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 	/* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
224 	shost->cmd_per_lun = min_t(int, shost->cmd_per_lun,
225 				   shost->can_queue);
226 
227 	error = scsi_init_sense_cache(shost);
228 	if (error)
229 		goto fail;
230 
231 	error = scsi_mq_setup_tags(shost);
232 	if (error)
233 		goto fail;
234 
235 	if (!shost->shost_gendev.parent)
236 		shost->shost_gendev.parent = dev ? dev : &platform_bus;
237 	if (!dma_dev)
238 		dma_dev = shost->shost_gendev.parent;
239 
240 	shost->dma_dev = dma_dev;
241 
242 	/*
243 	 * Increase usage count temporarily here so that calling
244 	 * scsi_autopm_put_host() will trigger runtime idle if there is
245 	 * nothing else preventing suspending the device.
246 	 */
247 	pm_runtime_get_noresume(&shost->shost_gendev);
248 	pm_runtime_set_active(&shost->shost_gendev);
249 	pm_runtime_enable(&shost->shost_gendev);
250 	device_enable_async_suspend(&shost->shost_gendev);
251 
252 	error = device_add(&shost->shost_gendev);
253 	if (error)
254 		goto out_disable_runtime_pm;
255 
256 	scsi_host_set_state(shost, SHOST_RUNNING);
257 	get_device(shost->shost_gendev.parent);
258 
259 	device_enable_async_suspend(&shost->shost_dev);
260 
261 	get_device(&shost->shost_gendev);
262 	error = device_add(&shost->shost_dev);
263 	if (error)
264 		goto out_del_gendev;
265 
266 	if (shost->transportt->host_size) {
267 		shost->shost_data = kzalloc(shost->transportt->host_size,
268 					 GFP_KERNEL);
269 		if (shost->shost_data == NULL) {
270 			error = -ENOMEM;
271 			goto out_del_dev;
272 		}
273 	}
274 
275 	if (shost->transportt->create_work_queue) {
276 		snprintf(shost->work_q_name, sizeof(shost->work_q_name),
277 			 "scsi_wq_%d", shost->host_no);
278 		shost->work_q = alloc_workqueue("%s",
279 			WQ_SYSFS | __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_UNBOUND,
280 			1, shost->work_q_name);
281 
282 		if (!shost->work_q) {
283 			error = -EINVAL;
284 			goto out_del_dev;
285 		}
286 	}
287 
288 	error = scsi_sysfs_add_host(shost);
289 	if (error)
290 		goto out_del_dev;
291 
292 	scsi_proc_host_add(shost);
293 	scsi_autopm_put_host(shost);
294 	return error;
295 
296 	/*
297 	 * Any host allocation in this function will be freed in
298 	 * scsi_host_dev_release().
299 	 */
300  out_del_dev:
301 	device_del(&shost->shost_dev);
302  out_del_gendev:
303 	/*
304 	 * Host state is SHOST_RUNNING so we have to explicitly release
305 	 * ->shost_dev.
306 	 */
307 	put_device(&shost->shost_dev);
308 	device_del(&shost->shost_gendev);
309  out_disable_runtime_pm:
310 	device_disable_async_suspend(&shost->shost_gendev);
311 	pm_runtime_disable(&shost->shost_gendev);
312 	pm_runtime_set_suspended(&shost->shost_gendev);
313 	pm_runtime_put_noidle(&shost->shost_gendev);
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(&scmd->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->tag_set.tags)
348 		scsi_mq_destroy_tags(shost);
349 
350 	kfree(shost->shost_data);
351 
352 	ida_simple_remove(&host_index_ida, shost->host_no);
353 
354 	if (shost->shost_state != SHOST_CREATED)
355 		put_device(parent);
356 	kfree(shost);
357 }
358 
359 static struct device_type scsi_host_type = {
360 	.name =		"scsi_host",
361 	.release =	scsi_host_dev_release,
362 };
363 
364 /**
365  * scsi_host_alloc - register a scsi host adapter instance.
366  * @sht:	pointer to scsi host template
367  * @privsize:	extra bytes to allocate for driver
368  *
369  * Note:
370  * 	Allocate a new Scsi_Host and perform basic initialization.
371  * 	The host is not published to the scsi midlayer until scsi_add_host
372  * 	is called.
373  *
374  * Return value:
375  * 	Pointer to a new Scsi_Host
376  **/
scsi_host_alloc(struct scsi_host_template * sht,int privsize)377 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
378 {
379 	struct Scsi_Host *shost;
380 	int index, i, j = 0;
381 
382 	shost = kzalloc(sizeof(struct Scsi_Host) + privsize, GFP_KERNEL);
383 	if (!shost)
384 		return NULL;
385 
386 	shost->host_lock = &shost->default_lock;
387 	spin_lock_init(shost->host_lock);
388 	shost->shost_state = SHOST_CREATED;
389 	INIT_LIST_HEAD(&shost->__devices);
390 	INIT_LIST_HEAD(&shost->__targets);
391 	INIT_LIST_HEAD(&shost->eh_abort_list);
392 	INIT_LIST_HEAD(&shost->eh_cmd_q);
393 	INIT_LIST_HEAD(&shost->starved_list);
394 	init_waitqueue_head(&shost->host_wait);
395 	mutex_init(&shost->scan_mutex);
396 
397 	index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
398 	if (index < 0) {
399 		kfree(shost);
400 		return NULL;
401 	}
402 	shost->host_no = index;
403 
404 	shost->dma_channel = 0xff;
405 
406 	/* These three are default values which can be overridden */
407 	shost->max_channel = 0;
408 	shost->max_id = 8;
409 	shost->max_lun = 8;
410 
411 	/* Give each shost a default transportt */
412 	shost->transportt = &blank_transport_template;
413 
414 	/*
415 	 * All drivers right now should be able to handle 12 byte
416 	 * commands.  Every so often there are requests for 16 byte
417 	 * commands, but individual low-level drivers need to certify that
418 	 * they actually do something sensible with such commands.
419 	 */
420 	shost->max_cmd_len = 12;
421 	shost->hostt = sht;
422 	shost->this_id = sht->this_id;
423 	shost->can_queue = sht->can_queue;
424 	shost->sg_tablesize = sht->sg_tablesize;
425 	shost->sg_prot_tablesize = sht->sg_prot_tablesize;
426 	shost->cmd_per_lun = sht->cmd_per_lun;
427 	shost->no_write_same = sht->no_write_same;
428 	shost->host_tagset = sht->host_tagset;
429 
430 	if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
431 		shost->eh_deadline = -1;
432 	else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
433 		shost_printk(KERN_WARNING, shost,
434 			     "eh_deadline %u too large, setting to %u\n",
435 			     shost_eh_deadline, INT_MAX / HZ);
436 		shost->eh_deadline = INT_MAX;
437 	} else
438 		shost->eh_deadline = shost_eh_deadline * HZ;
439 
440 	if (sht->supported_mode == MODE_UNKNOWN)
441 		/* means we didn't set it ... default to INITIATOR */
442 		shost->active_mode = MODE_INITIATOR;
443 	else
444 		shost->active_mode = sht->supported_mode;
445 
446 	if (sht->max_host_blocked)
447 		shost->max_host_blocked = sht->max_host_blocked;
448 	else
449 		shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
450 
451 	/*
452 	 * If the driver imposes no hard sector transfer limit, start at
453 	 * machine infinity initially.
454 	 */
455 	if (sht->max_sectors)
456 		shost->max_sectors = sht->max_sectors;
457 	else
458 		shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
459 
460 	if (sht->max_segment_size)
461 		shost->max_segment_size = sht->max_segment_size;
462 	else
463 		shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
464 
465 	/*
466 	 * assume a 4GB boundary, if not set
467 	 */
468 	if (sht->dma_boundary)
469 		shost->dma_boundary = sht->dma_boundary;
470 	else
471 		shost->dma_boundary = 0xffffffff;
472 
473 	if (sht->virt_boundary_mask)
474 		shost->virt_boundary_mask = sht->virt_boundary_mask;
475 
476 	device_initialize(&shost->shost_gendev);
477 	dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
478 	shost->shost_gendev.bus = &scsi_bus_type;
479 	shost->shost_gendev.type = &scsi_host_type;
480 	scsi_enable_async_suspend(&shost->shost_gendev);
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 = shost->shost_dev_attr_groups;
487 	shost->shost_dev_attr_groups[j++] = &scsi_shost_attr_group;
488 	if (sht->shost_groups) {
489 		for (i = 0; sht->shost_groups[i] &&
490 			     j < ARRAY_SIZE(shost->shost_dev_attr_groups);
491 		     i++, j++) {
492 			shost->shost_dev_attr_groups[j] =
493 				sht->shost_groups[i];
494 		}
495 	}
496 	WARN_ON_ONCE(j >= ARRAY_SIZE(shost->shost_dev_attr_groups));
497 
498 	shost->ehandler = kthread_run(scsi_error_handler, shost,
499 			"scsi_eh_%d", shost->host_no);
500 	if (IS_ERR(shost->ehandler)) {
501 		shost_printk(KERN_WARNING, shost,
502 			"error handler thread failed to spawn, error = %ld\n",
503 			PTR_ERR(shost->ehandler));
504 		shost->ehandler = NULL;
505 		goto fail;
506 	}
507 
508 	shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
509 					WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS,
510 					   1, shost->host_no);
511 	if (!shost->tmf_work_q) {
512 		shost_printk(KERN_WARNING, shost,
513 			     "failed to create tmf workq\n");
514 		goto fail;
515 	}
516 	scsi_proc_hostdir_add(shost->hostt);
517 	return shost;
518  fail:
519 	/*
520 	 * Host state is still SHOST_CREATED and that is enough to release
521 	 * ->shost_gendev. scsi_host_dev_release() will free
522 	 * dev_name(&shost->shost_dev).
523 	 */
524 	put_device(&shost->shost_gendev);
525 
526 	return NULL;
527 }
528 EXPORT_SYMBOL(scsi_host_alloc);
529 
__scsi_host_match(struct device * dev,const void * data)530 static int __scsi_host_match(struct device *dev, const void *data)
531 {
532 	struct Scsi_Host *p;
533 	const unsigned short *hostnum = data;
534 
535 	p = class_to_shost(dev);
536 	return p->host_no == *hostnum;
537 }
538 
539 /**
540  * scsi_host_lookup - get a reference to a Scsi_Host by host no
541  * @hostnum:	host number to locate
542  *
543  * Return value:
544  *	A pointer to located Scsi_Host or NULL.
545  *
546  *	The caller must do a scsi_host_put() to drop the reference
547  *	that scsi_host_get() took. The put_device() below dropped
548  *	the reference from class_find_device().
549  **/
scsi_host_lookup(unsigned short hostnum)550 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
551 {
552 	struct device *cdev;
553 	struct Scsi_Host *shost = NULL;
554 
555 	cdev = class_find_device(&shost_class, NULL, &hostnum,
556 				 __scsi_host_match);
557 	if (cdev) {
558 		shost = scsi_host_get(class_to_shost(cdev));
559 		put_device(cdev);
560 	}
561 	return shost;
562 }
563 EXPORT_SYMBOL(scsi_host_lookup);
564 
565 /**
566  * scsi_host_get - inc a Scsi_Host ref count
567  * @shost:	Pointer to Scsi_Host to inc.
568  **/
scsi_host_get(struct Scsi_Host * shost)569 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
570 {
571 	if ((shost->shost_state == SHOST_DEL) ||
572 		!get_device(&shost->shost_gendev))
573 		return NULL;
574 	return shost;
575 }
576 EXPORT_SYMBOL(scsi_host_get);
577 
scsi_host_check_in_flight(struct request * rq,void * data,bool reserved)578 static bool scsi_host_check_in_flight(struct request *rq, void *data,
579 				      bool reserved)
580 {
581 	int *count = data;
582 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
583 
584 	if (test_bit(SCMD_STATE_INFLIGHT, &cmd->state))
585 		(*count)++;
586 
587 	return true;
588 }
589 
590 /**
591  * scsi_host_busy - Return the host busy counter
592  * @shost:	Pointer to Scsi_Host to inc.
593  **/
scsi_host_busy(struct Scsi_Host * shost)594 int scsi_host_busy(struct Scsi_Host *shost)
595 {
596 	int cnt = 0;
597 
598 	blk_mq_tagset_busy_iter(&shost->tag_set,
599 				scsi_host_check_in_flight, &cnt);
600 	return cnt;
601 }
602 EXPORT_SYMBOL(scsi_host_busy);
603 
604 /**
605  * scsi_host_put - dec a Scsi_Host ref count
606  * @shost:	Pointer to Scsi_Host to dec.
607  **/
scsi_host_put(struct Scsi_Host * shost)608 void scsi_host_put(struct Scsi_Host *shost)
609 {
610 	put_device(&shost->shost_gendev);
611 }
612 EXPORT_SYMBOL(scsi_host_put);
613 
scsi_init_hosts(void)614 int scsi_init_hosts(void)
615 {
616 	return class_register(&shost_class);
617 }
618 
scsi_exit_hosts(void)619 void scsi_exit_hosts(void)
620 {
621 	class_unregister(&shost_class);
622 	ida_destroy(&host_index_ida);
623 }
624 
scsi_is_host_device(const struct device * dev)625 int scsi_is_host_device(const struct device *dev)
626 {
627 	return dev->type == &scsi_host_type;
628 }
629 EXPORT_SYMBOL(scsi_is_host_device);
630 
631 /**
632  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
633  * @shost:	Pointer to Scsi_Host.
634  * @work:	Work to queue for execution.
635  *
636  * Return value:
637  * 	1 - work queued for execution
638  *	0 - work is already queued
639  *	-EINVAL - work queue doesn't exist
640  **/
scsi_queue_work(struct Scsi_Host * shost,struct work_struct * work)641 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
642 {
643 	if (unlikely(!shost->work_q)) {
644 		shost_printk(KERN_ERR, shost,
645 			"ERROR: Scsi host '%s' attempted to queue scsi-work, "
646 			"when no workqueue created.\n", shost->hostt->name);
647 		dump_stack();
648 
649 		return -EINVAL;
650 	}
651 
652 	return queue_work(shost->work_q, work);
653 }
654 EXPORT_SYMBOL_GPL(scsi_queue_work);
655 
656 /**
657  * scsi_flush_work - Flush a Scsi_Host's workqueue.
658  * @shost:	Pointer to Scsi_Host.
659  **/
scsi_flush_work(struct Scsi_Host * shost)660 void scsi_flush_work(struct Scsi_Host *shost)
661 {
662 	if (!shost->work_q) {
663 		shost_printk(KERN_ERR, shost,
664 			"ERROR: Scsi host '%s' attempted to flush scsi-work, "
665 			"when no workqueue created.\n", shost->hostt->name);
666 		dump_stack();
667 		return;
668 	}
669 
670 	flush_workqueue(shost->work_q);
671 }
672 EXPORT_SYMBOL_GPL(scsi_flush_work);
673 
complete_all_cmds_iter(struct request * rq,void * data,bool rsvd)674 static bool complete_all_cmds_iter(struct request *rq, void *data, bool rsvd)
675 {
676 	struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
677 	enum scsi_host_status status = *(enum scsi_host_status *)data;
678 
679 	scsi_dma_unmap(scmd);
680 	scmd->result = 0;
681 	set_host_byte(scmd, status);
682 	scsi_done(scmd);
683 	return true;
684 }
685 
686 /**
687  * scsi_host_complete_all_commands - Terminate all running commands
688  * @shost:	Scsi Host on which commands should be terminated
689  * @status:	Status to be set for the terminated commands
690  *
691  * There is no protection against modification of the number
692  * of outstanding commands. It is the responsibility of the
693  * caller to ensure that concurrent I/O submission and/or
694  * completion is stopped when calling this function.
695  */
scsi_host_complete_all_commands(struct Scsi_Host * shost,enum scsi_host_status status)696 void scsi_host_complete_all_commands(struct Scsi_Host *shost,
697 				     enum scsi_host_status status)
698 {
699 	blk_mq_tagset_busy_iter(&shost->tag_set, complete_all_cmds_iter,
700 				&status);
701 }
702 EXPORT_SYMBOL_GPL(scsi_host_complete_all_commands);
703 
704 struct scsi_host_busy_iter_data {
705 	bool (*fn)(struct scsi_cmnd *, void *, bool);
706 	void *priv;
707 };
708 
__scsi_host_busy_iter_fn(struct request * req,void * priv,bool reserved)709 static bool __scsi_host_busy_iter_fn(struct request *req, void *priv,
710 				   bool reserved)
711 {
712 	struct scsi_host_busy_iter_data *iter_data = priv;
713 	struct scsi_cmnd *sc = blk_mq_rq_to_pdu(req);
714 
715 	return iter_data->fn(sc, iter_data->priv, reserved);
716 }
717 
718 /**
719  * scsi_host_busy_iter - Iterate over all busy commands
720  * @shost:	Pointer to Scsi_Host.
721  * @fn:		Function to call on each busy command
722  * @priv:	Data pointer passed to @fn
723  *
724  * If locking against concurrent command completions is required
725  * ithas to be provided by the caller
726  **/
scsi_host_busy_iter(struct Scsi_Host * shost,bool (* fn)(struct scsi_cmnd *,void *,bool),void * priv)727 void scsi_host_busy_iter(struct Scsi_Host *shost,
728 			 bool (*fn)(struct scsi_cmnd *, void *, bool),
729 			 void *priv)
730 {
731 	struct scsi_host_busy_iter_data iter_data = {
732 		.fn = fn,
733 		.priv = priv,
734 	};
735 
736 	blk_mq_tagset_busy_iter(&shost->tag_set, __scsi_host_busy_iter_fn,
737 				&iter_data);
738 }
739 EXPORT_SYMBOL_GPL(scsi_host_busy_iter);
740