[SCSI] host state model update: reimplement scsi_host_cancel
[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/string.h>
28 #include <linux/mm.h>
29 #include <linux/init.h>
30 #include <linux/completion.h>
31 #include <linux/transport_class.h>
32
33 #include <scsi/scsi_device.h>
34 #include <scsi/scsi_host.h>
35 #include <scsi/scsi_transport.h>
36
37 #include "scsi_priv.h"
38 #include "scsi_logging.h"
39
40
41 static int scsi_host_next_hn;           /* host_no for next new host */
42
43
44 static void scsi_host_cls_release(struct class_device *class_dev)
45 {
46         put_device(&class_to_shost(class_dev)->shost_gendev);
47 }
48
49 static struct class shost_class = {
50         .name           = "scsi_host",
51         .release        = scsi_host_cls_release,
52 };
53
54 /**
55  *      scsi_host_set_state - Take the given host through the host
56  *              state model.
57  *      @shost: scsi host to change the state of.
58  *      @state: state to change to.
59  *
60  *      Returns zero if unsuccessful or an error if the requested
61  *      transition is illegal.
62  **/
63 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
64 {
65         enum scsi_host_state oldstate = shost->shost_state;
66
67         if (state == oldstate)
68                 return 0;
69
70         switch (state) {
71         case SHOST_CREATED:
72                 /* There are no legal states that come back to
73                  * created.  This is the manually initialised start
74                  * state */
75                 goto illegal;
76
77         case SHOST_RUNNING:
78                 switch (oldstate) {
79                 case SHOST_CREATED:
80                 case SHOST_RECOVERY:
81                         break;
82                 default:
83                         goto illegal;
84                 }
85                 break;
86
87         case SHOST_RECOVERY:
88                 switch (oldstate) {
89                 case SHOST_RUNNING:
90                         break;
91                 default:
92                         goto illegal;
93                 }
94                 break;
95
96         case SHOST_CANCEL:
97                 switch (oldstate) {
98                 case SHOST_CREATED:
99                 case SHOST_RUNNING:
100                         break;
101                 default:
102                         goto illegal;
103                 }
104                 break;
105
106         case SHOST_DEL:
107                 switch (oldstate) {
108                 case SHOST_CANCEL:
109                         break;
110                 default:
111                         goto illegal;
112                 }
113                 break;
114
115         }
116         shost->shost_state = state;
117         return 0;
118
119  illegal:
120         SCSI_LOG_ERROR_RECOVERY(1,
121                                 dev_printk(KERN_ERR, &shost->shost_gendev,
122                                            "Illegal host state transition"
123                                            "%s->%s\n",
124                                            scsi_host_state_name(oldstate),
125                                            scsi_host_state_name(state)));
126         return -EINVAL;
127 }
128 EXPORT_SYMBOL(scsi_host_set_state);
129
130 /**
131  * scsi_remove_host - remove a scsi host
132  * @shost:      a pointer to a scsi host to remove
133  **/
134 void scsi_remove_host(struct Scsi_Host *shost)
135 {
136         scsi_host_set_state(shost, SHOST_CANCEL);
137         scsi_forget_host(shost);
138         scsi_proc_host_rm(shost);
139
140         scsi_host_set_state(shost, SHOST_DEL);
141
142         transport_unregister_device(&shost->shost_gendev);
143         class_device_unregister(&shost->shost_classdev);
144         device_del(&shost->shost_gendev);
145 }
146 EXPORT_SYMBOL(scsi_remove_host);
147
148 /**
149  * scsi_add_host - add a scsi host
150  * @shost:      scsi host pointer to add
151  * @dev:        a struct device of type scsi class
152  *
153  * Return value: 
154  *      0 on success / != 0 for error
155  **/
156 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
157 {
158         struct scsi_host_template *sht = shost->hostt;
159         int error = -EINVAL;
160
161         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
162                         sht->info ? sht->info(shost) : sht->name);
163
164         if (!shost->can_queue) {
165                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
166                                 sht->name);
167                 goto out;
168         }
169
170         if (!shost->shost_gendev.parent)
171                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
172
173         error = device_add(&shost->shost_gendev);
174         if (error)
175                 goto out;
176
177         scsi_host_set_state(shost, SHOST_RUNNING);
178         get_device(shost->shost_gendev.parent);
179
180         error = class_device_add(&shost->shost_classdev);
181         if (error)
182                 goto out_del_gendev;
183
184         get_device(&shost->shost_gendev);
185
186         if (shost->transportt->host_size &&
187             (shost->shost_data = kmalloc(shost->transportt->host_size,
188                                          GFP_KERNEL)) == NULL)
189                 goto out_del_classdev;
190
191         if (shost->transportt->create_work_queue) {
192                 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
193                         shost->host_no);
194                 shost->work_q = create_singlethread_workqueue(
195                                         shost->work_q_name);
196                 if (!shost->work_q)
197                         goto out_free_shost_data;
198         }
199
200         error = scsi_sysfs_add_host(shost);
201         if (error)
202                 goto out_destroy_host;
203
204         scsi_proc_host_add(shost);
205         return error;
206
207  out_destroy_host:
208         if (shost->work_q)
209                 destroy_workqueue(shost->work_q);
210  out_free_shost_data:
211         kfree(shost->shost_data);
212  out_del_classdev:
213         class_device_del(&shost->shost_classdev);
214  out_del_gendev:
215         device_del(&shost->shost_gendev);
216  out:
217         return error;
218 }
219 EXPORT_SYMBOL(scsi_add_host);
220
221 static void scsi_host_dev_release(struct device *dev)
222 {
223         struct Scsi_Host *shost = dev_to_shost(dev);
224         struct device *parent = dev->parent;
225
226         if (shost->ehandler) {
227                 DECLARE_COMPLETION(sem);
228                 shost->eh_notify = &sem;
229                 shost->eh_kill = 1;
230                 up(shost->eh_wait);
231                 wait_for_completion(&sem);
232                 shost->eh_notify = NULL;
233         }
234
235         if (shost->work_q)
236                 destroy_workqueue(shost->work_q);
237
238         scsi_proc_hostdir_rm(shost->hostt);
239         scsi_destroy_command_freelist(shost);
240         kfree(shost->shost_data);
241
242         if (parent)
243                 put_device(parent);
244         kfree(shost);
245 }
246
247 /**
248  * scsi_host_alloc - register a scsi host adapter instance.
249  * @sht:        pointer to scsi host template
250  * @privsize:   extra bytes to allocate for driver
251  *
252  * Note:
253  *      Allocate a new Scsi_Host and perform basic initialization.
254  *      The host is not published to the scsi midlayer until scsi_add_host
255  *      is called.
256  *
257  * Return value:
258  *      Pointer to a new Scsi_Host
259  **/
260 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
261 {
262         struct Scsi_Host *shost;
263         int gfp_mask = GFP_KERNEL, rval;
264         DECLARE_COMPLETION(complete);
265
266         if (sht->unchecked_isa_dma && privsize)
267                 gfp_mask |= __GFP_DMA;
268
269         /* Check to see if this host has any error handling facilities */
270         if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
271             !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
272             !sht->eh_host_reset_handler) {
273                 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
274                                 "ERROR: This is not a safe way to run your "
275                                         "SCSI host\n"
276                                 "ERROR: The error handling must be added to "
277                                 "this driver\n", sht->proc_name);
278                 dump_stack();
279         }
280
281         shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
282         if (!shost)
283                 return NULL;
284         memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
285
286         spin_lock_init(&shost->default_lock);
287         scsi_assign_lock(shost, &shost->default_lock);
288         shost->shost_state = SHOST_CREATED;
289         INIT_LIST_HEAD(&shost->__devices);
290         INIT_LIST_HEAD(&shost->__targets);
291         INIT_LIST_HEAD(&shost->eh_cmd_q);
292         INIT_LIST_HEAD(&shost->starved_list);
293         init_waitqueue_head(&shost->host_wait);
294
295         init_MUTEX(&shost->scan_mutex);
296
297         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
298         shost->dma_channel = 0xff;
299
300         /* These three are default values which can be overridden */
301         shost->max_channel = 0;
302         shost->max_id = 8;
303         shost->max_lun = 8;
304
305         /* Give each shost a default transportt */
306         shost->transportt = &blank_transport_template;
307
308         /*
309          * All drivers right now should be able to handle 12 byte
310          * commands.  Every so often there are requests for 16 byte
311          * commands, but individual low-level drivers need to certify that
312          * they actually do something sensible with such commands.
313          */
314         shost->max_cmd_len = 12;
315         shost->hostt = sht;
316         shost->this_id = sht->this_id;
317         shost->can_queue = sht->can_queue;
318         shost->sg_tablesize = sht->sg_tablesize;
319         shost->cmd_per_lun = sht->cmd_per_lun;
320         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
321         shost->use_clustering = sht->use_clustering;
322         shost->ordered_flush = sht->ordered_flush;
323         shost->ordered_tag = sht->ordered_tag;
324
325         /*
326          * hosts/devices that do queueing must support ordered tags
327          */
328         if (shost->can_queue > 1 && shost->ordered_flush) {
329                 printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
330                 shost->ordered_flush = 0;
331         }
332
333         if (sht->max_host_blocked)
334                 shost->max_host_blocked = sht->max_host_blocked;
335         else
336                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
337
338         /*
339          * If the driver imposes no hard sector transfer limit, start at
340          * machine infinity initially.
341          */
342         if (sht->max_sectors)
343                 shost->max_sectors = sht->max_sectors;
344         else
345                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
346
347         /*
348          * assume a 4GB boundary, if not set
349          */
350         if (sht->dma_boundary)
351                 shost->dma_boundary = sht->dma_boundary;
352         else
353                 shost->dma_boundary = 0xffffffff;
354
355         rval = scsi_setup_command_freelist(shost);
356         if (rval)
357                 goto fail_kfree;
358
359         device_initialize(&shost->shost_gendev);
360         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
361                 shost->host_no);
362         shost->shost_gendev.release = scsi_host_dev_release;
363
364         class_device_initialize(&shost->shost_classdev);
365         shost->shost_classdev.dev = &shost->shost_gendev;
366         shost->shost_classdev.class = &shost_class;
367         snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
368                   shost->host_no);
369
370         shost->eh_notify = &complete;
371         rval = kernel_thread(scsi_error_handler, shost, 0);
372         if (rval < 0)
373                 goto fail_destroy_freelist;
374         wait_for_completion(&complete);
375         shost->eh_notify = NULL;
376
377         scsi_proc_hostdir_add(shost->hostt);
378         return shost;
379
380  fail_destroy_freelist:
381         scsi_destroy_command_freelist(shost);
382  fail_kfree:
383         kfree(shost);
384         return NULL;
385 }
386 EXPORT_SYMBOL(scsi_host_alloc);
387
388 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
389 {
390         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
391
392         if (!sht->detect) {
393                 printk(KERN_WARNING "scsi_register() called on new-style "
394                                     "template for driver %s\n", sht->name);
395                 dump_stack();
396         }
397
398         if (shost)
399                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
400         return shost;
401 }
402 EXPORT_SYMBOL(scsi_register);
403
404 void scsi_unregister(struct Scsi_Host *shost)
405 {
406         list_del(&shost->sht_legacy_list);
407         scsi_host_put(shost);
408 }
409 EXPORT_SYMBOL(scsi_unregister);
410
411 /**
412  * scsi_host_lookup - get a reference to a Scsi_Host by host no
413  *
414  * @hostnum:    host number to locate
415  *
416  * Return value:
417  *      A pointer to located Scsi_Host or NULL.
418  **/
419 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
420 {
421         struct class *class = &shost_class;
422         struct class_device *cdev;
423         struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
424
425         down_read(&class->subsys.rwsem);
426         list_for_each_entry(cdev, &class->children, node) {
427                 p = class_to_shost(cdev);
428                 if (p->host_no == hostnum) {
429                         shost = scsi_host_get(p);
430                         break;
431                 }
432         }
433         up_read(&class->subsys.rwsem);
434
435         return shost;
436 }
437 EXPORT_SYMBOL(scsi_host_lookup);
438
439 /**
440  * scsi_host_get - inc a Scsi_Host ref count
441  * @shost:      Pointer to Scsi_Host to inc.
442  **/
443 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
444 {
445         if ((shost->shost_state == SHOST_DEL) ||
446                 !get_device(&shost->shost_gendev))
447                 return NULL;
448         return shost;
449 }
450 EXPORT_SYMBOL(scsi_host_get);
451
452 /**
453  * scsi_host_put - dec a Scsi_Host ref count
454  * @shost:      Pointer to Scsi_Host to dec.
455  **/
456 void scsi_host_put(struct Scsi_Host *shost)
457 {
458         put_device(&shost->shost_gendev);
459 }
460 EXPORT_SYMBOL(scsi_host_put);
461
462 int scsi_init_hosts(void)
463 {
464         return class_register(&shost_class);
465 }
466
467 void scsi_exit_hosts(void)
468 {
469         class_unregister(&shost_class);
470 }
471
472 int scsi_is_host_device(const struct device *dev)
473 {
474         return dev->release == scsi_host_dev_release;
475 }
476 EXPORT_SYMBOL(scsi_is_host_device);
477
478 /**
479  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
480  * @shost:      Pointer to Scsi_Host.
481  * @work:       Work to queue for execution.
482  *
483  * Return value:
484  *      0 on success / != 0 for error
485  **/
486 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
487 {
488         if (unlikely(!shost->work_q)) {
489                 printk(KERN_ERR
490                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
491                         "when no workqueue created.\n", shost->hostt->name);
492                 dump_stack();
493
494                 return -EINVAL;
495         }
496
497         return queue_work(shost->work_q, work);
498 }
499 EXPORT_SYMBOL_GPL(scsi_queue_work);
500
501 /**
502  * scsi_flush_work - Flush a Scsi_Host's workqueue.
503  * @shost:      Pointer to Scsi_Host.
504  **/
505 void scsi_flush_work(struct Scsi_Host *shost)
506 {
507         if (!shost->work_q) {
508                 printk(KERN_ERR
509                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
510                         "when no workqueue created.\n", shost->hostt->name);
511                 dump_stack();
512                 return;
513         }
514
515         flush_workqueue(shost->work_q);
516 }
517 EXPORT_SYMBOL_GPL(scsi_flush_work);