Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
[sfrench/cifs-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 class_device *class_dev)
47 {
48         put_device(&class_to_shost(class_dev)->shost_gendev);
49 }
50
51 static struct class shost_class = {
52         .name           = "scsi_host",
53         .release        = scsi_host_cls_release,
54 };
55
56 /**
57  *      scsi_host_set_state - Take the given host through the host
58  *              state model.
59  *      @shost: scsi host to change the state of.
60  *      @state: state to change to.
61  *
62  *      Returns zero if unsuccessful or an error if the requested
63  *      transition is illegal.
64  **/
65 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
66 {
67         enum scsi_host_state oldstate = shost->shost_state;
68
69         if (state == oldstate)
70                 return 0;
71
72         switch (state) {
73         case SHOST_CREATED:
74                 /* There are no legal states that come back to
75                  * created.  This is the manually initialised start
76                  * state */
77                 goto illegal;
78
79         case SHOST_RUNNING:
80                 switch (oldstate) {
81                 case SHOST_CREATED:
82                 case SHOST_RECOVERY:
83                         break;
84                 default:
85                         goto illegal;
86                 }
87                 break;
88
89         case SHOST_RECOVERY:
90                 switch (oldstate) {
91                 case SHOST_RUNNING:
92                         break;
93                 default:
94                         goto illegal;
95                 }
96                 break;
97
98         case SHOST_CANCEL:
99                 switch (oldstate) {
100                 case SHOST_CREATED:
101                 case SHOST_RUNNING:
102                 case SHOST_CANCEL_RECOVERY:
103                         break;
104                 default:
105                         goto illegal;
106                 }
107                 break;
108
109         case SHOST_DEL:
110                 switch (oldstate) {
111                 case SHOST_CANCEL:
112                 case SHOST_DEL_RECOVERY:
113                         break;
114                 default:
115                         goto illegal;
116                 }
117                 break;
118
119         case SHOST_CANCEL_RECOVERY:
120                 switch (oldstate) {
121                 case SHOST_CANCEL:
122                 case SHOST_RECOVERY:
123                         break;
124                 default:
125                         goto illegal;
126                 }
127                 break;
128
129         case SHOST_DEL_RECOVERY:
130                 switch (oldstate) {
131                 case SHOST_CANCEL_RECOVERY:
132                         break;
133                 default:
134                         goto illegal;
135                 }
136                 break;
137         }
138         shost->shost_state = state;
139         return 0;
140
141  illegal:
142         SCSI_LOG_ERROR_RECOVERY(1,
143                                 shost_printk(KERN_ERR, shost,
144                                              "Illegal host state transition"
145                                              "%s->%s\n",
146                                              scsi_host_state_name(oldstate),
147                                              scsi_host_state_name(state)));
148         return -EINVAL;
149 }
150 EXPORT_SYMBOL(scsi_host_set_state);
151
152 /**
153  * scsi_remove_host - remove a scsi host
154  * @shost:      a pointer to a scsi host to remove
155  **/
156 void scsi_remove_host(struct Scsi_Host *shost)
157 {
158         unsigned long flags;
159         mutex_lock(&shost->scan_mutex);
160         spin_lock_irqsave(shost->host_lock, flags);
161         if (scsi_host_set_state(shost, SHOST_CANCEL))
162                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
163                         spin_unlock_irqrestore(shost->host_lock, flags);
164                         mutex_unlock(&shost->scan_mutex);
165                         return;
166                 }
167         spin_unlock_irqrestore(shost->host_lock, flags);
168         mutex_unlock(&shost->scan_mutex);
169         scsi_forget_host(shost);
170         scsi_proc_host_rm(shost);
171
172         spin_lock_irqsave(shost->host_lock, flags);
173         if (scsi_host_set_state(shost, SHOST_DEL))
174                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
175         spin_unlock_irqrestore(shost->host_lock, flags);
176
177         transport_unregister_device(&shost->shost_gendev);
178         class_device_unregister(&shost->shost_classdev);
179         device_del(&shost->shost_gendev);
180         scsi_proc_hostdir_rm(shost->hostt);
181 }
182 EXPORT_SYMBOL(scsi_remove_host);
183
184 /**
185  * scsi_add_host - add a scsi host
186  * @shost:      scsi host pointer to add
187  * @dev:        a struct device of type scsi class
188  *
189  * Return value: 
190  *      0 on success / != 0 for error
191  **/
192 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
193 {
194         struct scsi_host_template *sht = shost->hostt;
195         int error = -EINVAL;
196
197         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
198                         sht->info ? sht->info(shost) : sht->name);
199
200         if (!shost->can_queue) {
201                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
202                                 sht->name);
203                 goto out;
204         }
205
206         if (!shost->shost_gendev.parent)
207                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
208
209         error = device_add(&shost->shost_gendev);
210         if (error)
211                 goto out;
212
213         scsi_host_set_state(shost, SHOST_RUNNING);
214         get_device(shost->shost_gendev.parent);
215
216         error = class_device_add(&shost->shost_classdev);
217         if (error)
218                 goto out_del_gendev;
219
220         get_device(&shost->shost_gendev);
221
222         if (shost->transportt->host_size &&
223             (shost->shost_data = kzalloc(shost->transportt->host_size,
224                                          GFP_KERNEL)) == NULL)
225                 goto out_del_classdev;
226
227         if (shost->transportt->create_work_queue) {
228                 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
229                         shost->host_no);
230                 shost->work_q = create_singlethread_workqueue(
231                                         shost->work_q_name);
232                 if (!shost->work_q)
233                         goto out_free_shost_data;
234         }
235
236         error = scsi_sysfs_add_host(shost);
237         if (error)
238                 goto out_destroy_host;
239
240         scsi_proc_host_add(shost);
241         return error;
242
243  out_destroy_host:
244         if (shost->work_q)
245                 destroy_workqueue(shost->work_q);
246  out_free_shost_data:
247         kfree(shost->shost_data);
248  out_del_classdev:
249         class_device_del(&shost->shost_classdev);
250  out_del_gendev:
251         device_del(&shost->shost_gendev);
252  out:
253         return error;
254 }
255 EXPORT_SYMBOL(scsi_add_host);
256
257 static void scsi_host_dev_release(struct device *dev)
258 {
259         struct Scsi_Host *shost = dev_to_shost(dev);
260         struct device *parent = dev->parent;
261
262         if (shost->ehandler)
263                 kthread_stop(shost->ehandler);
264         if (shost->work_q)
265                 destroy_workqueue(shost->work_q);
266         if (shost->uspace_req_q) {
267                 kfree(shost->uspace_req_q->queuedata);
268                 scsi_free_queue(shost->uspace_req_q);
269         }
270
271         scsi_destroy_command_freelist(shost);
272         if (shost->bqt)
273                 blk_free_tags(shost->bqt);
274
275         kfree(shost->shost_data);
276
277         if (parent)
278                 put_device(parent);
279         kfree(shost);
280 }
281
282 /**
283  * scsi_host_alloc - register a scsi host adapter instance.
284  * @sht:        pointer to scsi host template
285  * @privsize:   extra bytes to allocate for driver
286  *
287  * Note:
288  *      Allocate a new Scsi_Host and perform basic initialization.
289  *      The host is not published to the scsi midlayer until scsi_add_host
290  *      is called.
291  *
292  * Return value:
293  *      Pointer to a new Scsi_Host
294  **/
295 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
296 {
297         struct Scsi_Host *shost;
298         gfp_t gfp_mask = GFP_KERNEL;
299         int rval;
300
301         if (sht->unchecked_isa_dma && privsize)
302                 gfp_mask |= __GFP_DMA;
303
304         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
305         if (!shost)
306                 return NULL;
307
308         shost->host_lock = &shost->default_lock;
309         spin_lock_init(shost->host_lock);
310         shost->shost_state = SHOST_CREATED;
311         INIT_LIST_HEAD(&shost->__devices);
312         INIT_LIST_HEAD(&shost->__targets);
313         INIT_LIST_HEAD(&shost->eh_cmd_q);
314         INIT_LIST_HEAD(&shost->starved_list);
315         init_waitqueue_head(&shost->host_wait);
316
317         mutex_init(&shost->scan_mutex);
318
319         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
320         shost->dma_channel = 0xff;
321
322         /* These three are default values which can be overridden */
323         shost->max_channel = 0;
324         shost->max_id = 8;
325         shost->max_lun = 8;
326
327         /* Give each shost a default transportt */
328         shost->transportt = &blank_transport_template;
329
330         /*
331          * All drivers right now should be able to handle 12 byte
332          * commands.  Every so often there are requests for 16 byte
333          * commands, but individual low-level drivers need to certify that
334          * they actually do something sensible with such commands.
335          */
336         shost->max_cmd_len = 12;
337         shost->hostt = sht;
338         shost->this_id = sht->this_id;
339         shost->can_queue = sht->can_queue;
340         shost->sg_tablesize = sht->sg_tablesize;
341         shost->cmd_per_lun = sht->cmd_per_lun;
342         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
343         shost->use_clustering = sht->use_clustering;
344         shost->ordered_tag = sht->ordered_tag;
345         shost->active_mode = sht->supported_mode;
346         shost->use_sg_chaining = sht->use_sg_chaining;
347
348         if (sht->supported_mode == MODE_UNKNOWN)
349                 /* means we didn't set it ... default to INITIATOR */
350                 shost->active_mode = MODE_INITIATOR;
351         else
352                 shost->active_mode = sht->supported_mode;
353
354         if (sht->max_host_blocked)
355                 shost->max_host_blocked = sht->max_host_blocked;
356         else
357                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
358
359         /*
360          * If the driver imposes no hard sector transfer limit, start at
361          * machine infinity initially.
362          */
363         if (sht->max_sectors)
364                 shost->max_sectors = sht->max_sectors;
365         else
366                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
367
368         /*
369          * assume a 4GB boundary, if not set
370          */
371         if (sht->dma_boundary)
372                 shost->dma_boundary = sht->dma_boundary;
373         else
374                 shost->dma_boundary = 0xffffffff;
375
376         rval = scsi_setup_command_freelist(shost);
377         if (rval)
378                 goto fail_kfree;
379
380         device_initialize(&shost->shost_gendev);
381         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
382                 shost->host_no);
383         shost->shost_gendev.release = scsi_host_dev_release;
384
385         class_device_initialize(&shost->shost_classdev);
386         shost->shost_classdev.dev = &shost->shost_gendev;
387         shost->shost_classdev.class = &shost_class;
388         snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
389                   shost->host_no);
390
391         shost->ehandler = kthread_run(scsi_error_handler, shost,
392                         "scsi_eh_%d", shost->host_no);
393         if (IS_ERR(shost->ehandler)) {
394                 rval = PTR_ERR(shost->ehandler);
395                 goto fail_destroy_freelist;
396         }
397
398         scsi_proc_hostdir_add(shost->hostt);
399         return shost;
400
401  fail_destroy_freelist:
402         scsi_destroy_command_freelist(shost);
403  fail_kfree:
404         kfree(shost);
405         return NULL;
406 }
407 EXPORT_SYMBOL(scsi_host_alloc);
408
409 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
410 {
411         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
412
413         if (!sht->detect) {
414                 printk(KERN_WARNING "scsi_register() called on new-style "
415                                     "template for driver %s\n", sht->name);
416                 dump_stack();
417         }
418
419         if (shost)
420                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
421         return shost;
422 }
423 EXPORT_SYMBOL(scsi_register);
424
425 void scsi_unregister(struct Scsi_Host *shost)
426 {
427         list_del(&shost->sht_legacy_list);
428         scsi_host_put(shost);
429 }
430 EXPORT_SYMBOL(scsi_unregister);
431
432 static int __scsi_host_match(struct class_device *cdev, void *data)
433 {
434         struct Scsi_Host *p;
435         unsigned short *hostnum = (unsigned short *)data;
436
437         p = class_to_shost(cdev);
438         return p->host_no == *hostnum;
439 }
440
441 /**
442  * scsi_host_lookup - get a reference to a Scsi_Host by host no
443  *
444  * @hostnum:    host number to locate
445  *
446  * Return value:
447  *      A pointer to located Scsi_Host or NULL.
448  **/
449 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
450 {
451         struct class_device *cdev;
452         struct Scsi_Host *shost = ERR_PTR(-ENXIO);
453
454         cdev = class_find_child(&shost_class, &hostnum, __scsi_host_match);
455         if (cdev)
456                 shost = scsi_host_get(class_to_shost(cdev));
457
458         return shost;
459 }
460 EXPORT_SYMBOL(scsi_host_lookup);
461
462 /**
463  * scsi_host_get - inc a Scsi_Host ref count
464  * @shost:      Pointer to Scsi_Host to inc.
465  **/
466 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
467 {
468         if ((shost->shost_state == SHOST_DEL) ||
469                 !get_device(&shost->shost_gendev))
470                 return NULL;
471         return shost;
472 }
473 EXPORT_SYMBOL(scsi_host_get);
474
475 /**
476  * scsi_host_put - dec a Scsi_Host ref count
477  * @shost:      Pointer to Scsi_Host to dec.
478  **/
479 void scsi_host_put(struct Scsi_Host *shost)
480 {
481         put_device(&shost->shost_gendev);
482 }
483 EXPORT_SYMBOL(scsi_host_put);
484
485 int scsi_init_hosts(void)
486 {
487         return class_register(&shost_class);
488 }
489
490 void scsi_exit_hosts(void)
491 {
492         class_unregister(&shost_class);
493 }
494
495 int scsi_is_host_device(const struct device *dev)
496 {
497         return dev->release == scsi_host_dev_release;
498 }
499 EXPORT_SYMBOL(scsi_is_host_device);
500
501 /**
502  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
503  * @shost:      Pointer to Scsi_Host.
504  * @work:       Work to queue for execution.
505  *
506  * Return value:
507  *      1 - work queued for execution
508  *      0 - work is already queued
509  *      -EINVAL - work queue doesn't exist
510  **/
511 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
512 {
513         if (unlikely(!shost->work_q)) {
514                 printk(KERN_ERR
515                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
516                         "when no workqueue created.\n", shost->hostt->name);
517                 dump_stack();
518
519                 return -EINVAL;
520         }
521
522         return queue_work(shost->work_q, work);
523 }
524 EXPORT_SYMBOL_GPL(scsi_queue_work);
525
526 /**
527  * scsi_flush_work - Flush a Scsi_Host's workqueue.
528  * @shost:      Pointer to Scsi_Host.
529  **/
530 void scsi_flush_work(struct Scsi_Host *shost)
531 {
532         if (!shost->work_q) {
533                 printk(KERN_ERR
534                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
535                         "when no workqueue created.\n", shost->hostt->name);
536                 dump_stack();
537                 return;
538         }
539
540         flush_workqueue(shost->work_q);
541 }
542 EXPORT_SYMBOL_GPL(scsi_flush_work);