Merge master.kernel.org:/pub/scm/linux/kernel/git/chrisw/lsm-2.6
[linux-2.6] / 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
34 #include <scsi/scsi_device.h>
35 #include <scsi/scsi_host.h>
36 #include <scsi/scsi_transport.h>
37
38 #include "scsi_priv.h"
39 #include "scsi_logging.h"
40
41
42 static int scsi_host_next_hn;           /* host_no for next new host */
43
44
45 static void scsi_host_cls_release(struct class_device *class_dev)
46 {
47         put_device(&class_to_shost(class_dev)->shost_gendev);
48 }
49
50 static struct class shost_class = {
51         .name           = "scsi_host",
52         .release        = scsi_host_cls_release,
53 };
54
55 /**
56  *      scsi_host_set_state - Take the given host through the host
57  *              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                         break;
102                 default:
103                         goto illegal;
104                 }
105                 break;
106
107         case SHOST_DEL:
108                 switch (oldstate) {
109                 case SHOST_CANCEL:
110                         break;
111                 default:
112                         goto illegal;
113                 }
114                 break;
115
116         }
117         shost->shost_state = state;
118         return 0;
119
120  illegal:
121         SCSI_LOG_ERROR_RECOVERY(1,
122                                 dev_printk(KERN_ERR, &shost->shost_gendev,
123                                            "Illegal host state transition"
124                                            "%s->%s\n",
125                                            scsi_host_state_name(oldstate),
126                                            scsi_host_state_name(state)));
127         return -EINVAL;
128 }
129 EXPORT_SYMBOL(scsi_host_set_state);
130
131 /**
132  * scsi_remove_host - remove a scsi host
133  * @shost:      a pointer to a scsi host to remove
134  **/
135 void scsi_remove_host(struct Scsi_Host *shost)
136 {
137         down(&shost->scan_mutex);
138         scsi_host_set_state(shost, SHOST_CANCEL);
139         up(&shost->scan_mutex);
140         scsi_forget_host(shost);
141         scsi_proc_host_rm(shost);
142
143         scsi_host_set_state(shost, SHOST_DEL);
144
145         transport_unregister_device(&shost->shost_gendev);
146         class_device_unregister(&shost->shost_classdev);
147         device_del(&shost->shost_gendev);
148 }
149 EXPORT_SYMBOL(scsi_remove_host);
150
151 /**
152  * scsi_add_host - add a scsi host
153  * @shost:      scsi host pointer to add
154  * @dev:        a struct device of type scsi class
155  *
156  * Return value: 
157  *      0 on success / != 0 for error
158  **/
159 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
160 {
161         struct scsi_host_template *sht = shost->hostt;
162         int error = -EINVAL;
163
164         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
165                         sht->info ? sht->info(shost) : sht->name);
166
167         if (!shost->can_queue) {
168                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
169                                 sht->name);
170                 goto out;
171         }
172
173         if (!shost->shost_gendev.parent)
174                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
175
176         error = device_add(&shost->shost_gendev);
177         if (error)
178                 goto out;
179
180         scsi_host_set_state(shost, SHOST_RUNNING);
181         get_device(shost->shost_gendev.parent);
182
183         error = class_device_add(&shost->shost_classdev);
184         if (error)
185                 goto out_del_gendev;
186
187         get_device(&shost->shost_gendev);
188
189         if (shost->transportt->host_size &&
190             (shost->shost_data = kmalloc(shost->transportt->host_size,
191                                          GFP_KERNEL)) == NULL)
192                 goto out_del_classdev;
193
194         if (shost->transportt->create_work_queue) {
195                 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
196                         shost->host_no);
197                 shost->work_q = create_singlethread_workqueue(
198                                         shost->work_q_name);
199                 if (!shost->work_q)
200                         goto out_free_shost_data;
201         }
202
203         error = scsi_sysfs_add_host(shost);
204         if (error)
205                 goto out_destroy_host;
206
207         scsi_proc_host_add(shost);
208         return error;
209
210  out_destroy_host:
211         if (shost->work_q)
212                 destroy_workqueue(shost->work_q);
213  out_free_shost_data:
214         kfree(shost->shost_data);
215  out_del_classdev:
216         class_device_del(&shost->shost_classdev);
217  out_del_gendev:
218         device_del(&shost->shost_gendev);
219  out:
220         return error;
221 }
222 EXPORT_SYMBOL(scsi_add_host);
223
224 static void scsi_host_dev_release(struct device *dev)
225 {
226         struct Scsi_Host *shost = dev_to_shost(dev);
227         struct device *parent = dev->parent;
228
229         if (shost->ehandler)
230                 kthread_stop(shost->ehandler);
231         if (shost->work_q)
232                 destroy_workqueue(shost->work_q);
233
234         scsi_proc_hostdir_rm(shost->hostt);
235         scsi_destroy_command_freelist(shost);
236         kfree(shost->shost_data);
237
238         if (parent)
239                 put_device(parent);
240         kfree(shost);
241 }
242
243 /**
244  * scsi_host_alloc - register a scsi host adapter instance.
245  * @sht:        pointer to scsi host template
246  * @privsize:   extra bytes to allocate for driver
247  *
248  * Note:
249  *      Allocate a new Scsi_Host and perform basic initialization.
250  *      The host is not published to the scsi midlayer until scsi_add_host
251  *      is called.
252  *
253  * Return value:
254  *      Pointer to a new Scsi_Host
255  **/
256 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
257 {
258         struct Scsi_Host *shost;
259         int gfp_mask = GFP_KERNEL, rval;
260
261         if (sht->unchecked_isa_dma && privsize)
262                 gfp_mask |= __GFP_DMA;
263
264         /* Check to see if this host has any error handling facilities */
265         if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
266             !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
267             !sht->eh_host_reset_handler) {
268                 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
269                                 "ERROR: This is not a safe way to run your "
270                                         "SCSI host\n"
271                                 "ERROR: The error handling must be added to "
272                                 "this driver\n", sht->proc_name);
273                 dump_stack();
274         }
275
276         shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
277         if (!shost)
278                 return NULL;
279         memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
280
281         spin_lock_init(&shost->default_lock);
282         scsi_assign_lock(shost, &shost->default_lock);
283         shost->shost_state = SHOST_CREATED;
284         INIT_LIST_HEAD(&shost->__devices);
285         INIT_LIST_HEAD(&shost->__targets);
286         INIT_LIST_HEAD(&shost->eh_cmd_q);
287         INIT_LIST_HEAD(&shost->starved_list);
288         init_waitqueue_head(&shost->host_wait);
289
290         init_MUTEX(&shost->scan_mutex);
291
292         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
293         shost->dma_channel = 0xff;
294
295         /* These three are default values which can be overridden */
296         shost->max_channel = 0;
297         shost->max_id = 8;
298         shost->max_lun = 8;
299
300         /* Give each shost a default transportt */
301         shost->transportt = &blank_transport_template;
302
303         /*
304          * All drivers right now should be able to handle 12 byte
305          * commands.  Every so often there are requests for 16 byte
306          * commands, but individual low-level drivers need to certify that
307          * they actually do something sensible with such commands.
308          */
309         shost->max_cmd_len = 12;
310         shost->hostt = sht;
311         shost->this_id = sht->this_id;
312         shost->can_queue = sht->can_queue;
313         shost->sg_tablesize = sht->sg_tablesize;
314         shost->cmd_per_lun = sht->cmd_per_lun;
315         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
316         shost->use_clustering = sht->use_clustering;
317         shost->ordered_flush = sht->ordered_flush;
318         shost->ordered_tag = sht->ordered_tag;
319
320         /*
321          * hosts/devices that do queueing must support ordered tags
322          */
323         if (shost->can_queue > 1 && shost->ordered_flush) {
324                 printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
325                 shost->ordered_flush = 0;
326         }
327
328         if (sht->max_host_blocked)
329                 shost->max_host_blocked = sht->max_host_blocked;
330         else
331                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
332
333         /*
334          * If the driver imposes no hard sector transfer limit, start at
335          * machine infinity initially.
336          */
337         if (sht->max_sectors)
338                 shost->max_sectors = sht->max_sectors;
339         else
340                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
341
342         /*
343          * assume a 4GB boundary, if not set
344          */
345         if (sht->dma_boundary)
346                 shost->dma_boundary = sht->dma_boundary;
347         else
348                 shost->dma_boundary = 0xffffffff;
349
350         rval = scsi_setup_command_freelist(shost);
351         if (rval)
352                 goto fail_kfree;
353
354         device_initialize(&shost->shost_gendev);
355         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
356                 shost->host_no);
357         shost->shost_gendev.release = scsi_host_dev_release;
358
359         class_device_initialize(&shost->shost_classdev);
360         shost->shost_classdev.dev = &shost->shost_gendev;
361         shost->shost_classdev.class = &shost_class;
362         snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
363                   shost->host_no);
364
365         shost->ehandler = kthread_run(scsi_error_handler, shost,
366                         "scsi_eh_%d", shost->host_no);
367         if (IS_ERR(shost->ehandler)) {
368                 rval = PTR_ERR(shost->ehandler);
369                 goto fail_destroy_freelist;
370         }
371
372         scsi_proc_hostdir_add(shost->hostt);
373         return shost;
374
375  fail_destroy_freelist:
376         scsi_destroy_command_freelist(shost);
377  fail_kfree:
378         kfree(shost);
379         return NULL;
380 }
381 EXPORT_SYMBOL(scsi_host_alloc);
382
383 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
384 {
385         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
386
387         if (!sht->detect) {
388                 printk(KERN_WARNING "scsi_register() called on new-style "
389                                     "template for driver %s\n", sht->name);
390                 dump_stack();
391         }
392
393         if (shost)
394                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
395         return shost;
396 }
397 EXPORT_SYMBOL(scsi_register);
398
399 void scsi_unregister(struct Scsi_Host *shost)
400 {
401         list_del(&shost->sht_legacy_list);
402         scsi_host_put(shost);
403 }
404 EXPORT_SYMBOL(scsi_unregister);
405
406 /**
407  * scsi_host_lookup - get a reference to a Scsi_Host by host no
408  *
409  * @hostnum:    host number to locate
410  *
411  * Return value:
412  *      A pointer to located Scsi_Host or NULL.
413  **/
414 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
415 {
416         struct class *class = &shost_class;
417         struct class_device *cdev;
418         struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
419
420         down_read(&class->subsys.rwsem);
421         list_for_each_entry(cdev, &class->children, node) {
422                 p = class_to_shost(cdev);
423                 if (p->host_no == hostnum) {
424                         shost = scsi_host_get(p);
425                         break;
426                 }
427         }
428         up_read(&class->subsys.rwsem);
429
430         return shost;
431 }
432 EXPORT_SYMBOL(scsi_host_lookup);
433
434 /**
435  * scsi_host_get - inc a Scsi_Host ref count
436  * @shost:      Pointer to Scsi_Host to inc.
437  **/
438 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
439 {
440         if ((shost->shost_state == SHOST_DEL) ||
441                 !get_device(&shost->shost_gendev))
442                 return NULL;
443         return shost;
444 }
445 EXPORT_SYMBOL(scsi_host_get);
446
447 /**
448  * scsi_host_put - dec a Scsi_Host ref count
449  * @shost:      Pointer to Scsi_Host to dec.
450  **/
451 void scsi_host_put(struct Scsi_Host *shost)
452 {
453         put_device(&shost->shost_gendev);
454 }
455 EXPORT_SYMBOL(scsi_host_put);
456
457 int scsi_init_hosts(void)
458 {
459         return class_register(&shost_class);
460 }
461
462 void scsi_exit_hosts(void)
463 {
464         class_unregister(&shost_class);
465 }
466
467 int scsi_is_host_device(const struct device *dev)
468 {
469         return dev->release == scsi_host_dev_release;
470 }
471 EXPORT_SYMBOL(scsi_is_host_device);
472
473 /**
474  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
475  * @shost:      Pointer to Scsi_Host.
476  * @work:       Work to queue for execution.
477  *
478  * Return value:
479  *      0 on success / != 0 for error
480  **/
481 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
482 {
483         if (unlikely(!shost->work_q)) {
484                 printk(KERN_ERR
485                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
486                         "when no workqueue created.\n", shost->hostt->name);
487                 dump_stack();
488
489                 return -EINVAL;
490         }
491
492         return queue_work(shost->work_q, work);
493 }
494 EXPORT_SYMBOL_GPL(scsi_queue_work);
495
496 /**
497  * scsi_flush_work - Flush a Scsi_Host's workqueue.
498  * @shost:      Pointer to Scsi_Host.
499  **/
500 void scsi_flush_work(struct Scsi_Host *shost)
501 {
502         if (!shost->work_q) {
503                 printk(KERN_ERR
504                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
505                         "when no workqueue created.\n", shost->hostt->name);
506                 dump_stack();
507                 return;
508         }
509
510         flush_workqueue(shost->work_q);
511 }
512 EXPORT_SYMBOL_GPL(scsi_flush_work);