[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 <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,
				dev_printk(KERN_ERR, &shost->shost_gendev,
					   "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;
	down(&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);
			up(&shost->scan_mutex);
			return;
		}
	spin_unlock_irqrestore(shost->host_lock, flags);
	up(&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 = kmalloc(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);

	scsi_destroy_command_freelist(shost);
	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;

        /* Check to see if this host has any error handling facilities */
        if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
	    !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
            !sht->eh_host_reset_handler) {
		printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
				"ERROR: This is not a safe way to run your "
				        "SCSI host\n"
				"ERROR: The error handling must be added to "
				"this driver\n", sht->proc_name);
		dump_stack();
        }

	shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
	if (!shost)
		return NULL;
	memset(shost, 0, sizeof(struct Scsi_Host) + privsize);

	spin_lock_init(&shost->default_lock);
	scsi_assign_lock(shost, &shost->default_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);

	init_MUTEX(&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_flush = sht->ordered_flush;
	shost->ordered_tag = sht->ordered_tag;

	/*
	 * hosts/devices that do queueing must support ordered tags
	 */
	if (shost->can_queue > 1 && shost->ordered_flush) {
		printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
		shost->ordered_flush = 0;
	}

	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_read(&class->subsys.rwsem);
	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_read(&class->subsys.rwsem);

	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:
 * 	0 on success / != 0 for error
 **/
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>
	33
	34	#include <scsi/scsi_device.h>
	35	#include <scsi/scsi_host.h>
	36	#include <scsi/scsi_transport.h>
	37
	38	#include "scsi_priv.h"
	39	#include "scsi_logging.h"
	40
	41
	42	static int scsi_host_next_hn; /* host_no for next new host */
	43
	44
	45	static void scsi_host_cls_release(struct class_device *class_dev)
	46	{
	47	put_device(&class_to_shost(class_dev)->shost_gendev);
	48	}
	49
	50	static struct class shost_class = {
	51	.name = "scsi_host",
	52	.release = scsi_host_cls_release,
	53	};
	54
d3301874 MA	55	/**
	56	* scsi_host_set_state - Take the given host through the host
	57	* state model.
	58	* @shost: scsi host to change the state of.
	59	* @state: state to change to.
	60	*
	61	* Returns zero if unsuccessful or an error if the requested
	62	* transition is illegal.
	63	**/
	64	int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
	65	{
	66	enum scsi_host_state oldstate = shost->shost_state;
	67
	68	if (state == oldstate)
	69	return 0;
	70
	71	switch (state) {
	72	case SHOST_CREATED:
	73	/* There are no legal states that come back to
	74	* created. This is the manually initialised start
	75	* state */
	76	goto illegal;
	77
	78	case SHOST_RUNNING:
	79	switch (oldstate) {
	80	case SHOST_CREATED:
	81	case SHOST_RECOVERY:
	82	break;
	83	default:
	84	goto illegal;
	85	}
	86	break;
	87
	88	case SHOST_RECOVERY:
	89	switch (oldstate) {
	90	case SHOST_RUNNING:
	91	break;
	92	default:
	93	goto illegal;
	94	}
	95	break;
	96
	97	case SHOST_CANCEL:
	98	switch (oldstate) {
	99	case SHOST_CREATED:
	100	case SHOST_RUNNING:
939647ee	101	case SHOST_CANCEL_RECOVERY:
d3301874 MA	102	break;
	103	default:
	104	goto illegal;
	105	}
	106	break;
	107
	108	case SHOST_DEL:
	109	switch (oldstate) {
	110	case SHOST_CANCEL:
939647ee	111	case SHOST_DEL_RECOVERY:
d3301874 MA	112	break;
	113	default:
	114	goto illegal;
	115	}
	116	break;
	117
939647ee JB	118	case SHOST_CANCEL_RECOVERY:
	119	switch (oldstate) {
	120	case SHOST_CANCEL:
	121	case SHOST_RECOVERY:
	122	break;
	123	default:
	124	goto illegal;
	125	}
	126	break;
	127
	128	case SHOST_DEL_RECOVERY:
	129	switch (oldstate) {
	130	case SHOST_CANCEL_RECOVERY:
	131	break;
	132	default:
	133	goto illegal;
	134	}
	135	break;
d3301874 MA	136	}
	137	shost->shost_state = state;
	138	return 0;
	139
	140	illegal:
	141	SCSI_LOG_ERROR_RECOVERY(1,
	142	dev_printk(KERN_ERR, &shost->shost_gendev,
	143	"Illegal host state transition"
	144	"%s->%s\n",
	145	scsi_host_state_name(oldstate),
	146	scsi_host_state_name(state)));
	147	return -EINVAL;
	148	}
	149	EXPORT_SYMBOL(scsi_host_set_state);
	150
1da177e4 LT	151	/**
	152	* scsi_remove_host - remove a scsi host
	153	* @shost: a pointer to a scsi host to remove
	154	**/
	155	void scsi_remove_host(struct Scsi_Host *shost)
	156	{
939647ee	157	unsigned long flags;
82f29467	158	down(&shost->scan_mutex);
939647ee JB	159	spin_lock_irqsave(shost->host_lock, flags);
	160	if (scsi_host_set_state(shost, SHOST_CANCEL))
	161	if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
	162	spin_unlock_irqrestore(shost->host_lock, flags);
	163	up(&shost->scan_mutex);
	164	return;
	165	}
	166	spin_unlock_irqrestore(shost->host_lock, flags);
82f29467	167	up(&shost->scan_mutex);
1da177e4	168	scsi_forget_host(shost);
1da177e4 LT	169	scsi_proc_host_rm(shost);
1da177e4 LT	170
939647ee JB	171	spin_lock_irqsave(shost->host_lock, flags);
	172	if (scsi_host_set_state(shost, SHOST_DEL))
	173	BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
	174	spin_unlock_irqrestore(shost->host_lock, flags);
1da177e4 LT	175
	176	transport_unregister_device(&shost->shost_gendev);
	177	class_device_unregister(&shost->shost_classdev);
	178	device_del(&shost->shost_gendev);
9e70592f	179	scsi_proc_hostdir_rm(shost->hostt);
1da177e4 LT	180	}
	181	EXPORT_SYMBOL(scsi_remove_host);
	182
	183	/**
	184	* scsi_add_host - add a scsi host
	185	* @shost: scsi host pointer to add
	186	* @dev: a struct device of type scsi class
	187	*
	188	* Return value:
	189	* 0 on success / != 0 for error
	190	**/
	191	int scsi_add_host(struct Scsi_Host shost, struct device dev)
	192	{
	193	struct scsi_host_template *sht = shost->hostt;
	194	int error = -EINVAL;
	195
	196	printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
	197	sht->info ? sht->info(shost) : sht->name);
	198
	199	if (!shost->can_queue) {
	200	printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
	201	sht->name);
	202	goto out;
	203	}
	204
	205	if (!shost->shost_gendev.parent)
	206	shost->shost_gendev.parent = dev ? dev : &platform_bus;
	207
	208	error = device_add(&shost->shost_gendev);
	209	if (error)
	210	goto out;
	211
d3301874	212	scsi_host_set_state(shost, SHOST_RUNNING);
1da177e4 LT	213	get_device(shost->shost_gendev.parent);
	214
	215	error = class_device_add(&shost->shost_classdev);
	216	if (error)
	217	goto out_del_gendev;
	218
	219	get_device(&shost->shost_gendev);
	220
	221	if (shost->transportt->host_size &&
	222	(shost->shost_data = kmalloc(shost->transportt->host_size,
	223	GFP_KERNEL)) == NULL)
	224	goto out_del_classdev;
	225
	226	if (shost->transportt->create_work_queue) {
	227	snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
	228	shost->host_no);
	229	shost->work_q = create_singlethread_workqueue(
	230	shost->work_q_name);
	231	if (!shost->work_q)
	232	goto out_free_shost_data;
	233	}
	234
	235	error = scsi_sysfs_add_host(shost);
	236	if (error)
	237	goto out_destroy_host;
	238
	239	scsi_proc_host_add(shost);
	240	return error;
	241
	242	out_destroy_host:
	243	if (shost->work_q)
	244	destroy_workqueue(shost->work_q);
	245	out_free_shost_data:
	246	kfree(shost->shost_data);
	247	out_del_classdev:
	248	class_device_del(&shost->shost_classdev);
	249	out_del_gendev:
	250	device_del(&shost->shost_gendev);
	251	out:
	252	return error;
	253	}
	254	EXPORT_SYMBOL(scsi_add_host);
	255
	256	static void scsi_host_dev_release(struct device *dev)
	257	{
	258	struct Scsi_Host *shost = dev_to_shost(dev);
	259	struct device *parent = dev->parent;
	260
c5478def CH	261	if (shost->ehandler)
c5478def CH	262	kthread_stop(shost->ehandler);
1da177e4 LT	263	if (shost->work_q)
	264	destroy_workqueue(shost->work_q);
	265
1da177e4 LT	266	scsi_destroy_command_freelist(shost);
	267	kfree(shost->shost_data);
	268
1da177e4 LT	269	if (parent)
	270	put_device(parent);
	271	kfree(shost);
	272	}
	273
	274	/**
	275	* scsi_host_alloc - register a scsi host adapter instance.
	276	* @sht: pointer to scsi host template
	277	* @privsize: extra bytes to allocate for driver
	278	*
	279	* Note:
	280	* Allocate a new Scsi_Host and perform basic initialization.
	281	* The host is not published to the scsi midlayer until scsi_add_host
	282	* is called.
	283	*
	284	* Return value:
	285	* Pointer to a new Scsi_Host
	286	**/
	287	struct Scsi_Host scsi_host_alloc(struct scsi_host_template sht, int privsize)
	288	{
	289	struct Scsi_Host *shost;
c53033f6 AV	290	gfp_t gfp_mask = GFP_KERNEL;
c53033f6 AV	291	int rval;
1da177e4 LT	292
	293	if (sht->unchecked_isa_dma && privsize)
	294	gfp_mask \|= __GFP_DMA;
	295
	296	/* Check to see if this host has any error handling facilities */
	297	if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
	298	!sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
	299	!sht->eh_host_reset_handler) {
	300	printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
	301	"ERROR: This is not a safe way to run your "
	302	"SCSI host\n"
	303	"ERROR: The error handling must be added to "
	304	"this driver\n", sht->proc_name);
	305	dump_stack();
	306	}
	307
	308	shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
	309	if (!shost)
	310	return NULL;
	311	memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
	312
	313	spin_lock_init(&shost->default_lock);
	314	scsi_assign_lock(shost, &shost->default_lock);
d3301874	315	shost->shost_state = SHOST_CREATED;
1da177e4 LT	316	INIT_LIST_HEAD(&shost->__devices);
	317	INIT_LIST_HEAD(&shost->__targets);
	318	INIT_LIST_HEAD(&shost->eh_cmd_q);
	319	INIT_LIST_HEAD(&shost->starved_list);
	320	init_waitqueue_head(&shost->host_wait);
	321
	322	init_MUTEX(&shost->scan_mutex);
	323
	324	shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
	325	shost->dma_channel = 0xff;
	326
	327	/* These three are default values which can be overridden */
	328	shost->max_channel = 0;
	329	shost->max_id = 8;
	330	shost->max_lun = 8;
	331
	332	/* Give each shost a default transportt */
	333	shost->transportt = &blank_transport_template;
	334
	335	/*
	336	* All drivers right now should be able to handle 12 byte
	337	* commands. Every so often there are requests for 16 byte
	338	* commands, but individual low-level drivers need to certify that
	339	* they actually do something sensible with such commands.
	340	*/
	341	shost->max_cmd_len = 12;
	342	shost->hostt = sht;
	343	shost->this_id = sht->this_id;
	344	shost->can_queue = sht->can_queue;
	345	shost->sg_tablesize = sht->sg_tablesize;
	346	shost->cmd_per_lun = sht->cmd_per_lun;
	347	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
	348	shost->use_clustering = sht->use_clustering;
	349	shost->ordered_flush = sht->ordered_flush;
	350	shost->ordered_tag = sht->ordered_tag;
	351
	352	/*
	353	* hosts/devices that do queueing must support ordered tags
	354	*/
	355	if (shost->can_queue > 1 && shost->ordered_flush) {
	356	printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
	357	shost->ordered_flush = 0;
	358	}
	359
	360	if (sht->max_host_blocked)
	361	shost->max_host_blocked = sht->max_host_blocked;
	362	else
	363	shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
	364
	365	/*
	366	* If the driver imposes no hard sector transfer limit, start at
	367	* machine infinity initially.
	368	*/
	369	if (sht->max_sectors)
	370	shost->max_sectors = sht->max_sectors;
	371	else
	372	shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
	373
	374	/*
	375	* assume a 4GB boundary, if not set
	376	*/
	377	if (sht->dma_boundary)
	378	shost->dma_boundary = sht->dma_boundary;
	379	else
380	shost->dma_boundary = 0xffffffff;
381
382	rval = scsi_setup_command_freelist(shost);
383	if (rval)
384	goto fail_kfree;
385
386	device_initialize(&shost->shost_gendev);
387	snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
388	shost->host_no);
389	shost->shost_gendev.release = scsi_host_dev_release;
390
391	class_device_initialize(&shost->shost_classdev);
392	shost->shost_classdev.dev = &shost->shost_gendev;
393	shost->shost_classdev.class = &shost_class;
394	snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
395	shost->host_no);
396
c5478def CH	397	shost->ehandler = kthread_run(scsi_error_handler, shost,
	398	"scsi_eh_%d", shost->host_no);
	399	if (IS_ERR(shost->ehandler)) {
	400	rval = PTR_ERR(shost->ehandler);
1da177e4	401	goto fail_destroy_freelist;
c5478def	402	}
1da177e4 LT	403
	404	scsi_proc_hostdir_add(shost->hostt);
	405	return shost;
	406
	407	fail_destroy_freelist:
	408	scsi_destroy_command_freelist(shost);
	409	fail_kfree:
	410	kfree(shost);
	411	return NULL;
	412	}
	413	EXPORT_SYMBOL(scsi_host_alloc);
	414
	415	struct Scsi_Host scsi_register(struct scsi_host_template sht, int privsize)
	416	{
	417	struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
	418
	419	if (!sht->detect) {
	420	printk(KERN_WARNING "scsi_register() called on new-style "
	421	"template for driver %s\n", sht->name);
	422	dump_stack();
	423	}
	424
	425	if (shost)
	426	list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
	427	return shost;
	428	}
	429	EXPORT_SYMBOL(scsi_register);
	430
	431	void scsi_unregister(struct Scsi_Host *shost)
	432	{
	433	list_del(&shost->sht_legacy_list);
	434	scsi_host_put(shost);
	435	}
	436	EXPORT_SYMBOL(scsi_unregister);
	437
	438	/**
	439	* scsi_host_lookup - get a reference to a Scsi_Host by host no
	440	*
	441	* @hostnum: host number to locate
	442	*
	443	* Return value:
	444	* A pointer to located Scsi_Host or NULL.
	445	**/
	446	struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
	447	{
	448	struct class *class = &shost_class;
	449	struct class_device *cdev;
	450	struct Scsi_Host shost = ERR_PTR(-ENXIO), p;
	451
	452	down_read(&class->subsys.rwsem);
	453	list_for_each_entry(cdev, &class->children, node) {
	454	p = class_to_shost(cdev);
	455	if (p->host_no == hostnum) {
	456	shost = scsi_host_get(p);
	457	break;
	458	}
	459	}
	460	up_read(&class->subsys.rwsem);
	461
	462	return shost;
	463	}
	464	EXPORT_SYMBOL(scsi_host_lookup);
	465
	466	/**
467	* scsi_host_get - inc a Scsi_Host ref count
468	* @shost: Pointer to Scsi_Host to inc.
469	**/
470	struct Scsi_Host scsi_host_get(struct Scsi_Host shost)
471	{
d3301874	472	if ((shost->shost_state == SHOST_DEL) \|\|
1da177e4 LT	473	!get_device(&shost->shost_gendev))
	474	return NULL;
	475	return shost;
	476	}
	477	EXPORT_SYMBOL(scsi_host_get);
	478
	479	/**
	480	* scsi_host_put - dec a Scsi_Host ref count
	481	* @shost: Pointer to Scsi_Host to dec.
	482	**/
	483	void scsi_host_put(struct Scsi_Host *shost)
	484	{
	485	put_device(&shost->shost_gendev);
	486	}
	487	EXPORT_SYMBOL(scsi_host_put);
	488
	489	int scsi_init_hosts(void)
	490	{
	491	return class_register(&shost_class);
	492	}
	493
	494	void scsi_exit_hosts(void)
	495	{
	496	class_unregister(&shost_class);
	497	}
	498
	499	int scsi_is_host_device(const struct device *dev)
	500	{
	501	return dev->release == scsi_host_dev_release;
	502	}
	503	EXPORT_SYMBOL(scsi_is_host_device);
	504
	505	/**
	506	* scsi_queue_work - Queue work to the Scsi_Host workqueue.
	507	* @shost: Pointer to Scsi_Host.
	508	* @work: Work to queue for execution.
	509	*
	510	* Return value:
	511	* 0 on success / != 0 for error
	512	**/
	513	int scsi_queue_work(struct Scsi_Host shost, struct work_struct work)
	514	{
	515	if (unlikely(!shost->work_q)) {
	516	printk(KERN_ERR
	517	"ERROR: Scsi host '%s' attempted to queue scsi-work, "
	518	"when no workqueue created.\n", shost->hostt->name);
	519	dump_stack();
	520
	521	return -EINVAL;
	522	}
	523
	524	return queue_work(shost->work_q, work);
	525	}
	526	EXPORT_SYMBOL_GPL(scsi_queue_work);
	527
	528	/**
	529	* scsi_flush_work - Flush a Scsi_Host's workqueue.
	530	* @shost: Pointer to Scsi_Host.
	531	**/
	532	void scsi_flush_work(struct Scsi_Host *shost)
	533	{
	534	if (!shost->work_q) {
	535	printk(KERN_ERR
	536	"ERROR: Scsi host '%s' attempted to flush scsi-work, "
537	"when no workqueue created.\n", shost->hostt->name);
538	dump_stack();
539	return;
540	}
541
542	flush_workqueue(shost->work_q);
543	}
544	EXPORT_SYMBOL_GPL(scsi_flush_work);