[mirror_ubuntu-artful-kernel.git] / drivers / scsi / scsi_dh.c

/*
 * SCSI device handler infrastruture.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Copyright IBM Corporation, 2007
 *      Authors:
 *               Chandra Seetharaman <sekharan@us.ibm.com>
 *               Mike Anderson <andmike@linux.vnet.ibm.com>
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <scsi/scsi_dh.h>
#include "scsi_priv.h"

static DEFINE_SPINLOCK(list_lock);
static LIST_HEAD(scsi_dh_list);

struct scsi_dh_blist {
	const char *vendor;
	const char *model;
	const char *driver;
};

static const struct scsi_dh_blist scsi_dh_blist[] = {
	{"DGC", "RAID",			"emc" },
	{"DGC", "DISK",			"emc" },
	{"DGC", "VRAID",		"emc" },

	{"COMPAQ", "MSA1000 VOLUME",	"hp_sw" },
	{"COMPAQ", "HSV110",		"hp_sw" },
	{"HP", "HSV100",		"hp_sw"},
	{"DEC", "HSG80",		"hp_sw"},

	{"IBM", "1722",			"rdac", },
	{"IBM", "1724",			"rdac", },
	{"IBM", "1726",			"rdac", },
	{"IBM", "1742",			"rdac", },
	{"IBM", "1745",			"rdac", },
	{"IBM", "1746",			"rdac", },
	{"IBM", "1813",			"rdac", },
	{"IBM", "1814",			"rdac", },
	{"IBM", "1815",			"rdac", },
	{"IBM", "1818",			"rdac", },
	{"IBM", "3526",			"rdac", },
	{"SGI", "TP9",			"rdac", },
	{"SGI", "IS",			"rdac", },
	{"STK", "OPENstorage D280",	"rdac", },
	{"STK", "FLEXLINE 380",		"rdac", },
	{"SUN", "CSM",			"rdac", },
	{"SUN", "LCSM100",		"rdac", },
	{"SUN", "STK6580_6780",		"rdac", },
	{"SUN", "SUN_6180",		"rdac", },
	{"SUN", "ArrayStorage",		"rdac", },
	{"DELL", "MD3",			"rdac", },
	{"NETAPP", "INF-01-00",		"rdac", },
	{"LSI", "INF-01-00",		"rdac", },
	{"ENGENIO", "INF-01-00",	"rdac", },
	{NULL, NULL,			NULL },
};

static const char *
scsi_dh_find_driver(struct scsi_device *sdev)
{
	const struct scsi_dh_blist *b;

	if (scsi_device_tpgs(sdev))
		return "alua";

	for (b = scsi_dh_blist; b->vendor; b++) {
		if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
		    !strncmp(sdev->model, b->model, strlen(b->model))) {
			return b->driver;
		}
	}
	return NULL;
}


static struct scsi_device_handler *__scsi_dh_lookup(const char *name)
{
	struct scsi_device_handler *tmp, *found = NULL;

	spin_lock(&list_lock);
	list_for_each_entry(tmp, &scsi_dh_list, list) {
		if (!strncmp(tmp->name, name, strlen(tmp->name))) {
			found = tmp;
			break;
		}
	}
	spin_unlock(&list_lock);
	return found;
}

static struct scsi_device_handler *scsi_dh_lookup(const char *name)
{
	struct scsi_device_handler *dh;

	dh = __scsi_dh_lookup(name);
	if (!dh) {
		request_module("scsi_dh_%s", name);
		dh = __scsi_dh_lookup(name);
	}

	return dh;
}

/*
 * scsi_dh_handler_attach - Attach a device handler to a device
 * @sdev - SCSI device the device handler should attach to
 * @scsi_dh - The device handler to attach
 */
static int scsi_dh_handler_attach(struct scsi_device *sdev,
				  struct scsi_device_handler *scsi_dh)
{
	int error;

	if (!try_module_get(scsi_dh->module))
		return -EINVAL;

	error = scsi_dh->attach(sdev);
	if (error) {
		sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
			    scsi_dh->name, error);
		module_put(scsi_dh->module);
	} else
		sdev->handler = scsi_dh;

	return error;
}

/*
 * scsi_dh_handler_detach - Detach a device handler from a device
 * @sdev - SCSI device the device handler should be detached from
 */
static void scsi_dh_handler_detach(struct scsi_device *sdev)
{
	sdev->handler->detach(sdev);
	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
	module_put(sdev->handler->module);
}

int scsi_dh_add_device(struct scsi_device *sdev)
{
	struct scsi_device_handler *devinfo = NULL;
	const char *drv;
	int err = 0;

	drv = scsi_dh_find_driver(sdev);
	if (drv)
		devinfo = __scsi_dh_lookup(drv);
	if (devinfo)
		err = scsi_dh_handler_attach(sdev, devinfo);
	return err;
}

void scsi_dh_release_device(struct scsi_device *sdev)
{
	if (sdev->handler)
		scsi_dh_handler_detach(sdev);
}

/*
 * scsi_register_device_handler - register a device handler personality
 *      module.
 * @scsi_dh - device handler to be registered.
 *
 * Returns 0 on success, -EBUSY if handler already registered.
 */
int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
{
	if (__scsi_dh_lookup(scsi_dh->name))
		return -EBUSY;

	if (!scsi_dh->attach || !scsi_dh->detach)
		return -EINVAL;

	spin_lock(&list_lock);
	list_add(&scsi_dh->list, &scsi_dh_list);
	spin_unlock(&list_lock);

	printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);

	return SCSI_DH_OK;
}
EXPORT_SYMBOL_GPL(scsi_register_device_handler);

/*
 * scsi_unregister_device_handler - register a device handler personality
 *      module.
 * @scsi_dh - device handler to be unregistered.
 *
 * Returns 0 on success, -ENODEV if handler not registered.
 */
int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
{
	if (!__scsi_dh_lookup(scsi_dh->name))
		return -ENODEV;

	spin_lock(&list_lock);
	list_del(&scsi_dh->list);
	spin_unlock(&list_lock);
	printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);

	return SCSI_DH_OK;
}
EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);

/*
 * scsi_dh_activate - activate the path associated with the scsi_device
 *      corresponding to the given request queue.
 *     Returns immediately without waiting for activation to be completed.
 * @q    - Request queue that is associated with the scsi_device to be
 *         activated.
 * @fn   - Function to be called upon completion of the activation.
 *         Function fn is called with data (below) and the error code.
 *         Function fn may be called from the same calling context. So,
 *         do not hold the lock in the caller which may be needed in fn.
 * @data - data passed to the function fn upon completion.
 *
 */
int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
{
	struct scsi_device *sdev;
	int err = SCSI_DH_NOSYS;

	sdev = scsi_device_from_queue(q);
	if (!sdev) {
		if (fn)
			fn(data, err);
		return err;
	}

	if (!sdev->handler)
		goto out_fn;
	err = SCSI_DH_NOTCONN;
	if (sdev->sdev_state == SDEV_CANCEL ||
	    sdev->sdev_state == SDEV_DEL)
		goto out_fn;

	err = SCSI_DH_DEV_OFFLINED;
	if (sdev->sdev_state == SDEV_OFFLINE)
		goto out_fn;

	if (sdev->handler->activate)
		err = sdev->handler->activate(sdev, fn, data);

out_put_device:
	put_device(&sdev->sdev_gendev);
	return err;

out_fn:
	if (fn)
		fn(data, err);
	goto out_put_device;
}
EXPORT_SYMBOL_GPL(scsi_dh_activate);

/*
 * scsi_dh_set_params - set the parameters for the device as per the
 *      string specified in params.
 * @q - Request queue that is associated with the scsi_device for
 *      which the parameters to be set.
 * @params - parameters in the following format
 *      "no_of_params\0param1\0param2\0param3\0...\0"
 *      for example, string for 2 parameters with value 10 and 21
 *      is specified as "2\010\021\0".
 */
int scsi_dh_set_params(struct request_queue *q, const char *params)
{
	struct scsi_device *sdev;
	int err = -SCSI_DH_NOSYS;

	sdev = scsi_device_from_queue(q);
	if (!sdev)
		return err;

	if (sdev->handler && sdev->handler->set_params)
		err = sdev->handler->set_params(sdev, params);
	put_device(&sdev->sdev_gendev);
	return err;
}
EXPORT_SYMBOL_GPL(scsi_dh_set_params);

/*
 * scsi_dh_attach - Attach device handler
 * @q - Request queue that is associated with the scsi_device
 *      the handler should be attached to
 * @name - name of the handler to attach
 */
int scsi_dh_attach(struct request_queue *q, const char *name)
{
	struct scsi_device *sdev;
	struct scsi_device_handler *scsi_dh;
	int err = 0;

	sdev = scsi_device_from_queue(q);
	if (!sdev)
		return -ENODEV;

	scsi_dh = scsi_dh_lookup(name);
	if (!scsi_dh) {
		err = -EINVAL;
		goto out_put_device;
	}

	if (sdev->handler) {
		if (sdev->handler != scsi_dh)
			err = -EBUSY;
		goto out_put_device;
	}

	err = scsi_dh_handler_attach(sdev, scsi_dh);

out_put_device:
	put_device(&sdev->sdev_gendev);
	return err;
}
EXPORT_SYMBOL_GPL(scsi_dh_attach);

/*
 * scsi_dh_attached_handler_name - Get attached device handler's name
 * @q - Request queue that is associated with the scsi_device
 *      that may have a device handler attached
 * @gfp - the GFP mask used in the kmalloc() call when allocating memory
 *
 * Returns name of attached handler, NULL if no handler is attached.
 * Caller must take care to free the returned string.
 */
const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
{
	struct scsi_device *sdev;
	const char *handler_name = NULL;

	sdev = scsi_device_from_queue(q);
	if (!sdev)
		return NULL;

	if (sdev->handler)
		handler_name = kstrdup(sdev->handler->name, gfp);
	put_device(&sdev->sdev_gendev);
	return handler_name;
}
EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);
Commit	Line	Data
a6a8d9f8 CS	1	/*
	2	* SCSI device handler infrastruture.
	3	*
	4	* This program is free software; you can redistribute it and/or modify it
	5	* under the terms of the GNU General Public License as published by the
	6	* Free Software Foundation; either version 2 of the License, or (at your
	7	* option) any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful, but
	10	* WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	12	* General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License along
	15	* with this program; if not, write to the Free Software Foundation, Inc.,
	16	* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	17	*
	18	* Copyright IBM Corporation, 2007
	19	* Authors:
	20	* Chandra Seetharaman <sekharan@us.ibm.com>
	21	* Mike Anderson <andmike@linux.vnet.ibm.com>
	22	*/
	23
5a0e3ad6	24	#include <linux/slab.h>
acf3368f	25	#include <linux/module.h>
a6a8d9f8	26	#include <scsi/scsi_dh.h>
daaa858b	27	#include "scsi_priv.h"
a6a8d9f8 CS	28
	29	static DEFINE_SPINLOCK(list_lock);
	30	static LIST_HEAD(scsi_dh_list);
	31
d95dbff2 CH	32	struct scsi_dh_blist {
	33	const char *vendor;
	34	const char *model;
	35	const char *driver;
	36	};
	37
	38	static const struct scsi_dh_blist scsi_dh_blist[] = {
0ba43a81 XVP	39	{"DGC", "RAID", "emc" },
	40	{"DGC", "DISK", "emc" },
	41	{"DGC", "VRAID", "emc" },
d95dbff2 CH	42
	43	{"COMPAQ", "MSA1000 VOLUME", "hp_sw" },
	44	{"COMPAQ", "HSV110", "hp_sw" },
	45	{"HP", "HSV100", "hp_sw"},
	46	{"DEC", "HSG80", "hp_sw"},
	47
	48	{"IBM", "1722", "rdac", },
	49	{"IBM", "1724", "rdac", },
	50	{"IBM", "1726", "rdac", },
	51	{"IBM", "1742", "rdac", },
	52	{"IBM", "1745", "rdac", },
	53	{"IBM", "1746", "rdac", },
	54	{"IBM", "1813", "rdac", },
	55	{"IBM", "1814", "rdac", },
	56	{"IBM", "1815", "rdac", },
	57	{"IBM", "1818", "rdac", },
	58	{"IBM", "3526", "rdac", },
	59	{"SGI", "TP9", "rdac", },
	60	{"SGI", "IS", "rdac", },
	61	{"STK", "OPENstorage D280", "rdac", },
	62	{"STK", "FLEXLINE 380", "rdac", },
	63	{"SUN", "CSM", "rdac", },
	64	{"SUN", "LCSM100", "rdac", },
	65	{"SUN", "STK6580_6780", "rdac", },
	66	{"SUN", "SUN_6180", "rdac", },
	67	{"SUN", "ArrayStorage", "rdac", },
	68	{"DELL", "MD3", "rdac", },
	69	{"NETAPP", "INF-01-00", "rdac", },
	70	{"LSI", "INF-01-00", "rdac", },
	71	{"ENGENIO", "INF-01-00", "rdac", },
	72	{NULL, NULL, NULL },
	73	};
	74
	75	static const char *
	76	scsi_dh_find_driver(struct scsi_device *sdev)
	77	{
	78	const struct scsi_dh_blist *b;
	79
	80	if (scsi_device_tpgs(sdev))
	81	return "alua";
	82
	83	for (b = scsi_dh_blist; b->vendor; b++) {
	84	if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
	85	!strncmp(sdev->model, b->model, strlen(b->model))) {
	86	return b->driver;
	87	}
	88	}
	89	return NULL;
	90	}
	91
	92
566079c8	93	static struct scsi_device_handler __scsi_dh_lookup(const char name)
a6a8d9f8 CS	94	{
	95	struct scsi_device_handler tmp, found = NULL;
	96
	97	spin_lock(&list_lock);
	98	list_for_each_entry(tmp, &scsi_dh_list, list) {
765cbc6d	99	if (!strncmp(tmp->name, name, strlen(tmp->name))) {
a6a8d9f8 CS	100	found = tmp;
	101	break;
	102	}
	103	}
	104	spin_unlock(&list_lock);
	105	return found;
	106	}
	107
566079c8 CH	108	static struct scsi_device_handler scsi_dh_lookup(const char name)
	109	{
	110	struct scsi_device_handler *dh;
	111
	112	dh = __scsi_dh_lookup(name);
	113	if (!dh) {
1378889c	114	request_module("scsi_dh_%s", name);
566079c8 CH	115	dh = __scsi_dh_lookup(name);
	116	}
	117
	118	return dh;
	119	}
	120
a6a8d9f8	121	/*
765cbc6d HR	122	* scsi_dh_handler_attach - Attach a device handler to a device
	123	* @sdev - SCSI device the device handler should attach to
	124	* @scsi_dh - The device handler to attach
	125	*/
	126	static int scsi_dh_handler_attach(struct scsi_device *sdev,
	127	struct scsi_device_handler *scsi_dh)
	128	{
ee14c674	129	int error;
765cbc6d	130
1f12ffa5 CH	131	if (!try_module_get(scsi_dh->module))
1f12ffa5 CH	132	return -EINVAL;
27c888f0	133
ee14c674 CH	134	error = scsi_dh->attach(sdev);
	135	if (error) {
	136	sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
	137	scsi_dh->name, error);
1f12ffa5	138	module_put(scsi_dh->module);
ee14c674 CH	139	} else
ee14c674 CH	140	sdev->handler = scsi_dh;
1d520328	141
ee14c674	142	return error;
765cbc6d HR	143	}
765cbc6d HR	144
1bab0de0 CH	145	/*
	146	* scsi_dh_handler_detach - Detach a device handler from a device
	147	* @sdev - SCSI device the device handler should be detached from
	148	*/
	149	static void scsi_dh_handler_detach(struct scsi_device *sdev)
6c10db72	150	{
ee14c674 CH	151	sdev->handler->detach(sdev);
	152	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
	153	module_put(sdev->handler->module);
6c10db72 CS	154	}
6c10db72 CS	155
086b91d0	156	int scsi_dh_add_device(struct scsi_device *sdev)
4c05ae52	157	{
d95dbff2 CH	158	struct scsi_device_handler *devinfo = NULL;
d95dbff2 CH	159	const char *drv;
41f95dd2	160	int err = 0;
4c05ae52	161
d95dbff2 CH	162	drv = scsi_dh_find_driver(sdev);
d95dbff2 CH	163	if (drv)
d6a32b98	164	devinfo = __scsi_dh_lookup(drv);
086b91d0 CH	165	if (devinfo)
086b91d0 CH	166	err = scsi_dh_handler_attach(sdev, devinfo);
765cbc6d	167	return err;
a6a8d9f8	168	}
a6a8d9f8	169
23695e41	170	void scsi_dh_release_device(struct scsi_device *sdev)
765cbc6d	171	{
ee14c674	172	if (sdev->handler)
1bab0de0	173	scsi_dh_handler_detach(sdev);
23695e41 JN	174	}
23695e41 JN	175
765cbc6d HR	176	/*
	177	* scsi_register_device_handler - register a device handler personality
	178	* module.
	179	* @scsi_dh - device handler to be registered.
	180	*
	181	* Returns 0 on success, -EBUSY if handler already registered.
	182	*/
	183	int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
	184	{
566079c8	185	if (__scsi_dh_lookup(scsi_dh->name))
765cbc6d HR	186	return -EBUSY;
765cbc6d HR	187
1f12ffa5 CH	188	if (!scsi_dh->attach \|\| !scsi_dh->detach)
	189	return -EINVAL;
	190
765cbc6d HR	191	spin_lock(&list_lock);
	192	list_add(&scsi_dh->list, &scsi_dh_list);
	193	spin_unlock(&list_lock);
940d7faa	194
765cbc6d HR	195	printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
	196
	197	return SCSI_DH_OK;
	198	}
	199	EXPORT_SYMBOL_GPL(scsi_register_device_handler);
	200
a6a8d9f8 CS	201	/*
	202	* scsi_unregister_device_handler - register a device handler personality
	203	* module.
	204	* @scsi_dh - device handler to be unregistered.
	205	*
	206	* Returns 0 on success, -ENODEV if handler not registered.
	207	*/
	208	int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
	209	{
566079c8	210	if (!__scsi_dh_lookup(scsi_dh->name))
765cbc6d	211	return -ENODEV;
a6a8d9f8	212
a6a8d9f8 CS	213	spin_lock(&list_lock);
	214	list_del(&scsi_dh->list);
	215	spin_unlock(&list_lock);
765cbc6d	216	printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
a6a8d9f8	217
765cbc6d	218	return SCSI_DH_OK;
a6a8d9f8 CS	219	}
	220	EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
	221
	222	/*
	223	* scsi_dh_activate - activate the path associated with the scsi_device
	224	* corresponding to the given request queue.
3ae31f6a CS	225	* Returns immediately without waiting for activation to be completed.
	226	* @q - Request queue that is associated with the scsi_device to be
	227	* activated.
	228	* @fn - Function to be called upon completion of the activation.
	229	* Function fn is called with data (below) and the error code.
	230	* Function fn may be called from the same calling context. So,
	231	* do not hold the lock in the caller which may be needed in fn.
	232	* @data - data passed to the function fn upon completion.
	233	*
a6a8d9f8	234	*/
3ae31f6a	235	int scsi_dh_activate(struct request_queue q, activate_complete fn, void data)
a6a8d9f8	236	{
a6a8d9f8	237	struct scsi_device *sdev;
e959ed9a	238	int err = SCSI_DH_NOSYS;
a6a8d9f8	239
857de6e0	240	sdev = scsi_device_from_queue(q);
a18a920c	241	if (!sdev) {
a18a920c MB	242	if (fn)
	243	fn(data, err);
	244	return err;
	245	}
	246
e959ed9a CH	247	if (!sdev->handler)
e959ed9a CH	248	goto out_fn;
710105fd	249	err = SCSI_DH_NOTCONN;
e959ed9a	250	if (sdev->sdev_state == SDEV_CANCEL \|\|
db422318	251	sdev->sdev_state == SDEV_DEL)
e959ed9a	252	goto out_fn;
a6a8d9f8	253
e959ed9a CH	254	err = SCSI_DH_DEV_OFFLINED;
	255	if (sdev->sdev_state == SDEV_OFFLINE)
	256	goto out_fn;
a6a8d9f8	257
ee14c674 CH	258	if (sdev->handler->activate)
ee14c674 CH	259	err = sdev->handler->activate(sdev, fn, data);
e959ed9a CH	260
	261	out_put_device:
	262	put_device(&sdev->sdev_gendev);
a6a8d9f8	263	return err;
e959ed9a CH	264
	265	out_fn:
	266	if (fn)
	267	fn(data, err);
	268	goto out_put_device;
a6a8d9f8 CS	269	}
	270	EXPORT_SYMBOL_GPL(scsi_dh_activate);
	271
18ee70c9 CS	272	/*
	273	* scsi_dh_set_params - set the parameters for the device as per the
	274	* string specified in params.
	275	* @q - Request queue that is associated with the scsi_device for
	276	* which the parameters to be set.
	277	* @params - parameters in the following format
	278	* "no_of_params\0param1\0param2\0param3\0...\0"
	279	* for example, string for 2 parameters with value 10 and 21
	280	* is specified as "2\010\021\0".
	281	*/
	282	int scsi_dh_set_params(struct request_queue q, const char params)
	283	{
18ee70c9	284	struct scsi_device *sdev;
e959ed9a	285	int err = -SCSI_DH_NOSYS;
18ee70c9	286
857de6e0	287	sdev = scsi_device_from_queue(q);
e959ed9a	288	if (!sdev)
18ee70c9	289	return err;
e959ed9a CH	290
	291	if (sdev->handler && sdev->handler->set_params)
	292	err = sdev->handler->set_params(sdev, params);
18ee70c9 CS	293	put_device(&sdev->sdev_gendev);
	294	return err;
	295	}
	296	EXPORT_SYMBOL_GPL(scsi_dh_set_params);
	297
ae11b1b3	298	/*
2a9ab40f	299	* scsi_dh_attach - Attach device handler
7e8a74b1 MS	300	* @q - Request queue that is associated with the scsi_device
7e8a74b1 MS	301	* the handler should be attached to
ae11b1b3 HR	302	* @name - name of the handler to attach
	303	*/
	304	int scsi_dh_attach(struct request_queue q, const char name)
	305	{
ae11b1b3 HR	306	struct scsi_device *sdev;
	307	struct scsi_device_handler *scsi_dh;
	308	int err = 0;
	309
857de6e0	310	sdev = scsi_device_from_queue(q);
e959ed9a CH	311	if (!sdev)
e959ed9a CH	312	return -ENODEV;
ae11b1b3	313
e959ed9a CH	314	scsi_dh = scsi_dh_lookup(name);
	315	if (!scsi_dh) {
	316	err = -EINVAL;
	317	goto out_put_device;
	318	}
ae11b1b3	319
ee14c674 CH	320	if (sdev->handler) {
ee14c674 CH	321	if (sdev->handler != scsi_dh)
1bab0de0 CH	322	err = -EBUSY;
1bab0de0 CH	323	goto out_put_device;
ae11b1b3	324	}
1bab0de0 CH	325
	326	err = scsi_dh_handler_attach(sdev, scsi_dh);
	327
	328	out_put_device:
ae11b1b3	329	put_device(&sdev->sdev_gendev);
1bab0de0	330	return err;
ae11b1b3	331	}
1bab0de0	332	EXPORT_SYMBOL_GPL(scsi_dh_attach);
ae11b1b3	333
7e8a74b1 MS	334	/*
	335	* scsi_dh_attached_handler_name - Get attached device handler's name
	336	* @q - Request queue that is associated with the scsi_device
	337	* that may have a device handler attached
	338	* @gfp - the GFP mask used in the kmalloc() call when allocating memory
	339	*
	340	* Returns name of attached handler, NULL if no handler is attached.
	341	* Caller must take care to free the returned string.
	342	*/
	343	const char scsi_dh_attached_handler_name(struct request_queue q, gfp_t gfp)
	344	{
7e8a74b1 MS	345	struct scsi_device *sdev;
	346	const char *handler_name = NULL;
	347
857de6e0	348	sdev = scsi_device_from_queue(q);
7e8a74b1 MS	349	if (!sdev)
	350	return NULL;
	351
ee14c674 CH	352	if (sdev->handler)
ee14c674 CH	353	handler_name = kstrdup(sdev->handler->name, gfp);
7e8a74b1 MS	354	put_device(&sdev->sdev_gendev);
	355	return handler_name;
	356	}
	357	EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);