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/slab.h>
28 #include <linux/kthread.h>
29 #include <linux/string.h>
30 #include <linux/mm.h>
31 #include <linux/init.h>
32 #include <linux/completion.h>
33 #include <linux/transport_class.h>
34 #include <linux/platform_device.h>
35 #include <linux/pm_runtime.h>
36 #include <linux/idr.h>
37 #include <scsi/scsi_device.h>
38 #include <scsi/scsi_host.h>
39 #include <scsi/scsi_transport.h>
40
41 #include "scsi_priv.h"
42 #include "scsi_logging.h"
43
44
45 static int shost_eh_deadline = -1;
46
47 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
48 MODULE_PARM_DESC(eh_deadline,
49 "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
50
51 static DEFINE_IDA(host_index_ida);
52
53
scsi_host_cls_release(struct device * dev)54 static void scsi_host_cls_release(struct device *dev)
55 {
56 put_device(&class_to_shost(dev)->shost_gendev);
57 }
58
59 static struct class shost_class = {
60 .name = "scsi_host",
61 .dev_release = scsi_host_cls_release,
62 };
63
64 /**
65 * scsi_host_set_state - Take the given host through the host state model.
66 * @shost: scsi host to change the state of.
67 * @state: state to change to.
68 *
69 * Returns zero if unsuccessful or an error if the requested
70 * transition is illegal.
71 **/
scsi_host_set_state(struct Scsi_Host * shost,enum scsi_host_state state)72 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
73 {
74 enum scsi_host_state oldstate = shost->shost_state;
75
76 if (state == oldstate)
77 return 0;
78
79 switch (state) {
80 case SHOST_CREATED:
81 /* There are no legal states that come back to
82 * created. This is the manually initialised start
83 * state */
84 goto illegal;
85
86 case SHOST_RUNNING:
87 switch (oldstate) {
88 case SHOST_CREATED:
89 case SHOST_RECOVERY:
90 break;
91 default:
92 goto illegal;
93 }
94 break;
95
96 case SHOST_RECOVERY:
97 switch (oldstate) {
98 case SHOST_RUNNING:
99 break;
100 default:
101 goto illegal;
102 }
103 break;
104
105 case SHOST_CANCEL:
106 switch (oldstate) {
107 case SHOST_CREATED:
108 case SHOST_RUNNING:
109 case SHOST_CANCEL_RECOVERY:
110 break;
111 default:
112 goto illegal;
113 }
114 break;
115
116 case SHOST_DEL:
117 switch (oldstate) {
118 case SHOST_CANCEL:
119 case SHOST_DEL_RECOVERY:
120 break;
121 default:
122 goto illegal;
123 }
124 break;
125
126 case SHOST_CANCEL_RECOVERY:
127 switch (oldstate) {
128 case SHOST_CANCEL:
129 case SHOST_RECOVERY:
130 break;
131 default:
132 goto illegal;
133 }
134 break;
135
136 case SHOST_DEL_RECOVERY:
137 switch (oldstate) {
138 case SHOST_CANCEL_RECOVERY:
139 break;
140 default:
141 goto illegal;
142 }
143 break;
144 }
145 shost->shost_state = state;
146 return 0;
147
148 illegal:
149 SCSI_LOG_ERROR_RECOVERY(1,
150 shost_printk(KERN_ERR, shost,
151 "Illegal host state transition"
152 "%s->%s\n",
153 scsi_host_state_name(oldstate),
154 scsi_host_state_name(state)));
155 return -EINVAL;
156 }
157
158 /**
159 * scsi_remove_host - remove a scsi host
160 * @shost: a pointer to a scsi host to remove
161 **/
scsi_remove_host(struct Scsi_Host * shost)162 void scsi_remove_host(struct Scsi_Host *shost)
163 {
164 unsigned long flags;
165
166 mutex_lock(&shost->scan_mutex);
167 spin_lock_irqsave(shost->host_lock, flags);
168 if (scsi_host_set_state(shost, SHOST_CANCEL))
169 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
170 spin_unlock_irqrestore(shost->host_lock, flags);
171 mutex_unlock(&shost->scan_mutex);
172 return;
173 }
174 spin_unlock_irqrestore(shost->host_lock, flags);
175
176 scsi_autopm_get_host(shost);
177 flush_workqueue(shost->tmf_work_q);
178 scsi_forget_host(shost);
179 mutex_unlock(&shost->scan_mutex);
180 scsi_proc_host_rm(shost);
181
182 spin_lock_irqsave(shost->host_lock, flags);
183 if (scsi_host_set_state(shost, SHOST_DEL))
184 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
185 spin_unlock_irqrestore(shost->host_lock, flags);
186
187 transport_unregister_device(&shost->shost_gendev);
188 device_unregister(&shost->shost_dev);
189 device_del(&shost->shost_gendev);
190 }
191 EXPORT_SYMBOL(scsi_remove_host);
192
193 /**
194 * scsi_add_host_with_dma - add a scsi host with dma device
195 * @shost: scsi host pointer to add
196 * @dev: a struct device of type scsi class
197 * @dma_dev: dma device for the host
198 *
199 * Note: You rarely need to worry about this unless you're in a
200 * virtualised host environments, so use the simpler scsi_add_host()
201 * function instead.
202 *
203 * Return value:
204 * 0 on success / != 0 for error
205 **/
scsi_add_host_with_dma(struct Scsi_Host * shost,struct device * dev,struct device * dma_dev)206 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
207 struct device *dma_dev)
208 {
209 struct scsi_host_template *sht = shost->hostt;
210 int error = -EINVAL;
211
212 shost_printk(KERN_INFO, shost, "%s\n",
213 sht->info ? sht->info(shost) : sht->name);
214
215 if (!shost->can_queue) {
216 shost_printk(KERN_ERR, shost,
217 "can_queue = 0 no longer supported\n");
218 goto fail;
219 }
220
221 error = scsi_init_sense_cache(shost);
222 if (error)
223 goto fail;
224
225 if (shost_use_blk_mq(shost)) {
226 error = scsi_mq_setup_tags(shost);
227 if (error)
228 goto fail;
229 } else {
230 shost->bqt = blk_init_tags(shost->can_queue,
231 shost->hostt->tag_alloc_policy);
232 if (!shost->bqt) {
233 error = -ENOMEM;
234 goto fail;
235 }
236 }
237
238 if (!shost->shost_gendev.parent)
239 shost->shost_gendev.parent = dev ? dev : &platform_bus;
240 if (!dma_dev)
241 dma_dev = shost->shost_gendev.parent;
242
243 shost->dma_dev = dma_dev;
244
245 /*
246 * Increase usage count temporarily here so that calling
247 * scsi_autopm_put_host() will trigger runtime idle if there is
248 * nothing else preventing suspending the device.
249 */
250 pm_runtime_get_noresume(&shost->shost_gendev);
251 pm_runtime_set_active(&shost->shost_gendev);
252 pm_runtime_enable(&shost->shost_gendev);
253 device_enable_async_suspend(&shost->shost_gendev);
254
255 error = device_add(&shost->shost_gendev);
256 if (error)
257 goto out_disable_runtime_pm;
258
259 scsi_host_set_state(shost, SHOST_RUNNING);
260 get_device(shost->shost_gendev.parent);
261
262 device_enable_async_suspend(&shost->shost_dev);
263
264 error = device_add(&shost->shost_dev);
265 if (error)
266 goto out_del_gendev;
267
268 get_device(&shost->shost_gendev);
269
270 if (shost->transportt->host_size) {
271 shost->shost_data = kzalloc(shost->transportt->host_size,
272 GFP_KERNEL);
273 if (shost->shost_data == NULL) {
274 error = -ENOMEM;
275 goto out_del_dev;
276 }
277 }
278
279 if (shost->transportt->create_work_queue) {
280 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
281 "scsi_wq_%d", shost->host_no);
282 shost->work_q = create_singlethread_workqueue(
283 shost->work_q_name);
284 if (!shost->work_q) {
285 error = -EINVAL;
286 goto out_free_shost_data;
287 }
288 }
289
290 error = scsi_sysfs_add_host(shost);
291 if (error)
292 goto out_destroy_host;
293
294 scsi_proc_host_add(shost);
295 scsi_autopm_put_host(shost);
296 return error;
297
298 out_destroy_host:
299 if (shost->work_q)
300 destroy_workqueue(shost->work_q);
301 out_free_shost_data:
302 kfree(shost->shost_data);
303 out_del_dev:
304 device_del(&shost->shost_dev);
305 out_del_gendev:
306 device_del(&shost->shost_gendev);
307 out_disable_runtime_pm:
308 device_disable_async_suspend(&shost->shost_gendev);
309 pm_runtime_disable(&shost->shost_gendev);
310 pm_runtime_set_suspended(&shost->shost_gendev);
311 pm_runtime_put_noidle(&shost->shost_gendev);
312 if (shost_use_blk_mq(shost))
313 scsi_mq_destroy_tags(shost);
314 fail:
315 return error;
316 }
317 EXPORT_SYMBOL(scsi_add_host_with_dma);
318
scsi_host_dev_release(struct device * dev)319 static void scsi_host_dev_release(struct device *dev)
320 {
321 struct Scsi_Host *shost = dev_to_shost(dev);
322 struct device *parent = dev->parent;
323
324 scsi_proc_hostdir_rm(shost->hostt);
325
326 /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
327 rcu_barrier();
328
329 if (shost->tmf_work_q)
330 destroy_workqueue(shost->tmf_work_q);
331 if (shost->ehandler)
332 kthread_stop(shost->ehandler);
333 if (shost->work_q)
334 destroy_workqueue(shost->work_q);
335
336 if (shost->shost_state == SHOST_CREATED) {
337 /*
338 * Free the shost_dev device name here if scsi_host_alloc()
339 * and scsi_host_put() have been called but neither
340 * scsi_host_add() nor scsi_host_remove() has been called.
341 * This avoids that the memory allocated for the shost_dev
342 * name is leaked.
343 */
344 kfree(dev_name(&shost->shost_dev));
345 }
346
347 if (shost_use_blk_mq(shost)) {
348 if (shost->tag_set.tags)
349 scsi_mq_destroy_tags(shost);
350 } else {
351 if (shost->bqt)
352 blk_free_tags(shost->bqt);
353 }
354
355 kfree(shost->shost_data);
356
357 ida_simple_remove(&host_index_ida, shost->host_no);
358
359 if (parent)
360 put_device(parent);
361 kfree(shost);
362 }
363
364 static struct device_type scsi_host_type = {
365 .name = "scsi_host",
366 .release = scsi_host_dev_release,
367 };
368
369 /**
370 * scsi_host_alloc - register a scsi host adapter instance.
371 * @sht: pointer to scsi host template
372 * @privsize: extra bytes to allocate for driver
373 *
374 * Note:
375 * Allocate a new Scsi_Host and perform basic initialization.
376 * The host is not published to the scsi midlayer until scsi_add_host
377 * is called.
378 *
379 * Return value:
380 * Pointer to a new Scsi_Host
381 **/
scsi_host_alloc(struct scsi_host_template * sht,int privsize)382 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
383 {
384 struct Scsi_Host *shost;
385 gfp_t gfp_mask = GFP_KERNEL;
386 int index;
387
388 if (sht->unchecked_isa_dma && privsize)
389 gfp_mask |= __GFP_DMA;
390
391 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
392 if (!shost)
393 return NULL;
394
395 shost->host_lock = &shost->default_lock;
396 spin_lock_init(shost->host_lock);
397 shost->shost_state = SHOST_CREATED;
398 INIT_LIST_HEAD(&shost->__devices);
399 INIT_LIST_HEAD(&shost->__targets);
400 INIT_LIST_HEAD(&shost->eh_cmd_q);
401 INIT_LIST_HEAD(&shost->starved_list);
402 init_waitqueue_head(&shost->host_wait);
403 mutex_init(&shost->scan_mutex);
404
405 index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
406 if (index < 0)
407 goto fail_kfree;
408 shost->host_no = index;
409
410 shost->dma_channel = 0xff;
411
412 /* These three are default values which can be overridden */
413 shost->max_channel = 0;
414 shost->max_id = 8;
415 shost->max_lun = 8;
416
417 /* Give each shost a default transportt */
418 shost->transportt = &blank_transport_template;
419
420 /*
421 * All drivers right now should be able to handle 12 byte
422 * commands. Every so often there are requests for 16 byte
423 * commands, but individual low-level drivers need to certify that
424 * they actually do something sensible with such commands.
425 */
426 shost->max_cmd_len = 12;
427 shost->hostt = sht;
428 shost->this_id = sht->this_id;
429 shost->can_queue = sht->can_queue;
430 shost->sg_tablesize = sht->sg_tablesize;
431 shost->sg_prot_tablesize = sht->sg_prot_tablesize;
432 shost->cmd_per_lun = sht->cmd_per_lun;
433 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
434 shost->use_clustering = sht->use_clustering;
435 shost->no_write_same = sht->no_write_same;
436
437 if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
438 shost->eh_deadline = -1;
439 else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
440 shost_printk(KERN_WARNING, shost,
441 "eh_deadline %u too large, setting to %u\n",
442 shost_eh_deadline, INT_MAX / HZ);
443 shost->eh_deadline = INT_MAX;
444 } else
445 shost->eh_deadline = shost_eh_deadline * HZ;
446
447 if (sht->supported_mode == MODE_UNKNOWN)
448 /* means we didn't set it ... default to INITIATOR */
449 shost->active_mode = MODE_INITIATOR;
450 else
451 shost->active_mode = sht->supported_mode;
452
453 if (sht->max_host_blocked)
454 shost->max_host_blocked = sht->max_host_blocked;
455 else
456 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
457
458 /*
459 * If the driver imposes no hard sector transfer limit, start at
460 * machine infinity initially.
461 */
462 if (sht->max_sectors)
463 shost->max_sectors = sht->max_sectors;
464 else
465 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
466
467 /*
468 * assume a 4GB boundary, if not set
469 */
470 if (sht->dma_boundary)
471 shost->dma_boundary = sht->dma_boundary;
472 else
473 shost->dma_boundary = 0xffffffff;
474
475 shost->use_blk_mq = scsi_use_blk_mq || shost->hostt->force_blk_mq;
476
477 device_initialize(&shost->shost_gendev);
478 dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
479 shost->shost_gendev.bus = &scsi_bus_type;
480 shost->shost_gendev.type = &scsi_host_type;
481
482 device_initialize(&shost->shost_dev);
483 shost->shost_dev.parent = &shost->shost_gendev;
484 shost->shost_dev.class = &shost_class;
485 dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
486 shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
487
488 shost->ehandler = kthread_run(scsi_error_handler, shost,
489 "scsi_eh_%d", shost->host_no);
490 if (IS_ERR(shost->ehandler)) {
491 shost_printk(KERN_WARNING, shost,
492 "error handler thread failed to spawn, error = %ld\n",
493 PTR_ERR(shost->ehandler));
494 goto fail_index_remove;
495 }
496
497 shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
498 WQ_UNBOUND | WQ_MEM_RECLAIM,
499 1, shost->host_no);
500 if (!shost->tmf_work_q) {
501 shost_printk(KERN_WARNING, shost,
502 "failed to create tmf workq\n");
503 goto fail_kthread;
504 }
505 scsi_proc_hostdir_add(shost->hostt);
506 return shost;
507
508 fail_kthread:
509 kthread_stop(shost->ehandler);
510 fail_index_remove:
511 ida_simple_remove(&host_index_ida, shost->host_no);
512 fail_kfree:
513 kfree(shost);
514 return NULL;
515 }
516 EXPORT_SYMBOL(scsi_host_alloc);
517
__scsi_host_match(struct device * dev,const void * data)518 static int __scsi_host_match(struct device *dev, const void *data)
519 {
520 struct Scsi_Host *p;
521 const unsigned short *hostnum = data;
522
523 p = class_to_shost(dev);
524 return p->host_no == *hostnum;
525 }
526
527 /**
528 * scsi_host_lookup - get a reference to a Scsi_Host by host no
529 * @hostnum: host number to locate
530 *
531 * Return value:
532 * A pointer to located Scsi_Host or NULL.
533 *
534 * The caller must do a scsi_host_put() to drop the reference
535 * that scsi_host_get() took. The put_device() below dropped
536 * the reference from class_find_device().
537 **/
scsi_host_lookup(unsigned short hostnum)538 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
539 {
540 struct device *cdev;
541 struct Scsi_Host *shost = NULL;
542
543 cdev = class_find_device(&shost_class, NULL, &hostnum,
544 __scsi_host_match);
545 if (cdev) {
546 shost = scsi_host_get(class_to_shost(cdev));
547 put_device(cdev);
548 }
549 return shost;
550 }
551 EXPORT_SYMBOL(scsi_host_lookup);
552
553 /**
554 * scsi_host_get - inc a Scsi_Host ref count
555 * @shost: Pointer to Scsi_Host to inc.
556 **/
scsi_host_get(struct Scsi_Host * shost)557 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
558 {
559 if ((shost->shost_state == SHOST_DEL) ||
560 !get_device(&shost->shost_gendev))
561 return NULL;
562 return shost;
563 }
564 EXPORT_SYMBOL(scsi_host_get);
565
566 /**
567 * scsi_host_busy - Return the host busy counter
568 * @shost: Pointer to Scsi_Host to inc.
569 **/
scsi_host_busy(struct Scsi_Host * shost)570 int scsi_host_busy(struct Scsi_Host *shost)
571 {
572 return atomic_read(&shost->host_busy);
573 }
574 EXPORT_SYMBOL(scsi_host_busy);
575
576 /**
577 * scsi_host_put - dec a Scsi_Host ref count
578 * @shost: Pointer to Scsi_Host to dec.
579 **/
scsi_host_put(struct Scsi_Host * shost)580 void scsi_host_put(struct Scsi_Host *shost)
581 {
582 put_device(&shost->shost_gendev);
583 }
584 EXPORT_SYMBOL(scsi_host_put);
585
scsi_init_hosts(void)586 int scsi_init_hosts(void)
587 {
588 return class_register(&shost_class);
589 }
590
scsi_exit_hosts(void)591 void scsi_exit_hosts(void)
592 {
593 class_unregister(&shost_class);
594 ida_destroy(&host_index_ida);
595 }
596
scsi_is_host_device(const struct device * dev)597 int scsi_is_host_device(const struct device *dev)
598 {
599 return dev->type == &scsi_host_type;
600 }
601 EXPORT_SYMBOL(scsi_is_host_device);
602
603 /**
604 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
605 * @shost: Pointer to Scsi_Host.
606 * @work: Work to queue for execution.
607 *
608 * Return value:
609 * 1 - work queued for execution
610 * 0 - work is already queued
611 * -EINVAL - work queue doesn't exist
612 **/
scsi_queue_work(struct Scsi_Host * shost,struct work_struct * work)613 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
614 {
615 if (unlikely(!shost->work_q)) {
616 shost_printk(KERN_ERR, shost,
617 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
618 "when no workqueue created.\n", shost->hostt->name);
619 dump_stack();
620
621 return -EINVAL;
622 }
623
624 return queue_work(shost->work_q, work);
625 }
626 EXPORT_SYMBOL_GPL(scsi_queue_work);
627
628 /**
629 * scsi_flush_work - Flush a Scsi_Host's workqueue.
630 * @shost: Pointer to Scsi_Host.
631 **/
scsi_flush_work(struct Scsi_Host * shost)632 void scsi_flush_work(struct Scsi_Host *shost)
633 {
634 if (!shost->work_q) {
635 shost_printk(KERN_ERR, shost,
636 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
637 "when no workqueue created.\n", shost->hostt->name);
638 dump_stack();
639 return;
640 }
641
642 flush_workqueue(shost->work_q);
643 }
644 EXPORT_SYMBOL_GPL(scsi_flush_work);
645
