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
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
45static atomic_t scsi_host_next_hn = ATOMIC_INIT(0);	/* host_no for next new host */
46
47
48static void scsi_host_cls_release(struct device *dev)
49{
50	put_device(&class_to_shost(dev)->shost_gendev);
51}
52
53static 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 **/
66int 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}
151EXPORT_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 **/
157void 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}
186EXPORT_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 **/
201int 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	}
221
222	/*
223	 * Note that we allocate the freelist even for the MQ case for now,
224	 * as we need a command set aside for scsi_reset_provider.  Having
225	 * the full host freelist and one command available for that is a
226	 * little heavy-handed, but avoids introducing a special allocator
227	 * just for this.  Eventually the structure of scsi_reset_provider
228	 * will need a major overhaul.
229	 */
230	error = scsi_setup_command_freelist(shost);
231	if (error)
232		goto out_destroy_tags;
233
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	error = device_add(&shost->shost_gendev);
243	if (error)
244		goto out_destroy_freelist;
245
246	pm_runtime_set_active(&shost->shost_gendev);
247	pm_runtime_enable(&shost->shost_gendev);
248	device_enable_async_suspend(&shost->shost_gendev);
249
250	scsi_host_set_state(shost, SHOST_RUNNING);
251	get_device(shost->shost_gendev.parent);
252
253	device_enable_async_suspend(&shost->shost_dev);
254
255	error = device_add(&shost->shost_dev);
256	if (error)
257		goto out_del_gendev;
258
259	get_device(&shost->shost_gendev);
260
261	if (shost->transportt->host_size) {
262		shost->shost_data = kzalloc(shost->transportt->host_size,
263					 GFP_KERNEL);
264		if (shost->shost_data == NULL) {
265			error = -ENOMEM;
266			goto out_del_dev;
267		}
268	}
269
270	if (shost->transportt->create_work_queue) {
271		snprintf(shost->work_q_name, sizeof(shost->work_q_name),
272			 "scsi_wq_%d", shost->host_no);
273		shost->work_q = create_singlethread_workqueue(
274					shost->work_q_name);
275		if (!shost->work_q) {
276			error = -EINVAL;
277			goto out_free_shost_data;
278		}
279	}
280
281	error = scsi_sysfs_add_host(shost);
282	if (error)
283		goto out_destroy_host;
284
285	scsi_proc_host_add(shost);
286	return error;
287
288 out_destroy_host:
289	if (shost->work_q)
290		destroy_workqueue(shost->work_q);
291 out_free_shost_data:
292	kfree(shost->shost_data);
293 out_del_dev:
294	device_del(&shost->shost_dev);
295 out_del_gendev:
296	device_del(&shost->shost_gendev);
297 out_destroy_freelist:
298	scsi_destroy_command_freelist(shost);
299 out_destroy_tags:
300	if (shost_use_blk_mq(shost))
301		scsi_mq_destroy_tags(shost);
302 fail:
303	return error;
304}
305EXPORT_SYMBOL(scsi_add_host_with_dma);
306
307static void scsi_host_dev_release(struct device *dev)
308{
309	struct Scsi_Host *shost = dev_to_shost(dev);
310	struct device *parent = dev->parent;
311	struct request_queue *q;
312	void *queuedata;
313
314	scsi_proc_hostdir_rm(shost->hostt);
315
316	if (shost->tmf_work_q)
317		destroy_workqueue(shost->tmf_work_q);
318	if (shost->ehandler)
319		kthread_stop(shost->ehandler);
320	if (shost->work_q)
321		destroy_workqueue(shost->work_q);
322	q = shost->uspace_req_q;
323	if (q) {
324		queuedata = q->queuedata;
325		blk_cleanup_queue(q);
326		kfree(queuedata);
327	}
328
329	scsi_destroy_command_freelist(shost);
330	if (shost_use_blk_mq(shost)) {
331		if (shost->tag_set.tags)
332			scsi_mq_destroy_tags(shost);
333	} else {
334		if (shost->bqt)
335			blk_free_tags(shost->bqt);
336	}
337
338	kfree(shost->shost_data);
339
340	if (parent)
341		put_device(parent);
342	kfree(shost);
343}
344
345static int shost_eh_deadline = -1;
346
347module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
348MODULE_PARM_DESC(eh_deadline,
349		 "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
350
351static struct device_type scsi_host_type = {
352	.name =		"scsi_host",
353	.release =	scsi_host_dev_release,
354};
355
356/**
357 * scsi_host_alloc - register a scsi host adapter instance.
358 * @sht:	pointer to scsi host template
359 * @privsize:	extra bytes to allocate for driver
360 *
361 * Note:
362 * 	Allocate a new Scsi_Host and perform basic initialization.
363 * 	The host is not published to the scsi midlayer until scsi_add_host
364 * 	is called.
365 *
366 * Return value:
367 * 	Pointer to a new Scsi_Host
368 **/
369struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
370{
371	struct Scsi_Host *shost;
372	gfp_t gfp_mask = GFP_KERNEL;
373
374	if (sht->unchecked_isa_dma && privsize)
375		gfp_mask |= __GFP_DMA;
376
377	shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
378	if (!shost)
379		return NULL;
380
381	shost->host_lock = &shost->default_lock;
382	spin_lock_init(shost->host_lock);
383	shost->shost_state = SHOST_CREATED;
384	INIT_LIST_HEAD(&shost->__devices);
385	INIT_LIST_HEAD(&shost->__targets);
386	INIT_LIST_HEAD(&shost->eh_cmd_q);
387	INIT_LIST_HEAD(&shost->starved_list);
388	init_waitqueue_head(&shost->host_wait);
389	mutex_init(&shost->scan_mutex);
390
391	/*
392	 * subtract one because we increment first then return, but we need to
393	 * know what the next host number was before increment
394	 */
395	shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
396	shost->dma_channel = 0xff;
397
398	/* These three are default values which can be overridden */
399	shost->max_channel = 0;
400	shost->max_id = 8;
401	shost->max_lun = 8;
402
403	/* Give each shost a default transportt */
404	shost->transportt = &blank_transport_template;
405
406	/*
407	 * All drivers right now should be able to handle 12 byte
408	 * commands.  Every so often there are requests for 16 byte
409	 * commands, but individual low-level drivers need to certify that
410	 * they actually do something sensible with such commands.
411	 */
412	shost->max_cmd_len = 12;
413	shost->hostt = sht;
414	shost->this_id = sht->this_id;
415	shost->can_queue = sht->can_queue;
416	shost->sg_tablesize = sht->sg_tablesize;
417	shost->sg_prot_tablesize = sht->sg_prot_tablesize;
418	shost->cmd_per_lun = sht->cmd_per_lun;
419	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
420	shost->use_clustering = sht->use_clustering;
421	shost->no_write_same = sht->no_write_same;
422
423	if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
424		shost->eh_deadline = -1;
425	else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
426		shost_printk(KERN_WARNING, shost,
427			     "eh_deadline %u too large, setting to %u\n",
428			     shost_eh_deadline, INT_MAX / HZ);
429		shost->eh_deadline = INT_MAX;
430	} else
431		shost->eh_deadline = shost_eh_deadline * HZ;
432
433	if (sht->supported_mode == MODE_UNKNOWN)
434		/* means we didn't set it ... default to INITIATOR */
435		shost->active_mode = MODE_INITIATOR;
436	else
437		shost->active_mode = sht->supported_mode;
438
439	if (sht->max_host_blocked)
440		shost->max_host_blocked = sht->max_host_blocked;
441	else
442		shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
443
444	/*
445	 * If the driver imposes no hard sector transfer limit, start at
446	 * machine infinity initially.
447	 */
448	if (sht->max_sectors)
449		shost->max_sectors = sht->max_sectors;
450	else
451		shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
452
453	/*
454	 * assume a 4GB boundary, if not set
455	 */
456	if (sht->dma_boundary)
457		shost->dma_boundary = sht->dma_boundary;
458	else
459		shost->dma_boundary = 0xffffffff;
460
461	shost->use_blk_mq = scsi_use_blk_mq && !shost->hostt->disable_blk_mq;
462
463	device_initialize(&shost->shost_gendev);
464	dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
465	shost->shost_gendev.bus = &scsi_bus_type;
466	shost->shost_gendev.type = &scsi_host_type;
467
468	device_initialize(&shost->shost_dev);
469	shost->shost_dev.parent = &shost->shost_gendev;
470	shost->shost_dev.class = &shost_class;
471	dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
472	shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
473
474	shost->ehandler = kthread_run(scsi_error_handler, shost,
475			"scsi_eh_%d", shost->host_no);
476	if (IS_ERR(shost->ehandler)) {
477		shost_printk(KERN_WARNING, shost,
478			"error handler thread failed to spawn, error = %ld\n",
479			PTR_ERR(shost->ehandler));
480		goto fail_kfree;
481	}
482
483	shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
484					    WQ_UNBOUND | WQ_MEM_RECLAIM,
485					   1, shost->host_no);
486	if (!shost->tmf_work_q) {
487		shost_printk(KERN_WARNING, shost,
488			     "failed to create tmf workq\n");
489		goto fail_kthread;
490	}
491	scsi_proc_hostdir_add(shost->hostt);
492	return shost;
493
494 fail_kthread:
495	kthread_stop(shost->ehandler);
496 fail_kfree:
497	kfree(shost);
498	return NULL;
499}
500EXPORT_SYMBOL(scsi_host_alloc);
501
502struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
503{
504	struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
505
506	if (!sht->detect) {
507		printk(KERN_WARNING "scsi_register() called on new-style "
508				    "template for driver %s\n", sht->name);
509		dump_stack();
510	}
511
512	if (shost)
513		list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
514	return shost;
515}
516EXPORT_SYMBOL(scsi_register);
517
518void scsi_unregister(struct Scsi_Host *shost)
519{
520	list_del(&shost->sht_legacy_list);
521	scsi_host_put(shost);
522}
523EXPORT_SYMBOL(scsi_unregister);
524
525static int __scsi_host_match(struct device *dev, const void *data)
526{
527	struct Scsi_Host *p;
528	const unsigned short *hostnum = data;
529
530	p = class_to_shost(dev);
531	return p->host_no == *hostnum;
532}
533
534/**
535 * scsi_host_lookup - get a reference to a Scsi_Host by host no
536 * @hostnum:	host number to locate
537 *
538 * Return value:
539 *	A pointer to located Scsi_Host or NULL.
540 *
541 *	The caller must do a scsi_host_put() to drop the reference
542 *	that scsi_host_get() took. The put_device() below dropped
543 *	the reference from class_find_device().
544 **/
545struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
546{
547	struct device *cdev;
548	struct Scsi_Host *shost = NULL;
549
550	cdev = class_find_device(&shost_class, NULL, &hostnum,
551				 __scsi_host_match);
552	if (cdev) {
553		shost = scsi_host_get(class_to_shost(cdev));
554		put_device(cdev);
555	}
556	return shost;
557}
558EXPORT_SYMBOL(scsi_host_lookup);
559
560/**
561 * scsi_host_get - inc a Scsi_Host ref count
562 * @shost:	Pointer to Scsi_Host to inc.
563 **/
564struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
565{
566	if ((shost->shost_state == SHOST_DEL) ||
567		!get_device(&shost->shost_gendev))
568		return NULL;
569	return shost;
570}
571EXPORT_SYMBOL(scsi_host_get);
572
573/**
574 * scsi_host_put - dec a Scsi_Host ref count
575 * @shost:	Pointer to Scsi_Host to dec.
576 **/
577void scsi_host_put(struct Scsi_Host *shost)
578{
579	put_device(&shost->shost_gendev);
580}
581EXPORT_SYMBOL(scsi_host_put);
582
583int scsi_init_hosts(void)
584{
585	return class_register(&shost_class);
586}
587
588void scsi_exit_hosts(void)
589{
590	class_unregister(&shost_class);
591}
592
593int scsi_is_host_device(const struct device *dev)
594{
595	return dev->type == &scsi_host_type;
596}
597EXPORT_SYMBOL(scsi_is_host_device);
598
599/**
600 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
601 * @shost:	Pointer to Scsi_Host.
602 * @work:	Work to queue for execution.
603 *
604 * Return value:
605 * 	1 - work queued for execution
606 *	0 - work is already queued
607 *	-EINVAL - work queue doesn't exist
608 **/
609int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
610{
611	if (unlikely(!shost->work_q)) {
612		shost_printk(KERN_ERR, shost,
613			"ERROR: Scsi host '%s' attempted to queue scsi-work, "
614			"when no workqueue created.\n", shost->hostt->name);
615		dump_stack();
616
617		return -EINVAL;
618	}
619
620	return queue_work(shost->work_q, work);
621}
622EXPORT_SYMBOL_GPL(scsi_queue_work);
623
624/**
625 * scsi_flush_work - Flush a Scsi_Host's workqueue.
626 * @shost:	Pointer to Scsi_Host.
627 **/
628void scsi_flush_work(struct Scsi_Host *shost)
629{
630	if (!shost->work_q) {
631		shost_printk(KERN_ERR, shost,
632			"ERROR: Scsi host '%s' attempted to flush scsi-work, "
633			"when no workqueue created.\n", shost->hostt->name);
634		dump_stack();
635		return;
636	}
637
638	flush_workqueue(shost->work_q);
639}
640EXPORT_SYMBOL_GPL(scsi_flush_work);
641