[SCSI] fix SLUB WARN_ON
[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 int 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         scsi_proc_hostdir_rm(shost->hostt);
180 }
181 EXPORT_SYMBOL(scsi_remove_host);
182
183 /**
184  * scsi_add_host - add a scsi host
185  * @shost:      scsi host pointer to add
186  * @dev:        a struct device of type scsi class
187  *
188  * Return value: 
189  *      0 on success / != 0 for error
190  **/
191 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
192 {
193         struct scsi_host_template *sht = shost->hostt;
194         int error = -EINVAL;
195
196         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
197                         sht->info ? sht->info(shost) : sht->name);
198
199         if (!shost->can_queue) {
200                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
201                                 sht->name);
202                 goto fail;
203         }
204
205         error = scsi_setup_command_freelist(shost);
206         if (error)
207                 goto fail;
208
209         if (!shost->shost_gendev.parent)
210                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
211
212         error = device_add(&shost->shost_gendev);
213         if (error)
214                 goto out;
215
216         scsi_host_set_state(shost, SHOST_RUNNING);
217         get_device(shost->shost_gendev.parent);
218
219         error = device_add(&shost->shost_dev);
220         if (error)
221                 goto out_del_gendev;
222
223         get_device(&shost->shost_gendev);
224
225         if (shost->transportt->host_size) {
226                 shost->shost_data = kzalloc(shost->transportt->host_size,
227                                          GFP_KERNEL);
228                 if (shost->shost_data == NULL) {
229                         error = -ENOMEM;
230                         goto out_del_dev;
231                 }
232         }
233
234         if (shost->transportt->create_work_queue) {
235                 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
236                         shost->host_no);
237                 shost->work_q = create_singlethread_workqueue(
238                                         shost->work_q_name);
239                 if (!shost->work_q) {
240                         error = -EINVAL;
241                         goto out_free_shost_data;
242                 }
243         }
244
245         error = scsi_sysfs_add_host(shost);
246         if (error)
247                 goto out_destroy_host;
248
249         scsi_proc_host_add(shost);
250         return error;
251
252  out_destroy_host:
253         if (shost->work_q)
254                 destroy_workqueue(shost->work_q);
255  out_free_shost_data:
256         kfree(shost->shost_data);
257  out_del_dev:
258         device_del(&shost->shost_dev);
259  out_del_gendev:
260         device_del(&shost->shost_gendev);
261  out:
262         scsi_destroy_command_freelist(shost);
263  fail:
264         return error;
265 }
266 EXPORT_SYMBOL(scsi_add_host);
267
268 static void scsi_host_dev_release(struct device *dev)
269 {
270         struct Scsi_Host *shost = dev_to_shost(dev);
271         struct device *parent = dev->parent;
272
273         if (shost->ehandler)
274                 kthread_stop(shost->ehandler);
275         if (shost->work_q)
276                 destroy_workqueue(shost->work_q);
277         if (shost->uspace_req_q) {
278                 kfree(shost->uspace_req_q->queuedata);
279                 scsi_free_queue(shost->uspace_req_q);
280         }
281
282         scsi_destroy_command_freelist(shost);
283         if (shost->bqt)
284                 blk_free_tags(shost->bqt);
285
286         kfree(shost->shost_data);
287
288         if (parent)
289                 put_device(parent);
290         kfree(shost);
291 }
292
293 struct device_type scsi_host_type = {
294         .name =         "scsi_host",
295         .release =      scsi_host_dev_release,
296 };
297
298 /**
299  * scsi_host_alloc - register a scsi host adapter instance.
300  * @sht:        pointer to scsi host template
301  * @privsize:   extra bytes to allocate for driver
302  *
303  * Note:
304  *      Allocate a new Scsi_Host and perform basic initialization.
305  *      The host is not published to the scsi midlayer until scsi_add_host
306  *      is called.
307  *
308  * Return value:
309  *      Pointer to a new Scsi_Host
310  **/
311 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
312 {
313         struct Scsi_Host *shost;
314         gfp_t gfp_mask = GFP_KERNEL;
315         int rval;
316
317         if (sht->unchecked_isa_dma && privsize)
318                 gfp_mask |= __GFP_DMA;
319
320         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
321         if (!shost)
322                 return NULL;
323
324         shost->host_lock = &shost->default_lock;
325         spin_lock_init(shost->host_lock);
326         shost->shost_state = SHOST_CREATED;
327         INIT_LIST_HEAD(&shost->__devices);
328         INIT_LIST_HEAD(&shost->__targets);
329         INIT_LIST_HEAD(&shost->eh_cmd_q);
330         INIT_LIST_HEAD(&shost->starved_list);
331         init_waitqueue_head(&shost->host_wait);
332
333         mutex_init(&shost->scan_mutex);
334
335         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
336         shost->dma_channel = 0xff;
337
338         /* These three are default values which can be overridden */
339         shost->max_channel = 0;
340         shost->max_id = 8;
341         shost->max_lun = 8;
342
343         /* Give each shost a default transportt */
344         shost->transportt = &blank_transport_template;
345
346         /*
347          * All drivers right now should be able to handle 12 byte
348          * commands.  Every so often there are requests for 16 byte
349          * commands, but individual low-level drivers need to certify that
350          * they actually do something sensible with such commands.
351          */
352         shost->max_cmd_len = 12;
353         shost->hostt = sht;
354         shost->this_id = sht->this_id;
355         shost->can_queue = sht->can_queue;
356         shost->sg_tablesize = sht->sg_tablesize;
357         shost->cmd_per_lun = sht->cmd_per_lun;
358         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
359         shost->use_clustering = sht->use_clustering;
360         shost->ordered_tag = sht->ordered_tag;
361
362         if (sht->supported_mode == MODE_UNKNOWN)
363                 /* means we didn't set it ... default to INITIATOR */
364                 shost->active_mode = MODE_INITIATOR;
365         else
366                 shost->active_mode = sht->supported_mode;
367
368         if (sht->max_host_blocked)
369                 shost->max_host_blocked = sht->max_host_blocked;
370         else
371                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
372
373         /*
374          * If the driver imposes no hard sector transfer limit, start at
375          * machine infinity initially.
376          */
377         if (sht->max_sectors)
378                 shost->max_sectors = sht->max_sectors;
379         else
380                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
381
382         /*
383          * assume a 4GB boundary, if not set
384          */
385         if (sht->dma_boundary)
386                 shost->dma_boundary = sht->dma_boundary;
387         else
388                 shost->dma_boundary = 0xffffffff;
389
390         device_initialize(&shost->shost_gendev);
391         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
392                 shost->host_no);
393 #ifndef CONFIG_SYSFS_DEPRECATED
394         shost->shost_gendev.bus = &scsi_bus_type;
395 #endif
396         shost->shost_gendev.type = &scsi_host_type;
397
398         device_initialize(&shost->shost_dev);
399         shost->shost_dev.parent = &shost->shost_gendev;
400         shost->shost_dev.class = &shost_class;
401         snprintf(shost->shost_dev.bus_id, BUS_ID_SIZE, "host%d",
402                  shost->host_no);
403         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
404
405         shost->ehandler = kthread_run(scsi_error_handler, shost,
406                         "scsi_eh_%d", shost->host_no);
407         if (IS_ERR(shost->ehandler)) {
408                 rval = PTR_ERR(shost->ehandler);
409                 goto fail_kfree;
410         }
411
412         scsi_proc_hostdir_add(shost->hostt);
413         return shost;
414
415  fail_kfree:
416         kfree(shost);
417         return NULL;
418 }
419 EXPORT_SYMBOL(scsi_host_alloc);
420
421 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
422 {
423         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
424
425         if (!sht->detect) {
426                 printk(KERN_WARNING "scsi_register() called on new-style "
427                                     "template for driver %s\n", sht->name);
428                 dump_stack();
429         }
430
431         if (shost)
432                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
433         return shost;
434 }
435 EXPORT_SYMBOL(scsi_register);
436
437 void scsi_unregister(struct Scsi_Host *shost)
438 {
439         list_del(&shost->sht_legacy_list);
440         scsi_host_put(shost);
441 }
442 EXPORT_SYMBOL(scsi_unregister);
443
444 static int __scsi_host_match(struct device *dev, void *data)
445 {
446         struct Scsi_Host *p;
447         unsigned short *hostnum = (unsigned short *)data;
448
449         p = class_to_shost(dev);
450         return p->host_no == *hostnum;
451 }
452
453 /**
454  * scsi_host_lookup - get a reference to a Scsi_Host by host no
455  * @hostnum:    host number to locate
456  *
457  * Return value:
458  *      A pointer to located Scsi_Host or NULL.
459  **/
460 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
461 {
462         struct device *cdev;
463         struct Scsi_Host *shost = ERR_PTR(-ENXIO);
464
465         cdev = class_find_device(&shost_class, &hostnum, __scsi_host_match);
466         if (cdev)
467                 shost = scsi_host_get(class_to_shost(cdev));
468
469         return shost;
470 }
471 EXPORT_SYMBOL(scsi_host_lookup);
472
473 /**
474  * scsi_host_get - inc a Scsi_Host ref count
475  * @shost:      Pointer to Scsi_Host to inc.
476  **/
477 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
478 {
479         if ((shost->shost_state == SHOST_DEL) ||
480                 !get_device(&shost->shost_gendev))
481                 return NULL;
482         return shost;
483 }
484 EXPORT_SYMBOL(scsi_host_get);
485
486 /**
487  * scsi_host_put - dec a Scsi_Host ref count
488  * @shost:      Pointer to Scsi_Host to dec.
489  **/
490 void scsi_host_put(struct Scsi_Host *shost)
491 {
492         put_device(&shost->shost_gendev);
493 }
494 EXPORT_SYMBOL(scsi_host_put);
495
496 int scsi_init_hosts(void)
497 {
498         return class_register(&shost_class);
499 }
500
501 void scsi_exit_hosts(void)
502 {
503         class_unregister(&shost_class);
504 }
505
506 int scsi_is_host_device(const struct device *dev)
507 {
508         return dev->type == &scsi_host_type;
509 }
510 EXPORT_SYMBOL(scsi_is_host_device);
511
512 /**
513  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
514  * @shost:      Pointer to Scsi_Host.
515  * @work:       Work to queue for execution.
516  *
517  * Return value:
518  *      1 - work queued for execution
519  *      0 - work is already queued
520  *      -EINVAL - work queue doesn't exist
521  **/
522 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
523 {
524         if (unlikely(!shost->work_q)) {
525                 printk(KERN_ERR
526                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
527                         "when no workqueue created.\n", shost->hostt->name);
528                 dump_stack();
529
530                 return -EINVAL;
531         }
532
533         return queue_work(shost->work_q, work);
534 }
535 EXPORT_SYMBOL_GPL(scsi_queue_work);
536
537 /**
538  * scsi_flush_work - Flush a Scsi_Host's workqueue.
539  * @shost:      Pointer to Scsi_Host.
540  **/
541 void scsi_flush_work(struct Scsi_Host *shost)
542 {
543         if (!shost->work_q) {
544                 printk(KERN_ERR
545                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
546                         "when no workqueue created.\n", shost->hostt->name);
547                 dump_stack();
548                 return;
549         }
550
551         flush_workqueue(shost->work_q);
552 }
553 EXPORT_SYMBOL_GPL(scsi_flush_work);