1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * hosts.c Copyright (C) 1992 Drew Eckhardt
4 * Copyright (C) 1993, 1994, 1995 Eric Youngdale
5 * Copyright (C) 2002-2003 Christoph Hellwig
6 *
7 * mid to lowlevel SCSI driver interface
8 * Initial versions: Drew Eckhardt
9 * Subsequent revisions: Eric Youngdale
10 *
11 * <drew@colorado.edu>
12 *
13 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
14 * Added QLOGIC QLA1280 SCSI controller kernel host support.
15 * August 4, 1999 Fred Lewis, Intel DuPont
16 *
17 * Updated to reflect the new initialization scheme for the higher
18 * level of scsi drivers (sd/sr/st)
19 * September 17, 2000 Torben Mathiasen <tmm@image.dk>
20 *
21 * Restructured scsi_host lists and associated functions.
22 * September 04, 2002 Mike Anderson (andmike@us.ibm.com)
23 */
24
25 #include <linux/module.h>
26 #include <linux/blkdev.h>
27 #include <linux/kernel.h>
28 #include <linux/slab.h>
29 #include <linux/kthread.h>
30 #include <linux/string.h>
31 #include <linux/mm.h>
32 #include <linux/init.h>
33 #include <linux/completion.h>
34 #include <linux/transport_class.h>
35 #include <linux/platform_device.h>
36 #include <linux/pm_runtime.h>
37 #include <linux/idr.h>
38 #include <scsi/scsi_device.h>
39 #include <scsi/scsi_host.h>
40 #include <scsi/scsi_transport.h>
41 #include <scsi/scsi_cmnd.h>
42
43 #include "scsi_priv.h"
44 #include "scsi_logging.h"
45
46
47 static int shost_eh_deadline = -1;
48
49 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
50 MODULE_PARM_DESC(eh_deadline,
51 "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
52
53 static DEFINE_IDA(host_index_ida);
54
55
scsi_host_cls_release(struct device * dev)56 static void scsi_host_cls_release(struct device *dev)
57 {
58 put_device(&class_to_shost(dev)->shost_gendev);
59 }
60
61 static struct class shost_class = {
62 .name = "scsi_host",
63 .dev_release = scsi_host_cls_release,
64 };
65
66 /**
67 * scsi_host_set_state - Take the given host through the host state model.
68 * @shost: scsi host to change the state of.
69 * @state: state to change to.
70 *
71 * Returns zero if unsuccessful or an error if the requested
72 * transition is illegal.
73 **/
scsi_host_set_state(struct Scsi_Host * shost,enum scsi_host_state state)74 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
75 {
76 enum scsi_host_state oldstate = shost->shost_state;
77
78 if (state == oldstate)
79 return 0;
80
81 switch (state) {
82 case SHOST_CREATED:
83 /* There are no legal states that come back to
84 * created. This is the manually initialised start
85 * state */
86 goto illegal;
87
88 case SHOST_RUNNING:
89 switch (oldstate) {
90 case SHOST_CREATED:
91 case SHOST_RECOVERY:
92 break;
93 default:
94 goto illegal;
95 }
96 break;
97
98 case SHOST_RECOVERY:
99 switch (oldstate) {
100 case SHOST_RUNNING:
101 break;
102 default:
103 goto illegal;
104 }
105 break;
106
107 case SHOST_CANCEL:
108 switch (oldstate) {
109 case SHOST_CREATED:
110 case SHOST_RUNNING:
111 case SHOST_CANCEL_RECOVERY:
112 break;
113 default:
114 goto illegal;
115 }
116 break;
117
118 case SHOST_DEL:
119 switch (oldstate) {
120 case SHOST_CANCEL:
121 case SHOST_DEL_RECOVERY:
122 break;
123 default:
124 goto illegal;
125 }
126 break;
127
128 case SHOST_CANCEL_RECOVERY:
129 switch (oldstate) {
130 case SHOST_CANCEL:
131 case SHOST_RECOVERY:
132 break;
133 default:
134 goto illegal;
135 }
136 break;
137
138 case SHOST_DEL_RECOVERY:
139 switch (oldstate) {
140 case SHOST_CANCEL_RECOVERY:
141 break;
142 default:
143 goto illegal;
144 }
145 break;
146 }
147 shost->shost_state = state;
148 return 0;
149
150 illegal:
151 SCSI_LOG_ERROR_RECOVERY(1,
152 shost_printk(KERN_ERR, shost,
153 "Illegal host state transition"
154 "%s->%s\n",
155 scsi_host_state_name(oldstate),
156 scsi_host_state_name(state)));
157 return -EINVAL;
158 }
159
160 /**
161 * scsi_remove_host - remove a scsi host
162 * @shost: a pointer to a scsi host to remove
163 **/
scsi_remove_host(struct Scsi_Host * shost)164 void scsi_remove_host(struct Scsi_Host *shost)
165 {
166 unsigned long flags;
167
168 mutex_lock(&shost->scan_mutex);
169 spin_lock_irqsave(shost->host_lock, flags);
170 if (scsi_host_set_state(shost, SHOST_CANCEL))
171 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
172 spin_unlock_irqrestore(shost->host_lock, flags);
173 mutex_unlock(&shost->scan_mutex);
174 return;
175 }
176 spin_unlock_irqrestore(shost->host_lock, flags);
177
178 scsi_autopm_get_host(shost);
179 flush_workqueue(shost->tmf_work_q);
180 scsi_forget_host(shost);
181 mutex_unlock(&shost->scan_mutex);
182 scsi_proc_host_rm(shost);
183
184 spin_lock_irqsave(shost->host_lock, flags);
185 if (scsi_host_set_state(shost, SHOST_DEL))
186 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
187 spin_unlock_irqrestore(shost->host_lock, flags);
188
189 transport_unregister_device(&shost->shost_gendev);
190 device_unregister(&shost->shost_dev);
191 device_del(&shost->shost_gendev);
192 }
193 EXPORT_SYMBOL(scsi_remove_host);
194
195 /**
196 * scsi_add_host_with_dma - add a scsi host with dma device
197 * @shost: scsi host pointer to add
198 * @dev: a struct device of type scsi class
199 * @dma_dev: dma device for the host
200 *
201 * Note: You rarely need to worry about this unless you're in a
202 * virtualised host environments, so use the simpler scsi_add_host()
203 * function instead.
204 *
205 * Return value:
206 * 0 on success / != 0 for error
207 **/
scsi_add_host_with_dma(struct Scsi_Host * shost,struct device * dev,struct device * dma_dev)208 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
209 struct device *dma_dev)
210 {
211 struct scsi_host_template *sht = shost->hostt;
212 int error = -EINVAL;
213
214 shost_printk(KERN_INFO, shost, "%s\n",
215 sht->info ? sht->info(shost) : sht->name);
216
217 if (!shost->can_queue) {
218 shost_printk(KERN_ERR, shost,
219 "can_queue = 0 no longer supported\n");
220 goto fail;
221 }
222
223 error = scsi_init_sense_cache(shost);
224 if (error)
225 goto fail;
226
227 error = scsi_mq_setup_tags(shost);
228 if (error)
229 goto fail;
230
231 if (!shost->shost_gendev.parent)
232 shost->shost_gendev.parent = dev ? dev : &platform_bus;
233 if (!dma_dev)
234 dma_dev = shost->shost_gendev.parent;
235
236 shost->dma_dev = dma_dev;
237
238 /*
239 * Increase usage count temporarily here so that calling
240 * scsi_autopm_put_host() will trigger runtime idle if there is
241 * nothing else preventing suspending the device.
242 */
243 pm_runtime_get_noresume(&shost->shost_gendev);
244 pm_runtime_set_active(&shost->shost_gendev);
245 pm_runtime_enable(&shost->shost_gendev);
246 device_enable_async_suspend(&shost->shost_gendev);
247
248 error = device_add(&shost->shost_gendev);
249 if (error)
250 goto out_disable_runtime_pm;
251
252 scsi_host_set_state(shost, SHOST_RUNNING);
253 get_device(shost->shost_gendev.parent);
254
255 device_enable_async_suspend(&shost->shost_dev);
256
257 error = device_add(&shost->shost_dev);
258 if (error)
259 goto out_del_gendev;
260
261 get_device(&shost->shost_gendev);
262
263 if (shost->transportt->host_size) {
264 shost->shost_data = kzalloc(shost->transportt->host_size,
265 GFP_KERNEL);
266 if (shost->shost_data == NULL) {
267 error = -ENOMEM;
268 goto out_del_dev;
269 }
270 }
271
272 if (shost->transportt->create_work_queue) {
273 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
274 "scsi_wq_%d", shost->host_no);
275 shost->work_q = alloc_workqueue("%s",
276 WQ_SYSFS | __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_UNBOUND,
277 1, shost->work_q_name);
278
279 if (!shost->work_q) {
280 error = -EINVAL;
281 goto out_free_shost_data;
282 }
283 }
284
285 error = scsi_sysfs_add_host(shost);
286 if (error)
287 goto out_destroy_host;
288
289 scsi_proc_host_add(shost);
290 scsi_autopm_put_host(shost);
291 return error;
292
293 out_destroy_host:
294 if (shost->work_q)
295 destroy_workqueue(shost->work_q);
296 out_free_shost_data:
297 kfree(shost->shost_data);
298 out_del_dev:
299 device_del(&shost->shost_dev);
300 out_del_gendev:
301 device_del(&shost->shost_gendev);
302 out_disable_runtime_pm:
303 device_disable_async_suspend(&shost->shost_gendev);
304 pm_runtime_disable(&shost->shost_gendev);
305 pm_runtime_set_suspended(&shost->shost_gendev);
306 pm_runtime_put_noidle(&shost->shost_gendev);
307 scsi_mq_destroy_tags(shost);
308 fail:
309 return error;
310 }
311 EXPORT_SYMBOL(scsi_add_host_with_dma);
312
scsi_host_dev_release(struct device * dev)313 static void scsi_host_dev_release(struct device *dev)
314 {
315 struct Scsi_Host *shost = dev_to_shost(dev);
316 struct device *parent = dev->parent;
317
318 scsi_proc_hostdir_rm(shost->hostt);
319
320 /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
321 rcu_barrier();
322
323 if (shost->tmf_work_q)
324 destroy_workqueue(shost->tmf_work_q);
325 if (shost->ehandler)
326 kthread_stop(shost->ehandler);
327 if (shost->work_q)
328 destroy_workqueue(shost->work_q);
329
330 if (shost->shost_state == SHOST_CREATED) {
331 /*
332 * Free the shost_dev device name here if scsi_host_alloc()
333 * and scsi_host_put() have been called but neither
334 * scsi_host_add() nor scsi_host_remove() has been called.
335 * This avoids that the memory allocated for the shost_dev
336 * name is leaked.
337 */
338 kfree(dev_name(&shost->shost_dev));
339 }
340
341 if (shost->tag_set.tags)
342 scsi_mq_destroy_tags(shost);
343
344 kfree(shost->shost_data);
345
346 ida_simple_remove(&host_index_ida, shost->host_no);
347
348 if (parent)
349 put_device(parent);
350 kfree(shost);
351 }
352
353 static struct device_type scsi_host_type = {
354 .name = "scsi_host",
355 .release = scsi_host_dev_release,
356 };
357
358 /**
359 * scsi_host_alloc - register a scsi host adapter instance.
360 * @sht: pointer to scsi host template
361 * @privsize: extra bytes to allocate for driver
362 *
363 * Note:
364 * Allocate a new Scsi_Host and perform basic initialization.
365 * The host is not published to the scsi midlayer until scsi_add_host
366 * is called.
367 *
368 * Return value:
369 * Pointer to a new Scsi_Host
370 **/
scsi_host_alloc(struct scsi_host_template * sht,int privsize)371 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
372 {
373 struct Scsi_Host *shost;
374 int index;
375
376 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, GFP_KERNEL);
377 if (!shost)
378 return NULL;
379
380 shost->host_lock = &shost->default_lock;
381 spin_lock_init(shost->host_lock);
382 shost->shost_state = SHOST_CREATED;
383 INIT_LIST_HEAD(&shost->__devices);
384 INIT_LIST_HEAD(&shost->__targets);
385 INIT_LIST_HEAD(&shost->eh_cmd_q);
386 INIT_LIST_HEAD(&shost->starved_list);
387 init_waitqueue_head(&shost->host_wait);
388 mutex_init(&shost->scan_mutex);
389
390 index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
391 if (index < 0)
392 goto fail_kfree;
393 shost->host_no = index;
394
395 shost->dma_channel = 0xff;
396
397 /* These three are default values which can be overridden */
398 shost->max_channel = 0;
399 shost->max_id = 8;
400 shost->max_lun = 8;
401
402 /* Give each shost a default transportt */
403 shost->transportt = &blank_transport_template;
404
405 /*
406 * All drivers right now should be able to handle 12 byte
407 * commands. Every so often there are requests for 16 byte
408 * commands, but individual low-level drivers need to certify that
409 * they actually do something sensible with such commands.
410 */
411 shost->max_cmd_len = 12;
412 shost->hostt = sht;
413 shost->this_id = sht->this_id;
414 shost->can_queue = sht->can_queue;
415 shost->sg_tablesize = sht->sg_tablesize;
416 shost->sg_prot_tablesize = sht->sg_prot_tablesize;
417 shost->cmd_per_lun = sht->cmd_per_lun;
418 shost->no_write_same = sht->no_write_same;
419 shost->host_tagset = sht->host_tagset;
420
421 if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
422 shost->eh_deadline = -1;
423 else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
424 shost_printk(KERN_WARNING, shost,
425 "eh_deadline %u too large, setting to %u\n",
426 shost_eh_deadline, INT_MAX / HZ);
427 shost->eh_deadline = INT_MAX;
428 } else
429 shost->eh_deadline = shost_eh_deadline * HZ;
430
431 if (sht->supported_mode == MODE_UNKNOWN)
432 /* means we didn't set it ... default to INITIATOR */
433 shost->active_mode = MODE_INITIATOR;
434 else
435 shost->active_mode = sht->supported_mode;
436
437 if (sht->max_host_blocked)
438 shost->max_host_blocked = sht->max_host_blocked;
439 else
440 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
441
442 /*
443 * If the driver imposes no hard sector transfer limit, start at
444 * machine infinity initially.
445 */
446 if (sht->max_sectors)
447 shost->max_sectors = sht->max_sectors;
448 else
449 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
450
451 if (sht->max_segment_size)
452 shost->max_segment_size = sht->max_segment_size;
453 else
454 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
455
456 /*
457 * assume a 4GB boundary, if not set
458 */
459 if (sht->dma_boundary)
460 shost->dma_boundary = sht->dma_boundary;
461 else
462 shost->dma_boundary = 0xffffffff;
463
464 if (sht->virt_boundary_mask)
465 shost->virt_boundary_mask = sht->virt_boundary_mask;
466
467 device_initialize(&shost->shost_gendev);
468 dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
469 shost->shost_gendev.bus = &scsi_bus_type;
470 shost->shost_gendev.type = &scsi_host_type;
471
472 device_initialize(&shost->shost_dev);
473 shost->shost_dev.parent = &shost->shost_gendev;
474 shost->shost_dev.class = &shost_class;
475 dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
476 shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
477
478 shost->ehandler = kthread_run(scsi_error_handler, shost,
479 "scsi_eh_%d", shost->host_no);
480 if (IS_ERR(shost->ehandler)) {
481 shost_printk(KERN_WARNING, shost,
482 "error handler thread failed to spawn, error = %ld\n",
483 PTR_ERR(shost->ehandler));
484 goto fail_index_remove;
485 }
486
487 shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
488 WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS,
489 1, shost->host_no);
490 if (!shost->tmf_work_q) {
491 shost_printk(KERN_WARNING, shost,
492 "failed to create tmf workq\n");
493 goto fail_kthread;
494 }
495 scsi_proc_hostdir_add(shost->hostt);
496 return shost;
497
498 fail_kthread:
499 kthread_stop(shost->ehandler);
500 fail_index_remove:
501 ida_simple_remove(&host_index_ida, shost->host_no);
502 fail_kfree:
503 kfree(shost);
504 return NULL;
505 }
506 EXPORT_SYMBOL(scsi_host_alloc);
507
__scsi_host_match(struct device * dev,const void * data)508 static int __scsi_host_match(struct device *dev, const void *data)
509 {
510 struct Scsi_Host *p;
511 const unsigned short *hostnum = data;
512
513 p = class_to_shost(dev);
514 return p->host_no == *hostnum;
515 }
516
517 /**
518 * scsi_host_lookup - get a reference to a Scsi_Host by host no
519 * @hostnum: host number to locate
520 *
521 * Return value:
522 * A pointer to located Scsi_Host or NULL.
523 *
524 * The caller must do a scsi_host_put() to drop the reference
525 * that scsi_host_get() took. The put_device() below dropped
526 * the reference from class_find_device().
527 **/
scsi_host_lookup(unsigned short hostnum)528 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
529 {
530 struct device *cdev;
531 struct Scsi_Host *shost = NULL;
532
533 cdev = class_find_device(&shost_class, NULL, &hostnum,
534 __scsi_host_match);
535 if (cdev) {
536 shost = scsi_host_get(class_to_shost(cdev));
537 put_device(cdev);
538 }
539 return shost;
540 }
541 EXPORT_SYMBOL(scsi_host_lookup);
542
543 /**
544 * scsi_host_get - inc a Scsi_Host ref count
545 * @shost: Pointer to Scsi_Host to inc.
546 **/
scsi_host_get(struct Scsi_Host * shost)547 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
548 {
549 if ((shost->shost_state == SHOST_DEL) ||
550 !get_device(&shost->shost_gendev))
551 return NULL;
552 return shost;
553 }
554 EXPORT_SYMBOL(scsi_host_get);
555
scsi_host_check_in_flight(struct request * rq,void * data,bool reserved)556 static bool scsi_host_check_in_flight(struct request *rq, void *data,
557 bool reserved)
558 {
559 int *count = data;
560 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
561
562 if (test_bit(SCMD_STATE_INFLIGHT, &cmd->state))
563 (*count)++;
564
565 return true;
566 }
567
568 /**
569 * scsi_host_busy - Return the host busy counter
570 * @shost: Pointer to Scsi_Host to inc.
571 **/
scsi_host_busy(struct Scsi_Host * shost)572 int scsi_host_busy(struct Scsi_Host *shost)
573 {
574 int cnt = 0;
575
576 blk_mq_tagset_busy_iter(&shost->tag_set,
577 scsi_host_check_in_flight, &cnt);
578 return cnt;
579 }
580 EXPORT_SYMBOL(scsi_host_busy);
581
582 /**
583 * scsi_host_put - dec a Scsi_Host ref count
584 * @shost: Pointer to Scsi_Host to dec.
585 **/
scsi_host_put(struct Scsi_Host * shost)586 void scsi_host_put(struct Scsi_Host *shost)
587 {
588 put_device(&shost->shost_gendev);
589 }
590 EXPORT_SYMBOL(scsi_host_put);
591
scsi_init_hosts(void)592 int scsi_init_hosts(void)
593 {
594 return class_register(&shost_class);
595 }
596
scsi_exit_hosts(void)597 void scsi_exit_hosts(void)
598 {
599 class_unregister(&shost_class);
600 ida_destroy(&host_index_ida);
601 }
602
scsi_is_host_device(const struct device * dev)603 int scsi_is_host_device(const struct device *dev)
604 {
605 return dev->type == &scsi_host_type;
606 }
607 EXPORT_SYMBOL(scsi_is_host_device);
608
609 /**
610 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
611 * @shost: Pointer to Scsi_Host.
612 * @work: Work to queue for execution.
613 *
614 * Return value:
615 * 1 - work queued for execution
616 * 0 - work is already queued
617 * -EINVAL - work queue doesn't exist
618 **/
scsi_queue_work(struct Scsi_Host * shost,struct work_struct * work)619 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
620 {
621 if (unlikely(!shost->work_q)) {
622 shost_printk(KERN_ERR, shost,
623 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
624 "when no workqueue created.\n", shost->hostt->name);
625 dump_stack();
626
627 return -EINVAL;
628 }
629
630 return queue_work(shost->work_q, work);
631 }
632 EXPORT_SYMBOL_GPL(scsi_queue_work);
633
634 /**
635 * scsi_flush_work - Flush a Scsi_Host's workqueue.
636 * @shost: Pointer to Scsi_Host.
637 **/
scsi_flush_work(struct Scsi_Host * shost)638 void scsi_flush_work(struct Scsi_Host *shost)
639 {
640 if (!shost->work_q) {
641 shost_printk(KERN_ERR, shost,
642 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
643 "when no workqueue created.\n", shost->hostt->name);
644 dump_stack();
645 return;
646 }
647
648 flush_workqueue(shost->work_q);
649 }
650 EXPORT_SYMBOL_GPL(scsi_flush_work);
651
complete_all_cmds_iter(struct request * rq,void * data,bool rsvd)652 static bool complete_all_cmds_iter(struct request *rq, void *data, bool rsvd)
653 {
654 struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
655 int status = *(int *)data;
656
657 scsi_dma_unmap(scmd);
658 scmd->result = status << 16;
659 scmd->scsi_done(scmd);
660 return true;
661 }
662
663 /**
664 * scsi_host_complete_all_commands - Terminate all running commands
665 * @shost: Scsi Host on which commands should be terminated
666 * @status: Status to be set for the terminated commands
667 *
668 * There is no protection against modification of the number
669 * of outstanding commands. It is the responsibility of the
670 * caller to ensure that concurrent I/O submission and/or
671 * completion is stopped when calling this function.
672 */
scsi_host_complete_all_commands(struct Scsi_Host * shost,int status)673 void scsi_host_complete_all_commands(struct Scsi_Host *shost, int status)
674 {
675 blk_mq_tagset_busy_iter(&shost->tag_set, complete_all_cmds_iter,
676 &status);
677 }
678 EXPORT_SYMBOL_GPL(scsi_host_complete_all_commands);
679
680 struct scsi_host_busy_iter_data {
681 bool (*fn)(struct scsi_cmnd *, void *, bool);
682 void *priv;
683 };
684
__scsi_host_busy_iter_fn(struct request * req,void * priv,bool reserved)685 static bool __scsi_host_busy_iter_fn(struct request *req, void *priv,
686 bool reserved)
687 {
688 struct scsi_host_busy_iter_data *iter_data = priv;
689 struct scsi_cmnd *sc = blk_mq_rq_to_pdu(req);
690
691 return iter_data->fn(sc, iter_data->priv, reserved);
692 }
693
694 /**
695 * scsi_host_busy_iter - Iterate over all busy commands
696 * @shost: Pointer to Scsi_Host.
697 * @fn: Function to call on each busy command
698 * @priv: Data pointer passed to @fn
699 *
700 * If locking against concurrent command completions is required
701 * ithas to be provided by the caller
702 **/
scsi_host_busy_iter(struct Scsi_Host * shost,bool (* fn)(struct scsi_cmnd *,void *,bool),void * priv)703 void scsi_host_busy_iter(struct Scsi_Host *shost,
704 bool (*fn)(struct scsi_cmnd *, void *, bool),
705 void *priv)
706 {
707 struct scsi_host_busy_iter_data iter_data = {
708 .fn = fn,
709 .priv = priv,
710 };
711
712 blk_mq_tagset_busy_iter(&shost->tag_set, __scsi_host_busy_iter_fn,
713 &iter_data);
714 }
715 EXPORT_SYMBOL_GPL(scsi_host_busy_iter);
716