[SCSI] fix /proc memory leak in the SCSI core
[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 }
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         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
337         shost->dma_channel = 0xff;
338
339         /* These three are default values which can be overridden */
340         shost->max_channel = 0;
341         shost->max_id = 8;
342         shost->max_lun = 8;
343
344         /* Give each shost a default transportt */
345         shost->transportt = &blank_transport_template;
346
347         /*
348          * All drivers right now should be able to handle 12 byte
349          * commands.  Every so often there are requests for 16 byte
350          * commands, but individual low-level drivers need to certify that
351          * they actually do something sensible with such commands.
352          */
353         shost->max_cmd_len = 12;
354         shost->hostt = sht;
355         shost->this_id = sht->this_id;
356         shost->can_queue = sht->can_queue;
357         shost->sg_tablesize = sht->sg_tablesize;
358         shost->cmd_per_lun = sht->cmd_per_lun;
359         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
360         shost->use_clustering = sht->use_clustering;
361         shost->ordered_tag = sht->ordered_tag;
362
363         if (sht->supported_mode == MODE_UNKNOWN)
364                 /* means we didn't set it ... default to INITIATOR */
365                 shost->active_mode = MODE_INITIATOR;
366         else
367                 shost->active_mode = sht->supported_mode;
368
369         if (sht->max_host_blocked)
370                 shost->max_host_blocked = sht->max_host_blocked;
371         else
372                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
373
374         /*
375          * If the driver imposes no hard sector transfer limit, start at
376          * machine infinity initially.
377          */
378         if (sht->max_sectors)
379                 shost->max_sectors = sht->max_sectors;
380         else
381                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
382
383         /*
384          * assume a 4GB boundary, if not set
385          */
386         if (sht->dma_boundary)
387                 shost->dma_boundary = sht->dma_boundary;
388         else
389                 shost->dma_boundary = 0xffffffff;
390
391         device_initialize(&shost->shost_gendev);
392         dev_set_name(&shost->shost_gendev, "host%d", 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         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
402         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
403
404         shost->ehandler = kthread_run(scsi_error_handler, shost,
405                         "scsi_eh_%d", shost->host_no);
406         if (IS_ERR(shost->ehandler)) {
407                 rval = PTR_ERR(shost->ehandler);
408                 goto fail_kfree;
409         }
410
411         scsi_proc_hostdir_add(shost->hostt);
412         return shost;
413
414  fail_kfree:
415         kfree(shost);
416         return NULL;
417 }
418 EXPORT_SYMBOL(scsi_host_alloc);
419
420 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
421 {
422         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
423
424         if (!sht->detect) {
425                 printk(KERN_WARNING "scsi_register() called on new-style "
426                                     "template for driver %s\n", sht->name);
427                 dump_stack();
428         }
429
430         if (shost)
431                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
432         return shost;
433 }
434 EXPORT_SYMBOL(scsi_register);
435
436 void scsi_unregister(struct Scsi_Host *shost)
437 {
438         list_del(&shost->sht_legacy_list);
439         scsi_host_put(shost);
440 }
441 EXPORT_SYMBOL(scsi_unregister);
442
443 static int __scsi_host_match(struct device *dev, void *data)
444 {
445         struct Scsi_Host *p;
446         unsigned short *hostnum = (unsigned short *)data;
447
448         p = class_to_shost(dev);
449         return p->host_no == *hostnum;
450 }
451
452 /**
453  * scsi_host_lookup - get a reference to a Scsi_Host by host no
454  * @hostnum:    host number to locate
455  *
456  * Return value:
457  *      A pointer to located Scsi_Host or NULL.
458  *
459  *      The caller must do a scsi_host_put() to drop the reference
460  *      that scsi_host_get() took. The put_device() below dropped
461  *      the reference from class_find_device().
462  **/
463 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
464 {
465         struct device *cdev;
466         struct Scsi_Host *shost = NULL;
467
468         cdev = class_find_device(&shost_class, NULL, &hostnum,
469                                  __scsi_host_match);
470         if (cdev) {
471                 shost = scsi_host_get(class_to_shost(cdev));
472                 put_device(cdev);
473         }
474         return shost;
475 }
476 EXPORT_SYMBOL(scsi_host_lookup);
477
478 /**
479  * scsi_host_get - inc a Scsi_Host ref count
480  * @shost:      Pointer to Scsi_Host to inc.
481  **/
482 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
483 {
484         if ((shost->shost_state == SHOST_DEL) ||
485                 !get_device(&shost->shost_gendev))
486                 return NULL;
487         return shost;
488 }
489 EXPORT_SYMBOL(scsi_host_get);
490
491 /**
492  * scsi_host_put - dec a Scsi_Host ref count
493  * @shost:      Pointer to Scsi_Host to dec.
494  **/
495 void scsi_host_put(struct Scsi_Host *shost)
496 {
497         put_device(&shost->shost_gendev);
498 }
499 EXPORT_SYMBOL(scsi_host_put);
500
501 int scsi_init_hosts(void)
502 {
503         return class_register(&shost_class);
504 }
505
506 void scsi_exit_hosts(void)
507 {
508         class_unregister(&shost_class);
509 }
510
511 int scsi_is_host_device(const struct device *dev)
512 {
513         return dev->type == &scsi_host_type;
514 }
515 EXPORT_SYMBOL(scsi_is_host_device);
516
517 /**
518  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
519  * @shost:      Pointer to Scsi_Host.
520  * @work:       Work to queue for execution.
521  *
522  * Return value:
523  *      1 - work queued for execution
524  *      0 - work is already queued
525  *      -EINVAL - work queue doesn't exist
526  **/
527 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
528 {
529         if (unlikely(!shost->work_q)) {
530                 printk(KERN_ERR
531                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
532                         "when no workqueue created.\n", shost->hostt->name);
533                 dump_stack();
534
535                 return -EINVAL;
536         }
537
538         return queue_work(shost->work_q, work);
539 }
540 EXPORT_SYMBOL_GPL(scsi_queue_work);
541
542 /**
543  * scsi_flush_work - Flush a Scsi_Host's workqueue.
544  * @shost:      Pointer to Scsi_Host.
545  **/
546 void scsi_flush_work(struct Scsi_Host *shost)
547 {
548         if (!shost->work_q) {
549                 printk(KERN_ERR
550                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
551                         "when no workqueue created.\n", shost->hostt->name);
552                 dump_stack();
553                 return;
554         }
555
556         flush_workqueue(shost->work_q);
557 }
558 EXPORT_SYMBOL_GPL(scsi_flush_work);