xref: /openbmc/linux/drivers/scsi/hosts.c (revision fa7f32422ea1ac276b45b96a540ed5981caaa61f)
1 /*
2  *  hosts.c Copyright (C) 1992 Drew Eckhardt
3  *          Copyright (C) 1993, 1994, 1995 Eric Youngdale
4  *          Copyright (C) 2002-2003 Christoph Hellwig
5  *
6  *  mid to lowlevel SCSI driver interface
7  *      Initial versions: Drew Eckhardt
8  *      Subsequent revisions: Eric Youngdale
9  *
10  *  <drew@colorado.edu>
11  *
12  *  Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
13  *  Added QLOGIC QLA1280 SCSI controller kernel host support.
14  *     August 4, 1999 Fred Lewis, Intel DuPont
15  *
16  *  Updated to reflect the new initialization scheme for the higher
17  *  level of scsi drivers (sd/sr/st)
18  *  September 17, 2000 Torben Mathiasen <tmm@image.dk>
19  *
20  *  Restructured scsi_host lists and associated functions.
21  *  September 04, 2002 Mike Anderson (andmike@us.ibm.com)
22  */
23 
24 #include <linux/module.h>
25 #include <linux/blkdev.h>
26 #include <linux/kernel.h>
27 #include <linux/slab.h>
28 #include <linux/kthread.h>
29 #include <linux/string.h>
30 #include <linux/mm.h>
31 #include <linux/init.h>
32 #include <linux/completion.h>
33 #include <linux/transport_class.h>
34 #include <linux/platform_device.h>
35 #include <linux/pm_runtime.h>
36 #include <linux/idr.h>
37 #include <scsi/scsi_device.h>
38 #include <scsi/scsi_host.h>
39 #include <scsi/scsi_transport.h>
40 
41 #include "scsi_priv.h"
42 #include "scsi_logging.h"
43 
44 
45 static DEFINE_IDA(host_index_ida);
46 
47 
48 static void scsi_host_cls_release(struct device *dev)
49 {
50 	put_device(&class_to_shost(dev)->shost_gendev);
51 }
52 
53 static struct class shost_class = {
54 	.name		= "scsi_host",
55 	.dev_release	= scsi_host_cls_release,
56 };
57 
58 /**
59  *	scsi_host_set_state - Take the given host through the host state model.
60  *	@shost:	scsi host to change the state of.
61  *	@state:	state to change to.
62  *
63  *	Returns zero if unsuccessful or an error if the requested
64  *	transition is illegal.
65  **/
66 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
67 {
68 	enum scsi_host_state oldstate = shost->shost_state;
69 
70 	if (state == oldstate)
71 		return 0;
72 
73 	switch (state) {
74 	case SHOST_CREATED:
75 		/* There are no legal states that come back to
76 		 * created.  This is the manually initialised start
77 		 * state */
78 		goto illegal;
79 
80 	case SHOST_RUNNING:
81 		switch (oldstate) {
82 		case SHOST_CREATED:
83 		case SHOST_RECOVERY:
84 			break;
85 		default:
86 			goto illegal;
87 		}
88 		break;
89 
90 	case SHOST_RECOVERY:
91 		switch (oldstate) {
92 		case SHOST_RUNNING:
93 			break;
94 		default:
95 			goto illegal;
96 		}
97 		break;
98 
99 	case SHOST_CANCEL:
100 		switch (oldstate) {
101 		case SHOST_CREATED:
102 		case SHOST_RUNNING:
103 		case SHOST_CANCEL_RECOVERY:
104 			break;
105 		default:
106 			goto illegal;
107 		}
108 		break;
109 
110 	case SHOST_DEL:
111 		switch (oldstate) {
112 		case SHOST_CANCEL:
113 		case SHOST_DEL_RECOVERY:
114 			break;
115 		default:
116 			goto illegal;
117 		}
118 		break;
119 
120 	case SHOST_CANCEL_RECOVERY:
121 		switch (oldstate) {
122 		case SHOST_CANCEL:
123 		case SHOST_RECOVERY:
124 			break;
125 		default:
126 			goto illegal;
127 		}
128 		break;
129 
130 	case SHOST_DEL_RECOVERY:
131 		switch (oldstate) {
132 		case SHOST_CANCEL_RECOVERY:
133 			break;
134 		default:
135 			goto illegal;
136 		}
137 		break;
138 	}
139 	shost->shost_state = state;
140 	return 0;
141 
142  illegal:
143 	SCSI_LOG_ERROR_RECOVERY(1,
144 				shost_printk(KERN_ERR, shost,
145 					     "Illegal host state transition"
146 					     "%s->%s\n",
147 					     scsi_host_state_name(oldstate),
148 					     scsi_host_state_name(state)));
149 	return -EINVAL;
150 }
151 EXPORT_SYMBOL(scsi_host_set_state);
152 
153 /**
154  * scsi_remove_host - remove a scsi host
155  * @shost:	a pointer to a scsi host to remove
156  **/
157 void scsi_remove_host(struct Scsi_Host *shost)
158 {
159 	unsigned long flags;
160 
161 	mutex_lock(&shost->scan_mutex);
162 	spin_lock_irqsave(shost->host_lock, flags);
163 	if (scsi_host_set_state(shost, SHOST_CANCEL))
164 		if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
165 			spin_unlock_irqrestore(shost->host_lock, flags);
166 			mutex_unlock(&shost->scan_mutex);
167 			return;
168 		}
169 	spin_unlock_irqrestore(shost->host_lock, flags);
170 
171 	scsi_autopm_get_host(shost);
172 	flush_workqueue(shost->tmf_work_q);
173 	scsi_forget_host(shost);
174 	mutex_unlock(&shost->scan_mutex);
175 	scsi_proc_host_rm(shost);
176 
177 	spin_lock_irqsave(shost->host_lock, flags);
178 	if (scsi_host_set_state(shost, SHOST_DEL))
179 		BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
180 	spin_unlock_irqrestore(shost->host_lock, flags);
181 
182 	transport_unregister_device(&shost->shost_gendev);
183 	device_unregister(&shost->shost_dev);
184 	device_del(&shost->shost_gendev);
185 }
186 EXPORT_SYMBOL(scsi_remove_host);
187 
188 /**
189  * scsi_add_host_with_dma - add a scsi host with dma device
190  * @shost:	scsi host pointer to add
191  * @dev:	a struct device of type scsi class
192  * @dma_dev:	dma device for the host
193  *
194  * Note: You rarely need to worry about this unless you're in a
195  * virtualised host environments, so use the simpler scsi_add_host()
196  * function instead.
197  *
198  * Return value:
199  * 	0 on success / != 0 for error
200  **/
201 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
202 			   struct device *dma_dev)
203 {
204 	struct scsi_host_template *sht = shost->hostt;
205 	int error = -EINVAL;
206 
207 	shost_printk(KERN_INFO, shost, "%s\n",
208 			sht->info ? sht->info(shost) : sht->name);
209 
210 	if (!shost->can_queue) {
211 		shost_printk(KERN_ERR, shost,
212 			     "can_queue = 0 no longer supported\n");
213 		goto fail;
214 	}
215 
216 	if (shost_use_blk_mq(shost)) {
217 		error = scsi_mq_setup_tags(shost);
218 		if (error)
219 			goto fail;
220 	} else {
221 		shost->bqt = blk_init_tags(shost->can_queue,
222 				shost->hostt->tag_alloc_policy);
223 		if (!shost->bqt) {
224 			error = -ENOMEM;
225 			goto fail;
226 		}
227 	}
228 
229 	/*
230 	 * Note that we allocate the freelist even for the MQ case for now,
231 	 * as we need a command set aside for scsi_reset_provider.  Having
232 	 * the full host freelist and one command available for that is a
233 	 * little heavy-handed, but avoids introducing a special allocator
234 	 * just for this.  Eventually the structure of scsi_reset_provider
235 	 * will need a major overhaul.
236 	 */
237 	error = scsi_setup_command_freelist(shost);
238 	if (error)
239 		goto out_destroy_tags;
240 
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 	/*
250 	 * Increase usage count temporarily here so that calling
251 	 * scsi_autopm_put_host() will trigger runtime idle if there is
252 	 * nothing else preventing suspending the device.
253 	 */
254 	pm_runtime_get_noresume(&shost->shost_gendev);
255 	pm_runtime_set_active(&shost->shost_gendev);
256 	pm_runtime_enable(&shost->shost_gendev);
257 	device_enable_async_suspend(&shost->shost_gendev);
258 
259 	error = device_add(&shost->shost_gendev);
260 	if (error)
261 		goto out_destroy_freelist;
262 
263 	scsi_host_set_state(shost, SHOST_RUNNING);
264 	get_device(shost->shost_gendev.parent);
265 
266 	device_enable_async_suspend(&shost->shost_dev);
267 
268 	error = device_add(&shost->shost_dev);
269 	if (error)
270 		goto out_del_gendev;
271 
272 	get_device(&shost->shost_gendev);
273 
274 	if (shost->transportt->host_size) {
275 		shost->shost_data = kzalloc(shost->transportt->host_size,
276 					 GFP_KERNEL);
277 		if (shost->shost_data == NULL) {
278 			error = -ENOMEM;
279 			goto out_del_dev;
280 		}
281 	}
282 
283 	if (shost->transportt->create_work_queue) {
284 		snprintf(shost->work_q_name, sizeof(shost->work_q_name),
285 			 "scsi_wq_%d", shost->host_no);
286 		shost->work_q = create_singlethread_workqueue(
287 					shost->work_q_name);
288 		if (!shost->work_q) {
289 			error = -EINVAL;
290 			goto out_free_shost_data;
291 		}
292 	}
293 
294 	error = scsi_sysfs_add_host(shost);
295 	if (error)
296 		goto out_destroy_host;
297 
298 	scsi_proc_host_add(shost);
299 	scsi_autopm_put_host(shost);
300 	return error;
301 
302  out_destroy_host:
303 	if (shost->work_q)
304 		destroy_workqueue(shost->work_q);
305  out_free_shost_data:
306 	kfree(shost->shost_data);
307  out_del_dev:
308 	device_del(&shost->shost_dev);
309  out_del_gendev:
310 	device_del(&shost->shost_gendev);
311  out_destroy_freelist:
312 	device_disable_async_suspend(&shost->shost_gendev);
313 	pm_runtime_disable(&shost->shost_gendev);
314 	pm_runtime_set_suspended(&shost->shost_gendev);
315 	pm_runtime_put_noidle(&shost->shost_gendev);
316 	scsi_destroy_command_freelist(shost);
317  out_destroy_tags:
318 	if (shost_use_blk_mq(shost))
319 		scsi_mq_destroy_tags(shost);
320  fail:
321 	return error;
322 }
323 EXPORT_SYMBOL(scsi_add_host_with_dma);
324 
325 static void scsi_host_dev_release(struct device *dev)
326 {
327 	struct Scsi_Host *shost = dev_to_shost(dev);
328 	struct device *parent = dev->parent;
329 	struct request_queue *q;
330 	void *queuedata;
331 
332 	scsi_proc_hostdir_rm(shost->hostt);
333 
334 	if (shost->tmf_work_q)
335 		destroy_workqueue(shost->tmf_work_q);
336 	if (shost->ehandler)
337 		kthread_stop(shost->ehandler);
338 	if (shost->work_q)
339 		destroy_workqueue(shost->work_q);
340 	q = shost->uspace_req_q;
341 	if (q) {
342 		queuedata = q->queuedata;
343 		blk_cleanup_queue(q);
344 		kfree(queuedata);
345 	}
346 
347 	if (shost->shost_state == SHOST_CREATED) {
348 		/*
349 		 * Free the shost_dev device name here if scsi_host_alloc()
350 		 * and scsi_host_put() have been called but neither
351 		 * scsi_host_add() nor scsi_host_remove() has been called.
352 		 * This avoids that the memory allocated for the shost_dev
353 		 * name is leaked.
354 		 */
355 		kfree(dev_name(&shost->shost_dev));
356 	}
357 
358 	scsi_destroy_command_freelist(shost);
359 	if (shost_use_blk_mq(shost)) {
360 		if (shost->tag_set.tags)
361 			scsi_mq_destroy_tags(shost);
362 	} else {
363 		if (shost->bqt)
364 			blk_free_tags(shost->bqt);
365 	}
366 
367 	kfree(shost->shost_data);
368 
369 	ida_simple_remove(&host_index_ida, shost->host_no);
370 
371 	if (parent)
372 		put_device(parent);
373 	kfree(shost);
374 }
375 
376 static int shost_eh_deadline = -1;
377 
378 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
379 MODULE_PARM_DESC(eh_deadline,
380 		 "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
381 
382 static struct device_type scsi_host_type = {
383 	.name =		"scsi_host",
384 	.release =	scsi_host_dev_release,
385 };
386 
387 /**
388  * scsi_host_alloc - register a scsi host adapter instance.
389  * @sht:	pointer to scsi host template
390  * @privsize:	extra bytes to allocate for driver
391  *
392  * Note:
393  * 	Allocate a new Scsi_Host and perform basic initialization.
394  * 	The host is not published to the scsi midlayer until scsi_add_host
395  * 	is called.
396  *
397  * Return value:
398  * 	Pointer to a new Scsi_Host
399  **/
400 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
401 {
402 	struct Scsi_Host *shost;
403 	gfp_t gfp_mask = GFP_KERNEL;
404 	int index;
405 
406 	if (sht->unchecked_isa_dma && privsize)
407 		gfp_mask |= __GFP_DMA;
408 
409 	shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
410 	if (!shost)
411 		return NULL;
412 
413 	shost->host_lock = &shost->default_lock;
414 	spin_lock_init(shost->host_lock);
415 	shost->shost_state = SHOST_CREATED;
416 	INIT_LIST_HEAD(&shost->__devices);
417 	INIT_LIST_HEAD(&shost->__targets);
418 	INIT_LIST_HEAD(&shost->eh_cmd_q);
419 	INIT_LIST_HEAD(&shost->starved_list);
420 	init_waitqueue_head(&shost->host_wait);
421 	mutex_init(&shost->scan_mutex);
422 
423 	index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
424 	if (index < 0)
425 		goto fail_kfree;
426 	shost->host_no = index;
427 
428 	shost->dma_channel = 0xff;
429 
430 	/* These three are default values which can be overridden */
431 	shost->max_channel = 0;
432 	shost->max_id = 8;
433 	shost->max_lun = 8;
434 
435 	/* Give each shost a default transportt */
436 	shost->transportt = &blank_transport_template;
437 
438 	/*
439 	 * All drivers right now should be able to handle 12 byte
440 	 * commands.  Every so often there are requests for 16 byte
441 	 * commands, but individual low-level drivers need to certify that
442 	 * they actually do something sensible with such commands.
443 	 */
444 	shost->max_cmd_len = 12;
445 	shost->hostt = sht;
446 	shost->this_id = sht->this_id;
447 	shost->can_queue = sht->can_queue;
448 	shost->sg_tablesize = sht->sg_tablesize;
449 	shost->sg_prot_tablesize = sht->sg_prot_tablesize;
450 	shost->cmd_per_lun = sht->cmd_per_lun;
451 	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
452 	shost->use_clustering = sht->use_clustering;
453 	shost->no_write_same = sht->no_write_same;
454 
455 	if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
456 		shost->eh_deadline = -1;
457 	else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
458 		shost_printk(KERN_WARNING, shost,
459 			     "eh_deadline %u too large, setting to %u\n",
460 			     shost_eh_deadline, INT_MAX / HZ);
461 		shost->eh_deadline = INT_MAX;
462 	} else
463 		shost->eh_deadline = shost_eh_deadline * HZ;
464 
465 	if (sht->supported_mode == MODE_UNKNOWN)
466 		/* means we didn't set it ... default to INITIATOR */
467 		shost->active_mode = MODE_INITIATOR;
468 	else
469 		shost->active_mode = sht->supported_mode;
470 
471 	if (sht->max_host_blocked)
472 		shost->max_host_blocked = sht->max_host_blocked;
473 	else
474 		shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
475 
476 	/*
477 	 * If the driver imposes no hard sector transfer limit, start at
478 	 * machine infinity initially.
479 	 */
480 	if (sht->max_sectors)
481 		shost->max_sectors = sht->max_sectors;
482 	else
483 		shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
484 
485 	/*
486 	 * assume a 4GB boundary, if not set
487 	 */
488 	if (sht->dma_boundary)
489 		shost->dma_boundary = sht->dma_boundary;
490 	else
491 		shost->dma_boundary = 0xffffffff;
492 
493 	shost->use_blk_mq = scsi_use_blk_mq;
494 
495 	device_initialize(&shost->shost_gendev);
496 	dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
497 	shost->shost_gendev.bus = &scsi_bus_type;
498 	shost->shost_gendev.type = &scsi_host_type;
499 
500 	device_initialize(&shost->shost_dev);
501 	shost->shost_dev.parent = &shost->shost_gendev;
502 	shost->shost_dev.class = &shost_class;
503 	dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
504 	shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
505 
506 	shost->ehandler = kthread_run(scsi_error_handler, shost,
507 			"scsi_eh_%d", shost->host_no);
508 	if (IS_ERR(shost->ehandler)) {
509 		shost_printk(KERN_WARNING, shost,
510 			"error handler thread failed to spawn, error = %ld\n",
511 			PTR_ERR(shost->ehandler));
512 		goto fail_index_remove;
513 	}
514 
515 	shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
516 					    WQ_UNBOUND | WQ_MEM_RECLAIM,
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_kthread;
522 	}
523 	scsi_proc_hostdir_add(shost->hostt);
524 	return shost;
525 
526  fail_kthread:
527 	kthread_stop(shost->ehandler);
528  fail_index_remove:
529 	ida_simple_remove(&host_index_ida, shost->host_no);
530  fail_kfree:
531 	kfree(shost);
532 	return NULL;
533 }
534 EXPORT_SYMBOL(scsi_host_alloc);
535 
536 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
537 {
538 	struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
539 
540 	if (!sht->detect) {
541 		printk(KERN_WARNING "scsi_register() called on new-style "
542 				    "template for driver %s\n", sht->name);
543 		dump_stack();
544 	}
545 
546 	if (shost)
547 		list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
548 	return shost;
549 }
550 EXPORT_SYMBOL(scsi_register);
551 
552 void scsi_unregister(struct Scsi_Host *shost)
553 {
554 	list_del(&shost->sht_legacy_list);
555 	scsi_host_put(shost);
556 }
557 EXPORT_SYMBOL(scsi_unregister);
558 
559 static int __scsi_host_match(struct device *dev, const void *data)
560 {
561 	struct Scsi_Host *p;
562 	const unsigned short *hostnum = data;
563 
564 	p = class_to_shost(dev);
565 	return p->host_no == *hostnum;
566 }
567 
568 /**
569  * scsi_host_lookup - get a reference to a Scsi_Host by host no
570  * @hostnum:	host number to locate
571  *
572  * Return value:
573  *	A pointer to located Scsi_Host or NULL.
574  *
575  *	The caller must do a scsi_host_put() to drop the reference
576  *	that scsi_host_get() took. The put_device() below dropped
577  *	the reference from class_find_device().
578  **/
579 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
580 {
581 	struct device *cdev;
582 	struct Scsi_Host *shost = NULL;
583 
584 	cdev = class_find_device(&shost_class, NULL, &hostnum,
585 				 __scsi_host_match);
586 	if (cdev) {
587 		shost = scsi_host_get(class_to_shost(cdev));
588 		put_device(cdev);
589 	}
590 	return shost;
591 }
592 EXPORT_SYMBOL(scsi_host_lookup);
593 
594 /**
595  * scsi_host_get - inc a Scsi_Host ref count
596  * @shost:	Pointer to Scsi_Host to inc.
597  **/
598 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
599 {
600 	if ((shost->shost_state == SHOST_DEL) ||
601 		!get_device(&shost->shost_gendev))
602 		return NULL;
603 	return shost;
604 }
605 EXPORT_SYMBOL(scsi_host_get);
606 
607 /**
608  * scsi_host_put - dec a Scsi_Host ref count
609  * @shost:	Pointer to Scsi_Host to dec.
610  **/
611 void scsi_host_put(struct Scsi_Host *shost)
612 {
613 	put_device(&shost->shost_gendev);
614 }
615 EXPORT_SYMBOL(scsi_host_put);
616 
617 int scsi_init_hosts(void)
618 {
619 	return class_register(&shost_class);
620 }
621 
622 void scsi_exit_hosts(void)
623 {
624 	class_unregister(&shost_class);
625 	ida_destroy(&host_index_ida);
626 }
627 
628 int scsi_is_host_device(const struct device *dev)
629 {
630 	return dev->type == &scsi_host_type;
631 }
632 EXPORT_SYMBOL(scsi_is_host_device);
633 
634 /**
635  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
636  * @shost:	Pointer to Scsi_Host.
637  * @work:	Work to queue for execution.
638  *
639  * Return value:
640  * 	1 - work queued for execution
641  *	0 - work is already queued
642  *	-EINVAL - work queue doesn't exist
643  **/
644 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
645 {
646 	if (unlikely(!shost->work_q)) {
647 		shost_printk(KERN_ERR, shost,
648 			"ERROR: Scsi host '%s' attempted to queue scsi-work, "
649 			"when no workqueue created.\n", shost->hostt->name);
650 		dump_stack();
651 
652 		return -EINVAL;
653 	}
654 
655 	return queue_work(shost->work_q, work);
656 }
657 EXPORT_SYMBOL_GPL(scsi_queue_work);
658 
659 /**
660  * scsi_flush_work - Flush a Scsi_Host's workqueue.
661  * @shost:	Pointer to Scsi_Host.
662  **/
663 void scsi_flush_work(struct Scsi_Host *shost)
664 {
665 	if (!shost->work_q) {
666 		shost_printk(KERN_ERR, shost,
667 			"ERROR: Scsi host '%s' attempted to flush scsi-work, "
668 			"when no workqueue created.\n", shost->hostt->name);
669 		dump_stack();
670 		return;
671 	}
672 
673 	flush_workqueue(shost->work_q);
674 }
675 EXPORT_SYMBOL_GPL(scsi_flush_work);
676