diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
index 91209e3..22f54b0 100644
--- a/drivers/scsi/Makefile
+++ b/drivers/scsi/Makefile
@@ -171,6 +171,7 @@ scsi_mod-$(CONFIG_SYSCTL)	+= scsi_sysctl.o
 scsi_mod-$(CONFIG_SCSI_PROC_FS)	+= scsi_proc.o
 scsi_mod-y			+= scsi_trace.o scsi_logging.o
 scsi_mod-$(CONFIG_PM)		+= scsi_pm.o
+obj-$(CONFIG_SCSI_DH)		+= scsi_dh.o
 
 hv_storvsc-y			:= storvsc_drv.o
 
diff --git a/drivers/scsi/device_handler/Makefile b/drivers/scsi/device_handler/Makefile
index e1d2ea0..09866c5 100644
--- a/drivers/scsi/device_handler/Makefile
+++ b/drivers/scsi/device_handler/Makefile
@@ -1,7 +1,6 @@
 #
 # SCSI Device Handler
 #
-obj-$(CONFIG_SCSI_DH)		+= scsi_dh.o
 obj-$(CONFIG_SCSI_DH_RDAC)	+= scsi_dh_rdac.o
 obj-$(CONFIG_SCSI_DH_HP_SW)	+= scsi_dh_hp_sw.o
 obj-$(CONFIG_SCSI_DH_EMC)	+= scsi_dh_emc.o
diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
deleted file mode 100644
index 5bd0af6..0000000
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ /dev/null
@@ -1,570 +0,0 @@
-/*
- * 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);
-
-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(name);
-		dh = __scsi_dh_lookup(name);
-	}
-
-	return dh;
-}
-
-/*
- * device_handler_match_function - Match a device handler to a device
- * @sdev - SCSI device to be tested
- *
- * Tests @sdev against the match function of all registered device_handler.
- * Returns the found device handler or NULL if not found.
- */
-static struct scsi_device_handler *
-device_handler_match_function(struct scsi_device *sdev)
-{
-	struct scsi_device_handler *tmp_dh, *found_dh = NULL;
-
-	spin_lock(&list_lock);
-	list_for_each_entry(tmp_dh, &scsi_dh_list, list) {
-		if (tmp_dh->match && tmp_dh->match(sdev)) {
-			found_dh = tmp_dh;
-			break;
-		}
-	}
-	spin_unlock(&list_lock);
-	return found_dh;
-}
-
-/*
- * device_handler_match - Attach a device handler to a device
- * @scsi_dh - The device handler to match against or NULL
- * @sdev - SCSI device to be tested against @scsi_dh
- *
- * Tests @sdev against the device handler @scsi_dh or against
- * all registered device_handler if @scsi_dh == NULL.
- * Returns the found device handler or NULL if not found.
- */
-static struct scsi_device_handler *
-device_handler_match(struct scsi_device_handler *scsi_dh,
-		     struct scsi_device *sdev)
-{
-	struct scsi_device_handler *found_dh;
-
-	found_dh = device_handler_match_function(sdev);
-
-	if (scsi_dh && found_dh != scsi_dh)
-		found_dh = NULL;
-
-	return found_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)
-{
-	struct scsi_dh_data *d;
-
-	if (!try_module_get(scsi_dh->module))
-		return -EINVAL;
-
-	d = scsi_dh->attach(sdev);
-	if (IS_ERR(d)) {
-		sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%ld)\n",
-			    scsi_dh->name, PTR_ERR(d));
-		module_put(scsi_dh->module);
-		return PTR_ERR(d);
-	}
-
-	d->scsi_dh = scsi_dh;
-	d->sdev = sdev;
-
-	spin_lock_irq(sdev->request_queue->queue_lock);
-	sdev->scsi_dh_data = d;
-	spin_unlock_irq(sdev->request_queue->queue_lock);
-	return 0;
-}
-
-/*
- * 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)
-{
-	struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
-	struct scsi_device_handler *scsi_dh = scsi_dh_data->scsi_dh;
-
-	scsi_dh->detach(sdev);
-
-	spin_lock_irq(sdev->request_queue->queue_lock);
-	sdev->scsi_dh_data = NULL;
-	spin_unlock_irq(sdev->request_queue->queue_lock);
-
-	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", scsi_dh->name);
-	module_put(scsi_dh->module);
-}
-
-/*
- * Functions for sysfs attribute 'dh_state'
- */
-static ssize_t
-store_dh_state(struct device *dev, struct device_attribute *attr,
-	       const char *buf, size_t count)
-{
-	struct scsi_device *sdev = to_scsi_device(dev);
-	struct scsi_device_handler *scsi_dh;
-	int err = -EINVAL;
-
-	if (sdev->sdev_state == SDEV_CANCEL ||
-	    sdev->sdev_state == SDEV_DEL)
-		return -ENODEV;
-
-	if (!sdev->scsi_dh_data) {
-		/*
-		 * Attach to a device handler
-		 */
-		if (!(scsi_dh = scsi_dh_lookup(buf)))
-			return err;
-		err = scsi_dh_handler_attach(sdev, scsi_dh);
-	} else {
-		scsi_dh = sdev->scsi_dh_data->scsi_dh;
-		if (!strncmp(buf, "detach", 6)) {
-			/*
-			 * Detach from a device handler
-			 */
-			scsi_dh_handler_detach(sdev);
-			err = 0;
-		} else if (!strncmp(buf, "activate", 8)) {
-			/*
-			 * Activate a device handler
-			 */
-			if (scsi_dh->activate)
-				err = scsi_dh->activate(sdev, NULL, NULL);
-			else
-				err = 0;
-		}
-	}
-
-	return err<0?err:count;
-}
-
-static ssize_t
-show_dh_state(struct device *dev, struct device_attribute *attr, char *buf)
-{
-	struct scsi_device *sdev = to_scsi_device(dev);
-
-	if (!sdev->scsi_dh_data)
-		return snprintf(buf, 20, "detached\n");
-
-	return snprintf(buf, 20, "%s\n", sdev->scsi_dh_data->scsi_dh->name);
-}
-
-static struct device_attribute scsi_dh_state_attr =
-	__ATTR(dh_state, S_IRUGO | S_IWUSR, show_dh_state,
-	       store_dh_state);
-
-/*
- * scsi_dh_sysfs_attr_add - Callback for scsi_init_dh
- */
-static int scsi_dh_sysfs_attr_add(struct device *dev, void *data)
-{
-	struct scsi_device *sdev;
-	int err;
-
-	if (!scsi_is_sdev_device(dev))
-		return 0;
-
-	sdev = to_scsi_device(dev);
-
-	err = device_create_file(&sdev->sdev_gendev,
-				 &scsi_dh_state_attr);
-
-	return 0;
-}
-
-/*
- * scsi_dh_sysfs_attr_remove - Callback for scsi_exit_dh
- */
-static int scsi_dh_sysfs_attr_remove(struct device *dev, void *data)
-{
-	struct scsi_device *sdev;
-
-	if (!scsi_is_sdev_device(dev))
-		return 0;
-
-	sdev = to_scsi_device(dev);
-
-	device_remove_file(&sdev->sdev_gendev,
-			   &scsi_dh_state_attr);
-
-	return 0;
-}
-
-/*
- * scsi_dh_notifier - notifier chain callback
- */
-static int scsi_dh_notifier(struct notifier_block *nb,
-			    unsigned long action, void *data)
-{
-	struct device *dev = data;
-	struct scsi_device *sdev;
-	int err = 0;
-	struct scsi_device_handler *devinfo = NULL;
-
-	if (!scsi_is_sdev_device(dev))
-		return 0;
-
-	sdev = to_scsi_device(dev);
-
-	if (action == BUS_NOTIFY_ADD_DEVICE) {
-		err = device_create_file(dev, &scsi_dh_state_attr);
-		/* don't care about err */
-		devinfo = device_handler_match(NULL, sdev);
-		if (devinfo)
-			err = scsi_dh_handler_attach(sdev, devinfo);
-	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
-		device_remove_file(dev, &scsi_dh_state_attr);
-		if (sdev->scsi_dh_data)
-			scsi_dh_handler_detach(sdev);
-	}
-	return err;
-}
-
-/*
- * scsi_dh_notifier_add - Callback for scsi_register_device_handler
- */
-static int scsi_dh_notifier_add(struct device *dev, void *data)
-{
-	struct scsi_device_handler *scsi_dh = data;
-	struct scsi_device *sdev;
-
-	if (!scsi_is_sdev_device(dev))
-		return 0;
-
-	if (!get_device(dev))
-		return 0;
-
-	sdev = to_scsi_device(dev);
-
-	if (device_handler_match(scsi_dh, sdev))
-		scsi_dh_handler_attach(sdev, scsi_dh);
-
-	put_device(dev);
-
-	return 0;
-}
-
-/*
- * scsi_dh_notifier_remove - Callback for scsi_unregister_device_handler
- */
-static int scsi_dh_notifier_remove(struct device *dev, void *data)
-{
-	struct scsi_device_handler *scsi_dh = data;
-	struct scsi_device *sdev;
-
-	if (!scsi_is_sdev_device(dev))
-		return 0;
-
-	if (!get_device(dev))
-		return 0;
-
-	sdev = to_scsi_device(dev);
-
-	if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh == scsi_dh)
-		scsi_dh_handler_detach(sdev);
-
-	put_device(dev);
-
-	return 0;
-}
-
-/*
- * 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);
-
-	bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh, scsi_dh_notifier_add);
-	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;
-
-	bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh,
-			 scsi_dh_notifier_remove);
-
-	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)
-{
-	int err = 0;
-	unsigned long flags;
-	struct scsi_device *sdev;
-	struct scsi_device_handler *scsi_dh = NULL;
-	struct device *dev = NULL;
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	sdev = q->queuedata;
-	if (!sdev) {
-		spin_unlock_irqrestore(q->queue_lock, flags);
-		err = SCSI_DH_NOSYS;
-		if (fn)
-			fn(data, err);
-		return err;
-	}
-
-	if (sdev->scsi_dh_data)
-		scsi_dh = sdev->scsi_dh_data->scsi_dh;
-	dev = get_device(&sdev->sdev_gendev);
-	if (!scsi_dh || !dev ||
-	    sdev->sdev_state == SDEV_CANCEL ||
-	    sdev->sdev_state == SDEV_DEL)
-		err = SCSI_DH_NOSYS;
-	if (sdev->sdev_state == SDEV_OFFLINE)
-		err = SCSI_DH_DEV_OFFLINED;
-	spin_unlock_irqrestore(q->queue_lock, flags);
-
-	if (err) {
-		if (fn)
-			fn(data, err);
-		goto out;
-	}
-
-	if (scsi_dh->activate)
-		err = scsi_dh->activate(sdev, fn, data);
-out:
-	put_device(dev);
-	return err;
-}
-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)
-{
-	int err = -SCSI_DH_NOSYS;
-	unsigned long flags;
-	struct scsi_device *sdev;
-	struct scsi_device_handler *scsi_dh = NULL;
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	sdev = q->queuedata;
-	if (sdev && sdev->scsi_dh_data)
-		scsi_dh = sdev->scsi_dh_data->scsi_dh;
-	if (scsi_dh && scsi_dh->set_params && get_device(&sdev->sdev_gendev))
-		err = 0;
-	spin_unlock_irqrestore(q->queue_lock, flags);
-
-	if (err)
-		return err;
-	err = scsi_dh->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)
-{
-	unsigned long flags;
-	struct scsi_device *sdev;
-	struct scsi_device_handler *scsi_dh;
-	int err = 0;
-
-	scsi_dh = scsi_dh_lookup(name);
-	if (!scsi_dh)
-		return -EINVAL;
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	sdev = q->queuedata;
-	if (!sdev || !get_device(&sdev->sdev_gendev))
-		err = -ENODEV;
-	spin_unlock_irqrestore(q->queue_lock, flags);
-
-	if (err)
-		return err;
-
-	if (sdev->scsi_dh_data) {
-		if (sdev->scsi_dh_data->scsi_dh != 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)
-{
-	unsigned long flags;
-	struct scsi_device *sdev;
-	const char *handler_name = NULL;
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	sdev = q->queuedata;
-	if (!sdev || !get_device(&sdev->sdev_gendev))
-		sdev = NULL;
-	spin_unlock_irqrestore(q->queue_lock, flags);
-
-	if (!sdev)
-		return NULL;
-
-	if (sdev->scsi_dh_data)
-		handler_name = kstrdup(sdev->scsi_dh_data->scsi_dh->name, gfp);
-
-	put_device(&sdev->sdev_gendev);
-	return handler_name;
-}
-EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);
-
-static struct notifier_block scsi_dh_nb = {
-	.notifier_call = scsi_dh_notifier
-};
-
-static int __init scsi_dh_init(void)
-{
-	int r;
-
-	r = bus_register_notifier(&scsi_bus_type, &scsi_dh_nb);
-
-	if (!r)
-		bus_for_each_dev(&scsi_bus_type, NULL, NULL,
-				 scsi_dh_sysfs_attr_add);
-
-	return r;
-}
-
-static void __exit scsi_dh_exit(void)
-{
-	bus_for_each_dev(&scsi_bus_type, NULL, NULL,
-			 scsi_dh_sysfs_attr_remove);
-	bus_unregister_notifier(&scsi_bus_type, &scsi_dh_nb);
-}
-
-module_init(scsi_dh_init);
-module_exit(scsi_dh_exit);
-
-MODULE_DESCRIPTION("SCSI device handler");
-MODULE_AUTHOR("Chandra Seetharaman <sekharan@us.ibm.com>");
-MODULE_LICENSE("GPL");
diff --git a/drivers/scsi/scsi_dh.c b/drivers/scsi/scsi_dh.c
new file mode 100644
index 0000000..3c06c72
--- /dev/null
+++ b/drivers/scsi/scsi_dh.c
@@ -0,0 +1,570 @@
+/*
+ * 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);
+
+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(name);
+		dh = __scsi_dh_lookup(name);
+	}
+
+	return dh;
+}
+
+/*
+ * device_handler_match_function - Match a device handler to a device
+ * @sdev - SCSI device to be tested
+ *
+ * Tests @sdev against the match function of all registered device_handler.
+ * Returns the found device handler or NULL if not found.
+ */
+static struct scsi_device_handler *
+device_handler_match_function(struct scsi_device *sdev)
+{
+	struct scsi_device_handler *tmp_dh, *found_dh = NULL;
+
+	spin_lock(&list_lock);
+	list_for_each_entry(tmp_dh, &scsi_dh_list, list) {
+		if (tmp_dh->match && tmp_dh->match(sdev)) {
+			found_dh = tmp_dh;
+			break;
+		}
+	}
+	spin_unlock(&list_lock);
+	return found_dh;
+}
+
+/*
+ * device_handler_match - Attach a device handler to a device
+ * @scsi_dh - The device handler to match against or NULL
+ * @sdev - SCSI device to be tested against @scsi_dh
+ *
+ * Tests @sdev against the device handler @scsi_dh or against
+ * all registered device_handler if @scsi_dh == NULL.
+ * Returns the found device handler or NULL if not found.
+ */
+static struct scsi_device_handler *
+device_handler_match(struct scsi_device_handler *scsi_dh,
+		     struct scsi_device *sdev)
+{
+	struct scsi_device_handler *found_dh;
+
+	found_dh = device_handler_match_function(sdev);
+
+	if (scsi_dh && found_dh != scsi_dh)
+		found_dh = NULL;
+
+	return found_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)
+{
+	struct scsi_dh_data *d;
+
+	if (!try_module_get(scsi_dh->module))
+		return -EINVAL;
+
+	d = scsi_dh->attach(sdev);
+	if (IS_ERR(d)) {
+		sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%ld)\n",
+			    scsi_dh->name, PTR_ERR(d));
+		module_put(scsi_dh->module);
+		return PTR_ERR(d);
+	}
+
+	d->scsi_dh = scsi_dh;
+	d->sdev = sdev;
+
+	spin_lock_irq(sdev->request_queue->queue_lock);
+	sdev->scsi_dh_data = d;
+	spin_unlock_irq(sdev->request_queue->queue_lock);
+	return 0;
+}
+
+/*
+ * 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)
+{
+	struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
+	struct scsi_device_handler *scsi_dh = scsi_dh_data->scsi_dh;
+
+	scsi_dh->detach(sdev);
+
+	spin_lock_irq(sdev->request_queue->queue_lock);
+	sdev->scsi_dh_data = NULL;
+	spin_unlock_irq(sdev->request_queue->queue_lock);
+
+	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", scsi_dh->name);
+	module_put(scsi_dh->module);
+}
+
+/*
+ * Functions for sysfs attribute 'dh_state'
+ */
+static ssize_t
+store_dh_state(struct device *dev, struct device_attribute *attr,
+	       const char *buf, size_t count)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct scsi_device_handler *scsi_dh;
+	int err = -EINVAL;
+
+	if (sdev->sdev_state == SDEV_CANCEL ||
+	    sdev->sdev_state == SDEV_DEL)
+		return -ENODEV;
+
+	if (!sdev->scsi_dh_data) {
+		/*
+		 * Attach to a device handler
+		 */
+		if (!(scsi_dh = scsi_dh_lookup(buf)))
+			return err;
+		err = scsi_dh_handler_attach(sdev, scsi_dh);
+	} else {
+		scsi_dh = sdev->scsi_dh_data->scsi_dh;
+		if (!strncmp(buf, "detach", 6)) {
+			/*
+			 * Detach from a device handler
+			 */
+			scsi_dh_handler_detach(sdev);
+			err = 0;
+		} else if (!strncmp(buf, "activate", 8)) {
+			/*
+			 * Activate a device handler
+			 */
+			if (scsi_dh->activate)
+				err = scsi_dh->activate(sdev, NULL, NULL);
+			else
+				err = 0;
+		}
+	}
+
+	return err<0?err:count;
+}
+
+static ssize_t
+show_dh_state(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+
+	if (!sdev->scsi_dh_data)
+		return snprintf(buf, 20, "detached\n");
+
+	return snprintf(buf, 20, "%s\n", sdev->scsi_dh_data->scsi_dh->name);
+}
+
+static struct device_attribute scsi_dh_state_attr =
+	__ATTR(dh_state, S_IRUGO | S_IWUSR, show_dh_state,
+	       store_dh_state);
+
+/*
+ * scsi_dh_sysfs_attr_add - Callback for scsi_init_dh
+ */
+static int scsi_dh_sysfs_attr_add(struct device *dev, void *data)
+{
+	struct scsi_device *sdev;
+	int err;
+
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	sdev = to_scsi_device(dev);
+
+	err = device_create_file(&sdev->sdev_gendev,
+				 &scsi_dh_state_attr);
+
+	return 0;
+}
+
+/*
+ * scsi_dh_sysfs_attr_remove - Callback for scsi_exit_dh
+ */
+static int scsi_dh_sysfs_attr_remove(struct device *dev, void *data)
+{
+	struct scsi_device *sdev;
+
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	sdev = to_scsi_device(dev);
+
+	device_remove_file(&sdev->sdev_gendev,
+			   &scsi_dh_state_attr);
+
+	return 0;
+}
+
+/*
+ * scsi_dh_notifier - notifier chain callback
+ */
+static int scsi_dh_notifier(struct notifier_block *nb,
+			    unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct scsi_device *sdev;
+	int err = 0;
+	struct scsi_device_handler *devinfo = NULL;
+
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	sdev = to_scsi_device(dev);
+
+	if (action == BUS_NOTIFY_ADD_DEVICE) {
+		err = device_create_file(dev, &scsi_dh_state_attr);
+		/* don't care about err */
+		devinfo = device_handler_match(NULL, sdev);
+		if (devinfo)
+			err = scsi_dh_handler_attach(sdev, devinfo);
+	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
+		device_remove_file(dev, &scsi_dh_state_attr);
+		if (sdev->scsi_dh_data)
+			scsi_dh_handler_detach(sdev);
+	}
+	return err;
+}
+
+/*
+ * scsi_dh_notifier_add - Callback for scsi_register_device_handler
+ */
+static int scsi_dh_notifier_add(struct device *dev, void *data)
+{
+	struct scsi_device_handler *scsi_dh = data;
+	struct scsi_device *sdev;
+
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	if (!get_device(dev))
+		return 0;
+
+	sdev = to_scsi_device(dev);
+
+	if (device_handler_match(scsi_dh, sdev))
+		scsi_dh_handler_attach(sdev, scsi_dh);
+
+	put_device(dev);
+
+	return 0;
+}
+
+/*
+ * scsi_dh_notifier_remove - Callback for scsi_unregister_device_handler
+ */
+static int scsi_dh_notifier_remove(struct device *dev, void *data)
+{
+	struct scsi_device_handler *scsi_dh = data;
+	struct scsi_device *sdev;
+
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	if (!get_device(dev))
+		return 0;
+
+	sdev = to_scsi_device(dev);
+
+	if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh == scsi_dh)
+		scsi_dh_handler_detach(sdev);
+
+	put_device(dev);
+
+	return 0;
+}
+
+/*
+ * 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);
+
+	bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh, scsi_dh_notifier_add);
+	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;
+
+	bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh,
+			 scsi_dh_notifier_remove);
+
+	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)
+{
+	int err = 0;
+	unsigned long flags;
+	struct scsi_device *sdev;
+	struct scsi_device_handler *scsi_dh = NULL;
+	struct device *dev = NULL;
+
+	spin_lock_irqsave(q->queue_lock, flags);
+	sdev = q->queuedata;
+	if (!sdev) {
+		spin_unlock_irqrestore(q->queue_lock, flags);
+		err = SCSI_DH_NOSYS;
+		if (fn)
+			fn(data, err);
+		return err;
+	}
+
+	if (sdev->scsi_dh_data)
+		scsi_dh = sdev->scsi_dh_data->scsi_dh;
+	dev = get_device(&sdev->sdev_gendev);
+	if (!scsi_dh || !dev ||
+	    sdev->sdev_state == SDEV_CANCEL ||
+	    sdev->sdev_state == SDEV_DEL)
+		err = SCSI_DH_NOSYS;
+	if (sdev->sdev_state == SDEV_OFFLINE)
+		err = SCSI_DH_DEV_OFFLINED;
+	spin_unlock_irqrestore(q->queue_lock, flags);
+
+	if (err) {
+		if (fn)
+			fn(data, err);
+		goto out;
+	}
+
+	if (scsi_dh->activate)
+		err = scsi_dh->activate(sdev, fn, data);
+out:
+	put_device(dev);
+	return err;
+}
+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)
+{
+	int err = -SCSI_DH_NOSYS;
+	unsigned long flags;
+	struct scsi_device *sdev;
+	struct scsi_device_handler *scsi_dh = NULL;
+
+	spin_lock_irqsave(q->queue_lock, flags);
+	sdev = q->queuedata;
+	if (sdev && sdev->scsi_dh_data)
+		scsi_dh = sdev->scsi_dh_data->scsi_dh;
+	if (scsi_dh && scsi_dh->set_params && get_device(&sdev->sdev_gendev))
+		err = 0;
+	spin_unlock_irqrestore(q->queue_lock, flags);
+
+	if (err)
+		return err;
+	err = scsi_dh->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)
+{
+	unsigned long flags;
+	struct scsi_device *sdev;
+	struct scsi_device_handler *scsi_dh;
+	int err = 0;
+
+	scsi_dh = scsi_dh_lookup(name);
+	if (!scsi_dh)
+		return -EINVAL;
+
+	spin_lock_irqsave(q->queue_lock, flags);
+	sdev = q->queuedata;
+	if (!sdev || !get_device(&sdev->sdev_gendev))
+		err = -ENODEV;
+	spin_unlock_irqrestore(q->queue_lock, flags);
+
+	if (err)
+		return err;
+
+	if (sdev->scsi_dh_data) {
+		if (sdev->scsi_dh_data->scsi_dh != 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)
+{
+	unsigned long flags;
+	struct scsi_device *sdev;
+	const char *handler_name = NULL;
+
+	spin_lock_irqsave(q->queue_lock, flags);
+	sdev = q->queuedata;
+	if (!sdev || !get_device(&sdev->sdev_gendev))
+		sdev = NULL;
+	spin_unlock_irqrestore(q->queue_lock, flags);
+
+	if (!sdev)
+		return NULL;
+
+	if (sdev->scsi_dh_data)
+		handler_name = kstrdup(sdev->scsi_dh_data->scsi_dh->name, gfp);
+
+	put_device(&sdev->sdev_gendev);
+	return handler_name;
+}
+EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);
+
+static struct notifier_block scsi_dh_nb = {
+	.notifier_call = scsi_dh_notifier
+};
+
+static int __init scsi_dh_init(void)
+{
+	int r;
+
+	r = bus_register_notifier(&scsi_bus_type, &scsi_dh_nb);
+
+	if (!r)
+		bus_for_each_dev(&scsi_bus_type, NULL, NULL,
+				 scsi_dh_sysfs_attr_add);
+
+	return r;
+}
+
+static void __exit scsi_dh_exit(void)
+{
+	bus_for_each_dev(&scsi_bus_type, NULL, NULL,
+			 scsi_dh_sysfs_attr_remove);
+	bus_unregister_notifier(&scsi_bus_type, &scsi_dh_nb);
+}
+
+module_init(scsi_dh_init);
+module_exit(scsi_dh_exit);
+
+MODULE_DESCRIPTION("SCSI device handler");
+MODULE_AUTHOR("Chandra Seetharaman <sekharan@us.ibm.com>");
+MODULE_LICENSE("GPL");
