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 
185 	/*
186 	 * New SCSI devices cannot be attached anymore because of the SCSI host
187 	 * state so drop the tag set refcnt. Wait until the tag set refcnt drops
188 	 * to zero because .exit_cmd_priv implementations may need the host
189 	 * pointer.
190 	 */
191 	kref_put(&shost->tagset_refcnt, scsi_mq_free_tags);
192 	wait_for_completion(&shost->tagset_freed);
193 
194 	spin_lock_irqsave(shost->host_lock, flags);
195 	if (scsi_host_set_state(shost, SHOST_DEL))
196 		BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
197 	spin_unlock_irqrestore(shost->host_lock, flags);
198 
199 	transport_unregister_device(&shost->shost_gendev);
200 	device_unregister(&shost->shost_dev);
201 	device_del(&shost->shost_gendev);
202 }
203 EXPORT_SYMBOL(scsi_remove_host);
204 
205 /**
206  * scsi_add_host_with_dma - add a scsi host with dma device
207  * @shost:	scsi host pointer to add
208  * @dev:	a struct device of type scsi class
209  * @dma_dev:	dma device for the host
210  *
211  * Note: You rarely need to worry about this unless you're in a
212  * virtualised host environments, so use the simpler scsi_add_host()
213  * function instead.
214  *
215  * Return value:
216  * 	0 on success / != 0 for error
217  **/
scsi_add_host_with_dma(struct Scsi_Host * shost,struct device * dev,struct device * dma_dev)218 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
219 			   struct device *dma_dev)
220 {
221 	struct scsi_host_template *sht = shost->hostt;
222 	int error = -EINVAL;
223 
224 	shost_printk(KERN_INFO, shost, "%s\n",
225 			sht->info ? sht->info(shost) : sht->name);
226 
227 	if (!shost->can_queue) {
228 		shost_printk(KERN_ERR, shost,
229 			     "can_queue = 0 no longer supported\n");
230 		goto fail;
231 	}
232 
233 	/* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
234 	shost->cmd_per_lun = min_t(int, shost->cmd_per_lun,
235 				   shost->can_queue);
236 
237 	error = scsi_init_sense_cache(shost);
238 	if (error)
239 		goto fail;
240 
241 	if (!shost->shost_gendev.parent)
242 		shost->shost_gendev.parent = dev ? dev : &platform_bus;
243 	if (!dma_dev)
244 		dma_dev = shost->shost_gendev.parent;
245 
246 	shost->dma_dev = dma_dev;
247 
248 	if (dma_dev->dma_mask) {
249 		shost->max_sectors = min_t(unsigned int, shost->max_sectors,
250 				dma_max_mapping_size(dma_dev) >> SECTOR_SHIFT);
251 	}
252 
253 	error = scsi_mq_setup_tags(shost);
254 	if (error)
255 		goto fail;
256 
257 	kref_init(&shost->tagset_refcnt);
258 	init_completion(&shost->tagset_freed);
259 
260 	/*
261 	 * Increase usage count temporarily here so that calling
262 	 * scsi_autopm_put_host() will trigger runtime idle if there is
263 	 * nothing else preventing suspending the device.
264 	 */
265 	pm_runtime_get_noresume(&shost->shost_gendev);
266 	pm_runtime_set_active(&shost->shost_gendev);
267 	pm_runtime_enable(&shost->shost_gendev);
268 	device_enable_async_suspend(&shost->shost_gendev);
269 
270 	error = device_add(&shost->shost_gendev);
271 	if (error)
272 		goto out_disable_runtime_pm;
273 
274 	scsi_host_set_state(shost, SHOST_RUNNING);
275 	get_device(shost->shost_gendev.parent);
276 
277 	device_enable_async_suspend(&shost->shost_dev);
278 
279 	get_device(&shost->shost_gendev);
280 	error = device_add(&shost->shost_dev);
281 	if (error)
282 		goto out_del_gendev;
283 
284 	if (shost->transportt->host_size) {
285 		shost->shost_data = kzalloc(shost->transportt->host_size,
286 					 GFP_KERNEL);
287 		if (shost->shost_data == NULL) {
288 			error = -ENOMEM;
289 			goto out_del_dev;
290 		}
291 	}
292 
293 	if (shost->transportt->create_work_queue) {
294 		snprintf(shost->work_q_name, sizeof(shost->work_q_name),
295 			 "scsi_wq_%d", shost->host_no);
296 		shost->work_q = alloc_workqueue("%s",
297 			WQ_SYSFS | __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_UNBOUND,
298 			1, shost->work_q_name);
299 
300 		if (!shost->work_q) {
301 			error = -EINVAL;
302 			goto out_del_dev;
303 		}
304 	}
305 
306 	error = scsi_sysfs_add_host(shost);
307 	if (error)
308 		goto out_del_dev;
309 
310 	scsi_proc_host_add(shost);
311 	scsi_autopm_put_host(shost);
312 	return error;
313 
314 	/*
315 	 * Any host allocation in this function will be freed in
316 	 * scsi_host_dev_release().
317 	 */
318  out_del_dev:
319 	device_del(&shost->shost_dev);
320  out_del_gendev:
321 	/*
322 	 * Host state is SHOST_RUNNING so we have to explicitly release
323 	 * ->shost_dev.
324 	 */
325 	put_device(&shost->shost_dev);
326 	device_del(&shost->shost_gendev);
327  out_disable_runtime_pm:
328 	device_disable_async_suspend(&shost->shost_gendev);
329 	pm_runtime_disable(&shost->shost_gendev);
330 	pm_runtime_set_suspended(&shost->shost_gendev);
331 	pm_runtime_put_noidle(&shost->shost_gendev);
332 	kref_put(&shost->tagset_refcnt, scsi_mq_free_tags);
333  fail:
334 	return error;
335 }
336 EXPORT_SYMBOL(scsi_add_host_with_dma);
337 
scsi_host_dev_release(struct device * dev)338 static void scsi_host_dev_release(struct device *dev)
339 {
340 	struct Scsi_Host *shost = dev_to_shost(dev);
341 	struct device *parent = dev->parent;
342 
343 	scsi_proc_hostdir_rm(shost->hostt);
344 
345 	/* Wait for functions invoked through call_rcu(&scmd->rcu, ...) */
346 	rcu_barrier();
347 
348 	if (shost->tmf_work_q)
349 		destroy_workqueue(shost->tmf_work_q);
350 	if (shost->ehandler)
351 		kthread_stop(shost->ehandler);
352 	if (shost->work_q)
353 		destroy_workqueue(shost->work_q);
354 
355 	if (shost->shost_state == SHOST_CREATED) {
356 		/*
357 		 * Free the shost_dev device name here if scsi_host_alloc()
358 		 * and scsi_host_put() have been called but neither
359 		 * scsi_host_add() nor scsi_host_remove() has been called.
360 		 * This avoids that the memory allocated for the shost_dev
361 		 * name is leaked.
362 		 */
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 
375 static 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  **/
scsi_host_alloc(struct scsi_host_template * sht,int privsize)393 struct Scsi_Host *scsi_host_alloc(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 
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 	scsi_proc_hostdir_add(shost->hostt);
523 	return shost;
524  fail:
525 	/*
526 	 * Host state is still SHOST_CREATED and that is enough to release
527 	 * ->shost_gendev. scsi_host_dev_release() will free
528 	 * dev_name(&shost->shost_dev).
529 	 */
530 	put_device(&shost->shost_gendev);
531 
532 	return NULL;
533 }
534 EXPORT_SYMBOL(scsi_host_alloc);
535 
__scsi_host_match(struct device * dev,const void * data)536 static int __scsi_host_match(struct device *dev, const void *data)
537 {
538 	struct Scsi_Host *p;
539 	const unsigned short *hostnum = data;
540 
541 	p = class_to_shost(dev);
542 	return p->host_no == *hostnum;
543 }
544 
545 /**
546  * scsi_host_lookup - get a reference to a Scsi_Host by host no
547  * @hostnum:	host number to locate
548  *
549  * Return value:
550  *	A pointer to located Scsi_Host or NULL.
551  *
552  *	The caller must do a scsi_host_put() to drop the reference
553  *	that scsi_host_get() took. The put_device() below dropped
554  *	the reference from class_find_device().
555  **/
scsi_host_lookup(unsigned short hostnum)556 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
557 {
558 	struct device *cdev;
559 	struct Scsi_Host *shost = NULL;
560 
561 	cdev = class_find_device(&shost_class, NULL, &hostnum,
562 				 __scsi_host_match);
563 	if (cdev) {
564 		shost = scsi_host_get(class_to_shost(cdev));
565 		put_device(cdev);
566 	}
567 	return shost;
568 }
569 EXPORT_SYMBOL(scsi_host_lookup);
570 
571 /**
572  * scsi_host_get - inc a Scsi_Host ref count
573  * @shost:	Pointer to Scsi_Host to inc.
574  **/
scsi_host_get(struct Scsi_Host * shost)575 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
576 {
577 	if ((shost->shost_state == SHOST_DEL) ||
578 		!get_device(&shost->shost_gendev))
579 		return NULL;
580 	return shost;
581 }
582 EXPORT_SYMBOL(scsi_host_get);
583 
scsi_host_check_in_flight(struct request * rq,void * data)584 static bool scsi_host_check_in_flight(struct request *rq, void *data)
585 {
586 	int *count = data;
587 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
588 
589 	if (test_bit(SCMD_STATE_INFLIGHT, &cmd->state))
590 		(*count)++;
591 
592 	return true;
593 }
594 
595 /**
596  * scsi_host_busy - Return the host busy counter
597  * @shost:	Pointer to Scsi_Host to inc.
598  **/
scsi_host_busy(struct Scsi_Host * shost)599 int scsi_host_busy(struct Scsi_Host *shost)
600 {
601 	int cnt = 0;
602 
603 	blk_mq_tagset_busy_iter(&shost->tag_set,
604 				scsi_host_check_in_flight, &cnt);
605 	return cnt;
606 }
607 EXPORT_SYMBOL(scsi_host_busy);
608 
609 /**
610  * scsi_host_put - dec a Scsi_Host ref count
611  * @shost:	Pointer to Scsi_Host to dec.
612  **/
scsi_host_put(struct Scsi_Host * shost)613 void scsi_host_put(struct Scsi_Host *shost)
614 {
615 	put_device(&shost->shost_gendev);
616 }
617 EXPORT_SYMBOL(scsi_host_put);
618 
scsi_init_hosts(void)619 int scsi_init_hosts(void)
620 {
621 	return class_register(&shost_class);
622 }
623 
scsi_exit_hosts(void)624 void scsi_exit_hosts(void)
625 {
626 	class_unregister(&shost_class);
627 	ida_destroy(&host_index_ida);
628 }
629 
scsi_is_host_device(const struct device * dev)630 int scsi_is_host_device(const struct device *dev)
631 {
632 	return dev->type == &scsi_host_type;
633 }
634 EXPORT_SYMBOL(scsi_is_host_device);
635 
636 /**
637  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
638  * @shost:	Pointer to Scsi_Host.
639  * @work:	Work to queue for execution.
640  *
641  * Return value:
642  * 	1 - work queued for execution
643  *	0 - work is already queued
644  *	-EINVAL - work queue doesn't exist
645  **/
scsi_queue_work(struct Scsi_Host * shost,struct work_struct * work)646 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
647 {
648 	if (unlikely(!shost->work_q)) {
649 		shost_printk(KERN_ERR, shost,
650 			"ERROR: Scsi host '%s' attempted to queue scsi-work, "
651 			"when no workqueue created.\n", shost->hostt->name);
652 		dump_stack();
653 
654 		return -EINVAL;
655 	}
656 
657 	return queue_work(shost->work_q, work);
658 }
659 EXPORT_SYMBOL_GPL(scsi_queue_work);
660 
661 /**
662  * scsi_flush_work - Flush a Scsi_Host's workqueue.
663  * @shost:	Pointer to Scsi_Host.
664  **/
scsi_flush_work(struct Scsi_Host * shost)665 void scsi_flush_work(struct Scsi_Host *shost)
666 {
667 	if (!shost->work_q) {
668 		shost_printk(KERN_ERR, shost,
669 			"ERROR: Scsi host '%s' attempted to flush scsi-work, "
670 			"when no workqueue created.\n", shost->hostt->name);
671 		dump_stack();
672 		return;
673 	}
674 
675 	flush_workqueue(shost->work_q);
676 }
677 EXPORT_SYMBOL_GPL(scsi_flush_work);
678 
complete_all_cmds_iter(struct request * rq,void * data)679 static bool complete_all_cmds_iter(struct request *rq, void *data)
680 {
681 	struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
682 	enum scsi_host_status status = *(enum scsi_host_status *)data;
683 
684 	scsi_dma_unmap(scmd);
685 	scmd->result = 0;
686 	set_host_byte(scmd, status);
687 	scsi_done(scmd);
688 	return true;
689 }
690 
691 /**
692  * scsi_host_complete_all_commands - Terminate all running commands
693  * @shost:	Scsi Host on which commands should be terminated
694  * @status:	Status to be set for the terminated commands
695  *
696  * There is no protection against modification of the number
697  * of outstanding commands. It is the responsibility of the
698  * caller to ensure that concurrent I/O submission and/or
699  * completion is stopped when calling this function.
700  */
scsi_host_complete_all_commands(struct Scsi_Host * shost,enum scsi_host_status status)701 void scsi_host_complete_all_commands(struct Scsi_Host *shost,
702 				     enum scsi_host_status status)
703 {
704 	blk_mq_tagset_busy_iter(&shost->tag_set, complete_all_cmds_iter,
705 				&status);
706 }
707 EXPORT_SYMBOL_GPL(scsi_host_complete_all_commands);
708 
709 struct scsi_host_busy_iter_data {
710 	bool (*fn)(struct scsi_cmnd *, void *);
711 	void *priv;
712 };
713 
__scsi_host_busy_iter_fn(struct request * req,void * priv)714 static bool __scsi_host_busy_iter_fn(struct request *req, void *priv)
715 {
716 	struct scsi_host_busy_iter_data *iter_data = priv;
717 	struct scsi_cmnd *sc = blk_mq_rq_to_pdu(req);
718 
719 	return iter_data->fn(sc, iter_data->priv);
720 }
721 
722 /**
723  * scsi_host_busy_iter - Iterate over all busy commands
724  * @shost:	Pointer to Scsi_Host.
725  * @fn:		Function to call on each busy command
726  * @priv:	Data pointer passed to @fn
727  *
728  * If locking against concurrent command completions is required
729  * ithas to be provided by the caller
730  **/
scsi_host_busy_iter(struct Scsi_Host * shost,bool (* fn)(struct scsi_cmnd *,void *),void * priv)731 void scsi_host_busy_iter(struct Scsi_Host *shost,
732 			 bool (*fn)(struct scsi_cmnd *, void *),
733 			 void *priv)
734 {
735 	struct scsi_host_busy_iter_data iter_data = {
736 		.fn = fn,
737 		.priv = priv,
738 	};
739 
740 	blk_mq_tagset_busy_iter(&shost->tag_set, __scsi_host_busy_iter_fn,
741 				&iter_data);
742 }
743 EXPORT_SYMBOL_GPL(scsi_host_busy_iter);
744