[SCSI] scsi_lib_dma: fix bug with dma maps on nested scsi objects
[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 atomic_t 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_with_dma - add a scsi host with dma device
184  * @shost:      scsi host pointer to add
185  * @dev:        a struct device of type scsi class
186  * @dma_dev:    dma device for the host
187  *
188  * Note: You rarely need to worry about this unless you're in a
189  * virtualised host environments, so use the simpler scsi_add_host()
190  * function instead.
191  *
192  * Return value: 
193  *      0 on success / != 0 for error
194  **/
195 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
196                            struct device *dma_dev)
197 {
198         struct scsi_host_template *sht = shost->hostt;
199         int error = -EINVAL;
200
201         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
202                         sht->info ? sht->info(shost) : sht->name);
203
204         if (!shost->can_queue) {
205                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
206                                 sht->name);
207                 goto fail;
208         }
209
210         error = scsi_setup_command_freelist(shost);
211         if (error)
212                 goto fail;
213
214         if (!shost->shost_gendev.parent)
215                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
216         shost->dma_dev = dma_dev;
217
218         error = device_add(&shost->shost_gendev);
219         if (error)
220                 goto out;
221
222         scsi_host_set_state(shost, SHOST_RUNNING);
223         get_device(shost->shost_gendev.parent);
224
225         error = device_add(&shost->shost_dev);
226         if (error)
227                 goto out_del_gendev;
228
229         get_device(&shost->shost_gendev);
230
231         if (shost->transportt->host_size) {
232                 shost->shost_data = kzalloc(shost->transportt->host_size,
233                                          GFP_KERNEL);
234                 if (shost->shost_data == NULL) {
235                         error = -ENOMEM;
236                         goto out_del_dev;
237                 }
238         }
239
240         if (shost->transportt->create_work_queue) {
241                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
242                          "scsi_wq_%d", shost->host_no);
243                 shost->work_q = create_singlethread_workqueue(
244                                         shost->work_q_name);
245                 if (!shost->work_q) {
246                         error = -EINVAL;
247                         goto out_free_shost_data;
248                 }
249         }
250
251         error = scsi_sysfs_add_host(shost);
252         if (error)
253                 goto out_destroy_host;
254
255         scsi_proc_host_add(shost);
256         return error;
257
258  out_destroy_host:
259         if (shost->work_q)
260                 destroy_workqueue(shost->work_q);
261  out_free_shost_data:
262         kfree(shost->shost_data);
263  out_del_dev:
264         device_del(&shost->shost_dev);
265  out_del_gendev:
266         device_del(&shost->shost_gendev);
267  out:
268         scsi_destroy_command_freelist(shost);
269  fail:
270         return error;
271 }
272 EXPORT_SYMBOL(scsi_add_host_with_dma);
273
274 static void scsi_host_dev_release(struct device *dev)
275 {
276         struct Scsi_Host *shost = dev_to_shost(dev);
277         struct device *parent = dev->parent;
278
279         scsi_proc_hostdir_rm(shost->hostt);
280
281         if (shost->ehandler)
282                 kthread_stop(shost->ehandler);
283         if (shost->work_q)
284                 destroy_workqueue(shost->work_q);
285         if (shost->uspace_req_q) {
286                 kfree(shost->uspace_req_q->queuedata);
287                 scsi_free_queue(shost->uspace_req_q);
288         }
289
290         scsi_destroy_command_freelist(shost);
291         if (shost->bqt)
292                 blk_free_tags(shost->bqt);
293
294         kfree(shost->shost_data);
295
296         if (parent)
297                 put_device(parent);
298         kfree(shost);
299 }
300
301 static struct device_type scsi_host_type = {
302         .name =         "scsi_host",
303         .release =      scsi_host_dev_release,
304 };
305
306 /**
307  * scsi_host_alloc - register a scsi host adapter instance.
308  * @sht:        pointer to scsi host template
309  * @privsize:   extra bytes to allocate for driver
310  *
311  * Note:
312  *      Allocate a new Scsi_Host and perform basic initialization.
313  *      The host is not published to the scsi midlayer until scsi_add_host
314  *      is called.
315  *
316  * Return value:
317  *      Pointer to a new Scsi_Host
318  **/
319 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
320 {
321         struct Scsi_Host *shost;
322         gfp_t gfp_mask = GFP_KERNEL;
323         int rval;
324
325         if (sht->unchecked_isa_dma && privsize)
326                 gfp_mask |= __GFP_DMA;
327
328         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
329         if (!shost)
330                 return NULL;
331
332         shost->host_lock = &shost->default_lock;
333         spin_lock_init(shost->host_lock);
334         shost->shost_state = SHOST_CREATED;
335         INIT_LIST_HEAD(&shost->__devices);
336         INIT_LIST_HEAD(&shost->__targets);
337         INIT_LIST_HEAD(&shost->eh_cmd_q);
338         INIT_LIST_HEAD(&shost->starved_list);
339         init_waitqueue_head(&shost->host_wait);
340
341         mutex_init(&shost->scan_mutex);
342
343         /*
344          * subtract one because we increment first then return, but we need to
345          * know what the next host number was before increment
346          */
347         shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
348         shost->dma_channel = 0xff;
349
350         /* These three are default values which can be overridden */
351         shost->max_channel = 0;
352         shost->max_id = 8;
353         shost->max_lun = 8;
354
355         /* Give each shost a default transportt */
356         shost->transportt = &blank_transport_template;
357
358         /*
359          * All drivers right now should be able to handle 12 byte
360          * commands.  Every so often there are requests for 16 byte
361          * commands, but individual low-level drivers need to certify that
362          * they actually do something sensible with such commands.
363          */
364         shost->max_cmd_len = 12;
365         shost->hostt = sht;
366         shost->this_id = sht->this_id;
367         shost->can_queue = sht->can_queue;
368         shost->sg_tablesize = sht->sg_tablesize;
369         shost->cmd_per_lun = sht->cmd_per_lun;
370         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
371         shost->use_clustering = sht->use_clustering;
372         shost->ordered_tag = sht->ordered_tag;
373
374         if (sht->supported_mode == MODE_UNKNOWN)
375                 /* means we didn't set it ... default to INITIATOR */
376                 shost->active_mode = MODE_INITIATOR;
377         else
378                 shost->active_mode = sht->supported_mode;
379
380         if (sht->max_host_blocked)
381                 shost->max_host_blocked = sht->max_host_blocked;
382         else
383                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
384
385         /*
386          * If the driver imposes no hard sector transfer limit, start at
387          * machine infinity initially.
388          */
389         if (sht->max_sectors)
390                 shost->max_sectors = sht->max_sectors;
391         else
392                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
393
394         /*
395          * assume a 4GB boundary, if not set
396          */
397         if (sht->dma_boundary)
398                 shost->dma_boundary = sht->dma_boundary;
399         else
400                 shost->dma_boundary = 0xffffffff;
401
402         device_initialize(&shost->shost_gendev);
403         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
404 #ifndef CONFIG_SYSFS_DEPRECATED
405         shost->shost_gendev.bus = &scsi_bus_type;
406 #endif
407         shost->shost_gendev.type = &scsi_host_type;
408
409         device_initialize(&shost->shost_dev);
410         shost->shost_dev.parent = &shost->shost_gendev;
411         shost->shost_dev.class = &shost_class;
412         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
413         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
414
415         shost->ehandler = kthread_run(scsi_error_handler, shost,
416                         "scsi_eh_%d", shost->host_no);
417         if (IS_ERR(shost->ehandler)) {
418                 rval = PTR_ERR(shost->ehandler);
419                 goto fail_kfree;
420         }
421
422         scsi_proc_hostdir_add(shost->hostt);
423         return shost;
424
425  fail_kfree:
426         kfree(shost);
427         return NULL;
428 }
429 EXPORT_SYMBOL(scsi_host_alloc);
430
431 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
432 {
433         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
434
435         if (!sht->detect) {
436                 printk(KERN_WARNING "scsi_register() called on new-style "
437                                     "template for driver %s\n", sht->name);
438                 dump_stack();
439         }
440
441         if (shost)
442                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
443         return shost;
444 }
445 EXPORT_SYMBOL(scsi_register);
446
447 void scsi_unregister(struct Scsi_Host *shost)
448 {
449         list_del(&shost->sht_legacy_list);
450         scsi_host_put(shost);
451 }
452 EXPORT_SYMBOL(scsi_unregister);
453
454 static int __scsi_host_match(struct device *dev, void *data)
455 {
456         struct Scsi_Host *p;
457         unsigned short *hostnum = (unsigned short *)data;
458
459         p = class_to_shost(dev);
460         return p->host_no == *hostnum;
461 }
462
463 /**
464  * scsi_host_lookup - get a reference to a Scsi_Host by host no
465  * @hostnum:    host number to locate
466  *
467  * Return value:
468  *      A pointer to located Scsi_Host or NULL.
469  *
470  *      The caller must do a scsi_host_put() to drop the reference
471  *      that scsi_host_get() took. The put_device() below dropped
472  *      the reference from class_find_device().
473  **/
474 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
475 {
476         struct device *cdev;
477         struct Scsi_Host *shost = NULL;
478
479         cdev = class_find_device(&shost_class, NULL, &hostnum,
480                                  __scsi_host_match);
481         if (cdev) {
482                 shost = scsi_host_get(class_to_shost(cdev));
483                 put_device(cdev);
484         }
485         return shost;
486 }
487 EXPORT_SYMBOL(scsi_host_lookup);
488
489 /**
490  * scsi_host_get - inc a Scsi_Host ref count
491  * @shost:      Pointer to Scsi_Host to inc.
492  **/
493 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
494 {
495         if ((shost->shost_state == SHOST_DEL) ||
496                 !get_device(&shost->shost_gendev))
497                 return NULL;
498         return shost;
499 }
500 EXPORT_SYMBOL(scsi_host_get);
501
502 /**
503  * scsi_host_put - dec a Scsi_Host ref count
504  * @shost:      Pointer to Scsi_Host to dec.
505  **/
506 void scsi_host_put(struct Scsi_Host *shost)
507 {
508         put_device(&shost->shost_gendev);
509 }
510 EXPORT_SYMBOL(scsi_host_put);
511
512 int scsi_init_hosts(void)
513 {
514         return class_register(&shost_class);
515 }
516
517 void scsi_exit_hosts(void)
518 {
519         class_unregister(&shost_class);
520 }
521
522 int scsi_is_host_device(const struct device *dev)
523 {
524         return dev->type == &scsi_host_type;
525 }
526 EXPORT_SYMBOL(scsi_is_host_device);
527
528 /**
529  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
530  * @shost:      Pointer to Scsi_Host.
531  * @work:       Work to queue for execution.
532  *
533  * Return value:
534  *      1 - work queued for execution
535  *      0 - work is already queued
536  *      -EINVAL - work queue doesn't exist
537  **/
538 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
539 {
540         if (unlikely(!shost->work_q)) {
541                 printk(KERN_ERR
542                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
543                         "when no workqueue created.\n", shost->hostt->name);
544                 dump_stack();
545
546                 return -EINVAL;
547         }
548
549         return queue_work(shost->work_q, work);
550 }
551 EXPORT_SYMBOL_GPL(scsi_queue_work);
552
553 /**
554  * scsi_flush_work - Flush a Scsi_Host's workqueue.
555  * @shost:      Pointer to Scsi_Host.
556  **/
557 void scsi_flush_work(struct Scsi_Host *shost)
558 {
559         if (!shost->work_q) {
560                 printk(KERN_ERR
561                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
562                         "when no workqueue created.\n", shost->hostt->name);
563                 dump_stack();
564                 return;
565         }
566
567         flush_workqueue(shost->work_q);
568 }
569 EXPORT_SYMBOL_GPL(scsi_flush_work);