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
47static int shost_eh_deadline = -1;
48
49module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
50MODULE_PARM_DESC(eh_deadline,
51		 "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
52
53static DEFINE_IDA(host_index_ida);
54
55
56static void scsi_host_cls_release(struct device *dev)
57{
58	put_device(&class_to_shost(dev)->shost_gendev);
59}
60
61static struct class shost_class = {
62	.name		= "scsi_host",
63	.dev_release	= scsi_host_cls_release,
64	.dev_groups	= scsi_shost_groups,
65};
66
67/**
68 *	scsi_host_set_state - Take the given host through the host state model.
69 *	@shost:	scsi host to change the state of.
70 *	@state:	state to change to.
71 *
72 *	Returns zero if unsuccessful or an error if the requested
73 *	transition is illegal.
74 **/
75int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
76{
77	enum scsi_host_state oldstate = shost->shost_state;
78
79	if (state == oldstate)
80		return 0;
81
82	switch (state) {
83	case SHOST_CREATED:
84		/* There are no legal states that come back to
85		 * created.  This is the manually initialised start
86		 * state */
87		goto illegal;
88
89	case SHOST_RUNNING:
90		switch (oldstate) {
91		case SHOST_CREATED:
92		case SHOST_RECOVERY:
93			break;
94		default:
95			goto illegal;
96		}
97		break;
98
99	case SHOST_RECOVERY:
100		switch (oldstate) {
101		case SHOST_RUNNING:
102			break;
103		default:
104			goto illegal;
105		}
106		break;
107
108	case SHOST_CANCEL:
109		switch (oldstate) {
110		case SHOST_CREATED:
111		case SHOST_RUNNING:
112		case SHOST_CANCEL_RECOVERY:
113			break;
114		default:
115			goto illegal;
116		}
117		break;
118
119	case SHOST_DEL:
120		switch (oldstate) {
121		case SHOST_CANCEL:
122		case SHOST_DEL_RECOVERY:
123			break;
124		default:
125			goto illegal;
126		}
127		break;
128
129	case SHOST_CANCEL_RECOVERY:
130		switch (oldstate) {
131		case SHOST_CANCEL:
132		case SHOST_RECOVERY:
133			break;
134		default:
135			goto illegal;
136		}
137		break;
138
139	case SHOST_DEL_RECOVERY:
140		switch (oldstate) {
141		case SHOST_CANCEL_RECOVERY:
142			break;
143		default:
144			goto illegal;
145		}
146		break;
147	}
148	shost->shost_state = state;
149	return 0;
150
151 illegal:
152	SCSI_LOG_ERROR_RECOVERY(1,
153				shost_printk(KERN_ERR, shost,
154					     "Illegal host state transition"
155					     "%s->%s\n",
156					     scsi_host_state_name(oldstate),
157					     scsi_host_state_name(state)));
158	return -EINVAL;
159}
160
161/**
162 * scsi_remove_host - remove a scsi host
163 * @shost:	a pointer to a scsi host to remove
164 **/
165void scsi_remove_host(struct Scsi_Host *shost)
166{
167	unsigned long flags;
168
169	mutex_lock(&shost->scan_mutex);
170	spin_lock_irqsave(shost->host_lock, flags);
171	if (scsi_host_set_state(shost, SHOST_CANCEL))
172		if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
173			spin_unlock_irqrestore(shost->host_lock, flags);
174			mutex_unlock(&shost->scan_mutex);
175			return;
176		}
177	spin_unlock_irqrestore(shost->host_lock, flags);
178
179	scsi_autopm_get_host(shost);
180	flush_workqueue(shost->tmf_work_q);
181	scsi_forget_host(shost);
182	mutex_unlock(&shost->scan_mutex);
183	scsi_proc_host_rm(shost);
184	scsi_proc_hostdir_rm(shost->hostt);
185
186	/*
187	 * New SCSI devices cannot be attached anymore because of the SCSI host
188	 * state so drop the tag set refcnt. Wait until the tag set refcnt drops
189	 * to zero because .exit_cmd_priv implementations may need the host
190	 * pointer.
191	 */
192	kref_put(&shost->tagset_refcnt, scsi_mq_free_tags);
193	wait_for_completion(&shost->tagset_freed);
194
195	spin_lock_irqsave(shost->host_lock, flags);
196	if (scsi_host_set_state(shost, SHOST_DEL))
197		BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
198	spin_unlock_irqrestore(shost->host_lock, flags);
199
200	transport_unregister_device(&shost->shost_gendev);
201	device_unregister(&shost->shost_dev);
202	device_del(&shost->shost_gendev);
203}
204EXPORT_SYMBOL(scsi_remove_host);
205
206/**
207 * scsi_add_host_with_dma - add a scsi host with dma device
208 * @shost:	scsi host pointer to add
209 * @dev:	a struct device of type scsi class
210 * @dma_dev:	dma device for the host
211 *
212 * Note: You rarely need to worry about this unless you're in a
213 * virtualised host environments, so use the simpler scsi_add_host()
214 * function instead.
215 *
216 * Return value:
217 * 	0 on success / != 0 for error
218 **/
219int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
220			   struct device *dma_dev)
221{
222	const struct scsi_host_template *sht = shost->hostt;
223	int error = -EINVAL;
224
225	shost_printk(KERN_INFO, shost, "%s\n",
226			sht->info ? sht->info(shost) : sht->name);
227
228	if (!shost->can_queue) {
229		shost_printk(KERN_ERR, shost,
230			     "can_queue = 0 no longer supported\n");
231		goto fail;
232	}
233
234	/* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
235	shost->cmd_per_lun = min_t(int, shost->cmd_per_lun,
236				   shost->can_queue);
237
238	error = scsi_init_sense_cache(shost);
239	if (error)
240		goto fail;
241
242	if (!shost->shost_gendev.parent)
243		shost->shost_gendev.parent = dev ? dev : &platform_bus;
244	if (!dma_dev)
245		dma_dev = shost->shost_gendev.parent;
246
247	shost->dma_dev = dma_dev;
248
249	if (dma_dev->dma_mask) {
250		shost->max_sectors = min_t(unsigned int, shost->max_sectors,
251				dma_max_mapping_size(dma_dev) >> SECTOR_SHIFT);
252	}
253
254	error = scsi_mq_setup_tags(shost);
255	if (error)
256		goto fail;
257
258	kref_init(&shost->tagset_refcnt);
259	init_completion(&shost->tagset_freed);
260
261	/*
262	 * Increase usage count temporarily here so that calling
263	 * scsi_autopm_put_host() will trigger runtime idle if there is
264	 * nothing else preventing suspending the device.
265	 */
266	pm_runtime_get_noresume(&shost->shost_gendev);
267	pm_runtime_set_active(&shost->shost_gendev);
268	pm_runtime_enable(&shost->shost_gendev);
269	device_enable_async_suspend(&shost->shost_gendev);
270
271	error = device_add(&shost->shost_gendev);
272	if (error)
273		goto out_disable_runtime_pm;
274
275	scsi_host_set_state(shost, SHOST_RUNNING);
276	get_device(shost->shost_gendev.parent);
277
278	device_enable_async_suspend(&shost->shost_dev);
279
280	get_device(&shost->shost_gendev);
281	error = device_add(&shost->shost_dev);
282	if (error)
283		goto out_del_gendev;
284
285	if (shost->transportt->host_size) {
286		shost->shost_data = kzalloc(shost->transportt->host_size,
287					 GFP_KERNEL);
288		if (shost->shost_data == NULL) {
289			error = -ENOMEM;
290			goto out_del_dev;
291		}
292	}
293
294	if (shost->transportt->create_work_queue) {
295		snprintf(shost->work_q_name, sizeof(shost->work_q_name),
296			 "scsi_wq_%d", shost->host_no);
297		shost->work_q = alloc_workqueue("%s",
298			WQ_SYSFS | __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_UNBOUND,
299			1, shost->work_q_name);
300
301		if (!shost->work_q) {
302			error = -EINVAL;
303			goto out_del_dev;
304		}
305	}
306
307	error = scsi_sysfs_add_host(shost);
308	if (error)
309		goto out_del_dev;
310
311	scsi_proc_host_add(shost);
312	scsi_autopm_put_host(shost);
313	return error;
314
315	/*
316	 * Any host allocation in this function will be freed in
317	 * scsi_host_dev_release().
318	 */
319 out_del_dev:
320	device_del(&shost->shost_dev);
321 out_del_gendev:
322	/*
323	 * Host state is SHOST_RUNNING so we have to explicitly release
324	 * ->shost_dev.
325	 */
326	put_device(&shost->shost_dev);
327	device_del(&shost->shost_gendev);
328 out_disable_runtime_pm:
329	device_disable_async_suspend(&shost->shost_gendev);
330	pm_runtime_disable(&shost->shost_gendev);
331	pm_runtime_set_suspended(&shost->shost_gendev);
332	pm_runtime_put_noidle(&shost->shost_gendev);
333	kref_put(&shost->tagset_refcnt, scsi_mq_free_tags);
334 fail:
335	return error;
336}
337EXPORT_SYMBOL(scsi_add_host_with_dma);
338
339static void scsi_host_dev_release(struct device *dev)
340{
341	struct Scsi_Host *shost = dev_to_shost(dev);
342	struct device *parent = dev->parent;
343
344	/* Wait for functions invoked through call_rcu(&scmd->rcu, ...) */
345	rcu_barrier();
346
347	if (shost->tmf_work_q)
348		destroy_workqueue(shost->tmf_work_q);
349	if (shost->ehandler)
350		kthread_stop(shost->ehandler);
351	if (shost->work_q)
352		destroy_workqueue(shost->work_q);
353
354	if (shost->shost_state == SHOST_CREATED) {
355		/*
356		 * Free the shost_dev device name and remove the proc host dir
357		 * here if scsi_host_{alloc,put}() have been called but neither
358		 * scsi_host_add() nor scsi_remove_host() has been called.
359		 * This avoids that the memory allocated for the shost_dev
360		 * name as well as the proc dir structure are leaked.
361		 */
362		scsi_proc_hostdir_rm(shost->hostt);
363		kfree(dev_name(&shost->shost_dev));
364	}
365
366	kfree(shost->shost_data);
367
368	ida_free(&host_index_ida, shost->host_no);
369
370	if (shost->shost_state != SHOST_CREATED)
371		put_device(parent);
372	kfree(shost);
373}
374
375static const struct device_type scsi_host_type = {
376	.name =		"scsi_host",
377	.release =	scsi_host_dev_release,
378};
379
380/**
381 * scsi_host_alloc - register a scsi host adapter instance.
382 * @sht:	pointer to scsi host template
383 * @privsize:	extra bytes to allocate for driver
384 *
385 * Note:
386 * 	Allocate a new Scsi_Host and perform basic initialization.
387 * 	The host is not published to the scsi midlayer until scsi_add_host
388 * 	is called.
389 *
390 * Return value:
391 * 	Pointer to a new Scsi_Host
392 **/
393struct Scsi_Host *scsi_host_alloc(const struct scsi_host_template *sht, int privsize)
394{
395	struct Scsi_Host *shost;
396	int index;
397
398	shost = kzalloc(sizeof(struct Scsi_Host) + privsize, GFP_KERNEL);
399	if (!shost)
400		return NULL;
401
402	shost->host_lock = &shost->default_lock;
403	spin_lock_init(shost->host_lock);
404	shost->shost_state = SHOST_CREATED;
405	INIT_LIST_HEAD(&shost->__devices);
406	INIT_LIST_HEAD(&shost->__targets);
407	INIT_LIST_HEAD(&shost->eh_abort_list);
408	INIT_LIST_HEAD(&shost->eh_cmd_q);
409	INIT_LIST_HEAD(&shost->starved_list);
410	init_waitqueue_head(&shost->host_wait);
411	mutex_init(&shost->scan_mutex);
412
413	index = ida_alloc(&host_index_ida, GFP_KERNEL);
414	if (index < 0) {
415		kfree(shost);
416		return NULL;
417	}
418	shost->host_no = index;
419
420	shost->dma_channel = 0xff;
421
422	/* These three are default values which can be overridden */
423	shost->max_channel = 0;
424	shost->max_id = 8;
425	shost->max_lun = 8;
426
427	/* Give each shost a default transportt */
428	shost->transportt = &blank_transport_template;
429
430	/*
431	 * All drivers right now should be able to handle 12 byte
432	 * commands.  Every so often there are requests for 16 byte
433	 * commands, but individual low-level drivers need to certify that
434	 * they actually do something sensible with such commands.
435	 */
436	shost->max_cmd_len = 12;
437	shost->hostt = sht;
438	shost->this_id = sht->this_id;
439	shost->can_queue = sht->can_queue;
440	shost->sg_tablesize = sht->sg_tablesize;
441	shost->sg_prot_tablesize = sht->sg_prot_tablesize;
442	shost->cmd_per_lun = sht->cmd_per_lun;
443	shost->no_write_same = sht->no_write_same;
444	shost->host_tagset = sht->host_tagset;
445	shost->queuecommand_may_block = sht->queuecommand_may_block;
446
447	if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
448		shost->eh_deadline = -1;
449	else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
450		shost_printk(KERN_WARNING, shost,
451			     "eh_deadline %u too large, setting to %u\n",
452			     shost_eh_deadline, INT_MAX / HZ);
453		shost->eh_deadline = INT_MAX;
454	} else
455		shost->eh_deadline = shost_eh_deadline * HZ;
456
457	if (sht->supported_mode == MODE_UNKNOWN)
458		/* means we didn't set it ... default to INITIATOR */
459		shost->active_mode = MODE_INITIATOR;
460	else
461		shost->active_mode = sht->supported_mode;
462
463	if (sht->max_host_blocked)
464		shost->max_host_blocked = sht->max_host_blocked;
465	else
466		shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
467
468	/*
469	 * If the driver imposes no hard sector transfer limit, start at
470	 * machine infinity initially.
471	 */
472	if (sht->max_sectors)
473		shost->max_sectors = sht->max_sectors;
474	else
475		shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
476
477	if (sht->max_segment_size)
478		shost->max_segment_size = sht->max_segment_size;
479	else
480		shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
481
482	/*
483	 * assume a 4GB boundary, if not set
484	 */
485	if (sht->dma_boundary)
486		shost->dma_boundary = sht->dma_boundary;
487	else
488		shost->dma_boundary = 0xffffffff;
489
490	if (sht->virt_boundary_mask)
491		shost->virt_boundary_mask = sht->virt_boundary_mask;
492
493	device_initialize(&shost->shost_gendev);
494	dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
495	shost->shost_gendev.bus = &scsi_bus_type;
496	shost->shost_gendev.type = &scsi_host_type;
497	scsi_enable_async_suspend(&shost->shost_gendev);
498
499	device_initialize(&shost->shost_dev);
500	shost->shost_dev.parent = &shost->shost_gendev;
501	shost->shost_dev.class = &shost_class;
502	dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
503	shost->shost_dev.groups = sht->shost_groups;
504
505	shost->ehandler = kthread_run(scsi_error_handler, shost,
506			"scsi_eh_%d", shost->host_no);
507	if (IS_ERR(shost->ehandler)) {
508		shost_printk(KERN_WARNING, shost,
509			"error handler thread failed to spawn, error = %ld\n",
510			PTR_ERR(shost->ehandler));
511		shost->ehandler = NULL;
512		goto fail;
513	}
514
515	shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
516					WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS,
517					   1, shost->host_no);
518	if (!shost->tmf_work_q) {
519		shost_printk(KERN_WARNING, shost,
520			     "failed to create tmf workq\n");
521		goto fail;
522	}
523	if (scsi_proc_hostdir_add(shost->hostt) < 0)
524		goto fail;
525	return shost;
526 fail:
527	/*
528	 * Host state is still SHOST_CREATED and that is enough to release
529	 * ->shost_gendev. scsi_host_dev_release() will free
530	 * dev_name(&shost->shost_dev).
531	 */
532	put_device(&shost->shost_gendev);
533
534	return NULL;
535}
536EXPORT_SYMBOL(scsi_host_alloc);
537
538static int __scsi_host_match(struct device *dev, const void *data)
539{
540	struct Scsi_Host *p;
541	const unsigned int *hostnum = data;
542
543	p = class_to_shost(dev);
544	return p->host_no == *hostnum;
545}
546
547/**
548 * scsi_host_lookup - get a reference to a Scsi_Host by host no
549 * @hostnum:	host number to locate
550 *
551 * Return value:
552 *	A pointer to located Scsi_Host or NULL.
553 *
554 *	The caller must do a scsi_host_put() to drop the reference
555 *	that scsi_host_get() took. The put_device() below dropped
556 *	the reference from class_find_device().
557 **/
558struct Scsi_Host *scsi_host_lookup(unsigned int hostnum)
559{
560	struct device *cdev;
561	struct Scsi_Host *shost = NULL;
562
563	cdev = class_find_device(&shost_class, NULL, &hostnum,
564				 __scsi_host_match);
565	if (cdev) {
566		shost = scsi_host_get(class_to_shost(cdev));
567		put_device(cdev);
568	}
569	return shost;
570}
571EXPORT_SYMBOL(scsi_host_lookup);
572
573/**
574 * scsi_host_get - inc a Scsi_Host ref count
575 * @shost:	Pointer to Scsi_Host to inc.
576 **/
577struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
578{
579	if ((shost->shost_state == SHOST_DEL) ||
580		!get_device(&shost->shost_gendev))
581		return NULL;
582	return shost;
583}
584EXPORT_SYMBOL(scsi_host_get);
585
586static bool scsi_host_check_in_flight(struct request *rq, void *data)
587{
588	int *count = data;
589	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
590
591	if (test_bit(SCMD_STATE_INFLIGHT, &cmd->state))
592		(*count)++;
593
594	return true;
595}
596
597/**
598 * scsi_host_busy - Return the host busy counter
599 * @shost:	Pointer to Scsi_Host to inc.
600 **/
601int scsi_host_busy(struct Scsi_Host *shost)
602{
603	int cnt = 0;
604
605	blk_mq_tagset_busy_iter(&shost->tag_set,
606				scsi_host_check_in_flight, &cnt);
607	return cnt;
608}
609EXPORT_SYMBOL(scsi_host_busy);
610
611/**
612 * scsi_host_put - dec a Scsi_Host ref count
613 * @shost:	Pointer to Scsi_Host to dec.
614 **/
615void scsi_host_put(struct Scsi_Host *shost)
616{
617	put_device(&shost->shost_gendev);
618}
619EXPORT_SYMBOL(scsi_host_put);
620
621int scsi_init_hosts(void)
622{
623	return class_register(&shost_class);
624}
625
626void scsi_exit_hosts(void)
627{
628	class_unregister(&shost_class);
629	ida_destroy(&host_index_ida);
630}
631
632int scsi_is_host_device(const struct device *dev)
633{
634	return dev->type == &scsi_host_type;
635}
636EXPORT_SYMBOL(scsi_is_host_device);
637
638/**
639 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
640 * @shost:	Pointer to Scsi_Host.
641 * @work:	Work to queue for execution.
642 *
643 * Return value:
644 * 	1 - work queued for execution
645 *	0 - work is already queued
646 *	-EINVAL - work queue doesn't exist
647 **/
648int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
649{
650	if (unlikely(!shost->work_q)) {
651		shost_printk(KERN_ERR, shost,
652			"ERROR: Scsi host '%s' attempted to queue scsi-work, "
653			"when no workqueue created.\n", shost->hostt->name);
654		dump_stack();
655
656		return -EINVAL;
657	}
658
659	return queue_work(shost->work_q, work);
660}
661EXPORT_SYMBOL_GPL(scsi_queue_work);
662
663/**
664 * scsi_flush_work - Flush a Scsi_Host's workqueue.
665 * @shost:	Pointer to Scsi_Host.
666 **/
667void scsi_flush_work(struct Scsi_Host *shost)
668{
669	if (!shost->work_q) {
670		shost_printk(KERN_ERR, shost,
671			"ERROR: Scsi host '%s' attempted to flush scsi-work, "
672			"when no workqueue created.\n", shost->hostt->name);
673		dump_stack();
674		return;
675	}
676
677	flush_workqueue(shost->work_q);
678}
679EXPORT_SYMBOL_GPL(scsi_flush_work);
680
681static bool complete_all_cmds_iter(struct request *rq, void *data)
682{
683	struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
684	enum scsi_host_status status = *(enum scsi_host_status *)data;
685
686	scsi_dma_unmap(scmd);
687	scmd->result = 0;
688	set_host_byte(scmd, status);
689	scsi_done(scmd);
690	return true;
691}
692
693/**
694 * scsi_host_complete_all_commands - Terminate all running commands
695 * @shost:	Scsi Host on which commands should be terminated
696 * @status:	Status to be set for the terminated commands
697 *
698 * There is no protection against modification of the number
699 * of outstanding commands. It is the responsibility of the
700 * caller to ensure that concurrent I/O submission and/or
701 * completion is stopped when calling this function.
702 */
703void scsi_host_complete_all_commands(struct Scsi_Host *shost,
704				     enum scsi_host_status status)
705{
706	blk_mq_tagset_busy_iter(&shost->tag_set, complete_all_cmds_iter,
707				&status);
708}
709EXPORT_SYMBOL_GPL(scsi_host_complete_all_commands);
710
711struct scsi_host_busy_iter_data {
712	bool (*fn)(struct scsi_cmnd *, void *);
713	void *priv;
714};
715
716static bool __scsi_host_busy_iter_fn(struct request *req, void *priv)
717{
718	struct scsi_host_busy_iter_data *iter_data = priv;
719	struct scsi_cmnd *sc = blk_mq_rq_to_pdu(req);
720
721	return iter_data->fn(sc, iter_data->priv);
722}
723
724/**
725 * scsi_host_busy_iter - Iterate over all busy commands
726 * @shost:	Pointer to Scsi_Host.
727 * @fn:		Function to call on each busy command
728 * @priv:	Data pointer passed to @fn
729 *
730 * If locking against concurrent command completions is required
731 * ithas to be provided by the caller
732 **/
733void scsi_host_busy_iter(struct Scsi_Host *shost,
734			 bool (*fn)(struct scsi_cmnd *, void *),
735			 void *priv)
736{
737	struct scsi_host_busy_iter_data iter_data = {
738		.fn = fn,
739		.priv = priv,
740	};
741
742	blk_mq_tagset_busy_iter(&shost->tag_set, __scsi_host_busy_iter_fn,
743				&iter_data);
744}
745EXPORT_SYMBOL_GPL(scsi_host_busy_iter);
746