[deliverable/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
 *
 *  <drew@colorado.edu>
 *
 *  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 <tmm@image.dk>
 *
 *  Restructured scsi_host lists and associated functions.
 *  September 04, 2002 Mike Anderson (andmike@us.ibm.com)
 */

#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/kernel.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 <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport.h>

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


static int scsi_host_next_hn;		/* host_no for next new host */


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

static struct class shost_class = {
	.name		= "scsi_host",
	.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);
	mutex_unlock(&shost->scan_mutex);
	scsi_forget_host(shost);
	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);
	class_device_unregister(&shost->shost_classdev);
	device_del(&shost->shost_gendev);
	scsi_proc_hostdir_rm(shost->hostt);
}
EXPORT_SYMBOL(scsi_remove_host);

/**
 * scsi_add_host - add a scsi host
 * @shost:	scsi host pointer to add
 * @dev:	a struct device of type scsi class
 *
 * Return value: 
 * 	0 on success / != 0 for error
 **/
int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
{
	struct scsi_host_template *sht = shost->hostt;
	int error = -EINVAL;

	printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
			sht->info ? sht->info(shost) : sht->name);

	if (!shost->can_queue) {
		printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
				sht->name);
		goto out;
	}

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

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

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

	error = class_device_add(&shost->shost_classdev);
	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)) == NULL)
		goto out_del_classdev;

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

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

	scsi_proc_host_add(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_classdev:
	class_device_del(&shost->shost_classdev);
 out_del_gendev:
	device_del(&shost->shost_gendev);
 out:
	return error;
}
EXPORT_SYMBOL(scsi_add_host);

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

	if (shost->ehandler)
		kthread_stop(shost->ehandler);
	if (shost->work_q)
		destroy_workqueue(shost->work_q);
	if (shost->uspace_req_q) {
		kfree(shost->uspace_req_q->queuedata);
		scsi_free_queue(shost->uspace_req_q);
	}

	scsi_destroy_command_freelist(shost);
	if (shost->bqt)
		blk_free_tags(shost->bqt);

	kfree(shost->shost_data);

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

/**
 * 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 rval;

	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);

	shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
	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->cmd_per_lun = sht->cmd_per_lun;
	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
	shost->use_clustering = sht->use_clustering;
	shost->ordered_tag = sht->ordered_tag;
	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;

	rval = scsi_setup_command_freelist(shost);
	if (rval)
		goto fail_kfree;

	device_initialize(&shost->shost_gendev);
	snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
		shost->host_no);
	shost->shost_gendev.release = scsi_host_dev_release;

	class_device_initialize(&shost->shost_classdev);
	shost->shost_classdev.dev = &shost->shost_gendev;
	shost->shost_classdev.class = &shost_class;
	snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
		  shost->host_no);

	shost->ehandler = kthread_run(scsi_error_handler, shost,
			"scsi_eh_%d", shost->host_no);
	if (IS_ERR(shost->ehandler)) {
		rval = PTR_ERR(shost->ehandler);
		goto fail_destroy_freelist;
	}

	scsi_proc_hostdir_add(shost->hostt);
	return shost;

 fail_destroy_freelist:
	scsi_destroy_command_freelist(shost);
 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);

/**
 * 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.
 **/
struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
{
	struct class *class = &shost_class;
	struct class_device *cdev;
	struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;

	down(&class->sem);
	list_for_each_entry(cdev, &class->children, node) {
		p = class_to_shost(cdev);
		if (p->host_no == hostnum) {
			shost = scsi_host_get(p);
			break;
		}
	}
	up(&class->sem);

	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);
}

int scsi_is_host_device(const struct device *dev)
{
	return dev->release == scsi_host_dev_release;
}
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)) {
		printk(KERN_ERR
			"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) {
		printk(KERN_ERR
			"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	* <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>
c5478def	27	#include <linux/kthread.h>
1da177e4 LT	28	#include <linux/string.h>
	29	#include <linux/mm.h>
	30	#include <linux/init.h>
	31	#include <linux/completion.h>
	32	#include <linux/transport_class.h>
d052d1be	33	#include <linux/platform_device.h>
1da177e4 LT	34
	35	#include <scsi/scsi_device.h>
	36	#include <scsi/scsi_host.h>
	37	#include <scsi/scsi_transport.h>
	38
	39	#include "scsi_priv.h"
	40	#include "scsi_logging.h"
	41
	42
	43	static int scsi_host_next_hn; /* host_no for next new host */
	44
	45
	46	static void scsi_host_cls_release(struct class_device *class_dev)
	47	{
	48	put_device(&class_to_shost(class_dev)->shost_gendev);
	49	}
	50
	51	static struct class shost_class = {
	52	.name = "scsi_host",
	53	.release = scsi_host_cls_release,
	54	};
	55
d3301874 MA	56	/**
	57	* scsi_host_set_state - Take the given host through the host
	58	* state model.
	59	* @shost: scsi host to change the state of.
	60	* @state: state to change to.
	61	*
	62	* Returns zero if unsuccessful or an error if the requested
	63	* transition is illegal.
	64	**/
	65	int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
	66	{
	67	enum scsi_host_state oldstate = shost->shost_state;
	68
	69	if (state == oldstate)
	70	return 0;
	71
	72	switch (state) {
	73	case SHOST_CREATED:
	74	/* There are no legal states that come back to
	75	* created. This is the manually initialised start
	76	* state */
	77	goto illegal;
	78
	79	case SHOST_RUNNING:
	80	switch (oldstate) {
	81	case SHOST_CREATED:
	82	case SHOST_RECOVERY:
	83	break;
	84	default:
	85	goto illegal;
	86	}
	87	break;
	88
	89	case SHOST_RECOVERY:
	90	switch (oldstate) {
	91	case SHOST_RUNNING:
	92	break;
	93	default:
	94	goto illegal;
	95	}
	96	break;
	97
	98	case SHOST_CANCEL:
	99	switch (oldstate) {
	100	case SHOST_CREATED:
	101	case SHOST_RUNNING:
939647ee	102	case SHOST_CANCEL_RECOVERY:
d3301874 MA	103	break;
	104	default:
	105	goto illegal;
	106	}
	107	break;
	108
	109	case SHOST_DEL:
	110	switch (oldstate) {
	111	case SHOST_CANCEL:
939647ee	112	case SHOST_DEL_RECOVERY:
d3301874 MA	113	break;
	114	default:
	115	goto illegal;
	116	}
	117	break;
	118
939647ee JB	119	case SHOST_CANCEL_RECOVERY:
	120	switch (oldstate) {
	121	case SHOST_CANCEL:
	122	case SHOST_RECOVERY:
	123	break;
	124	default:
	125	goto illegal;
	126	}
	127	break;
	128
	129	case SHOST_DEL_RECOVERY:
	130	switch (oldstate) {
	131	case SHOST_CANCEL_RECOVERY:
	132	break;
	133	default:
	134	goto illegal;
	135	}
	136	break;
d3301874 MA	137	}
	138	shost->shost_state = state;
	139	return 0;
	140
	141	illegal:
	142	SCSI_LOG_ERROR_RECOVERY(1,
9ccfc756 JB	143	shost_printk(KERN_ERR, shost,
	144	"Illegal host state transition"
	145	"%s->%s\n",
	146	scsi_host_state_name(oldstate),
	147	scsi_host_state_name(state)));
d3301874 MA	148	return -EINVAL;
	149	}
	150	EXPORT_SYMBOL(scsi_host_set_state);
	151
1da177e4 LT	152	/**
	153	* scsi_remove_host - remove a scsi host
	154	* @shost: a pointer to a scsi host to remove
	155	**/
	156	void scsi_remove_host(struct Scsi_Host *shost)
	157	{
939647ee	158	unsigned long flags;
0b950672	159	mutex_lock(&shost->scan_mutex);
939647ee JB	160	spin_lock_irqsave(shost->host_lock, flags);
	161	if (scsi_host_set_state(shost, SHOST_CANCEL))
	162	if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
	163	spin_unlock_irqrestore(shost->host_lock, flags);
0b950672	164	mutex_unlock(&shost->scan_mutex);
939647ee JB	165	return;
	166	}
	167	spin_unlock_irqrestore(shost->host_lock, flags);
0b950672	168	mutex_unlock(&shost->scan_mutex);
1da177e4	169	scsi_forget_host(shost);
1da177e4 LT	170	scsi_proc_host_rm(shost);
1da177e4 LT	171
939647ee JB	172	spin_lock_irqsave(shost->host_lock, flags);
	173	if (scsi_host_set_state(shost, SHOST_DEL))
	174	BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
	175	spin_unlock_irqrestore(shost->host_lock, flags);
1da177e4 LT	176
	177	transport_unregister_device(&shost->shost_gendev);
	178	class_device_unregister(&shost->shost_classdev);
	179	device_del(&shost->shost_gendev);
9e70592f	180	scsi_proc_hostdir_rm(shost->hostt);
1da177e4 LT	181	}
	182	EXPORT_SYMBOL(scsi_remove_host);
	183
	184	/**
	185	* scsi_add_host - add a scsi host
	186	* @shost: scsi host pointer to add
	187	* @dev: a struct device of type scsi class
	188	*
	189	* Return value:
	190	* 0 on success / != 0 for error
	191	**/
	192	int scsi_add_host(struct Scsi_Host shost, struct device dev)
	193	{
	194	struct scsi_host_template *sht = shost->hostt;
	195	int error = -EINVAL;
	196
	197	printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
	198	sht->info ? sht->info(shost) : sht->name);
	199
	200	if (!shost->can_queue) {
	201	printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
	202	sht->name);
	203	goto out;
	204	}
	205
	206	if (!shost->shost_gendev.parent)
	207	shost->shost_gendev.parent = dev ? dev : &platform_bus;
	208
	209	error = device_add(&shost->shost_gendev);
	210	if (error)
	211	goto out;
	212
d3301874	213	scsi_host_set_state(shost, SHOST_RUNNING);
1da177e4 LT	214	get_device(shost->shost_gendev.parent);
	215
	216	error = class_device_add(&shost->shost_classdev);
	217	if (error)
	218	goto out_del_gendev;
	219
	220	get_device(&shost->shost_gendev);
	221
	222	if (shost->transportt->host_size &&
c000c43c	223	(shost->shost_data = kzalloc(shost->transportt->host_size,
1da177e4 LT	224	GFP_KERNEL)) == NULL)
	225	goto out_del_classdev;
	226
	227	if (shost->transportt->create_work_queue) {
	228	snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
	229	shost->host_no);
	230	shost->work_q = create_singlethread_workqueue(
	231	shost->work_q_name);
	232	if (!shost->work_q)
	233	goto out_free_shost_data;
	234	}
	235
	236	error = scsi_sysfs_add_host(shost);
	237	if (error)
	238	goto out_destroy_host;
	239
	240	scsi_proc_host_add(shost);
	241	return error;
	242
	243	out_destroy_host:
	244	if (shost->work_q)
	245	destroy_workqueue(shost->work_q);
	246	out_free_shost_data:
	247	kfree(shost->shost_data);
	248	out_del_classdev:
	249	class_device_del(&shost->shost_classdev);
	250	out_del_gendev:
	251	device_del(&shost->shost_gendev);
	252	out:
	253	return error;
	254	}
	255	EXPORT_SYMBOL(scsi_add_host);
	256
	257	static void scsi_host_dev_release(struct device *dev)
	258	{
	259	struct Scsi_Host *shost = dev_to_shost(dev);
	260	struct device *parent = dev->parent;
	261
c5478def CH	262	if (shost->ehandler)
c5478def CH	263	kthread_stop(shost->ehandler);
1da177e4 LT	264	if (shost->work_q)
1da177e4 LT	265	destroy_workqueue(shost->work_q);
b58d9154 FT	266	if (shost->uspace_req_q) {
	267	kfree(shost->uspace_req_q->queuedata);
	268	scsi_free_queue(shost->uspace_req_q);
	269	}
1da177e4	270
1da177e4	271	scsi_destroy_command_freelist(shost);
86e33a29 JB	272	if (shost->bqt)
	273	blk_free_tags(shost->bqt);
	274
1da177e4 LT	275	kfree(shost->shost_data);
1da177e4 LT	276
1da177e4 LT	277	if (parent)
	278	put_device(parent);
	279	kfree(shost);
	280	}
	281
	282	/**
	283	* scsi_host_alloc - register a scsi host adapter instance.
	284	* @sht: pointer to scsi host template
	285	* @privsize: extra bytes to allocate for driver
	286	*
	287	* Note:
	288	* Allocate a new Scsi_Host and perform basic initialization.
	289	* The host is not published to the scsi midlayer until scsi_add_host
	290	* is called.
	291	*
	292	* Return value:
	293	* Pointer to a new Scsi_Host
	294	**/
	295	struct Scsi_Host scsi_host_alloc(struct scsi_host_template sht, int privsize)
	296	{
	297	struct Scsi_Host *shost;
c53033f6 AV	298	gfp_t gfp_mask = GFP_KERNEL;
c53033f6 AV	299	int rval;
1da177e4 LT	300
	301	if (sht->unchecked_isa_dma && privsize)
	302	gfp_mask \|= __GFP_DMA;
	303
24669f75	304	shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
1da177e4 LT	305	if (!shost)
1da177e4 LT	306	return NULL;
1da177e4	307
4f777ed2 CH	308	shost->host_lock = &shost->default_lock;
4f777ed2 CH	309	spin_lock_init(shost->host_lock);
d3301874	310	shost->shost_state = SHOST_CREATED;
1da177e4 LT	311	INIT_LIST_HEAD(&shost->__devices);
	312	INIT_LIST_HEAD(&shost->__targets);
	313	INIT_LIST_HEAD(&shost->eh_cmd_q);
	314	INIT_LIST_HEAD(&shost->starved_list);
	315	init_waitqueue_head(&shost->host_wait);
	316
0b950672	317	mutex_init(&shost->scan_mutex);
1da177e4 LT	318
	319	shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
	320	shost->dma_channel = 0xff;
	321
	322	/* These three are default values which can be overridden */
	323	shost->max_channel = 0;
	324	shost->max_id = 8;
	325	shost->max_lun = 8;
	326
	327	/* Give each shost a default transportt */
	328	shost->transportt = &blank_transport_template;
	329
	330	/*
	331	* All drivers right now should be able to handle 12 byte
	332	* commands. Every so often there are requests for 16 byte
	333	* commands, but individual low-level drivers need to certify that
	334	* they actually do something sensible with such commands.
	335	*/
	336	shost->max_cmd_len = 12;
	337	shost->hostt = sht;
	338	shost->this_id = sht->this_id;
	339	shost->can_queue = sht->can_queue;
	340	shost->sg_tablesize = sht->sg_tablesize;
	341	shost->cmd_per_lun = sht->cmd_per_lun;
	342	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
	343	shost->use_clustering = sht->use_clustering;
1da177e4	344	shost->ordered_tag = sht->ordered_tag;
5dc2b89e	345	shost->active_mode = sht->supported_mode;
1da177e4	346
1da177e4 LT	347	if (sht->max_host_blocked)
	348	shost->max_host_blocked = sht->max_host_blocked;
	349	else
	350	shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
	351
	352	/*
	353	* If the driver imposes no hard sector transfer limit, start at
	354	* machine infinity initially.
	355	*/
	356	if (sht->max_sectors)
	357	shost->max_sectors = sht->max_sectors;
	358	else
	359	shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
	360
	361	/*
	362	* assume a 4GB boundary, if not set
	363	*/
	364	if (sht->dma_boundary)
	365	shost->dma_boundary = sht->dma_boundary;
	366	else
	367	shost->dma_boundary = 0xffffffff;
	368
	369	rval = scsi_setup_command_freelist(shost);
	370	if (rval)
	371	goto fail_kfree;
	372
	373	device_initialize(&shost->shost_gendev);
	374	snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
	375	shost->host_no);
	376	shost->shost_gendev.release = scsi_host_dev_release;
	377
	378	class_device_initialize(&shost->shost_classdev);
	379	shost->shost_classdev.dev = &shost->shost_gendev;
	380	shost->shost_classdev.class = &shost_class;
	381	snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
	382	shost->host_no);
	383
c5478def CH	384	shost->ehandler = kthread_run(scsi_error_handler, shost,
	385	"scsi_eh_%d", shost->host_no);
	386	if (IS_ERR(shost->ehandler)) {
	387	rval = PTR_ERR(shost->ehandler);
1da177e4	388	goto fail_destroy_freelist;
c5478def	389	}
1da177e4 LT	390
	391	scsi_proc_hostdir_add(shost->hostt);
	392	return shost;
	393
	394	fail_destroy_freelist:
	395	scsi_destroy_command_freelist(shost);
	396	fail_kfree:
	397	kfree(shost);
	398	return NULL;
	399	}
	400	EXPORT_SYMBOL(scsi_host_alloc);
	401
	402	struct Scsi_Host scsi_register(struct scsi_host_template sht, int privsize)
	403	{
	404	struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
	405
	406	if (!sht->detect) {
	407	printk(KERN_WARNING "scsi_register() called on new-style "
	408	"template for driver %s\n", sht->name);
	409	dump_stack();
	410	}
	411
	412	if (shost)
	413	list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
	414	return shost;
	415	}
	416	EXPORT_SYMBOL(scsi_register);
	417
	418	void scsi_unregister(struct Scsi_Host *shost)
	419	{
	420	list_del(&shost->sht_legacy_list);
	421	scsi_host_put(shost);
	422	}
	423	EXPORT_SYMBOL(scsi_unregister);
	424
	425	/**
	426	* scsi_host_lookup - get a reference to a Scsi_Host by host no
	427	*
	428	* @hostnum: host number to locate
	429	*
	430	* Return value:
	431	* A pointer to located Scsi_Host or NULL.
	432	**/
	433	struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
	434	{
	435	struct class *class = &shost_class;
	436	struct class_device *cdev;
	437	struct Scsi_Host shost = ERR_PTR(-ENXIO), p;
	438
b7bb125d	439	down(&class->sem);
1da177e4 LT	440	list_for_each_entry(cdev, &class->children, node) {
	441	p = class_to_shost(cdev);
	442	if (p->host_no == hostnum) {
	443	shost = scsi_host_get(p);
	444	break;
	445	}
	446	}
b7bb125d	447	up(&class->sem);
1da177e4 LT	448
	449	return shost;
	450	}
	451	EXPORT_SYMBOL(scsi_host_lookup);
	452
	453	/**
	454	* scsi_host_get - inc a Scsi_Host ref count
	455	* @shost: Pointer to Scsi_Host to inc.
	456	**/
	457	struct Scsi_Host scsi_host_get(struct Scsi_Host shost)
	458	{
d3301874	459	if ((shost->shost_state == SHOST_DEL) \|\|
1da177e4 LT	460	!get_device(&shost->shost_gendev))
	461	return NULL;
	462	return shost;
	463	}
	464	EXPORT_SYMBOL(scsi_host_get);
	465
	466	/**
	467	* scsi_host_put - dec a Scsi_Host ref count
	468	* @shost: Pointer to Scsi_Host to dec.
	469	**/
	470	void scsi_host_put(struct Scsi_Host *shost)
	471	{
	472	put_device(&shost->shost_gendev);
	473	}
	474	EXPORT_SYMBOL(scsi_host_put);
	475
	476	int scsi_init_hosts(void)
	477	{
	478	return class_register(&shost_class);
	479	}
	480
	481	void scsi_exit_hosts(void)
	482	{
	483	class_unregister(&shost_class);
	484	}
	485
	486	int scsi_is_host_device(const struct device *dev)
	487	{
	488	return dev->release == scsi_host_dev_release;
	489	}
	490	EXPORT_SYMBOL(scsi_is_host_device);
	491
	492	/**
	493	* scsi_queue_work - Queue work to the Scsi_Host workqueue.
	494	* @shost: Pointer to Scsi_Host.
	495	* @work: Work to queue for execution.
	496	*
	497	* Return value:
dd7e2f22 MR	498	* 1 - work queued for execution
	499	* 0 - work is already queued
	500	* -EINVAL - work queue doesn't exist
1da177e4 LT	501	**/
	502	int scsi_queue_work(struct Scsi_Host shost, struct work_struct work)
	503	{
	504	if (unlikely(!shost->work_q)) {
	505	printk(KERN_ERR
	506	"ERROR: Scsi host '%s' attempted to queue scsi-work, "
	507	"when no workqueue created.\n", shost->hostt->name);
	508	dump_stack();
	509
	510	return -EINVAL;
	511	}
	512
	513	return queue_work(shost->work_q, work);
	514	}
	515	EXPORT_SYMBOL_GPL(scsi_queue_work);
	516
	517	/**
	518	* scsi_flush_work - Flush a Scsi_Host's workqueue.
	519	* @shost: Pointer to Scsi_Host.
	520	**/
	521	void scsi_flush_work(struct Scsi_Host *shost)
	522	{
	523	if (!shost->work_q) {
	524	printk(KERN_ERR
	525	"ERROR: Scsi host '%s' attempted to flush scsi-work, "
	526	"when no workqueue created.\n", shost->hostt->name);
	527	dump_stack();
	528	return;
	529	}
	530
	531	flush_workqueue(shost->work_q);
	532	}
	533	EXPORT_SYMBOL_GPL(scsi_flush_work);