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	} 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	error = device_add(&shost->shost_gendev);
250	if (error)
251		goto out_destroy_freelist;
252
253	pm_runtime_set_active(&shost->shost_gendev);
254	pm_runtime_enable(&shost->shost_gendev);
255	device_enable_async_suspend(&shost->shost_gendev);
256
257	scsi_host_set_state(shost, SHOST_RUNNING);
258	get_device(shost->shost_gendev.parent);
259
260	device_enable_async_suspend(&shost->shost_dev);
261
262	error = device_add(&shost->shost_dev);
263	if (error)
264		goto out_del_gendev;
265
266	get_device(&shost->shost_gendev);
267
268	if (shost->transportt->host_size) {
269		shost->shost_data = kzalloc(shost->transportt->host_size,
270					 GFP_KERNEL);
271		if (shost->shost_data == NULL) {
272			error = -ENOMEM;
273			goto out_del_dev;
274		}
275	}
276
277	if (shost->transportt->create_work_queue) {
278		snprintf(shost->work_q_name, sizeof(shost->work_q_name),
279			 "scsi_wq_%d", shost->host_no);
280		shost->work_q = create_singlethread_workqueue(
281					shost->work_q_name);
282		if (!shost->work_q) {
283			error = -EINVAL;
284			goto out_free_shost_data;
285		}
286	}
287
288	error = scsi_sysfs_add_host(shost);
289	if (error)
290		goto out_destroy_host;
291
292	scsi_proc_host_add(shost);
293	return error;
294
295 out_destroy_host:
296	if (shost->work_q)
297		destroy_workqueue(shost->work_q);
298 out_free_shost_data:
299	kfree(shost->shost_data);
300 out_del_dev:
301	device_del(&shost->shost_dev);
302 out_del_gendev:
303	device_del(&shost->shost_gendev);
304 out_destroy_freelist:
305	scsi_destroy_command_freelist(shost);
306 out_destroy_tags:
307	if (shost_use_blk_mq(shost))
308		scsi_mq_destroy_tags(shost);
309 fail:
310	return error;
311}
312EXPORT_SYMBOL(scsi_add_host_with_dma);
313
314static void scsi_host_dev_release(struct device *dev)
315{
316	struct Scsi_Host *shost = dev_to_shost(dev);
317	struct device *parent = dev->parent;
318	struct request_queue *q;
319	void *queuedata;
320
321	scsi_proc_hostdir_rm(shost->hostt);
322
323	if (shost->tmf_work_q)
324		destroy_workqueue(shost->tmf_work_q);
325	if (shost->ehandler)
326		kthread_stop(shost->ehandler);
327	if (shost->work_q)
328		destroy_workqueue(shost->work_q);
329	q = shost->uspace_req_q;
330	if (q) {
331		queuedata = q->queuedata;
332		blk_cleanup_queue(q);
333		kfree(queuedata);
334	}
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	scsi_destroy_command_freelist(shost);
348	if (shost_use_blk_mq(shost)) {
349		if (shost->tag_set.tags)
350			scsi_mq_destroy_tags(shost);
351	} else {
352		if (shost->bqt)
353			blk_free_tags(shost->bqt);
354	}
355
356	kfree(shost->shost_data);
357
358	if (parent)
359		put_device(parent);
360	kfree(shost);
361}
362
363static int shost_eh_deadline = -1;
364
365module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
366MODULE_PARM_DESC(eh_deadline,
367		 "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
368
369static struct device_type scsi_host_type = {
370	.name =		"scsi_host",
371	.release =	scsi_host_dev_release,
372};
373
374/**
375 * scsi_host_alloc - register a scsi host adapter instance.
376 * @sht:	pointer to scsi host template
377 * @privsize:	extra bytes to allocate for driver
378 *
379 * Note:
380 * 	Allocate a new Scsi_Host and perform basic initialization.
381 * 	The host is not published to the scsi midlayer until scsi_add_host
382 * 	is called.
383 *
384 * Return value:
385 * 	Pointer to a new Scsi_Host
386 **/
387struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
388{
389	struct Scsi_Host *shost;
390	gfp_t gfp_mask = GFP_KERNEL;
391
392	if (sht->unchecked_isa_dma && privsize)
393		gfp_mask |= __GFP_DMA;
394
395	shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
396	if (!shost)
397		return NULL;
398
399	shost->host_lock = &shost->default_lock;
400	spin_lock_init(shost->host_lock);
401	shost->shost_state = SHOST_CREATED;
402	INIT_LIST_HEAD(&shost->__devices);
403	INIT_LIST_HEAD(&shost->__targets);
404	INIT_LIST_HEAD(&shost->eh_cmd_q);
405	INIT_LIST_HEAD(&shost->starved_list);
406	init_waitqueue_head(&shost->host_wait);
407	mutex_init(&shost->scan_mutex);
408
409	/*
410	 * subtract one because we increment first then return, but we need to
411	 * know what the next host number was before increment
412	 */
413	shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
414	shost->dma_channel = 0xff;
415
416	/* These three are default values which can be overridden */
417	shost->max_channel = 0;
418	shost->max_id = 8;
419	shost->max_lun = 8;
420
421	/* Give each shost a default transportt */
422	shost->transportt = &blank_transport_template;
423
424	/*
425	 * All drivers right now should be able to handle 12 byte
426	 * commands.  Every so often there are requests for 16 byte
427	 * commands, but individual low-level drivers need to certify that
428	 * they actually do something sensible with such commands.
429	 */
430	shost->max_cmd_len = 12;
431	shost->hostt = sht;
432	shost->this_id = sht->this_id;
433	shost->can_queue = sht->can_queue;
434	shost->sg_tablesize = sht->sg_tablesize;
435	shost->sg_prot_tablesize = sht->sg_prot_tablesize;
436	shost->cmd_per_lun = sht->cmd_per_lun;
437	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
438	shost->use_clustering = sht->use_clustering;
439	shost->no_write_same = sht->no_write_same;
440
441	if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
442		shost->eh_deadline = -1;
443	else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
444		shost_printk(KERN_WARNING, shost,
445			     "eh_deadline %u too large, setting to %u\n",
446			     shost_eh_deadline, INT_MAX / HZ);
447		shost->eh_deadline = INT_MAX;
448	} else
449		shost->eh_deadline = shost_eh_deadline * HZ;
450
451	if (sht->supported_mode == MODE_UNKNOWN)
452		/* means we didn't set it ... default to INITIATOR */
453		shost->active_mode = MODE_INITIATOR;
454	else
455		shost->active_mode = sht->supported_mode;
456
457	if (sht->max_host_blocked)
458		shost->max_host_blocked = sht->max_host_blocked;
459	else
460		shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
461
462	/*
463	 * If the driver imposes no hard sector transfer limit, start at
464	 * machine infinity initially.
465	 */
466	if (sht->max_sectors)
467		shost->max_sectors = sht->max_sectors;
468	else
469		shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
470
471	/*
472	 * assume a 4GB boundary, if not set
473	 */
474	if (sht->dma_boundary)
475		shost->dma_boundary = sht->dma_boundary;
476	else
477		shost->dma_boundary = 0xffffffff;
478
479	shost->use_blk_mq = scsi_use_blk_mq && !shost->hostt->disable_blk_mq;
480
481	device_initialize(&shost->shost_gendev);
482	dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
483	shost->shost_gendev.bus = &scsi_bus_type;
484	shost->shost_gendev.type = &scsi_host_type;
485
486	device_initialize(&shost->shost_dev);
487	shost->shost_dev.parent = &shost->shost_gendev;
488	shost->shost_dev.class = &shost_class;
489	dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
490	shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
491
492	shost->ehandler = kthread_run(scsi_error_handler, shost,
493			"scsi_eh_%d", shost->host_no);
494	if (IS_ERR(shost->ehandler)) {
495		shost_printk(KERN_WARNING, shost,
496			"error handler thread failed to spawn, error = %ld\n",
497			PTR_ERR(shost->ehandler));
498		goto fail_kfree;
499	}
500
501	shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
502					    WQ_UNBOUND | WQ_MEM_RECLAIM,
503					   1, shost->host_no);
504	if (!shost->tmf_work_q) {
505		shost_printk(KERN_WARNING, shost,
506			     "failed to create tmf workq\n");
507		goto fail_kthread;
508	}
509	scsi_proc_hostdir_add(shost->hostt);
510	return shost;
511
512 fail_kthread:
513	kthread_stop(shost->ehandler);
514 fail_kfree:
515	kfree(shost);
516	return NULL;
517}
518EXPORT_SYMBOL(scsi_host_alloc);
519
520struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
521{
522	struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
523
524	if (!sht->detect) {
525		printk(KERN_WARNING "scsi_register() called on new-style "
526				    "template for driver %s\n", sht->name);
527		dump_stack();
528	}
529
530	if (shost)
531		list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
532	return shost;
533}
534EXPORT_SYMBOL(scsi_register);
535
536void scsi_unregister(struct Scsi_Host *shost)
537{
538	list_del(&shost->sht_legacy_list);
539	scsi_host_put(shost);
540}
541EXPORT_SYMBOL(scsi_unregister);
542
543static int __scsi_host_match(struct device *dev, const void *data)
544{
545	struct Scsi_Host *p;
546	const unsigned short *hostnum = data;
547
548	p = class_to_shost(dev);
549	return p->host_no == *hostnum;
550}
551
552/**
553 * scsi_host_lookup - get a reference to a Scsi_Host by host no
554 * @hostnum:	host number to locate
555 *
556 * Return value:
557 *	A pointer to located Scsi_Host or NULL.
558 *
559 *	The caller must do a scsi_host_put() to drop the reference
560 *	that scsi_host_get() took. The put_device() below dropped
561 *	the reference from class_find_device().
562 **/
563struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
564{
565	struct device *cdev;
566	struct Scsi_Host *shost = NULL;
567
568	cdev = class_find_device(&shost_class, NULL, &hostnum,
569				 __scsi_host_match);
570	if (cdev) {
571		shost = scsi_host_get(class_to_shost(cdev));
572		put_device(cdev);
573	}
574	return shost;
575}
576EXPORT_SYMBOL(scsi_host_lookup);
577
578/**
579 * scsi_host_get - inc a Scsi_Host ref count
580 * @shost:	Pointer to Scsi_Host to inc.
581 **/
582struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
583{
584	if ((shost->shost_state == SHOST_DEL) ||
585		!get_device(&shost->shost_gendev))
586		return NULL;
587	return shost;
588}
589EXPORT_SYMBOL(scsi_host_get);
590
591/**
592 * scsi_host_put - dec a Scsi_Host ref count
593 * @shost:	Pointer to Scsi_Host to dec.
594 **/
595void scsi_host_put(struct Scsi_Host *shost)
596{
597	put_device(&shost->shost_gendev);
598}
599EXPORT_SYMBOL(scsi_host_put);
600
601int scsi_init_hosts(void)
602{
603	return class_register(&shost_class);
604}
605
606void scsi_exit_hosts(void)
607{
608	class_unregister(&shost_class);
609}
610
611int scsi_is_host_device(const struct device *dev)
612{
613	return dev->type == &scsi_host_type;
614}
615EXPORT_SYMBOL(scsi_is_host_device);
616
617/**
618 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
619 * @shost:	Pointer to Scsi_Host.
620 * @work:	Work to queue for execution.
621 *
622 * Return value:
623 * 	1 - work queued for execution
624 *	0 - work is already queued
625 *	-EINVAL - work queue doesn't exist
626 **/
627int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
628{
629	if (unlikely(!shost->work_q)) {
630		shost_printk(KERN_ERR, shost,
631			"ERROR: Scsi host '%s' attempted to queue scsi-work, "
632			"when no workqueue created.\n", shost->hostt->name);
633		dump_stack();
634
635		return -EINVAL;
636	}
637
638	return queue_work(shost->work_q, work);
639}
640EXPORT_SYMBOL_GPL(scsi_queue_work);
641
642/**
643 * scsi_flush_work - Flush a Scsi_Host's workqueue.
644 * @shost:	Pointer to Scsi_Host.
645 **/
646void scsi_flush_work(struct Scsi_Host *shost)
647{
648	if (!shost->work_q) {
649		shost_printk(KERN_ERR, shost,
650			"ERROR: Scsi host '%s' attempted to flush scsi-work, "
651			"when no workqueue created.\n", shost->hostt->name);
652		dump_stack();
653		return;
654	}
655
656	flush_workqueue(shost->work_q);
657}
658EXPORT_SYMBOL_GPL(scsi_flush_work);
659