[linux.git] / drivers / scsi / hosts.c

/*
 *  hosts.c Copyright (C) 1992 Drew Eckhardt
 *          Copyright (C) 1993, 1994, 1995 Eric Youngdale
 *          Copyright (C) 2002-2003 Christoph Hellwig
 *
 *  mid to lowlevel SCSI driver interface
 *      Initial versions: Drew Eckhardt
 *      Subsequent revisions: Eric Youngdale
 *
 *  <[email protected]>
 *
 *  Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
 *  Added QLOGIC QLA1280 SCSI controller kernel host support. 
 *     August 4, 1999 Fred Lewis, Intel DuPont
 *
 *  Updated to reflect the new initialization scheme for the higher 
 *  level of scsi drivers (sd/sr/st)
 *  September 17, 2000 Torben Mathiasen <[email protected]>
 *
 *  Restructured scsi_host lists and associated functions.
 *  September 04, 2002 Mike Anderson ([email protected])
 */

#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/transport_class.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/idr.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport.h>

#include "scsi_priv.h"
#include "scsi_logging.h"


static DEFINE_IDA(host_index_ida);


static void scsi_host_cls_release(struct device *dev)
{
	put_device(&class_to_shost(dev)->shost_gendev);
}

static struct class shost_class = {
	.name		= "scsi_host",
	.dev_release	= scsi_host_cls_release,
};

/**
 *	scsi_host_set_state - Take the given host through the host state model.
 *	@shost:	scsi host to change the state of.
 *	@state:	state to change to.
 *
 *	Returns zero if unsuccessful or an error if the requested
 *	transition is illegal.
 **/
int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
{
	enum scsi_host_state oldstate = shost->shost_state;

	if (state == oldstate)
		return 0;

	switch (state) {
	case SHOST_CREATED:
		/* There are no legal states that come back to
		 * created.  This is the manually initialised start
		 * state */
		goto illegal;

	case SHOST_RUNNING:
		switch (oldstate) {
		case SHOST_CREATED:
		case SHOST_RECOVERY:
			break;
		default:
			goto illegal;
		}
		break;

	case SHOST_RECOVERY:
		switch (oldstate) {
		case SHOST_RUNNING:
			break;
		default:
			goto illegal;
		}
		break;

	case SHOST_CANCEL:
		switch (oldstate) {
		case SHOST_CREATED:
		case SHOST_RUNNING:
		case SHOST_CANCEL_RECOVERY:
			break;
		default:
			goto illegal;
		}
		break;

	case SHOST_DEL:
		switch (oldstate) {
		case SHOST_CANCEL:
		case SHOST_DEL_RECOVERY:
			break;
		default:
			goto illegal;
		}
		break;

	case SHOST_CANCEL_RECOVERY:
		switch (oldstate) {
		case SHOST_CANCEL:
		case SHOST_RECOVERY:
			break;
		default:
			goto illegal;
		}
		break;

	case SHOST_DEL_RECOVERY:
		switch (oldstate) {
		case SHOST_CANCEL_RECOVERY:
			break;
		default:
			goto illegal;
		}
		break;
	}
	shost->shost_state = state;
	return 0;

 illegal:
	SCSI_LOG_ERROR_RECOVERY(1,
				shost_printk(KERN_ERR, shost,
					     "Illegal host state transition"
					     "%s->%s\n",
					     scsi_host_state_name(oldstate),
					     scsi_host_state_name(state)));
	return -EINVAL;
}
EXPORT_SYMBOL(scsi_host_set_state);

/**
 * scsi_remove_host - remove a scsi host
 * @shost:	a pointer to a scsi host to remove
 **/
void scsi_remove_host(struct Scsi_Host *shost)
{
	unsigned long flags;

	mutex_lock(&shost->scan_mutex);
	spin_lock_irqsave(shost->host_lock, flags);
	if (scsi_host_set_state(shost, SHOST_CANCEL))
		if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
			spin_unlock_irqrestore(shost->host_lock, flags);
			mutex_unlock(&shost->scan_mutex);
			return;
		}
	spin_unlock_irqrestore(shost->host_lock, flags);

	scsi_autopm_get_host(shost);
	flush_workqueue(shost->tmf_work_q);
	scsi_forget_host(shost);
	mutex_unlock(&shost->scan_mutex);
	scsi_proc_host_rm(shost);

	spin_lock_irqsave(shost->host_lock, flags);
	if (scsi_host_set_state(shost, SHOST_DEL))
		BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
	spin_unlock_irqrestore(shost->host_lock, flags);

	transport_unregister_device(&shost->shost_gendev);
	device_unregister(&shost->shost_dev);
	device_del(&shost->shost_gendev);
}
EXPORT_SYMBOL(scsi_remove_host);

/**
 * scsi_add_host_with_dma - add a scsi host with dma device
 * @shost:	scsi host pointer to add
 * @dev:	a struct device of type scsi class
 * @dma_dev:	dma device for the host
 *
 * Note: You rarely need to worry about this unless you're in a
 * virtualised host environments, so use the simpler scsi_add_host()
 * function instead.
 *
 * Return value: 
 * 	0 on success / != 0 for error
 **/
int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
			   struct device *dma_dev)
{
	struct scsi_host_template *sht = shost->hostt;
	int error = -EINVAL;

	shost_printk(KERN_INFO, shost, "%s\n",
			sht->info ? sht->info(shost) : sht->name);

	if (!shost->can_queue) {
		shost_printk(KERN_ERR, shost,
			     "can_queue = 0 no longer supported\n");
		goto fail;
	}

	error = scsi_init_sense_cache(shost);
	if (error)
		goto fail;

	if (shost_use_blk_mq(shost)) {
		error = scsi_mq_setup_tags(shost);
		if (error)
			goto fail;
	} else {
		shost->bqt = blk_init_tags(shost->can_queue,
				shost->hostt->tag_alloc_policy);
		if (!shost->bqt) {
			error = -ENOMEM;
			goto fail;
		}
	}

	if (!shost->shost_gendev.parent)
		shost->shost_gendev.parent = dev ? dev : &platform_bus;
	if (!dma_dev)
		dma_dev = shost->shost_gendev.parent;

	shost->dma_dev = dma_dev;

	/*
	 * Increase usage count temporarily here so that calling
	 * scsi_autopm_put_host() will trigger runtime idle if there is
	 * nothing else preventing suspending the device.
	 */
	pm_runtime_get_noresume(&shost->shost_gendev);
	pm_runtime_set_active(&shost->shost_gendev);
	pm_runtime_enable(&shost->shost_gendev);
	device_enable_async_suspend(&shost->shost_gendev);

	error = device_add(&shost->shost_gendev);
	if (error)
		goto out_disable_runtime_pm;

	scsi_host_set_state(shost, SHOST_RUNNING);
	get_device(shost->shost_gendev.parent);

	device_enable_async_suspend(&shost->shost_dev);

	error = device_add(&shost->shost_dev);
	if (error)
		goto out_del_gendev;

	get_device(&shost->shost_gendev);

	if (shost->transportt->host_size) {
		shost->shost_data = kzalloc(shost->transportt->host_size,
					 GFP_KERNEL);
		if (shost->shost_data == NULL) {
			error = -ENOMEM;
			goto out_del_dev;
		}
	}

	if (shost->transportt->create_work_queue) {
		snprintf(shost->work_q_name, sizeof(shost->work_q_name),
			 "scsi_wq_%d", shost->host_no);
		shost->work_q = create_singlethread_workqueue(
					shost->work_q_name);
		if (!shost->work_q) {
			error = -EINVAL;
			goto out_free_shost_data;
		}
	}

	error = scsi_sysfs_add_host(shost);
	if (error)
		goto out_destroy_host;

	scsi_proc_host_add(shost);
	scsi_autopm_put_host(shost);
	return error;

 out_destroy_host:
	if (shost->work_q)
		destroy_workqueue(shost->work_q);
 out_free_shost_data:
	kfree(shost->shost_data);
 out_del_dev:
	device_del(&shost->shost_dev);
 out_del_gendev:
	device_del(&shost->shost_gendev);
 out_disable_runtime_pm:
	device_disable_async_suspend(&shost->shost_gendev);
	pm_runtime_disable(&shost->shost_gendev);
	pm_runtime_set_suspended(&shost->shost_gendev);
	pm_runtime_put_noidle(&shost->shost_gendev);
	if (shost_use_blk_mq(shost))
		scsi_mq_destroy_tags(shost);
 fail:
	return error;
}
EXPORT_SYMBOL(scsi_add_host_with_dma);

static void scsi_host_dev_release(struct device *dev)
{
	struct Scsi_Host *shost = dev_to_shost(dev);
	struct device *parent = dev->parent;

	scsi_proc_hostdir_rm(shost->hostt);

	/* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
	rcu_barrier();

	if (shost->tmf_work_q)
		destroy_workqueue(shost->tmf_work_q);
	if (shost->ehandler)
		kthread_stop(shost->ehandler);
	if (shost->work_q)
		destroy_workqueue(shost->work_q);

	if (shost->shost_state == SHOST_CREATED) {
		/*
		 * Free the shost_dev device name here if scsi_host_alloc()
		 * and scsi_host_put() have been called but neither
		 * scsi_host_add() nor scsi_host_remove() has been called.
		 * This avoids that the memory allocated for the shost_dev
		 * name is leaked.
		 */
		kfree(dev_name(&shost->shost_dev));
	}

	if (shost_use_blk_mq(shost)) {
		if (shost->tag_set.tags)
			scsi_mq_destroy_tags(shost);
	} else {
		if (shost->bqt)
			blk_free_tags(shost->bqt);
	}

	kfree(shost->shost_data);

	ida_simple_remove(&host_index_ida, shost->host_no);

	if (parent)
		put_device(parent);
	kfree(shost);
}

static int shost_eh_deadline = -1;

module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(eh_deadline,
		 "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");

static struct device_type scsi_host_type = {
	.name =		"scsi_host",
	.release =	scsi_host_dev_release,
};

/**
 * scsi_host_alloc - register a scsi host adapter instance.
 * @sht:	pointer to scsi host template
 * @privsize:	extra bytes to allocate for driver
 *
 * Note:
 * 	Allocate a new Scsi_Host and perform basic initialization.
 * 	The host is not published to the scsi midlayer until scsi_add_host
 * 	is called.
 *
 * Return value:
 * 	Pointer to a new Scsi_Host
 **/
struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
{
	struct Scsi_Host *shost;
	gfp_t gfp_mask = GFP_KERNEL;
	int index;

	if (sht->unchecked_isa_dma && privsize)
		gfp_mask |= __GFP_DMA;

	shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
	if (!shost)
		return NULL;

	shost->host_lock = &shost->default_lock;
	spin_lock_init(shost->host_lock);
	shost->shost_state = SHOST_CREATED;
	INIT_LIST_HEAD(&shost->__devices);
	INIT_LIST_HEAD(&shost->__targets);
	INIT_LIST_HEAD(&shost->eh_cmd_q);
	INIT_LIST_HEAD(&shost->starved_list);
	init_waitqueue_head(&shost->host_wait);
	mutex_init(&shost->scan_mutex);

	index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
	if (index < 0)
		goto fail_kfree;
	shost->host_no = index;

	shost->dma_channel = 0xff;

	/* These three are default values which can be overridden */
	shost->max_channel = 0;
	shost->max_id = 8;
	shost->max_lun = 8;

	/* Give each shost a default transportt */
	shost->transportt = &blank_transport_template;

	/*
	 * All drivers right now should be able to handle 12 byte
	 * commands.  Every so often there are requests for 16 byte
	 * commands, but individual low-level drivers need to certify that
	 * they actually do something sensible with such commands.
	 */
	shost->max_cmd_len = 12;
	shost->hostt = sht;
	shost->this_id = sht->this_id;
	shost->can_queue = sht->can_queue;
	shost->sg_tablesize = sht->sg_tablesize;
	shost->sg_prot_tablesize = sht->sg_prot_tablesize;
	shost->cmd_per_lun = sht->cmd_per_lun;
	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
	shost->use_clustering = sht->use_clustering;
	shost->no_write_same = sht->no_write_same;

	if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
		shost->eh_deadline = -1;
	else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
		shost_printk(KERN_WARNING, shost,
			     "eh_deadline %u too large, setting to %u\n",
			     shost_eh_deadline, INT_MAX / HZ);
		shost->eh_deadline = INT_MAX;
	} else
		shost->eh_deadline = shost_eh_deadline * HZ;

	if (sht->supported_mode == MODE_UNKNOWN)
		/* means we didn't set it ... default to INITIATOR */
		shost->active_mode = MODE_INITIATOR;
	else
		shost->active_mode = sht->supported_mode;

	if (sht->max_host_blocked)
		shost->max_host_blocked = sht->max_host_blocked;
	else
		shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;

	/*
	 * If the driver imposes no hard sector transfer limit, start at
	 * machine infinity initially.
	 */
	if (sht->max_sectors)
		shost->max_sectors = sht->max_sectors;
	else
		shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;

	/*
	 * assume a 4GB boundary, if not set
	 */
	if (sht->dma_boundary)
		shost->dma_boundary = sht->dma_boundary;
	else
		shost->dma_boundary = 0xffffffff;

	shost->use_blk_mq = scsi_use_blk_mq;

	device_initialize(&shost->shost_gendev);
	dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
	shost->shost_gendev.bus = &scsi_bus_type;
	shost->shost_gendev.type = &scsi_host_type;

	device_initialize(&shost->shost_dev);
	shost->shost_dev.parent = &shost->shost_gendev;
	shost->shost_dev.class = &shost_class;
	dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
	shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;

	shost->ehandler = kthread_run(scsi_error_handler, shost,
			"scsi_eh_%d", shost->host_no);
	if (IS_ERR(shost->ehandler)) {
		shost_printk(KERN_WARNING, shost,
			"error handler thread failed to spawn, error = %ld\n",
			PTR_ERR(shost->ehandler));
		goto fail_index_remove;
	}

	shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
					    WQ_UNBOUND | WQ_MEM_RECLAIM,
					   1, shost->host_no);
	if (!shost->tmf_work_q) {
		shost_printk(KERN_WARNING, shost,
			     "failed to create tmf workq\n");
		goto fail_kthread;
	}
	scsi_proc_hostdir_add(shost->hostt);
	return shost;

 fail_kthread:
	kthread_stop(shost->ehandler);
 fail_index_remove:
	ida_simple_remove(&host_index_ida, shost->host_no);
 fail_kfree:
	kfree(shost);
	return NULL;
}
EXPORT_SYMBOL(scsi_host_alloc);

struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
{
	struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);

	if (!sht->detect) {
		printk(KERN_WARNING "scsi_register() called on new-style "
				    "template for driver %s\n", sht->name);
		dump_stack();
	}

	if (shost)
		list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
	return shost;
}
EXPORT_SYMBOL(scsi_register);

void scsi_unregister(struct Scsi_Host *shost)
{
	list_del(&shost->sht_legacy_list);
	scsi_host_put(shost);
}
EXPORT_SYMBOL(scsi_unregister);

static int __scsi_host_match(struct device *dev, const void *data)
{
	struct Scsi_Host *p;
	const unsigned short *hostnum = data;

	p = class_to_shost(dev);
	return p->host_no == *hostnum;
}

/**
 * scsi_host_lookup - get a reference to a Scsi_Host by host no
 * @hostnum:	host number to locate
 *
 * Return value:
 *	A pointer to located Scsi_Host or NULL.
 *
 *	The caller must do a scsi_host_put() to drop the reference
 *	that scsi_host_get() took. The put_device() below dropped
 *	the reference from class_find_device().
 **/
struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
{
	struct device *cdev;
	struct Scsi_Host *shost = NULL;

	cdev = class_find_device(&shost_class, NULL, &hostnum,
				 __scsi_host_match);
	if (cdev) {
		shost = scsi_host_get(class_to_shost(cdev));
		put_device(cdev);
	}
	return shost;
}
EXPORT_SYMBOL(scsi_host_lookup);

/**
 * scsi_host_get - inc a Scsi_Host ref count
 * @shost:	Pointer to Scsi_Host to inc.
 **/
struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
{
	if ((shost->shost_state == SHOST_DEL) ||
		!get_device(&shost->shost_gendev))
		return NULL;
	return shost;
}
EXPORT_SYMBOL(scsi_host_get);

/**
 * scsi_host_put - dec a Scsi_Host ref count
 * @shost:	Pointer to Scsi_Host to dec.
 **/
void scsi_host_put(struct Scsi_Host *shost)
{
	put_device(&shost->shost_gendev);
}
EXPORT_SYMBOL(scsi_host_put);

int scsi_init_hosts(void)
{
	return class_register(&shost_class);
}

void scsi_exit_hosts(void)
{
	class_unregister(&shost_class);
	ida_destroy(&host_index_ida);
}

int scsi_is_host_device(const struct device *dev)
{
	return dev->type == &scsi_host_type;
}
EXPORT_SYMBOL(scsi_is_host_device);

/**
 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 * @shost:	Pointer to Scsi_Host.
 * @work:	Work to queue for execution.
 *
 * Return value:
 * 	1 - work queued for execution
 *	0 - work is already queued
 *	-EINVAL - work queue doesn't exist
 **/
int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
{
	if (unlikely(!shost->work_q)) {
		shost_printk(KERN_ERR, shost,
			"ERROR: Scsi host '%s' attempted to queue scsi-work, "
			"when no workqueue created.\n", shost->hostt->name);
		dump_stack();

		return -EINVAL;
	}

	return queue_work(shost->work_q, work);
}
EXPORT_SYMBOL_GPL(scsi_queue_work);

/**
 * scsi_flush_work - Flush a Scsi_Host's workqueue.
 * @shost:	Pointer to Scsi_Host.
 **/
void scsi_flush_work(struct Scsi_Host *shost)
{
	if (!shost->work_q) {
		shost_printk(KERN_ERR, shost,
			"ERROR: Scsi host '%s' attempted to flush scsi-work, "
			"when no workqueue created.\n", shost->hostt->name);
		dump_stack();
		return;
	}

	flush_workqueue(shost->work_q);
}
EXPORT_SYMBOL_GPL(scsi_flush_work);
Commit	Line	Data
1da177e4 LT	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	* <[email protected]>
	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 <[email protected]>
	19	*
	20	* Restructured scsi_host lists and associated functions.
	21	* September 04, 2002 Mike Anderson ([email protected])
	22	*/
	23
	24	#include <linux/module.h>
	25	#include <linux/blkdev.h>
	26	#include <linux/kernel.h>
5a0e3ad6	27	#include <linux/slab.h>
c5478def	28	#include <linux/kthread.h>
1da177e4 LT	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>
d052d1be	34	#include <linux/platform_device.h>
bc4f2401	35	#include <linux/pm_runtime.h>
126a4fe0	36	#include <linux/idr.h>
1da177e4 LT	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
126a4fe0	45	static DEFINE_IDA(host_index_ida);
1da177e4 LT	46
1da177e4 LT	47
ee959b00	48	static void scsi_host_cls_release(struct device *dev)
1da177e4	49	{
ee959b00	50	put_device(&class_to_shost(dev)->shost_gendev);
1da177e4 LT	51	}
	52
	53	static struct class shost_class = {
	54	.name = "scsi_host",
ee959b00	55	.dev_release = scsi_host_cls_release,
1da177e4 LT	56	};
1da177e4 LT	57
d3301874	58	/**
eb44820c	59	* scsi_host_set_state - Take the given host through the host state model.
d3301874 MA	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:
939647ee	103	case SHOST_CANCEL_RECOVERY:
d3301874 MA	104	break;
	105	default:
	106	goto illegal;
	107	}
	108	break;
	109
	110	case SHOST_DEL:
	111	switch (oldstate) {
	112	case SHOST_CANCEL:
939647ee	113	case SHOST_DEL_RECOVERY:
d3301874 MA	114	break;
	115	default:
	116	goto illegal;
	117	}
	118	break;
	119
939647ee JB	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;
d3301874 MA	138	}
	139	shost->shost_state = state;
	140	return 0;
	141
	142	illegal:
	143	SCSI_LOG_ERROR_RECOVERY(1,
9ccfc756 JB	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)));
d3301874 MA	149	return -EINVAL;
	150	}
	151	EXPORT_SYMBOL(scsi_host_set_state);
	152
1da177e4 LT	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	{
939647ee	159	unsigned long flags;
bc4f2401	160
0b950672	161	mutex_lock(&shost->scan_mutex);
939647ee JB	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);
0b950672	166	mutex_unlock(&shost->scan_mutex);
939647ee JB	167	return;
	168	}
	169	spin_unlock_irqrestore(shost->host_lock, flags);
bc4f2401 AS	170
bc4f2401 AS	171	scsi_autopm_get_host(shost);
e494f6a7	172	flush_workqueue(shost->tmf_work_q);
1da177e4	173	scsi_forget_host(shost);
4e46bf89	174	mutex_unlock(&shost->scan_mutex);
1da177e4 LT	175	scsi_proc_host_rm(shost);
1da177e4 LT	176
939647ee JB	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);
1da177e4 LT	181
1da177e4 LT	182	transport_unregister_device(&shost->shost_gendev);
ee959b00	183	device_unregister(&shost->shost_dev);
1da177e4 LT	184	device_del(&shost->shost_gendev);
	185	}
	186	EXPORT_SYMBOL(scsi_remove_host);
	187
	188	/**
d139b9bd	189	* scsi_add_host_with_dma - add a scsi host with dma device
1da177e4 LT	190	* @shost: scsi host pointer to add
1da177e4 LT	191	* @dev: a struct device of type scsi class
d139b9bd JB	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.
1da177e4 LT	197	*
	198	* Return value:
	199	* 0 on success / != 0 for error
	200	**/
d139b9bd JB	201	int scsi_add_host_with_dma(struct Scsi_Host shost, struct device dev,
d139b9bd JB	202	struct device *dma_dev)
1da177e4 LT	203	{
	204	struct scsi_host_template *sht = shost->hostt;
	205	int error = -EINVAL;
	206
91921e01	207	shost_printk(KERN_INFO, shost, "%s\n",
1da177e4 LT	208	sht->info ? sht->info(shost) : sht->name);
	209
	210	if (!shost->can_queue) {
91921e01 HR	211	shost_printk(KERN_ERR, shost,
91921e01 HR	212	"can_queue = 0 no longer supported\n");
542bd137	213	goto fail;
1da177e4 LT	214	}
1da177e4 LT	215
0a6ac4ee CH	216	error = scsi_init_sense_cache(shost);
	217	if (error)
	218	goto fail;
	219
d285203c CH	220	if (shost_use_blk_mq(shost)) {
	221	error = scsi_mq_setup_tags(shost);
	222	if (error)
	223	goto fail;
64d513ac CH	224	} else {
	225	shost->bqt = blk_init_tags(shost->can_queue,
	226	shost->hostt->tag_alloc_policy);
	227	if (!shost->bqt) {
	228	error = -ENOMEM;
	229	goto fail;
	230	}
d285203c CH	231	}
d285203c CH	232
1da177e4 LT	233	if (!shost->shost_gendev.parent)
1da177e4 LT	234	shost->shost_gendev.parent = dev ? dev : &platform_bus;
3c8d9a95 JB	235	if (!dma_dev)
	236	dma_dev = shost->shost_gendev.parent;
	237
d139b9bd	238	shost->dma_dev = dma_dev;
1da177e4	239
5c6fab9d MW	240	/*
	241	* Increase usage count temporarily here so that calling
	242	* scsi_autopm_put_host() will trigger runtime idle if there is
	243	* nothing else preventing suspending the device.
	244	*/
	245	pm_runtime_get_noresume(&shost->shost_gendev);
bc4f2401 AS	246	pm_runtime_set_active(&shost->shost_gendev);
	247	pm_runtime_enable(&shost->shost_gendev);
	248	device_enable_async_suspend(&shost->shost_gendev);
	249
0d5644b7 HK	250	error = device_add(&shost->shost_gendev);
0d5644b7 HK	251	if (error)
e9c787e6	252	goto out_disable_runtime_pm;
0d5644b7	253
d3301874	254	scsi_host_set_state(shost, SHOST_RUNNING);
1da177e4 LT	255	get_device(shost->shost_gendev.parent);
1da177e4 LT	256
4cb077d9 RW	257	device_enable_async_suspend(&shost->shost_dev);
4cb077d9 RW	258
ee959b00	259	error = device_add(&shost->shost_dev);
1da177e4 LT	260	if (error)
	261	goto out_del_gendev;
	262
	263	get_device(&shost->shost_gendev);
	264
77cca462 JS	265	if (shost->transportt->host_size) {
	266	shost->shost_data = kzalloc(shost->transportt->host_size,
	267	GFP_KERNEL);
	268	if (shost->shost_data == NULL) {
	269	error = -ENOMEM;
ee959b00	270	goto out_del_dev;
77cca462 JS	271	}
77cca462 JS	272	}
1da177e4 LT	273
1da177e4 LT	274	if (shost->transportt->create_work_queue) {
aab0de24 KS	275	snprintf(shost->work_q_name, sizeof(shost->work_q_name),
aab0de24 KS	276	"scsi_wq_%d", shost->host_no);
1da177e4 LT	277	shost->work_q = create_singlethread_workqueue(
1da177e4 LT	278	shost->work_q_name);
77cca462 JS	279	if (!shost->work_q) {
77cca462 JS	280	error = -EINVAL;
1da177e4	281	goto out_free_shost_data;
77cca462	282	}
1da177e4 LT	283	}
	284
	285	error = scsi_sysfs_add_host(shost);
	286	if (error)
	287	goto out_destroy_host;
	288
	289	scsi_proc_host_add(shost);
5c6fab9d	290	scsi_autopm_put_host(shost);
1da177e4 LT	291	return error;
	292
	293	out_destroy_host:
	294	if (shost->work_q)
	295	destroy_workqueue(shost->work_q);
	296	out_free_shost_data:
	297	kfree(shost->shost_data);
ee959b00 TJ	298	out_del_dev:
ee959b00 TJ	299	device_del(&shost->shost_dev);
1da177e4 LT	300	out_del_gendev:
1da177e4 LT	301	device_del(&shost->shost_gendev);
e9c787e6	302	out_disable_runtime_pm:
0d5644b7 HK	303	device_disable_async_suspend(&shost->shost_gendev);
	304	pm_runtime_disable(&shost->shost_gendev);
	305	pm_runtime_set_suspended(&shost->shost_gendev);
	306	pm_runtime_put_noidle(&shost->shost_gendev);
d285203c CH	307	if (shost_use_blk_mq(shost))
d285203c CH	308	scsi_mq_destroy_tags(shost);
542bd137	309	fail:
1da177e4 LT	310	return error;
1da177e4 LT	311	}
d139b9bd	312	EXPORT_SYMBOL(scsi_add_host_with_dma);
1da177e4 LT	313
	314	static 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
77c01976 AS	319	scsi_proc_hostdir_rm(shost->hostt);
77c01976 AS	320
3bd6f43f BVA	321	/* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
	322	rcu_barrier();
	323
e494f6a7 HR	324	if (shost->tmf_work_q)
e494f6a7 HR	325	destroy_workqueue(shost->tmf_work_q);
c5478def CH	326	if (shost->ehandler)
c5478def CH	327	kthread_stop(shost->ehandler);
1da177e4 LT	328	if (shost->work_q)
	329	destroy_workqueue(shost->work_q);
	330
b49493f9 BVA	331	if (shost->shost_state == SHOST_CREATED) {
	332	/*
	333	* Free the shost_dev device name here if scsi_host_alloc()
	334	* and scsi_host_put() have been called but neither
	335	* scsi_host_add() nor scsi_host_remove() has been called.
	336	* This avoids that the memory allocated for the shost_dev
	337	* name is leaked.
	338	*/
	339	kfree(dev_name(&shost->shost_dev));
	340	}
	341
d285203c CH	342	if (shost_use_blk_mq(shost)) {
	343	if (shost->tag_set.tags)
	344	scsi_mq_destroy_tags(shost);
	345	} else {
	346	if (shost->bqt)
	347	blk_free_tags(shost->bqt);
	348	}
86e33a29	349
1da177e4 LT	350	kfree(shost->shost_data);
1da177e4 LT	351
126a4fe0 LD	352	ida_simple_remove(&host_index_ida, shost->host_no);
126a4fe0 LD	353
1da177e4 LT	354	if (parent)
	355	put_device(parent);
	356	kfree(shost);
	357	}
	358
bb3b621a	359	static int shost_eh_deadline = -1;
b4562022	360
bb3b621a	361	module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO\|S_IWUSR);
b4562022	362	MODULE_PARM_DESC(eh_deadline,
bb3b621a	363	"SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
b4562022	364
453cd0f3	365	static struct device_type scsi_host_type = {
b0ed4336 HR	366	.name = "scsi_host",
	367	.release = scsi_host_dev_release,
	368	};
	369
1da177e4 LT	370	/**
	371	* scsi_host_alloc - register a scsi host adapter instance.
	372	* @sht: pointer to scsi host template
	373	* @privsize: extra bytes to allocate for driver
	374	*
	375	* Note:
	376	* Allocate a new Scsi_Host and perform basic initialization.
	377	* The host is not published to the scsi midlayer until scsi_add_host
	378	* is called.
	379	*
	380	* Return value:
	381	* Pointer to a new Scsi_Host
	382	**/
	383	struct Scsi_Host scsi_host_alloc(struct scsi_host_template sht, int privsize)
	384	{
	385	struct Scsi_Host *shost;
c53033f6	386	gfp_t gfp_mask = GFP_KERNEL;
126a4fe0	387	int index;
1da177e4 LT	388
	389	if (sht->unchecked_isa_dma && privsize)
	390	gfp_mask \|= __GFP_DMA;
	391
24669f75	392	shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
1da177e4 LT	393	if (!shost)
1da177e4 LT	394	return NULL;
1da177e4	395
4f777ed2 CH	396	shost->host_lock = &shost->default_lock;
4f777ed2 CH	397	spin_lock_init(shost->host_lock);
d3301874	398	shost->shost_state = SHOST_CREATED;
1da177e4 LT	399	INIT_LIST_HEAD(&shost->__devices);
	400	INIT_LIST_HEAD(&shost->__targets);
	401	INIT_LIST_HEAD(&shost->eh_cmd_q);
	402	INIT_LIST_HEAD(&shost->starved_list);
	403	init_waitqueue_head(&shost->host_wait);
0b950672	404	mutex_init(&shost->scan_mutex);
1da177e4	405
126a4fe0 LD	406	index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
	407	if (index < 0)
	408	goto fail_kfree;
	409	shost->host_no = index;
	410
1da177e4 LT	411	shost->dma_channel = 0xff;
	412
	413	/* These three are default values which can be overridden */
	414	shost->max_channel = 0;
	415	shost->max_id = 8;
	416	shost->max_lun = 8;
	417
	418	/* Give each shost a default transportt */
	419	shost->transportt = &blank_transport_template;
	420
	421	/*
	422	* All drivers right now should be able to handle 12 byte
	423	* commands. Every so often there are requests for 16 byte
	424	* commands, but individual low-level drivers need to certify that
	425	* they actually do something sensible with such commands.
	426	*/
	427	shost->max_cmd_len = 12;
	428	shost->hostt = sht;
	429	shost->this_id = sht->this_id;
	430	shost->can_queue = sht->can_queue;
	431	shost->sg_tablesize = sht->sg_tablesize;
13f05c8d	432	shost->sg_prot_tablesize = sht->sg_prot_tablesize;
1da177e4 LT	433	shost->cmd_per_lun = sht->cmd_per_lun;
	434	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
	435	shost->use_clustering = sht->use_clustering;
54b2b50c	436	shost->no_write_same = sht->no_write_same;
1da177e4	437
ad469a57	438	if (shost_eh_deadline == -1 \|\| !sht->eh_host_reset_handler)
bb3b621a RM	439	shost->eh_deadline = -1;
	440	else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
	441	shost_printk(KERN_WARNING, shost,
	442	"eh_deadline %u too large, setting to %u\n",
	443	shost_eh_deadline, INT_MAX / HZ);
	444	shost->eh_deadline = INT_MAX;
	445	} else
	446	shost->eh_deadline = shost_eh_deadline * HZ;
	447
7a39ac3f JB	448	if (sht->supported_mode == MODE_UNKNOWN)
	449	/* means we didn't set it ... default to INITIATOR */
	450	shost->active_mode = MODE_INITIATOR;
	451	else
	452	shost->active_mode = sht->supported_mode;
	453
1da177e4 LT	454	if (sht->max_host_blocked)
	455	shost->max_host_blocked = sht->max_host_blocked;
	456	else
	457	shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
	458
	459	/*
	460	* If the driver imposes no hard sector transfer limit, start at
	461	* machine infinity initially.
	462	*/
	463	if (sht->max_sectors)
	464	shost->max_sectors = sht->max_sectors;
	465	else
	466	shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
	467
	468	/*
	469	* assume a 4GB boundary, if not set
	470	*/
	471	if (sht->dma_boundary)
	472	shost->dma_boundary = sht->dma_boundary;
	473	else
	474	shost->dma_boundary = 0xffffffff;
	475
8d58881b BVA	476	shost->use_blk_mq = scsi_use_blk_mq;
8d58881b BVA	477
1da177e4	478	device_initialize(&shost->shost_gendev);
71610f55	479	dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
b0ed4336	480	shost->shost_gendev.bus = &scsi_bus_type;
b0ed4336	481	shost->shost_gendev.type = &scsi_host_type;
1da177e4	482
ee959b00 TJ	483	device_initialize(&shost->shost_dev);
	484	shost->shost_dev.parent = &shost->shost_gendev;
	485	shost->shost_dev.class = &shost_class;
71610f55	486	dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
f7120a4f	487	shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
1da177e4	488
c5478def CH	489	shost->ehandler = kthread_run(scsi_error_handler, shost,
	490	"scsi_eh_%d", shost->host_no);
	491	if (IS_ERR(shost->ehandler)) {
91921e01 HR	492	shost_printk(KERN_WARNING, shost,
	493	"error handler thread failed to spawn, error = %ld\n",
	494	PTR_ERR(shost->ehandler));
126a4fe0	495	goto fail_index_remove;
c5478def	496	}
1da177e4	497
e494f6a7 HR	498	shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
	499	WQ_UNBOUND \| WQ_MEM_RECLAIM,
	500	1, shost->host_no);
	501	if (!shost->tmf_work_q) {
a222b1e2 HR	502	shost_printk(KERN_WARNING, shost,
a222b1e2 HR	503	"failed to create tmf workq\n");
e494f6a7 HR	504	goto fail_kthread;
e494f6a7 HR	505	}
1da177e4 LT	506	scsi_proc_hostdir_add(shost->hostt);
	507	return shost;
	508
e494f6a7 HR	509	fail_kthread:
e494f6a7 HR	510	kthread_stop(shost->ehandler);
126a4fe0 LD	511	fail_index_remove:
126a4fe0 LD	512	ida_simple_remove(&host_index_ida, shost->host_no);
1da177e4 LT	513	fail_kfree:
	514	kfree(shost);
	515	return NULL;
	516	}
	517	EXPORT_SYMBOL(scsi_host_alloc);
	518
	519	struct Scsi_Host scsi_register(struct scsi_host_template sht, int privsize)
	520	{
	521	struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
	522
	523	if (!sht->detect) {
	524	printk(KERN_WARNING "scsi_register() called on new-style "
	525	"template for driver %s\n", sht->name);
	526	dump_stack();
	527	}
	528
	529	if (shost)
	530	list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
	531	return shost;
	532	}
	533	EXPORT_SYMBOL(scsi_register);
	534
	535	void scsi_unregister(struct Scsi_Host *shost)
	536	{
	537	list_del(&shost->sht_legacy_list);
	538	scsi_host_put(shost);
	539	}
	540	EXPORT_SYMBOL(scsi_unregister);
	541
9f3b795a	542	static int __scsi_host_match(struct device dev, const void data)
9c770108 DY	543	{
9c770108 DY	544	struct Scsi_Host *p;
9f3b795a	545	const unsigned short *hostnum = data;
9c770108	546
ee959b00	547	p = class_to_shost(dev);
9c770108 DY	548	return p->host_no == *hostnum;
	549	}
	550
1da177e4 LT	551	/**
1da177e4 LT	552	* scsi_host_lookup - get a reference to a Scsi_Host by host no
1da177e4 LT	553	* @hostnum: host number to locate
	554	*
	555	* Return value:
	556	* A pointer to located Scsi_Host or NULL.
3ed78972 MC	557	*
	558	* The caller must do a scsi_host_put() to drop the reference
	559	* that scsi_host_get() took. The put_device() below dropped
	560	* the reference from class_find_device().
1da177e4 LT	561	**/
	562	struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
	563	{
ee959b00	564	struct device *cdev;
315cb0ad	565	struct Scsi_Host *shost = NULL;
1da177e4	566
695794ae GKH	567	cdev = class_find_device(&shost_class, NULL, &hostnum,
695794ae GKH	568	__scsi_host_match);
3ed78972	569	if (cdev) {
9c770108	570	shost = scsi_host_get(class_to_shost(cdev));
3ed78972 MC	571	put_device(cdev);
3ed78972 MC	572	}
1da177e4 LT	573	return shost;
	574	}
	575	EXPORT_SYMBOL(scsi_host_lookup);
	576
	577	/**
	578	* scsi_host_get - inc a Scsi_Host ref count
	579	* @shost: Pointer to Scsi_Host to inc.
	580	**/
	581	struct Scsi_Host scsi_host_get(struct Scsi_Host shost)
	582	{
d3301874	583	if ((shost->shost_state == SHOST_DEL) \|\|
1da177e4 LT	584	!get_device(&shost->shost_gendev))
	585	return NULL;
	586	return shost;
	587	}
	588	EXPORT_SYMBOL(scsi_host_get);
	589
	590	/**
	591	* scsi_host_put - dec a Scsi_Host ref count
	592	* @shost: Pointer to Scsi_Host to dec.
	593	**/
	594	void scsi_host_put(struct Scsi_Host *shost)
	595	{
	596	put_device(&shost->shost_gendev);
	597	}
	598	EXPORT_SYMBOL(scsi_host_put);
	599
	600	int scsi_init_hosts(void)
	601	{
	602	return class_register(&shost_class);
	603	}
	604
	605	void scsi_exit_hosts(void)
	606	{
	607	class_unregister(&shost_class);
126a4fe0	608	ida_destroy(&host_index_ida);
1da177e4 LT	609	}
	610
	611	int scsi_is_host_device(const struct device *dev)
	612	{
b0ed4336	613	return dev->type == &scsi_host_type;
1da177e4 LT	614	}
	615	EXPORT_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:
dd7e2f22 MR	623	* 1 - work queued for execution
	624	* 0 - work is already queued
	625	* -EINVAL - work queue doesn't exist
1da177e4 LT	626	**/
	627	int scsi_queue_work(struct Scsi_Host shost, struct work_struct work)
	628	{
	629	if (unlikely(!shost->work_q)) {
91921e01	630	shost_printk(KERN_ERR, shost,
1da177e4 LT	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	}
	640	EXPORT_SYMBOL_GPL(scsi_queue_work);
	641
	642	/**
	643	* scsi_flush_work - Flush a Scsi_Host's workqueue.
	644	* @shost: Pointer to Scsi_Host.
	645	**/
	646	void scsi_flush_work(struct Scsi_Host *shost)
	647	{
	648	if (!shost->work_q) {
91921e01	649	shost_printk(KERN_ERR, shost,
1da177e4 LT	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	}
	658	EXPORT_SYMBOL_GPL(scsi_flush_work);