[SCSI] scsi_dh: create sysfs file, dh_state for all SCSI disk devices
[linux-2.6.git] / drivers / scsi / hosts.c
1 /*
2  *  hosts.c Copyright (C) 1992 Drew Eckhardt
3  *          Copyright (C) 1993, 1994, 1995 Eric Youngdale
4  *          Copyright (C) 2002-2003 Christoph Hellwig
5  *
6  *  mid to lowlevel SCSI driver interface
7  *      Initial versions: Drew Eckhardt
8  *      Subsequent revisions: Eric Youngdale
9  *
10  *  <drew@colorado.edu>
11  *
12  *  Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
13  *  Added QLOGIC QLA1280 SCSI controller kernel host support. 
14  *     August 4, 1999 Fred Lewis, Intel DuPont
15  *
16  *  Updated to reflect the new initialization scheme for the higher 
17  *  level of scsi drivers (sd/sr/st)
18  *  September 17, 2000 Torben Mathiasen <tmm@image.dk>
19  *
20  *  Restructured scsi_host lists and associated functions.
21  *  September 04, 2002 Mike Anderson (andmike@us.ibm.com)
22  */
23
24 #include <linux/module.h>
25 #include <linux/blkdev.h>
26 #include <linux/kernel.h>
27 #include <linux/kthread.h>
28 #include <linux/string.h>
29 #include <linux/mm.h>
30 #include <linux/init.h>
31 #include <linux/completion.h>
32 #include <linux/transport_class.h>
33 #include <linux/platform_device.h>
34
35 #include <scsi/scsi_device.h>
36 #include <scsi/scsi_host.h>
37 #include <scsi/scsi_transport.h>
38
39 #include "scsi_priv.h"
40 #include "scsi_logging.h"
41
42
43 static atomic_t scsi_host_next_hn;      /* host_no for next new host */
44
45
46 static void scsi_host_cls_release(struct device *dev)
47 {
48         put_device(&class_to_shost(dev)->shost_gendev);
49 }
50
51 static struct class shost_class = {
52         .name           = "scsi_host",
53         .dev_release    = scsi_host_cls_release,
54 };
55
56 /**
57  *      scsi_host_set_state - Take the given host through the host state model.
58  *      @shost: scsi host to change the state of.
59  *      @state: state to change to.
60  *
61  *      Returns zero if unsuccessful or an error if the requested
62  *      transition is illegal.
63  **/
64 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
65 {
66         enum scsi_host_state oldstate = shost->shost_state;
67
68         if (state == oldstate)
69                 return 0;
70
71         switch (state) {
72         case SHOST_CREATED:
73                 /* There are no legal states that come back to
74                  * created.  This is the manually initialised start
75                  * state */
76                 goto illegal;
77
78         case SHOST_RUNNING:
79                 switch (oldstate) {
80                 case SHOST_CREATED:
81                 case SHOST_RECOVERY:
82                         break;
83                 default:
84                         goto illegal;
85                 }
86                 break;
87
88         case SHOST_RECOVERY:
89                 switch (oldstate) {
90                 case SHOST_RUNNING:
91                         break;
92                 default:
93                         goto illegal;
94                 }
95                 break;
96
97         case SHOST_CANCEL:
98                 switch (oldstate) {
99                 case SHOST_CREATED:
100                 case SHOST_RUNNING:
101                 case SHOST_CANCEL_RECOVERY:
102                         break;
103                 default:
104                         goto illegal;
105                 }
106                 break;
107
108         case SHOST_DEL:
109                 switch (oldstate) {
110                 case SHOST_CANCEL:
111                 case SHOST_DEL_RECOVERY:
112                         break;
113                 default:
114                         goto illegal;
115                 }
116                 break;
117
118         case SHOST_CANCEL_RECOVERY:
119                 switch (oldstate) {
120                 case SHOST_CANCEL:
121                 case SHOST_RECOVERY:
122                         break;
123                 default:
124                         goto illegal;
125                 }
126                 break;
127
128         case SHOST_DEL_RECOVERY:
129                 switch (oldstate) {
130                 case SHOST_CANCEL_RECOVERY:
131                         break;
132                 default:
133                         goto illegal;
134                 }
135                 break;
136         }
137         shost->shost_state = state;
138         return 0;
139
140  illegal:
141         SCSI_LOG_ERROR_RECOVERY(1,
142                                 shost_printk(KERN_ERR, shost,
143                                              "Illegal host state transition"
144                                              "%s->%s\n",
145                                              scsi_host_state_name(oldstate),
146                                              scsi_host_state_name(state)));
147         return -EINVAL;
148 }
149 EXPORT_SYMBOL(scsi_host_set_state);
150
151 /**
152  * scsi_remove_host - remove a scsi host
153  * @shost:      a pointer to a scsi host to remove
154  **/
155 void scsi_remove_host(struct Scsi_Host *shost)
156 {
157         unsigned long flags;
158         mutex_lock(&shost->scan_mutex);
159         spin_lock_irqsave(shost->host_lock, flags);
160         if (scsi_host_set_state(shost, SHOST_CANCEL))
161                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
162                         spin_unlock_irqrestore(shost->host_lock, flags);
163                         mutex_unlock(&shost->scan_mutex);
164                         return;
165                 }
166         spin_unlock_irqrestore(shost->host_lock, flags);
167         mutex_unlock(&shost->scan_mutex);
168         scsi_forget_host(shost);
169         scsi_proc_host_rm(shost);
170
171         spin_lock_irqsave(shost->host_lock, flags);
172         if (scsi_host_set_state(shost, SHOST_DEL))
173                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
174         spin_unlock_irqrestore(shost->host_lock, flags);
175
176         transport_unregister_device(&shost->shost_gendev);
177         device_unregister(&shost->shost_dev);
178         device_del(&shost->shost_gendev);
179 }
180 EXPORT_SYMBOL(scsi_remove_host);
181
182 /**
183  * scsi_add_host - add a scsi host
184  * @shost:      scsi host pointer to add
185  * @dev:        a struct device of type scsi class
186  *
187  * Return value: 
188  *      0 on success / != 0 for error
189  **/
190 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
191 {
192         struct scsi_host_template *sht = shost->hostt;
193         int error = -EINVAL;
194
195         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
196                         sht->info ? sht->info(shost) : sht->name);
197
198         if (!shost->can_queue) {
199                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
200                                 sht->name);
201                 goto fail;
202         }
203
204         error = scsi_setup_command_freelist(shost);
205         if (error)
206                 goto fail;
207
208         if (!shost->shost_gendev.parent)
209                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
210
211         error = device_add(&shost->shost_gendev);
212         if (error)
213                 goto out;
214
215         scsi_host_set_state(shost, SHOST_RUNNING);
216         get_device(shost->shost_gendev.parent);
217
218         error = device_add(&shost->shost_dev);
219         if (error)
220                 goto out_del_gendev;
221
222         get_device(&shost->shost_gendev);
223
224         if (shost->transportt->host_size) {
225                 shost->shost_data = kzalloc(shost->transportt->host_size,
226                                          GFP_KERNEL);
227                 if (shost->shost_data == NULL) {
228                         error = -ENOMEM;
229                         goto out_del_dev;
230                 }
231         }
232
233         if (shost->transportt->create_work_queue) {
234                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
235                          "scsi_wq_%d", shost->host_no);
236                 shost->work_q = create_singlethread_workqueue(
237                                         shost->work_q_name);
238                 if (!shost->work_q) {
239                         error = -EINVAL;
240                         goto out_free_shost_data;
241                 }
242         }
243
244         error = scsi_sysfs_add_host(shost);
245         if (error)
246                 goto out_destroy_host;
247
248         scsi_proc_host_add(shost);
249         return error;
250
251  out_destroy_host:
252         if (shost->work_q)
253                 destroy_workqueue(shost->work_q);
254  out_free_shost_data:
255         kfree(shost->shost_data);
256  out_del_dev:
257         device_del(&shost->shost_dev);
258  out_del_gendev:
259         device_del(&shost->shost_gendev);
260  out:
261         scsi_destroy_command_freelist(shost);
262  fail:
263         return error;
264 }
265 EXPORT_SYMBOL(scsi_add_host);
266
267 static void scsi_host_dev_release(struct device *dev)
268 {
269         struct Scsi_Host *shost = dev_to_shost(dev);
270         struct device *parent = dev->parent;
271
272         scsi_proc_hostdir_rm(shost->hostt);
273
274         if (shost->ehandler)
275                 kthread_stop(shost->ehandler);
276         if (shost->work_q)
277                 destroy_workqueue(shost->work_q);
278         if (shost->uspace_req_q) {
279                 kfree(shost->uspace_req_q->queuedata);
280                 scsi_free_queue(shost->uspace_req_q);
281         }
282
283         scsi_destroy_command_freelist(shost);
284         if (shost->bqt)
285                 blk_free_tags(shost->bqt);
286
287         kfree(shost->shost_data);
288
289         if (parent)
290                 put_device(parent);
291         kfree(shost);
292 }
293
294 static struct device_type scsi_host_type = {
295         .name =         "scsi_host",
296         .release =      scsi_host_dev_release,
297 };
298
299 /**
300  * scsi_host_alloc - register a scsi host adapter instance.
301  * @sht:        pointer to scsi host template
302  * @privsize:   extra bytes to allocate for driver
303  *
304  * Note:
305  *      Allocate a new Scsi_Host and perform basic initialization.
306  *      The host is not published to the scsi midlayer until scsi_add_host
307  *      is called.
308  *
309  * Return value:
310  *      Pointer to a new Scsi_Host
311  **/
312 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
313 {
314         struct Scsi_Host *shost;
315         gfp_t gfp_mask = GFP_KERNEL;
316         int rval;
317
318         if (sht->unchecked_isa_dma && privsize)
319                 gfp_mask |= __GFP_DMA;
320
321         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
322         if (!shost)
323                 return NULL;
324
325         shost->host_lock = &shost->default_lock;
326         spin_lock_init(shost->host_lock);
327         shost->shost_state = SHOST_CREATED;
328         INIT_LIST_HEAD(&shost->__devices);
329         INIT_LIST_HEAD(&shost->__targets);
330         INIT_LIST_HEAD(&shost->eh_cmd_q);
331         INIT_LIST_HEAD(&shost->starved_list);
332         init_waitqueue_head(&shost->host_wait);
333
334         mutex_init(&shost->scan_mutex);
335
336         /*
337          * subtract one because we increment first then return, but we need to
338          * know what the next host number was before increment
339          */
340         shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
341         shost->dma_channel = 0xff;
342
343         /* These three are default values which can be overridden */
344         shost->max_channel = 0;
345         shost->max_id = 8;
346         shost->max_lun = 8;
347
348         /* Give each shost a default transportt */
349         shost->transportt = &blank_transport_template;
350
351         /*
352          * All drivers right now should be able to handle 12 byte
353          * commands.  Every so often there are requests for 16 byte
354          * commands, but individual low-level drivers need to certify that
355          * they actually do something sensible with such commands.
356          */
357         shost->max_cmd_len = 12;
358         shost->hostt = sht;
359         shost->this_id = sht->this_id;
360         shost->can_queue = sht->can_queue;
361         shost->sg_tablesize = sht->sg_tablesize;
362         shost->cmd_per_lun = sht->cmd_per_lun;
363         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
364         shost->use_clustering = sht->use_clustering;
365         shost->ordered_tag = sht->ordered_tag;
366
367         if (sht->supported_mode == MODE_UNKNOWN)
368                 /* means we didn't set it ... default to INITIATOR */
369                 shost->active_mode = MODE_INITIATOR;
370         else
371                 shost->active_mode = sht->supported_mode;
372
373         if (sht->max_host_blocked)
374                 shost->max_host_blocked = sht->max_host_blocked;
375         else
376                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
377
378         /*
379          * If the driver imposes no hard sector transfer limit, start at
380          * machine infinity initially.
381          */
382         if (sht->max_sectors)
383                 shost->max_sectors = sht->max_sectors;
384         else
385                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
386
387         /*
388          * assume a 4GB boundary, if not set
389          */
390         if (sht->dma_boundary)
391                 shost->dma_boundary = sht->dma_boundary;
392         else
393                 shost->dma_boundary = 0xffffffff;
394
395         device_initialize(&shost->shost_gendev);
396         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
397 #ifndef CONFIG_SYSFS_DEPRECATED
398         shost->shost_gendev.bus = &scsi_bus_type;
399 #endif
400         shost->shost_gendev.type = &scsi_host_type;
401
402         device_initialize(&shost->shost_dev);
403         shost->shost_dev.parent = &shost->shost_gendev;
404         shost->shost_dev.class = &shost_class;
405         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
406         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
407
408         shost->ehandler = kthread_run(scsi_error_handler, shost,
409                         "scsi_eh_%d", shost->host_no);
410         if (IS_ERR(shost->ehandler)) {
411                 rval = PTR_ERR(shost->ehandler);
412                 goto fail_kfree;
413         }
414
415         scsi_proc_hostdir_add(shost->hostt);
416         return shost;
417
418  fail_kfree:
419         kfree(shost);
420         return NULL;
421 }
422 EXPORT_SYMBOL(scsi_host_alloc);
423
424 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
425 {
426         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
427
428         if (!sht->detect) {
429                 printk(KERN_WARNING "scsi_register() called on new-style "
430                                     "template for driver %s\n", sht->name);
431                 dump_stack();
432         }
433
434         if (shost)
435                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
436         return shost;
437 }
438 EXPORT_SYMBOL(scsi_register);
439
440 void scsi_unregister(struct Scsi_Host *shost)
441 {
442         list_del(&shost->sht_legacy_list);
443         scsi_host_put(shost);
444 }
445 EXPORT_SYMBOL(scsi_unregister);
446
447 static int __scsi_host_match(struct device *dev, void *data)
448 {
449         struct Scsi_Host *p;
450         unsigned short *hostnum = (unsigned short *)data;
451
452         p = class_to_shost(dev);
453         return p->host_no == *hostnum;
454 }
455
456 /**
457  * scsi_host_lookup - get a reference to a Scsi_Host by host no
458  * @hostnum:    host number to locate
459  *
460  * Return value:
461  *      A pointer to located Scsi_Host or NULL.
462  *
463  *      The caller must do a scsi_host_put() to drop the reference
464  *      that scsi_host_get() took. The put_device() below dropped
465  *      the reference from class_find_device().
466  **/
467 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
468 {
469         struct device *cdev;
470         struct Scsi_Host *shost = NULL;
471
472         cdev = class_find_device(&shost_class, NULL, &hostnum,
473                                  __scsi_host_match);
474         if (cdev) {
475                 shost = scsi_host_get(class_to_shost(cdev));
476                 put_device(cdev);
477         }
478         return shost;
479 }
480 EXPORT_SYMBOL(scsi_host_lookup);
481
482 /**
483  * scsi_host_get - inc a Scsi_Host ref count
484  * @shost:      Pointer to Scsi_Host to inc.
485  **/
486 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
487 {
488         if ((shost->shost_state == SHOST_DEL) ||
489                 !get_device(&shost->shost_gendev))
490                 return NULL;
491         return shost;
492 }
493 EXPORT_SYMBOL(scsi_host_get);
494
495 /**
496  * scsi_host_put - dec a Scsi_Host ref count
497  * @shost:      Pointer to Scsi_Host to dec.
498  **/
499 void scsi_host_put(struct Scsi_Host *shost)
500 {
501         put_device(&shost->shost_gendev);
502 }
503 EXPORT_SYMBOL(scsi_host_put);
504
505 int scsi_init_hosts(void)
506 {
507         return class_register(&shost_class);
508 }
509
510 void scsi_exit_hosts(void)
511 {
512         class_unregister(&shost_class);
513 }
514
515 int scsi_is_host_device(const struct device *dev)
516 {
517         return dev->type == &scsi_host_type;
518 }
519 EXPORT_SYMBOL(scsi_is_host_device);
520
521 /**
522  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
523  * @shost:      Pointer to Scsi_Host.
524  * @work:       Work to queue for execution.
525  *
526  * Return value:
527  *      1 - work queued for execution
528  *      0 - work is already queued
529  *      -EINVAL - work queue doesn't exist
530  **/
531 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
532 {
533         if (unlikely(!shost->work_q)) {
534                 printk(KERN_ERR
535                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
536                         "when no workqueue created.\n", shost->hostt->name);
537                 dump_stack();
538
539                 return -EINVAL;
540         }
541
542         return queue_work(shost->work_q, work);
543 }
544 EXPORT_SYMBOL_GPL(scsi_queue_work);
545
546 /**
547  * scsi_flush_work - Flush a Scsi_Host's workqueue.
548  * @shost:      Pointer to Scsi_Host.
549  **/
550 void scsi_flush_work(struct Scsi_Host *shost)
551 {
552         if (!shost->work_q) {
553                 printk(KERN_ERR
554                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
555                         "when no workqueue created.\n", shost->hostt->name);
556                 dump_stack();
557                 return;
558         }
559
560         flush_workqueue(shost->work_q);
561 }
562 EXPORT_SYMBOL_GPL(scsi_flush_work);