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
scsi_host_cls_release(struct device * dev)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 **/
scsi_host_set_state(struct Scsi_Host * shost,enum scsi_host_state state)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 **/
scsi_remove_host(struct Scsi_Host * shost)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 scsi_proc_hostdir_rm(shost->hostt);
180 }
181 EXPORT_SYMBOL(scsi_remove_host);
182
183 /**
184 * scsi_add_host - add a scsi host
185 * @shost: scsi host pointer to add
186 * @dev: a struct device of type scsi class
187 *
188 * Return value:
189 * 0 on success / != 0 for error
190 **/
scsi_add_host(struct Scsi_Host * shost,struct device * dev)191 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
192 {
193 struct scsi_host_template *sht = shost->hostt;
194 int error = -EINVAL;
195
196 printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
197 sht->info ? sht->info(shost) : sht->name);
198
199 if (!shost->can_queue) {
200 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
201 sht->name);
202 goto fail;
203 }
204
205 error = scsi_setup_command_freelist(shost);
206 if (error)
207 goto fail;
208
209 if (!shost->shost_gendev.parent)
210 shost->shost_gendev.parent = dev ? dev : &platform_bus;
211
212 error = device_add(&shost->shost_gendev);
213 if (error)
214 goto out;
215
216 scsi_host_set_state(shost, SHOST_RUNNING);
217 get_device(shost->shost_gendev.parent);
218
219 error = device_add(&shost->shost_dev);
220 if (error)
221 goto out_del_gendev;
222
223 get_device(&shost->shost_gendev);
224
225 if (shost->transportt->host_size) {
226 shost->shost_data = kzalloc(shost->transportt->host_size,
227 GFP_KERNEL);
228 if (shost->shost_data == NULL) {
229 error = -ENOMEM;
230 goto out_del_dev;
231 }
232 }
233
234 if (shost->transportt->create_work_queue) {
235 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
236 "scsi_wq_%d", shost->host_no);
237 shost->work_q = create_singlethread_workqueue(
238 shost->work_q_name);
239 if (!shost->work_q) {
240 error = -EINVAL;
241 goto out_free_shost_data;
242 }
243 }
244
245 error = scsi_sysfs_add_host(shost);
246 if (error)
247 goto out_destroy_host;
248
249 scsi_proc_host_add(shost);
250 return error;
251
252 out_destroy_host:
253 if (shost->work_q)
254 destroy_workqueue(shost->work_q);
255 out_free_shost_data:
256 kfree(shost->shost_data);
257 out_del_dev:
258 device_del(&shost->shost_dev);
259 out_del_gendev:
260 device_del(&shost->shost_gendev);
261 out:
262 scsi_destroy_command_freelist(shost);
263 fail:
264 return error;
265 }
266 EXPORT_SYMBOL(scsi_add_host);
267
scsi_host_dev_release(struct device * dev)268 static void scsi_host_dev_release(struct device *dev)
269 {
270 struct Scsi_Host *shost = dev_to_shost(dev);
271 struct device *parent = dev->parent;
272
273 if (shost->ehandler)
274 kthread_stop(shost->ehandler);
275 if (shost->work_q)
276 destroy_workqueue(shost->work_q);
277 if (shost->uspace_req_q) {
278 kfree(shost->uspace_req_q->queuedata);
279 scsi_free_queue(shost->uspace_req_q);
280 }
281
282 scsi_destroy_command_freelist(shost);
283 if (shost->bqt)
284 blk_free_tags(shost->bqt);
285
286 kfree(shost->shost_data);
287
288 if (parent)
289 put_device(parent);
290 kfree(shost);
291 }
292
293 static struct device_type scsi_host_type = {
294 .name = "scsi_host",
295 .release = scsi_host_dev_release,
296 };
297
298 /**
299 * scsi_host_alloc - register a scsi host adapter instance.
300 * @sht: pointer to scsi host template
301 * @privsize: extra bytes to allocate for driver
302 *
303 * Note:
304 * Allocate a new Scsi_Host and perform basic initialization.
305 * The host is not published to the scsi midlayer until scsi_add_host
306 * is called.
307 *
308 * Return value:
309 * Pointer to a new Scsi_Host
310 **/
scsi_host_alloc(struct scsi_host_template * sht,int privsize)311 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
312 {
313 struct Scsi_Host *shost;
314 gfp_t gfp_mask = GFP_KERNEL;
315 int rval;
316
317 if (sht->unchecked_isa_dma && privsize)
318 gfp_mask |= __GFP_DMA;
319
320 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
321 if (!shost)
322 return NULL;
323
324 shost->host_lock = &shost->default_lock;
325 spin_lock_init(shost->host_lock);
326 shost->shost_state = SHOST_CREATED;
327 INIT_LIST_HEAD(&shost->__devices);
328 INIT_LIST_HEAD(&shost->__targets);
329 INIT_LIST_HEAD(&shost->eh_cmd_q);
330 INIT_LIST_HEAD(&shost->starved_list);
331 init_waitqueue_head(&shost->host_wait);
332
333 mutex_init(&shost->scan_mutex);
334
335 shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
336 shost->dma_channel = 0xff;
337
338 /* These three are default values which can be overridden */
339 shost->max_channel = 0;
340 shost->max_id = 8;
341 shost->max_lun = 8;
342
343 /* Give each shost a default transportt */
344 shost->transportt = &blank_transport_template;
345
346 /*
347 * All drivers right now should be able to handle 12 byte
348 * commands. Every so often there are requests for 16 byte
349 * commands, but individual low-level drivers need to certify that
350 * they actually do something sensible with such commands.
351 */
352 shost->max_cmd_len = 12;
353 shost->hostt = sht;
354 shost->this_id = sht->this_id;
355 shost->can_queue = sht->can_queue;
356 shost->sg_tablesize = sht->sg_tablesize;
357 shost->cmd_per_lun = sht->cmd_per_lun;
358 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
359 shost->use_clustering = sht->use_clustering;
360 shost->ordered_tag = sht->ordered_tag;
361
362 if (sht->supported_mode == MODE_UNKNOWN)
363 /* means we didn't set it ... default to INITIATOR */
364 shost->active_mode = MODE_INITIATOR;
365 else
366 shost->active_mode = sht->supported_mode;
367
368 if (sht->max_host_blocked)
369 shost->max_host_blocked = sht->max_host_blocked;
370 else
371 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
372
373 /*
374 * If the driver imposes no hard sector transfer limit, start at
375 * machine infinity initially.
376 */
377 if (sht->max_sectors)
378 shost->max_sectors = sht->max_sectors;
379 else
380 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
381
382 /*
383 * assume a 4GB boundary, if not set
384 */
385 if (sht->dma_boundary)
386 shost->dma_boundary = sht->dma_boundary;
387 else
388 shost->dma_boundary = 0xffffffff;
389
390 device_initialize(&shost->shost_gendev);
391 dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
392 #ifndef CONFIG_SYSFS_DEPRECATED
393 shost->shost_gendev.bus = &scsi_bus_type;
394 #endif
395 shost->shost_gendev.type = &scsi_host_type;
396
397 device_initialize(&shost->shost_dev);
398 shost->shost_dev.parent = &shost->shost_gendev;
399 shost->shost_dev.class = &shost_class;
400 dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
401 shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
402
403 shost->ehandler = kthread_run(scsi_error_handler, shost,
404 "scsi_eh_%d", shost->host_no);
405 if (IS_ERR(shost->ehandler)) {
406 rval = PTR_ERR(shost->ehandler);
407 goto fail_kfree;
408 }
409
410 scsi_proc_hostdir_add(shost->hostt);
411 return shost;
412
413 fail_kfree:
414 kfree(shost);
415 return NULL;
416 }
417 EXPORT_SYMBOL(scsi_host_alloc);
418
scsi_register(struct scsi_host_template * sht,int privsize)419 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
420 {
421 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
422
423 if (!sht->detect) {
424 printk(KERN_WARNING "scsi_register() called on new-style "
425 "template for driver %s\n", sht->name);
426 dump_stack();
427 }
428
429 if (shost)
430 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
431 return shost;
432 }
433 EXPORT_SYMBOL(scsi_register);
434
scsi_unregister(struct Scsi_Host * shost)435 void scsi_unregister(struct Scsi_Host *shost)
436 {
437 list_del(&shost->sht_legacy_list);
438 scsi_host_put(shost);
439 }
440 EXPORT_SYMBOL(scsi_unregister);
441
__scsi_host_match(struct device * dev,void * data)442 static int __scsi_host_match(struct device *dev, void *data)
443 {
444 struct Scsi_Host *p;
445 unsigned short *hostnum = (unsigned short *)data;
446
447 p = class_to_shost(dev);
448 return p->host_no == *hostnum;
449 }
450
451 /**
452 * scsi_host_lookup - get a reference to a Scsi_Host by host no
453 * @hostnum: host number to locate
454 *
455 * Return value:
456 * A pointer to located Scsi_Host or NULL.
457 *
458 * The caller must do a scsi_host_put() to drop the reference
459 * that scsi_host_get() took. The put_device() below dropped
460 * the reference from class_find_device().
461 **/
scsi_host_lookup(unsigned short hostnum)462 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
463 {
464 struct device *cdev;
465 struct Scsi_Host *shost = NULL;
466
467 cdev = class_find_device(&shost_class, NULL, &hostnum,
468 __scsi_host_match);
469 if (cdev) {
470 shost = scsi_host_get(class_to_shost(cdev));
471 put_device(cdev);
472 }
473 return shost;
474 }
475 EXPORT_SYMBOL(scsi_host_lookup);
476
477 /**
478 * scsi_host_get - inc a Scsi_Host ref count
479 * @shost: Pointer to Scsi_Host to inc.
480 **/
scsi_host_get(struct Scsi_Host * shost)481 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
482 {
483 if ((shost->shost_state == SHOST_DEL) ||
484 !get_device(&shost->shost_gendev))
485 return NULL;
486 return shost;
487 }
488 EXPORT_SYMBOL(scsi_host_get);
489
490 /**
491 * scsi_host_put - dec a Scsi_Host ref count
492 * @shost: Pointer to Scsi_Host to dec.
493 **/
scsi_host_put(struct Scsi_Host * shost)494 void scsi_host_put(struct Scsi_Host *shost)
495 {
496 put_device(&shost->shost_gendev);
497 }
498 EXPORT_SYMBOL(scsi_host_put);
499
scsi_init_hosts(void)500 int scsi_init_hosts(void)
501 {
502 return class_register(&shost_class);
503 }
504
scsi_exit_hosts(void)505 void scsi_exit_hosts(void)
506 {
507 class_unregister(&shost_class);
508 }
509
scsi_is_host_device(const struct device * dev)510 int scsi_is_host_device(const struct device *dev)
511 {
512 return dev->type == &scsi_host_type;
513 }
514 EXPORT_SYMBOL(scsi_is_host_device);
515
516 /**
517 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
518 * @shost: Pointer to Scsi_Host.
519 * @work: Work to queue for execution.
520 *
521 * Return value:
522 * 1 - work queued for execution
523 * 0 - work is already queued
524 * -EINVAL - work queue doesn't exist
525 **/
scsi_queue_work(struct Scsi_Host * shost,struct work_struct * work)526 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
527 {
528 if (unlikely(!shost->work_q)) {
529 printk(KERN_ERR
530 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
531 "when no workqueue created.\n", shost->hostt->name);
532 dump_stack();
533
534 return -EINVAL;
535 }
536
537 return queue_work(shost->work_q, work);
538 }
539 EXPORT_SYMBOL_GPL(scsi_queue_work);
540
541 /**
542 * scsi_flush_work - Flush a Scsi_Host's workqueue.
543 * @shost: Pointer to Scsi_Host.
544 **/
scsi_flush_work(struct Scsi_Host * shost)545 void scsi_flush_work(struct Scsi_Host *shost)
546 {
547 if (!shost->work_q) {
548 printk(KERN_ERR
549 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
550 "when no workqueue created.\n", shost->hostt->name);
551 dump_stack();
552 return;
553 }
554
555 flush_workqueue(shost->work_q);
556 }
557 EXPORT_SYMBOL_GPL(scsi_flush_work);
558