  		ret = 1;
2171  		break;
2172  	}
2173  	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
2174  	dasd_put_device(device);
2175  	return ret;
2176  }
2177  
2178  static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
2179  						   void *rdc_buffer,
2180  						   int rdc_buffer_size,
2181  						   char *magic)
2182  {
2183  	struct dasd_ccw_req *cqr;
2184  	struct ccw1 *ccw;
2185  
2186  	cqr = dasd_smalloc_request(magic, 1 /* RDC */, rdc_buffer_size, device);
2187  
2188  	if (IS_ERR(cqr)) {
2189  		DEV_MESSAGE(KERN_WARNING, device, "%s",
2190  			    "Could not allocate RDC request");
2191  		return cqr;
2192  	}
2193  
2194  	ccw = cqr->cpaddr;
2195  	ccw->cmd_code = CCW_CMD_RDC;
2196  	ccw->cda = (__u32)(addr_t)rdc_buffer;
2197  	ccw->count = rdc_buffer_size;
2198  
2199  	cqr->device = device;
2200  	cqr->expires = 10*HZ;
2201  	clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
2202  	cqr->retries = 2;
2203  	cqr->buildclk = get_clock();
2204  	cqr->status = DASD_CQR_FILLED;
2205  	return cqr;
2206  }
2207  
2208  
2209  int dasd_generic_read_dev_chars(struct dasd_device *device, char *magic,
2210  				void **rdc_buffer, int rdc_buffer_size)
2211  {
2212  	int ret;
2213  	struct dasd_ccw_req *cqr;
2214  
2215  	cqr = dasd_generic_build_rdc(device, *rdc_buffer, rdc_buffer_size,
2216  				     magic);
2217  	if (IS_ERR(cqr))
2218  		return PTR_ERR(cqr);
2219  
2220  	ret = dasd_sleep_on(cqr);
2221  	dasd_sfree_request(cqr, cqr->device);
2222  	return ret;
2223  }
2224  EXPORT_SYMBOL_GPL(dasd_generic_read_dev_chars);
2225  
2226  static int __init
2227  dasd_init(void)
2228  {
2229  	int rc;
2230  
2231  	init_waitqueue_head(&dasd_init_waitq);
2232  	init_waitqueue_head(&dasd_flush_wq);
2233  
2234  	/* register 'common' DASD debug area, used for all DBF_XXX calls */
2235  	dasd_debug_area = debug_register("dasd", 1, 2, 8 * sizeof (long));
2236  	if (dasd_debug_area == NULL) {
2237  		rc = -ENOMEM;
2238  		goto failed;
2239  	}
2240  	debug_register_view(dasd_debug_area, &debug_sprintf_view);
2241  	debug_set_level(dasd_debug_area, DBF_WARNING);
2242  
2243  	DBF_EVENT(DBF_EMERG, "%s", "debug area created");
2244  
2245  	dasd_diag_discipline_pointer = NULL;
2246  
2247  	rc = dasd_devmap_init();
2248  	if (rc)
2249  		goto failed;
2250  	rc = dasd_gendisk_init();
2251  	if (rc)
2252  		goto failed;
2253  	rc = dasd_parse();
2254  	if (rc)
2255  		goto failed;
2256  	rc = dasd_eer_init();
2257  	if (rc)
2258  		goto failed;
2259  #ifdef CONFIG_PROC_FS
2260  	rc = dasd_proc_init();
2261  	if (rc)
2262  		goto failed;
2263  #endif
2264  
2265  	return 0;
2266  failed:
2267  	MESSAGE(KERN_INFO, "%s", "initialization not performed due to errors");
2268  	dasd_exit();
2269  	return rc;
2270  }
2271  
2272  module_init(dasd_init);
2273  module_exit(dasd_exit);
2274  
2275  EXPORT_SYMBOL(dasd_debug_area);
2276  EXPORT_SYMBOL(dasd_diag_discipline_pointer);
2277  
2278  EXPORT_SYMBOL(dasd_add_request_head);
2279  EXPORT_SYMBOL(dasd_add_request_tail);
2280  EXPORT_SYMBOL(dasd_cancel_req);
2281  EXPORT_SYMBOL(dasd_clear_timer);
2282  EXPORT_SYMBOL(dasd_enable_device);
2283  EXPORT_SYMBOL(dasd_int_handler);
2284  EXPORT_SYMBOL(dasd_kfree_request);
2285  EXPORT_SYMBOL(dasd_kick_device);
2286  EXPORT_SYMBOL(dasd_kmalloc_request);
2287  EXPORT_SYMBOL(dasd_schedule_bh);
2288  EXPORT_SYMBOL(dasd_set_target_state);
2289  EXPORT_SYMBOL(dasd_set_timer);
2290  EXPORT_SYMBOL(dasd_sfree_request);
2291  EXPORT_SYMBOL(dasd_sleep_on);
2292  EXPORT_SYMBOL(dasd_sleep_on_immediatly);
2293  EXPORT_SYMBOL(dasd_sleep_on_interruptible);
2294  EXPORT_SYMBOL(dasd_smalloc_request);
2295  EXPORT_SYMBOL(dasd_start_IO);
2296  EXPORT_SYMBOL(dasd_term_IO);
2297  
2298  EXPORT_SYMBOL_GPL(dasd_generic_probe);
2299  EXPORT_SYMBOL_GPL(dasd_generic_remove);
2300  EXPORT_SYMBOL_GPL(dasd_generic_notify);
2301  EXPORT_SYMBOL_GPL(dasd_generic_set_online);
2302  EXPORT_SYMBOL_GPL(dasd_generic_set_offline);
2303  
2304