[linux-2.6-block.git] / drivers / scsi / scsi_dh.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * SCSI device handler infrastruture.
 *
 * 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", "TP9300",		"rdac", },
	{"SGI", "TP9400",		"rdac", },
	{"SGI", "TP9500",		"rdac", },
	{"SGI", "TP9700",		"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", },
	{"LENOVO", "DE_Series",		"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
1a59d1b8	1	// SPDX-License-Identifier: GPL-2.0-or-later
a6a8d9f8 CS	2	/*
	3	* SCSI device handler infrastruture.
	4	*
a6a8d9f8 CS	5	* Copyright IBM Corporation, 2007
	6	* Authors:
	7	* Chandra Seetharaman <sekharan@us.ibm.com>
	8	* Mike Anderson <andmike@linux.vnet.ibm.com>
	9	*/
	10
5a0e3ad6	11	#include <linux/slab.h>
acf3368f	12	#include <linux/module.h>
a6a8d9f8	13	#include <scsi/scsi_dh.h>
daaa858b	14	#include "scsi_priv.h"
a6a8d9f8 CS	15
	16	static DEFINE_SPINLOCK(list_lock);
	17	static LIST_HEAD(scsi_dh_list);
	18
d95dbff2 CH	19	struct scsi_dh_blist {
	20	const char *vendor;
	21	const char *model;
	22	const char *driver;
	23	};
	24
	25	static const struct scsi_dh_blist scsi_dh_blist[] = {
0ba43a81 XVP	26	{"DGC", "RAID", "emc" },
	27	{"DGC", "DISK", "emc" },
	28	{"DGC", "VRAID", "emc" },
d95dbff2 CH	29
	30	{"COMPAQ", "MSA1000 VOLUME", "hp_sw" },
	31	{"COMPAQ", "HSV110", "hp_sw" },
	32	{"HP", "HSV100", "hp_sw"},
	33	{"DEC", "HSG80", "hp_sw"},
	34
	35	{"IBM", "1722", "rdac", },
	36	{"IBM", "1724", "rdac", },
	37	{"IBM", "1726", "rdac", },
	38	{"IBM", "1742", "rdac", },
	39	{"IBM", "1745", "rdac", },
	40	{"IBM", "1746", "rdac", },
	41	{"IBM", "1813", "rdac", },
	42	{"IBM", "1814", "rdac", },
	43	{"IBM", "1815", "rdac", },
	44	{"IBM", "1818", "rdac", },
	45	{"IBM", "3526", "rdac", },
4b3aec2b XVP	46	{"IBM", "3542", "rdac", },
4b3aec2b XVP	47	{"IBM", "3552", "rdac", },
37b37d26 XVP	48	{"SGI", "TP9300", "rdac", },
	49	{"SGI", "TP9400", "rdac", },
	50	{"SGI", "TP9500", "rdac", },
	51	{"SGI", "TP9700", "rdac", },
d95dbff2	52	{"SGI", "IS", "rdac", },
4b3aec2b	53	{"STK", "OPENstorage", "rdac", },
d95dbff2	54	{"STK", "FLEXLINE 380", "rdac", },
4b3aec2b	55	{"STK", "BladeCtlr", "rdac", },
d95dbff2 CH	56	{"SUN", "CSM", "rdac", },
	57	{"SUN", "LCSM100", "rdac", },
	58	{"SUN", "STK6580_6780", "rdac", },
	59	{"SUN", "SUN_6180", "rdac", },
	60	{"SUN", "ArrayStorage", "rdac", },
	61	{"DELL", "MD3", "rdac", },
	62	{"NETAPP", "INF-01-00", "rdac", },
	63	{"LSI", "INF-01-00", "rdac", },
	64	{"ENGENIO", "INF-01-00", "rdac", },
1cb1d2c6	65	{"LENOVO", "DE_Series", "rdac", },
d95dbff2 CH	66	{NULL, NULL, NULL },
	67	};
	68
	69	static const char *
	70	scsi_dh_find_driver(struct scsi_device *sdev)
	71	{
	72	const struct scsi_dh_blist *b;
	73
	74	if (scsi_device_tpgs(sdev))
	75	return "alua";
	76
	77	for (b = scsi_dh_blist; b->vendor; b++) {
	78	if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
	79	!strncmp(sdev->model, b->model, strlen(b->model))) {
	80	return b->driver;
	81	}
	82	}
	83	return NULL;
	84	}
	85
	86
566079c8	87	static struct scsi_device_handler __scsi_dh_lookup(const char name)
a6a8d9f8 CS	88	{
	89	struct scsi_device_handler tmp, found = NULL;
	90
	91	spin_lock(&list_lock);
	92	list_for_each_entry(tmp, &scsi_dh_list, list) {
765cbc6d	93	if (!strncmp(tmp->name, name, strlen(tmp->name))) {
a6a8d9f8 CS	94	found = tmp;
	95	break;
	96	}
	97	}
	98	spin_unlock(&list_lock);
	99	return found;
	100	}
	101
566079c8 CH	102	static struct scsi_device_handler scsi_dh_lookup(const char name)
	103	{
	104	struct scsi_device_handler *dh;
	105
2ee5671e JT	106	if (!name \|\| strlen(name) == 0)
	107	return NULL;
	108
566079c8 CH	109	dh = __scsi_dh_lookup(name);
566079c8 CH	110	if (!dh) {
1378889c	111	request_module("scsi_dh_%s", name);
566079c8 CH	112	dh = __scsi_dh_lookup(name);
	113	}
	114
	115	return dh;
	116	}
	117
a6a8d9f8	118	/*
765cbc6d HR	119	* scsi_dh_handler_attach - Attach a device handler to a device
	120	* @sdev - SCSI device the device handler should attach to
	121	* @scsi_dh - The device handler to attach
	122	*/
	123	static int scsi_dh_handler_attach(struct scsi_device *sdev,
	124	struct scsi_device_handler *scsi_dh)
	125	{
2a8f7a03	126	int error, ret = 0;
765cbc6d	127
1f12ffa5 CH	128	if (!try_module_get(scsi_dh->module))
1f12ffa5 CH	129	return -EINVAL;
27c888f0	130
ee14c674	131	error = scsi_dh->attach(sdev);
2a8f7a03 HR	132	if (error != SCSI_DH_OK) {
	133	switch (error) {
	134	case SCSI_DH_NOMEM:
	135	ret = -ENOMEM;
	136	break;
	137	case SCSI_DH_RES_TEMP_UNAVAIL:
	138	ret = -EAGAIN;
	139	break;
2930f817 HR	140	case SCSI_DH_DEV_UNSUPP:
	141	case SCSI_DH_NOSYS:
	142	ret = -ENODEV;
	143	break;
2a8f7a03 HR	144	default:
	145	ret = -EINVAL;
	146	break;
	147	}
2930f817 HR	148	if (ret != -ENODEV)
	149	sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
	150	scsi_dh->name, error);
1f12ffa5	151	module_put(scsi_dh->module);
ee14c674 CH	152	} else
ee14c674 CH	153	sdev->handler = scsi_dh;
1d520328	154
2a8f7a03	155	return ret;
765cbc6d HR	156	}
765cbc6d HR	157
1bab0de0 CH	158	/*
	159	* scsi_dh_handler_detach - Detach a device handler from a device
	160	* @sdev - SCSI device the device handler should be detached from
	161	*/
	162	static void scsi_dh_handler_detach(struct scsi_device *sdev)
6c10db72	163	{
ee14c674 CH	164	sdev->handler->detach(sdev);
	165	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
	166	module_put(sdev->handler->module);
6c10db72 CS	167	}
6c10db72 CS	168
2930f817	169	void scsi_dh_add_device(struct scsi_device *sdev)
4c05ae52	170	{
d95dbff2 CH	171	struct scsi_device_handler *devinfo = NULL;
d95dbff2 CH	172	const char *drv;
4c05ae52	173
d95dbff2 CH	174	drv = scsi_dh_find_driver(sdev);
d95dbff2 CH	175	if (drv)
d6a32b98	176	devinfo = __scsi_dh_lookup(drv);
2930f817 HR	177	/*
	178	* device_handler is optional, so ignore errors
	179	* from scsi_dh_handler_attach()
	180	*/
086b91d0	181	if (devinfo)
2930f817	182	(void)scsi_dh_handler_attach(sdev, devinfo);
a6a8d9f8	183	}
a6a8d9f8	184
23695e41	185	void scsi_dh_release_device(struct scsi_device *sdev)
765cbc6d	186	{
ee14c674	187	if (sdev->handler)
1bab0de0	188	scsi_dh_handler_detach(sdev);
23695e41 JN	189	}
23695e41 JN	190
765cbc6d HR	191	/*
	192	* scsi_register_device_handler - register a device handler personality
	193	* module.
	194	* @scsi_dh - device handler to be registered.
	195	*
	196	* Returns 0 on success, -EBUSY if handler already registered.
	197	*/
	198	int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
	199	{
566079c8	200	if (__scsi_dh_lookup(scsi_dh->name))
765cbc6d HR	201	return -EBUSY;
765cbc6d HR	202
1f12ffa5 CH	203	if (!scsi_dh->attach \|\| !scsi_dh->detach)
	204	return -EINVAL;
	205
765cbc6d HR	206	spin_lock(&list_lock);
	207	list_add(&scsi_dh->list, &scsi_dh_list);
	208	spin_unlock(&list_lock);
940d7faa	209
765cbc6d HR	210	printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
	211
	212	return SCSI_DH_OK;
	213	}
	214	EXPORT_SYMBOL_GPL(scsi_register_device_handler);
	215
a6a8d9f8 CS	216	/*
	217	* scsi_unregister_device_handler - register a device handler personality
	218	* module.
	219	* @scsi_dh - device handler to be unregistered.
	220	*
	221	* Returns 0 on success, -ENODEV if handler not registered.
	222	*/
	223	int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
	224	{
566079c8	225	if (!__scsi_dh_lookup(scsi_dh->name))
765cbc6d	226	return -ENODEV;
a6a8d9f8	227
a6a8d9f8 CS	228	spin_lock(&list_lock);
	229	list_del(&scsi_dh->list);
	230	spin_unlock(&list_lock);
765cbc6d	231	printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
a6a8d9f8	232
765cbc6d	233	return SCSI_DH_OK;
a6a8d9f8 CS	234	}
	235	EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
	236
	237	/*
	238	* scsi_dh_activate - activate the path associated with the scsi_device
	239	* corresponding to the given request queue.
3ae31f6a CS	240	* Returns immediately without waiting for activation to be completed.
	241	* @q - Request queue that is associated with the scsi_device to be
	242	* activated.
	243	* @fn - Function to be called upon completion of the activation.
	244	* Function fn is called with data (below) and the error code.
	245	* Function fn may be called from the same calling context. So,
	246	* do not hold the lock in the caller which may be needed in fn.
	247	* @data - data passed to the function fn upon completion.
	248	*
a6a8d9f8	249	*/
3ae31f6a	250	int scsi_dh_activate(struct request_queue q, activate_complete fn, void data)
a6a8d9f8	251	{
a6a8d9f8	252	struct scsi_device *sdev;
e959ed9a	253	int err = SCSI_DH_NOSYS;
a6a8d9f8	254
857de6e0	255	sdev = scsi_device_from_queue(q);
a18a920c	256	if (!sdev) {
a18a920c MB	257	if (fn)
	258	fn(data, err);
	259	return err;
	260	}
	261
e959ed9a CH	262	if (!sdev->handler)
e959ed9a CH	263	goto out_fn;
710105fd	264	err = SCSI_DH_NOTCONN;
e959ed9a	265	if (sdev->sdev_state == SDEV_CANCEL \|\|
db422318	266	sdev->sdev_state == SDEV_DEL)
e959ed9a	267	goto out_fn;
a6a8d9f8	268
e959ed9a CH	269	err = SCSI_DH_DEV_OFFLINED;
	270	if (sdev->sdev_state == SDEV_OFFLINE)
	271	goto out_fn;
a6a8d9f8	272
ee14c674 CH	273	if (sdev->handler->activate)
ee14c674 CH	274	err = sdev->handler->activate(sdev, fn, data);
e959ed9a CH	275
	276	out_put_device:
	277	put_device(&sdev->sdev_gendev);
a6a8d9f8	278	return err;
e959ed9a CH	279
	280	out_fn:
	281	if (fn)
	282	fn(data, err);
	283	goto out_put_device;
a6a8d9f8 CS	284	}
	285	EXPORT_SYMBOL_GPL(scsi_dh_activate);
	286
18ee70c9 CS	287	/*
	288	* scsi_dh_set_params - set the parameters for the device as per the
	289	* string specified in params.
	290	* @q - Request queue that is associated with the scsi_device for
	291	* which the parameters to be set.
	292	* @params - parameters in the following format
	293	* "no_of_params\0param1\0param2\0param3\0...\0"
	294	* for example, string for 2 parameters with value 10 and 21
	295	* is specified as "2\010\021\0".
	296	*/
	297	int scsi_dh_set_params(struct request_queue q, const char params)
	298	{
18ee70c9	299	struct scsi_device *sdev;
e959ed9a	300	int err = -SCSI_DH_NOSYS;
18ee70c9	301
857de6e0	302	sdev = scsi_device_from_queue(q);
e959ed9a	303	if (!sdev)
18ee70c9	304	return err;
e959ed9a CH	305
	306	if (sdev->handler && sdev->handler->set_params)
	307	err = sdev->handler->set_params(sdev, params);
18ee70c9 CS	308	put_device(&sdev->sdev_gendev);
	309	return err;
	310	}
	311	EXPORT_SYMBOL_GPL(scsi_dh_set_params);
	312
ae11b1b3	313	/*
2a9ab40f	314	* scsi_dh_attach - Attach device handler
7e8a74b1 MS	315	* @q - Request queue that is associated with the scsi_device
7e8a74b1 MS	316	* the handler should be attached to
ae11b1b3 HR	317	* @name - name of the handler to attach
	318	*/
	319	int scsi_dh_attach(struct request_queue q, const char name)
	320	{
ae11b1b3 HR	321	struct scsi_device *sdev;
	322	struct scsi_device_handler *scsi_dh;
	323	int err = 0;
	324
857de6e0	325	sdev = scsi_device_from_queue(q);
e959ed9a CH	326	if (!sdev)
e959ed9a CH	327	return -ENODEV;
ae11b1b3	328
e959ed9a CH	329	scsi_dh = scsi_dh_lookup(name);
	330	if (!scsi_dh) {
	331	err = -EINVAL;
	332	goto out_put_device;
	333	}
ae11b1b3	334
ee14c674 CH	335	if (sdev->handler) {
ee14c674 CH	336	if (sdev->handler != scsi_dh)
1bab0de0 CH	337	err = -EBUSY;
1bab0de0 CH	338	goto out_put_device;
ae11b1b3	339	}
1bab0de0 CH	340
	341	err = scsi_dh_handler_attach(sdev, scsi_dh);
	342
	343	out_put_device:
ae11b1b3	344	put_device(&sdev->sdev_gendev);
1bab0de0	345	return err;
ae11b1b3	346	}
1bab0de0	347	EXPORT_SYMBOL_GPL(scsi_dh_attach);
ae11b1b3	348
7e8a74b1 MS	349	/*
	350	* scsi_dh_attached_handler_name - Get attached device handler's name
	351	* @q - Request queue that is associated with the scsi_device
	352	* that may have a device handler attached
	353	* @gfp - the GFP mask used in the kmalloc() call when allocating memory
	354	*
	355	* Returns name of attached handler, NULL if no handler is attached.
	356	* Caller must take care to free the returned string.
	357	*/
	358	const char scsi_dh_attached_handler_name(struct request_queue q, gfp_t gfp)
	359	{
7e8a74b1 MS	360	struct scsi_device *sdev;
	361	const char *handler_name = NULL;
	362
857de6e0	363	sdev = scsi_device_from_queue(q);
7e8a74b1 MS	364	if (!sdev)
	365	return NULL;
	366
ee14c674 CH	367	if (sdev->handler)
ee14c674 CH	368	handler_name = kstrdup(sdev->handler->name, gfp);
7e8a74b1 MS	369	put_device(&sdev->sdev_gendev);
	370	return handler_name;
	371	}
	372	EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);