config: tegra3: enable /dev mount with ACL
[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/slab.h>
28 #include <linux/kthread.h>
29 #include <linux/string.h>
30 #include <linux/mm.h>
31 #include <linux/init.h>
32 #include <linux/completion.h>
33 #include <linux/transport_class.h>
34 #include <linux/platform_device.h>
35 #include <linux/pm_runtime.h>
36
37 #include <scsi/scsi_device.h>
38 #include <scsi/scsi_host.h>
39 #include <scsi/scsi_transport.h>
40
41 #include "scsi_priv.h"
42 #include "scsi_logging.h"
43
44
45 static atomic_t scsi_host_next_hn;      /* host_no for next new host */
46
47
48 static void scsi_host_cls_release(struct device *dev)
49 {
50         put_device(&class_to_shost(dev)->shost_gendev);
51 }
52
53 static struct class shost_class = {
54         .name           = "scsi_host",
55         .dev_release    = scsi_host_cls_release,
56 };
57
58 /**
59  *      scsi_host_set_state - Take the given host through the host state model.
60  *      @shost: scsi host to change the state of.
61  *      @state: state to change to.
62  *
63  *      Returns zero if unsuccessful or an error if the requested
64  *      transition is illegal.
65  **/
66 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
67 {
68         enum scsi_host_state oldstate = shost->shost_state;
69
70         if (state == oldstate)
71                 return 0;
72
73         switch (state) {
74         case SHOST_CREATED:
75                 /* There are no legal states that come back to
76                  * created.  This is the manually initialised start
77                  * state */
78                 goto illegal;
79
80         case SHOST_RUNNING:
81                 switch (oldstate) {
82                 case SHOST_CREATED:
83                 case SHOST_RECOVERY:
84                         break;
85                 default:
86                         goto illegal;
87                 }
88                 break;
89
90         case SHOST_RECOVERY:
91                 switch (oldstate) {
92                 case SHOST_RUNNING:
93                         break;
94                 default:
95                         goto illegal;
96                 }
97                 break;
98
99         case SHOST_CANCEL:
100                 switch (oldstate) {
101                 case SHOST_CREATED:
102                 case SHOST_RUNNING:
103                 case SHOST_CANCEL_RECOVERY:
104                         break;
105                 default:
106                         goto illegal;
107                 }
108                 break;
109
110         case SHOST_DEL:
111                 switch (oldstate) {
112                 case SHOST_CANCEL:
113                 case SHOST_DEL_RECOVERY:
114                         break;
115                 default:
116                         goto illegal;
117                 }
118                 break;
119
120         case SHOST_CANCEL_RECOVERY:
121                 switch (oldstate) {
122                 case SHOST_CANCEL:
123                 case SHOST_RECOVERY:
124                         break;
125                 default:
126                         goto illegal;
127                 }
128                 break;
129
130         case SHOST_DEL_RECOVERY:
131                 switch (oldstate) {
132                 case SHOST_CANCEL_RECOVERY:
133                         break;
134                 default:
135                         goto illegal;
136                 }
137                 break;
138         }
139         shost->shost_state = state;
140         return 0;
141
142  illegal:
143         SCSI_LOG_ERROR_RECOVERY(1,
144                                 shost_printk(KERN_ERR, shost,
145                                              "Illegal host state transition"
146                                              "%s->%s\n",
147                                              scsi_host_state_name(oldstate),
148                                              scsi_host_state_name(state)));
149         return -EINVAL;
150 }
151 EXPORT_SYMBOL(scsi_host_set_state);
152
153 /**
154  * scsi_remove_host - remove a scsi host
155  * @shost:      a pointer to a scsi host to remove
156  **/
157 void scsi_remove_host(struct Scsi_Host *shost)
158 {
159         unsigned long flags;
160
161         mutex_lock(&shost->scan_mutex);
162         spin_lock_irqsave(shost->host_lock, flags);
163         if (scsi_host_set_state(shost, SHOST_CANCEL))
164                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
165                         spin_unlock_irqrestore(shost->host_lock, flags);
166                         mutex_unlock(&shost->scan_mutex);
167                         return;
168                 }
169         spin_unlock_irqrestore(shost->host_lock, flags);
170
171         scsi_autopm_get_host(shost);
172         scsi_forget_host(shost);
173         mutex_unlock(&shost->scan_mutex);
174         scsi_proc_host_rm(shost);
175
176         spin_lock_irqsave(shost->host_lock, flags);
177         if (scsi_host_set_state(shost, SHOST_DEL))
178                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
179         spin_unlock_irqrestore(shost->host_lock, flags);
180
181         transport_unregister_device(&shost->shost_gendev);
182         device_unregister(&shost->shost_dev);
183         device_del(&shost->shost_gendev);
184 }
185 EXPORT_SYMBOL(scsi_remove_host);
186
187 /**
188  * scsi_add_host_with_dma - add a scsi host with dma device
189  * @shost:      scsi host pointer to add
190  * @dev:        a struct device of type scsi class
191  * @dma_dev:    dma device for the host
192  *
193  * Note: You rarely need to worry about this unless you're in a
194  * virtualised host environments, so use the simpler scsi_add_host()
195  * function instead.
196  *
197  * Return value: 
198  *      0 on success / != 0 for error
199  **/
200 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
201                            struct device *dma_dev)
202 {
203         struct scsi_host_template *sht = shost->hostt;
204         int error = -EINVAL;
205
206         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
207                         sht->info ? sht->info(shost) : sht->name);
208
209         if (!shost->can_queue) {
210                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
211                                 sht->name);
212                 goto fail;
213         }
214
215         error = scsi_setup_command_freelist(shost);
216         if (error)
217                 goto fail;
218
219         if (!shost->shost_gendev.parent)
220                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
221         shost->dma_dev = dma_dev;
222
223         error = device_add(&shost->shost_gendev);
224         if (error)
225                 goto out;
226
227         pm_runtime_set_active(&shost->shost_gendev);
228         pm_runtime_enable(&shost->shost_gendev);
229         device_enable_async_suspend(&shost->shost_gendev);
230
231         scsi_host_set_state(shost, SHOST_RUNNING);
232         get_device(shost->shost_gendev.parent);
233
234         device_enable_async_suspend(&shost->shost_dev);
235
236         error = device_add(&shost->shost_dev);
237         if (error)
238                 goto out_del_gendev;
239
240         get_device(&shost->shost_gendev);
241
242         if (shost->transportt->host_size) {
243                 shost->shost_data = kzalloc(shost->transportt->host_size,
244                                          GFP_KERNEL);
245                 if (shost->shost_data == NULL) {
246                         error = -ENOMEM;
247                         goto out_del_dev;
248                 }
249         }
250
251         if (shost->transportt->create_work_queue) {
252                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
253                          "scsi_wq_%d", shost->host_no);
254                 shost->work_q = create_singlethread_workqueue(
255                                         shost->work_q_name);
256                 if (!shost->work_q) {
257                         error = -EINVAL;
258                         goto out_free_shost_data;
259                 }
260         }
261
262         error = scsi_sysfs_add_host(shost);
263         if (error)
264                 goto out_destroy_host;
265
266         scsi_proc_host_add(shost);
267         return error;
268
269  out_destroy_host:
270         if (shost->work_q)
271                 destroy_workqueue(shost->work_q);
272  out_free_shost_data:
273         kfree(shost->shost_data);
274  out_del_dev:
275         device_del(&shost->shost_dev);
276  out_del_gendev:
277         device_del(&shost->shost_gendev);
278  out:
279         scsi_destroy_command_freelist(shost);
280  fail:
281         return error;
282 }
283 EXPORT_SYMBOL(scsi_add_host_with_dma);
284
285 static void scsi_host_dev_release(struct device *dev)
286 {
287         struct Scsi_Host *shost = dev_to_shost(dev);
288         struct device *parent = dev->parent;
289         struct request_queue *q;
290
291         scsi_proc_hostdir_rm(shost->hostt);
292
293         if (shost->ehandler)
294                 kthread_stop(shost->ehandler);
295         if (shost->work_q)
296                 destroy_workqueue(shost->work_q);
297         q = shost->uspace_req_q;
298         if (q) {
299                 kfree(q->queuedata);
300                 q->queuedata = NULL;
301                 scsi_free_queue(q);
302         }
303
304         scsi_destroy_command_freelist(shost);
305         if (shost->bqt)
306                 blk_free_tags(shost->bqt);
307
308         kfree(shost->shost_data);
309
310         if (parent)
311                 put_device(parent);
312         kfree(shost);
313 }
314
315 static struct device_type scsi_host_type = {
316         .name =         "scsi_host",
317         .release =      scsi_host_dev_release,
318 };
319
320 /**
321  * scsi_host_alloc - register a scsi host adapter instance.
322  * @sht:        pointer to scsi host template
323  * @privsize:   extra bytes to allocate for driver
324  *
325  * Note:
326  *      Allocate a new Scsi_Host and perform basic initialization.
327  *      The host is not published to the scsi midlayer until scsi_add_host
328  *      is called.
329  *
330  * Return value:
331  *      Pointer to a new Scsi_Host
332  **/
333 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
334 {
335         struct Scsi_Host *shost;
336         gfp_t gfp_mask = GFP_KERNEL;
337
338         if (sht->unchecked_isa_dma && privsize)
339                 gfp_mask |= __GFP_DMA;
340
341         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
342         if (!shost)
343                 return NULL;
344
345         shost->host_lock = &shost->default_lock;
346         spin_lock_init(shost->host_lock);
347         shost->shost_state = SHOST_CREATED;
348         INIT_LIST_HEAD(&shost->__devices);
349         INIT_LIST_HEAD(&shost->__targets);
350         INIT_LIST_HEAD(&shost->eh_cmd_q);
351         INIT_LIST_HEAD(&shost->starved_list);
352         init_waitqueue_head(&shost->host_wait);
353
354         mutex_init(&shost->scan_mutex);
355
356         /*
357          * subtract one because we increment first then return, but we need to
358          * know what the next host number was before increment
359          */
360         shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
361         shost->dma_channel = 0xff;
362
363         /* These three are default values which can be overridden */
364         shost->max_channel = 0;
365         shost->max_id = 8;
366         shost->max_lun = 8;
367
368         /* Give each shost a default transportt */
369         shost->transportt = &blank_transport_template;
370
371         /*
372          * All drivers right now should be able to handle 12 byte
373          * commands.  Every so often there are requests for 16 byte
374          * commands, but individual low-level drivers need to certify that
375          * they actually do something sensible with such commands.
376          */
377         shost->max_cmd_len = 12;
378         shost->hostt = sht;
379         shost->this_id = sht->this_id;
380         shost->can_queue = sht->can_queue;
381         shost->sg_tablesize = sht->sg_tablesize;
382         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
383         shost->cmd_per_lun = sht->cmd_per_lun;
384         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
385         shost->use_clustering = sht->use_clustering;
386         shost->ordered_tag = sht->ordered_tag;
387
388         if (sht->supported_mode == MODE_UNKNOWN)
389                 /* means we didn't set it ... default to INITIATOR */
390                 shost->active_mode = MODE_INITIATOR;
391         else
392                 shost->active_mode = sht->supported_mode;
393
394         if (sht->max_host_blocked)
395                 shost->max_host_blocked = sht->max_host_blocked;
396         else
397                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
398
399         /*
400          * If the driver imposes no hard sector transfer limit, start at
401          * machine infinity initially.
402          */
403         if (sht->max_sectors)
404                 shost->max_sectors = sht->max_sectors;
405         else
406                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
407
408         /*
409          * assume a 4GB boundary, if not set
410          */
411         if (sht->dma_boundary)
412                 shost->dma_boundary = sht->dma_boundary;
413         else
414                 shost->dma_boundary = 0xffffffff;
415
416         device_initialize(&shost->shost_gendev);
417         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
418         shost->shost_gendev.bus = &scsi_bus_type;
419         shost->shost_gendev.type = &scsi_host_type;
420
421         device_initialize(&shost->shost_dev);
422         shost->shost_dev.parent = &shost->shost_gendev;
423         shost->shost_dev.class = &shost_class;
424         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
425         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
426
427         shost->ehandler = kthread_run(scsi_error_handler, shost,
428                         "scsi_eh_%d", shost->host_no);
429         if (IS_ERR(shost->ehandler)) {
430                 printk(KERN_WARNING "scsi%d: error handler thread failed to spawn, error = %ld\n",
431                         shost->host_no, PTR_ERR(shost->ehandler));
432                 goto fail_kfree;
433         }
434
435         scsi_proc_hostdir_add(shost->hostt);
436         return shost;
437
438  fail_kfree:
439         kfree(shost);
440         return NULL;
441 }
442 EXPORT_SYMBOL(scsi_host_alloc);
443
444 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
445 {
446         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
447
448         if (!sht->detect) {
449                 printk(KERN_WARNING "scsi_register() called on new-style "
450                                     "template for driver %s\n", sht->name);
451                 dump_stack();
452         }
453
454         if (shost)
455                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
456         return shost;
457 }
458 EXPORT_SYMBOL(scsi_register);
459
460 void scsi_unregister(struct Scsi_Host *shost)
461 {
462         list_del(&shost->sht_legacy_list);
463         scsi_host_put(shost);
464 }
465 EXPORT_SYMBOL(scsi_unregister);
466
467 static int __scsi_host_match(struct device *dev, void *data)
468 {
469         struct Scsi_Host *p;
470         unsigned short *hostnum = (unsigned short *)data;
471
472         p = class_to_shost(dev);
473         return p->host_no == *hostnum;
474 }
475
476 /**
477  * scsi_host_lookup - get a reference to a Scsi_Host by host no
478  * @hostnum:    host number to locate
479  *
480  * Return value:
481  *      A pointer to located Scsi_Host or NULL.
482  *
483  *      The caller must do a scsi_host_put() to drop the reference
484  *      that scsi_host_get() took. The put_device() below dropped
485  *      the reference from class_find_device().
486  **/
487 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
488 {
489         struct device *cdev;
490         struct Scsi_Host *shost = NULL;
491
492         cdev = class_find_device(&shost_class, NULL, &hostnum,
493                                  __scsi_host_match);
494         if (cdev) {
495                 shost = scsi_host_get(class_to_shost(cdev));
496                 put_device(cdev);
497         }
498         return shost;
499 }
500 EXPORT_SYMBOL(scsi_host_lookup);
501
502 /**
503  * scsi_host_get - inc a Scsi_Host ref count
504  * @shost:      Pointer to Scsi_Host to inc.
505  **/
506 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
507 {
508         if ((shost->shost_state == SHOST_DEL) ||
509                 !get_device(&shost->shost_gendev))
510                 return NULL;
511         return shost;
512 }
513 EXPORT_SYMBOL(scsi_host_get);
514
515 /**
516  * scsi_host_put - dec a Scsi_Host ref count
517  * @shost:      Pointer to Scsi_Host to dec.
518  **/
519 void scsi_host_put(struct Scsi_Host *shost)
520 {
521         put_device(&shost->shost_gendev);
522 }
523 EXPORT_SYMBOL(scsi_host_put);
524
525 int scsi_init_hosts(void)
526 {
527         return class_register(&shost_class);
528 }
529
530 void scsi_exit_hosts(void)
531 {
532         class_unregister(&shost_class);
533 }
534
535 int scsi_is_host_device(const struct device *dev)
536 {
537         return dev->type == &scsi_host_type;
538 }
539 EXPORT_SYMBOL(scsi_is_host_device);
540
541 /**
542  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
543  * @shost:      Pointer to Scsi_Host.
544  * @work:       Work to queue for execution.
545  *
546  * Return value:
547  *      1 - work queued for execution
548  *      0 - work is already queued
549  *      -EINVAL - work queue doesn't exist
550  **/
551 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
552 {
553         if (unlikely(!shost->work_q)) {
554                 printk(KERN_ERR
555                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
556                         "when no workqueue created.\n", shost->hostt->name);
557                 dump_stack();
558
559                 return -EINVAL;
560         }
561
562         return queue_work(shost->work_q, work);
563 }
564 EXPORT_SYMBOL_GPL(scsi_queue_work);
565
566 /**
567  * scsi_flush_work - Flush a Scsi_Host's workqueue.
568  * @shost:      Pointer to Scsi_Host.
569  **/
570 void scsi_flush_work(struct Scsi_Host *shost)
571 {
572         if (!shost->work_q) {
573                 printk(KERN_ERR
574                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
575                         "when no workqueue created.\n", shost->hostt->name);
576                 dump_stack();
577                 return;
578         }
579
580         flush_workqueue(shost->work_q);
581 }
582 EXPORT_SYMBOL_GPL(scsi_flush_work);