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 	.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  **/
scsi_host_set_state(struct Scsi_Host * shost,enum scsi_host_state state)75 int 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  **/
scsi_remove_host(struct Scsi_Host * shost)165 void 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 }
204 EXPORT_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  **/
scsi_add_host_with_dma(struct Scsi_Host * shost,struct device * dev,struct device * dma_dev)219 int 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 }
337 EXPORT_SYMBOL(scsi_add_host_with_dma);
338 
scsi_host_dev_release(struct device * dev)339 static 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 here if scsi_host_alloc()
357 		 * and scsi_host_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 is leaked.
361 		 */
362 		kfree(dev_name(&shost->shost_dev));
363 	}
364 
365 	kfree(shost->shost_data);
366 
367 	ida_free(&host_index_ida, shost->host_no);
368 
369 	if (shost->shost_state != SHOST_CREATED)
370 		put_device(parent);
371 	kfree(shost);
372 }
373 
374 static struct device_type scsi_host_type = {
375 	.name =		"scsi_host",
376 	.release =	scsi_host_dev_release,
377 };
378 
379 /**
380  * scsi_host_alloc - register a scsi host adapter instance.
381  * @sht:	pointer to scsi host template
382  * @privsize:	extra bytes to allocate for driver
383  *
384  * Note:
385  * 	Allocate a new Scsi_Host and perform basic initialization.
386  * 	The host is not published to the scsi midlayer until scsi_add_host
387  * 	is called.
388  *
389  * Return value:
390  * 	Pointer to a new Scsi_Host
391  **/
scsi_host_alloc(const struct scsi_host_template * sht,int privsize)392 struct Scsi_Host *scsi_host_alloc(const struct scsi_host_template *sht, int privsize)
393 {
394 	struct Scsi_Host *shost;
395 	int index;
396 
397 	shost = kzalloc(sizeof(struct Scsi_Host) + privsize, GFP_KERNEL);
398 	if (!shost)
399 		return NULL;
400 
401 	shost->host_lock = &shost->default_lock;
402 	spin_lock_init(shost->host_lock);
403 	shost->shost_state = SHOST_CREATED;
404 	INIT_LIST_HEAD(&shost->__devices);
405 	INIT_LIST_HEAD(&shost->__targets);
406 	INIT_LIST_HEAD(&shost->eh_abort_list);
407 	INIT_LIST_HEAD(&shost->eh_cmd_q);
408 	INIT_LIST_HEAD(&shost->starved_list);
409 	init_waitqueue_head(&shost->host_wait);
410 	mutex_init(&shost->scan_mutex);
411 
412 	index = ida_alloc(&host_index_ida, GFP_KERNEL);
413 	if (index < 0) {
414 		kfree(shost);
415 		return NULL;
416 	}
417 	shost->host_no = index;
418 
419 	shost->dma_channel = 0xff;
420 
421 	/* These three are default values which can be overridden */
422 	shost->max_channel = 0;
423 	shost->max_id = 8;
424 	shost->max_lun = 8;
425 
426 	/* Give each shost a default transportt */
427 	shost->transportt = &blank_transport_template;
428 
429 	/*
430 	 * All drivers right now should be able to handle 12 byte
431 	 * commands.  Every so often there are requests for 16 byte
432 	 * commands, but individual low-level drivers need to certify that
433 	 * they actually do something sensible with such commands.
434 	 */
435 	shost->max_cmd_len = 12;
436 	shost->hostt = sht;
437 	shost->this_id = sht->this_id;
438 	shost->can_queue = sht->can_queue;
439 	shost->sg_tablesize = sht->sg_tablesize;
440 	shost->sg_prot_tablesize = sht->sg_prot_tablesize;
441 	shost->cmd_per_lun = sht->cmd_per_lun;
442 	shost->no_write_same = sht->no_write_same;
443 	shost->host_tagset = sht->host_tagset;
444 	shost->queuecommand_may_block = sht->queuecommand_may_block;
445 
446 	if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
447 		shost->eh_deadline = -1;
448 	else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
449 		shost_printk(KERN_WARNING, shost,
450 			     "eh_deadline %u too large, setting to %u\n",
451 			     shost_eh_deadline, INT_MAX / HZ);
452 		shost->eh_deadline = INT_MAX;
453 	} else
454 		shost->eh_deadline = shost_eh_deadline * HZ;
455 
456 	if (sht->supported_mode == MODE_UNKNOWN)
457 		/* means we didn't set it ... default to INITIATOR */
458 		shost->active_mode = MODE_INITIATOR;
459 	else
460 		shost->active_mode = sht->supported_mode;
461 
462 	if (sht->max_host_blocked)
463 		shost->max_host_blocked = sht->max_host_blocked;
464 	else
465 		shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
466 
467 	/*
468 	 * If the driver imposes no hard sector transfer limit, start at
469 	 * machine infinity initially.
470 	 */
471 	if (sht->max_sectors)
472 		shost->max_sectors = sht->max_sectors;
473 	else
474 		shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
475 
476 	if (sht->max_segment_size)
477 		shost->max_segment_size = sht->max_segment_size;
478 	else
479 		shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
480 
481 	/*
482 	 * assume a 4GB boundary, if not set
483 	 */
484 	if (sht->dma_boundary)
485 		shost->dma_boundary = sht->dma_boundary;
486 	else
487 		shost->dma_boundary = 0xffffffff;
488 
489 	if (sht->virt_boundary_mask)
490 		shost->virt_boundary_mask = sht->virt_boundary_mask;
491 
492 	device_initialize(&shost->shost_gendev);
493 	dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
494 	shost->shost_gendev.bus = &scsi_bus_type;
495 	shost->shost_gendev.type = &scsi_host_type;
496 	scsi_enable_async_suspend(&shost->shost_gendev);
497 
498 	device_initialize(&shost->shost_dev);
499 	shost->shost_dev.parent = &shost->shost_gendev;
500 	shost->shost_dev.class = &shost_class;
501 	dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
502 	shost->shost_dev.groups = sht->shost_groups;
503 
504 	shost->ehandler = kthread_run(scsi_error_handler, shost,
505 			"scsi_eh_%d", shost->host_no);
506 	if (IS_ERR(shost->ehandler)) {
507 		shost_printk(KERN_WARNING, shost,
508 			"error handler thread failed to spawn, error = %ld\n",
509 			PTR_ERR(shost->ehandler));
510 		shost->ehandler = NULL;
511 		goto fail;
512 	}
513 
514 	shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
515 					WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS,
516 					   1, shost->host_no);
517 	if (!shost->tmf_work_q) {
518 		shost_printk(KERN_WARNING, shost,
519 			     "failed to create tmf workq\n");
520 		goto fail;
521 	}
522 	if (scsi_proc_hostdir_add(shost->hostt) < 0)
523 		goto fail;
524 	return shost;
525  fail:
526 	/*
527 	 * Host state is still SHOST_CREATED and that is enough to release
528 	 * ->shost_gendev. scsi_host_dev_release() will free
529 	 * dev_name(&shost->shost_dev).
530 	 */
531 	put_device(&shost->shost_gendev);
532 
533 	return NULL;
534 }
535 EXPORT_SYMBOL(scsi_host_alloc);
536 
__scsi_host_match(struct device * dev,const void * data)537 static int __scsi_host_match(struct device *dev, const void *data)
538 {
539 	struct Scsi_Host *p;
540 	const unsigned int *hostnum = data;
541 
542 	p = class_to_shost(dev);
543 	return p->host_no == *hostnum;
544 }
545 
546 /**
547  * scsi_host_lookup - get a reference to a Scsi_Host by host no
548  * @hostnum:	host number to locate
549  *
550  * Return value:
551  *	A pointer to located Scsi_Host or NULL.
552  *
553  *	The caller must do a scsi_host_put() to drop the reference
554  *	that scsi_host_get() took. The put_device() below dropped
555  *	the reference from class_find_device().
556  **/
scsi_host_lookup(unsigned int hostnum)557 struct Scsi_Host *scsi_host_lookup(unsigned int hostnum)
558 {
559 	struct device *cdev;
560 	struct Scsi_Host *shost = NULL;
561 
562 	cdev = class_find_device(&shost_class, NULL, &hostnum,
563 				 __scsi_host_match);
564 	if (cdev) {
565 		shost = scsi_host_get(class_to_shost(cdev));
566 		put_device(cdev);
567 	}
568 	return shost;
569 }
570 EXPORT_SYMBOL(scsi_host_lookup);
571 
572 /**
573  * scsi_host_get - inc a Scsi_Host ref count
574  * @shost:	Pointer to Scsi_Host to inc.
575  **/
scsi_host_get(struct Scsi_Host * shost)576 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
577 {
578 	if ((shost->shost_state == SHOST_DEL) ||
579 		!get_device(&shost->shost_gendev))
580 		return NULL;
581 	return shost;
582 }
583 EXPORT_SYMBOL(scsi_host_get);
584 
scsi_host_check_in_flight(struct request * rq,void * data)585 static bool scsi_host_check_in_flight(struct request *rq, void *data)
586 {
587 	int *count = data;
588 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
589 
590 	if (test_bit(SCMD_STATE_INFLIGHT, &cmd->state))
591 		(*count)++;
592 
593 	return true;
594 }
595 
596 /**
597  * scsi_host_busy - Return the host busy counter
598  * @shost:	Pointer to Scsi_Host to inc.
599  **/
scsi_host_busy(struct Scsi_Host * shost)600 int scsi_host_busy(struct Scsi_Host *shost)
601 {
602 	int cnt = 0;
603 
604 	blk_mq_tagset_busy_iter(&shost->tag_set,
605 				scsi_host_check_in_flight, &cnt);
606 	return cnt;
607 }
608 EXPORT_SYMBOL(scsi_host_busy);
609 
610 /**
611  * scsi_host_put - dec a Scsi_Host ref count
612  * @shost:	Pointer to Scsi_Host to dec.
613  **/
scsi_host_put(struct Scsi_Host * shost)614 void scsi_host_put(struct Scsi_Host *shost)
615 {
616 	put_device(&shost->shost_gendev);
617 }
618 EXPORT_SYMBOL(scsi_host_put);
619 
scsi_init_hosts(void)620 int scsi_init_hosts(void)
621 {
622 	return class_register(&shost_class);
623 }
624 
scsi_exit_hosts(void)625 void scsi_exit_hosts(void)
626 {
627 	class_unregister(&shost_class);
628 	ida_destroy(&host_index_ida);
629 }
630 
scsi_is_host_device(const struct device * dev)631 int scsi_is_host_device(const struct device *dev)
632 {
633 	return dev->type == &scsi_host_type;
634 }
635 EXPORT_SYMBOL(scsi_is_host_device);
636 
637 /**
638  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
639  * @shost:	Pointer to Scsi_Host.
640  * @work:	Work to queue for execution.
641  *
642  * Return value:
643  * 	1 - work queued for execution
644  *	0 - work is already queued
645  *	-EINVAL - work queue doesn't exist
646  **/
scsi_queue_work(struct Scsi_Host * shost,struct work_struct * work)647 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
648 {
649 	if (unlikely(!shost->work_q)) {
650 		shost_printk(KERN_ERR, shost,
651 			"ERROR: Scsi host '%s' attempted to queue scsi-work, "
652 			"when no workqueue created.\n", shost->hostt->name);
653 		dump_stack();
654 
655 		return -EINVAL;
656 	}
657 
658 	return queue_work(shost->work_q, work);
659 }
660 EXPORT_SYMBOL_GPL(scsi_queue_work);
661 
662 /**
663  * scsi_flush_work - Flush a Scsi_Host's workqueue.
664  * @shost:	Pointer to Scsi_Host.
665  **/
scsi_flush_work(struct Scsi_Host * shost)666 void scsi_flush_work(struct Scsi_Host *shost)
667 {
668 	if (!shost->work_q) {
669 		shost_printk(KERN_ERR, shost,
670 			"ERROR: Scsi host '%s' attempted to flush scsi-work, "
671 			"when no workqueue created.\n", shost->hostt->name);
672 		dump_stack();
673 		return;
674 	}
675 
676 	flush_workqueue(shost->work_q);
677 }
678 EXPORT_SYMBOL_GPL(scsi_flush_work);
679 
complete_all_cmds_iter(struct request * rq,void * data)680 static bool complete_all_cmds_iter(struct request *rq, void *data)
681 {
682 	struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
683 	enum scsi_host_status status = *(enum scsi_host_status *)data;
684 
685 	scsi_dma_unmap(scmd);
686 	scmd->result = 0;
687 	set_host_byte(scmd, status);
688 	scsi_done(scmd);
689 	return true;
690 }
691 
692 /**
693  * scsi_host_complete_all_commands - Terminate all running commands
694  * @shost:	Scsi Host on which commands should be terminated
695  * @status:	Status to be set for the terminated commands
696  *
697  * There is no protection against modification of the number
698  * of outstanding commands. It is the responsibility of the
699  * caller to ensure that concurrent I/O submission and/or
700  * completion is stopped when calling this function.
701  */
scsi_host_complete_all_commands(struct Scsi_Host * shost,enum scsi_host_status status)702 void scsi_host_complete_all_commands(struct Scsi_Host *shost,
703 				     enum scsi_host_status status)
704 {
705 	blk_mq_tagset_busy_iter(&shost->tag_set, complete_all_cmds_iter,
706 				&status);
707 }
708 EXPORT_SYMBOL_GPL(scsi_host_complete_all_commands);
709 
710 struct scsi_host_busy_iter_data {
711 	bool (*fn)(struct scsi_cmnd *, void *);
712 	void *priv;
713 };
714 
__scsi_host_busy_iter_fn(struct request * req,void * priv)715 static bool __scsi_host_busy_iter_fn(struct request *req, void *priv)
716 {
717 	struct scsi_host_busy_iter_data *iter_data = priv;
718 	struct scsi_cmnd *sc = blk_mq_rq_to_pdu(req);
719 
720 	return iter_data->fn(sc, iter_data->priv);
721 }
722 
723 /**
724  * scsi_host_busy_iter - Iterate over all busy commands
725  * @shost:	Pointer to Scsi_Host.
726  * @fn:		Function to call on each busy command
727  * @priv:	Data pointer passed to @fn
728  *
729  * If locking against concurrent command completions is required
730  * ithas to be provided by the caller
731  **/
scsi_host_busy_iter(struct Scsi_Host * shost,bool (* fn)(struct scsi_cmnd *,void *),void * priv)732 void scsi_host_busy_iter(struct Scsi_Host *shost,
733 			 bool (*fn)(struct scsi_cmnd *, void *),
734 			 void *priv)
735 {
736 	struct scsi_host_busy_iter_data iter_data = {
737 		.fn = fn,
738 		.priv = priv,
739 	};
740 
741 	blk_mq_tagset_busy_iter(&shost->tag_set, __scsi_host_busy_iter_fn,
742 				&iter_data);
743 }
744 EXPORT_SYMBOL_GPL(scsi_host_busy_iter);
745