[linux-2.6-block.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", },
	{"IBM", "3542",			"rdac", },
	{"IBM", "3552",			"rdac", },
	{"SGI", "TP9",			"rdac", },
	{"SGI", "IS",			"rdac", },
	{"STK", "OPENstorage",		"rdac", },
	{"STK", "FLEXLINE 380",		"rdac", },
	{"STK", "BladeCtlr",		"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;

	if (!name || strlen(name) == 0)
		return NULL;

	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, ret = 0;

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

	error = scsi_dh->attach(sdev);
	if (error != SCSI_DH_OK) {
		switch (error) {
		case SCSI_DH_NOMEM:
			ret = -ENOMEM;
			break;
		case SCSI_DH_RES_TEMP_UNAVAIL:
			ret = -EAGAIN;
			break;
		case SCSI_DH_DEV_UNSUPP:
		case SCSI_DH_NOSYS:
			ret = -ENODEV;
			break;
		default:
			ret = -EINVAL;
			break;
		}
		if (ret != -ENODEV)
			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 ret;
}

/*
 * 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);
}

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

	drv = scsi_dh_find_driver(sdev);
	if (drv)
		devinfo = __scsi_dh_lookup(drv);
	/*
	 * device_handler is optional, so ignore errors
	 * from scsi_dh_handler_attach()
	 */
	if (devinfo)
		(void)scsi_dh_handler_attach(sdev, devinfo);
}

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", },
4b3aec2b XVP	59	{"IBM", "3542", "rdac", },
4b3aec2b XVP	60	{"IBM", "3552", "rdac", },
d95dbff2 CH	61	{"SGI", "TP9", "rdac", },
d95dbff2 CH	62	{"SGI", "IS", "rdac", },
4b3aec2b	63	{"STK", "OPENstorage", "rdac", },
d95dbff2	64	{"STK", "FLEXLINE 380", "rdac", },
4b3aec2b	65	{"STK", "BladeCtlr", "rdac", },
d95dbff2 CH	66	{"SUN", "CSM", "rdac", },
	67	{"SUN", "LCSM100", "rdac", },
	68	{"SUN", "STK6580_6780", "rdac", },
	69	{"SUN", "SUN_6180", "rdac", },
	70	{"SUN", "ArrayStorage", "rdac", },
	71	{"DELL", "MD3", "rdac", },
	72	{"NETAPP", "INF-01-00", "rdac", },
	73	{"LSI", "INF-01-00", "rdac", },
	74	{"ENGENIO", "INF-01-00", "rdac", },
	75	{NULL, NULL, NULL },
	76	};
	77
	78	static const char *
	79	scsi_dh_find_driver(struct scsi_device *sdev)
	80	{
	81	const struct scsi_dh_blist *b;
	82
	83	if (scsi_device_tpgs(sdev))
	84	return "alua";
	85
	86	for (b = scsi_dh_blist; b->vendor; b++) {
	87	if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
	88	!strncmp(sdev->model, b->model, strlen(b->model))) {
	89	return b->driver;
	90	}
	91	}
	92	return NULL;
	93	}
	94
	95
566079c8	96	static struct scsi_device_handler __scsi_dh_lookup(const char name)
a6a8d9f8 CS	97	{
	98	struct scsi_device_handler tmp, found = NULL;
	99
	100	spin_lock(&list_lock);
	101	list_for_each_entry(tmp, &scsi_dh_list, list) {
765cbc6d	102	if (!strncmp(tmp->name, name, strlen(tmp->name))) {
a6a8d9f8 CS	103	found = tmp;
	104	break;
	105	}
	106	}
	107	spin_unlock(&list_lock);
	108	return found;
	109	}
	110
566079c8 CH	111	static struct scsi_device_handler scsi_dh_lookup(const char name)
	112	{
	113	struct scsi_device_handler *dh;
	114
2ee5671e JT	115	if (!name \|\| strlen(name) == 0)
	116	return NULL;
	117
566079c8 CH	118	dh = __scsi_dh_lookup(name);
566079c8 CH	119	if (!dh) {
1378889c	120	request_module("scsi_dh_%s", name);
566079c8 CH	121	dh = __scsi_dh_lookup(name);
	122	}
	123
	124	return dh;
	125	}
	126
a6a8d9f8	127	/*
765cbc6d HR	128	* scsi_dh_handler_attach - Attach a device handler to a device
	129	* @sdev - SCSI device the device handler should attach to
	130	* @scsi_dh - The device handler to attach
	131	*/
	132	static int scsi_dh_handler_attach(struct scsi_device *sdev,
	133	struct scsi_device_handler *scsi_dh)
	134	{
2a8f7a03	135	int error, ret = 0;
765cbc6d	136
1f12ffa5 CH	137	if (!try_module_get(scsi_dh->module))
1f12ffa5 CH	138	return -EINVAL;
27c888f0	139
ee14c674	140	error = scsi_dh->attach(sdev);
2a8f7a03 HR	141	if (error != SCSI_DH_OK) {
	142	switch (error) {
	143	case SCSI_DH_NOMEM:
	144	ret = -ENOMEM;
	145	break;
	146	case SCSI_DH_RES_TEMP_UNAVAIL:
	147	ret = -EAGAIN;
	148	break;
2930f817 HR	149	case SCSI_DH_DEV_UNSUPP:
	150	case SCSI_DH_NOSYS:
	151	ret = -ENODEV;
	152	break;
2a8f7a03 HR	153	default:
	154	ret = -EINVAL;
	155	break;
	156	}
2930f817 HR	157	if (ret != -ENODEV)
	158	sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
	159	scsi_dh->name, error);
1f12ffa5	160	module_put(scsi_dh->module);
ee14c674 CH	161	} else
ee14c674 CH	162	sdev->handler = scsi_dh;
1d520328	163
2a8f7a03	164	return ret;
765cbc6d HR	165	}
765cbc6d HR	166
1bab0de0 CH	167	/*
	168	* scsi_dh_handler_detach - Detach a device handler from a device
	169	* @sdev - SCSI device the device handler should be detached from
	170	*/
	171	static void scsi_dh_handler_detach(struct scsi_device *sdev)
6c10db72	172	{
ee14c674 CH	173	sdev->handler->detach(sdev);
	174	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
	175	module_put(sdev->handler->module);
6c10db72 CS	176	}
6c10db72 CS	177
2930f817	178	void scsi_dh_add_device(struct scsi_device *sdev)
4c05ae52	179	{
d95dbff2 CH	180	struct scsi_device_handler *devinfo = NULL;
d95dbff2 CH	181	const char *drv;
4c05ae52	182
d95dbff2 CH	183	drv = scsi_dh_find_driver(sdev);
d95dbff2 CH	184	if (drv)
d6a32b98	185	devinfo = __scsi_dh_lookup(drv);
2930f817 HR	186	/*
	187	* device_handler is optional, so ignore errors
	188	* from scsi_dh_handler_attach()
	189	*/
086b91d0	190	if (devinfo)
2930f817	191	(void)scsi_dh_handler_attach(sdev, devinfo);
a6a8d9f8	192	}
a6a8d9f8	193
23695e41	194	void scsi_dh_release_device(struct scsi_device *sdev)
765cbc6d	195	{
ee14c674	196	if (sdev->handler)
1bab0de0	197	scsi_dh_handler_detach(sdev);
23695e41 JN	198	}
23695e41 JN	199
765cbc6d HR	200	/*
	201	* scsi_register_device_handler - register a device handler personality
	202	* module.
	203	* @scsi_dh - device handler to be registered.
	204	*
	205	* Returns 0 on success, -EBUSY if handler already registered.
	206	*/
	207	int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
	208	{
566079c8	209	if (__scsi_dh_lookup(scsi_dh->name))
765cbc6d HR	210	return -EBUSY;
765cbc6d HR	211
1f12ffa5 CH	212	if (!scsi_dh->attach \|\| !scsi_dh->detach)
	213	return -EINVAL;
	214
765cbc6d HR	215	spin_lock(&list_lock);
	216	list_add(&scsi_dh->list, &scsi_dh_list);
	217	spin_unlock(&list_lock);
940d7faa	218
765cbc6d HR	219	printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
	220
	221	return SCSI_DH_OK;
	222	}
	223	EXPORT_SYMBOL_GPL(scsi_register_device_handler);
	224
a6a8d9f8 CS	225	/*
	226	* scsi_unregister_device_handler - register a device handler personality
	227	* module.
	228	* @scsi_dh - device handler to be unregistered.
	229	*
	230	* Returns 0 on success, -ENODEV if handler not registered.
	231	*/
	232	int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
	233	{
566079c8	234	if (!__scsi_dh_lookup(scsi_dh->name))
765cbc6d	235	return -ENODEV;
a6a8d9f8	236
a6a8d9f8 CS	237	spin_lock(&list_lock);
	238	list_del(&scsi_dh->list);
	239	spin_unlock(&list_lock);
765cbc6d	240	printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
a6a8d9f8	241
765cbc6d	242	return SCSI_DH_OK;
a6a8d9f8 CS	243	}
	244	EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
	245
	246	/*
	247	* scsi_dh_activate - activate the path associated with the scsi_device
	248	* corresponding to the given request queue.
3ae31f6a CS	249	* Returns immediately without waiting for activation to be completed.
	250	* @q - Request queue that is associated with the scsi_device to be
	251	* activated.
	252	* @fn - Function to be called upon completion of the activation.
	253	* Function fn is called with data (below) and the error code.
	254	* Function fn may be called from the same calling context. So,
	255	* do not hold the lock in the caller which may be needed in fn.
	256	* @data - data passed to the function fn upon completion.
	257	*
a6a8d9f8	258	*/
3ae31f6a	259	int scsi_dh_activate(struct request_queue q, activate_complete fn, void data)
a6a8d9f8	260	{
a6a8d9f8	261	struct scsi_device *sdev;
e959ed9a	262	int err = SCSI_DH_NOSYS;
a6a8d9f8	263
857de6e0	264	sdev = scsi_device_from_queue(q);
a18a920c	265	if (!sdev) {
a18a920c MB	266	if (fn)
	267	fn(data, err);
	268	return err;
	269	}
	270
e959ed9a CH	271	if (!sdev->handler)
e959ed9a CH	272	goto out_fn;
710105fd	273	err = SCSI_DH_NOTCONN;
e959ed9a	274	if (sdev->sdev_state == SDEV_CANCEL \|\|
db422318	275	sdev->sdev_state == SDEV_DEL)
e959ed9a	276	goto out_fn;
a6a8d9f8	277
e959ed9a CH	278	err = SCSI_DH_DEV_OFFLINED;
	279	if (sdev->sdev_state == SDEV_OFFLINE)
	280	goto out_fn;
a6a8d9f8	281
ee14c674 CH	282	if (sdev->handler->activate)
ee14c674 CH	283	err = sdev->handler->activate(sdev, fn, data);
e959ed9a CH	284
	285	out_put_device:
	286	put_device(&sdev->sdev_gendev);
a6a8d9f8	287	return err;
e959ed9a CH	288
	289	out_fn:
	290	if (fn)
	291	fn(data, err);
	292	goto out_put_device;
a6a8d9f8 CS	293	}
	294	EXPORT_SYMBOL_GPL(scsi_dh_activate);
	295
18ee70c9 CS	296	/*
	297	* scsi_dh_set_params - set the parameters for the device as per the
	298	* string specified in params.
	299	* @q - Request queue that is associated with the scsi_device for
	300	* which the parameters to be set.
	301	* @params - parameters in the following format
	302	* "no_of_params\0param1\0param2\0param3\0...\0"
	303	* for example, string for 2 parameters with value 10 and 21
	304	* is specified as "2\010\021\0".
	305	*/
	306	int scsi_dh_set_params(struct request_queue q, const char params)
	307	{
18ee70c9	308	struct scsi_device *sdev;
e959ed9a	309	int err = -SCSI_DH_NOSYS;
18ee70c9	310
857de6e0	311	sdev = scsi_device_from_queue(q);
e959ed9a	312	if (!sdev)
18ee70c9	313	return err;
e959ed9a CH	314
	315	if (sdev->handler && sdev->handler->set_params)
	316	err = sdev->handler->set_params(sdev, params);
18ee70c9 CS	317	put_device(&sdev->sdev_gendev);
	318	return err;
	319	}
	320	EXPORT_SYMBOL_GPL(scsi_dh_set_params);
	321
ae11b1b3	322	/*
2a9ab40f	323	* scsi_dh_attach - Attach device handler
7e8a74b1 MS	324	* @q - Request queue that is associated with the scsi_device
7e8a74b1 MS	325	* the handler should be attached to
ae11b1b3 HR	326	* @name - name of the handler to attach
	327	*/
	328	int scsi_dh_attach(struct request_queue q, const char name)
	329	{
ae11b1b3 HR	330	struct scsi_device *sdev;
	331	struct scsi_device_handler *scsi_dh;
	332	int err = 0;
	333
857de6e0	334	sdev = scsi_device_from_queue(q);
e959ed9a CH	335	if (!sdev)
e959ed9a CH	336	return -ENODEV;
ae11b1b3	337
e959ed9a CH	338	scsi_dh = scsi_dh_lookup(name);
	339	if (!scsi_dh) {
	340	err = -EINVAL;
	341	goto out_put_device;
	342	}
ae11b1b3	343
ee14c674 CH	344	if (sdev->handler) {
ee14c674 CH	345	if (sdev->handler != scsi_dh)
1bab0de0 CH	346	err = -EBUSY;
1bab0de0 CH	347	goto out_put_device;
ae11b1b3	348	}
1bab0de0 CH	349
	350	err = scsi_dh_handler_attach(sdev, scsi_dh);
	351
	352	out_put_device:
ae11b1b3	353	put_device(&sdev->sdev_gendev);
1bab0de0	354	return err;
ae11b1b3	355	}
1bab0de0	356	EXPORT_SYMBOL_GPL(scsi_dh_attach);
ae11b1b3	357
7e8a74b1 MS	358	/*
	359	* scsi_dh_attached_handler_name - Get attached device handler's name
	360	* @q - Request queue that is associated with the scsi_device
	361	* that may have a device handler attached
	362	* @gfp - the GFP mask used in the kmalloc() call when allocating memory
	363	*
	364	* Returns name of attached handler, NULL if no handler is attached.
	365	* Caller must take care to free the returned string.
	366	*/
	367	const char scsi_dh_attached_handler_name(struct request_queue q, gfp_t gfp)
	368	{
7e8a74b1 MS	369	struct scsi_device *sdev;
	370	const char *handler_name = NULL;
	371
857de6e0	372	sdev = scsi_device_from_queue(q);
7e8a74b1 MS	373	if (!sdev)
	374	return NULL;
	375
ee14c674 CH	376	if (sdev->handler)
ee14c674 CH	377	handler_name = kstrdup(sdev->handler->name, gfp);
7e8a74b1 MS	378	put_device(&sdev->sdev_gendev);
	379	return handler_name;
	380	}
	381	EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);