1 files changed, 150 insertions, 103 deletions

diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index a518f2eff19..33e422e7583 100644
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -21,19 +21,13 @@
  *               Mike Anderson <andmike@linux.vnet.ibm.com>
  */
 
+#include <linux/slab.h>
+#include <linux/module.h>
 #include <scsi/scsi_dh.h>
 #include "../scsi_priv.h"
 
-struct scsi_dh_devinfo_list {
-	struct list_head node;
-	char vendor[9];
-	char model[17];
-	struct scsi_device_handler *handler;
-};
-
 static DEFINE_SPINLOCK(list_lock);
 static LIST_HEAD(scsi_dh_list);
-static LIST_HEAD(scsi_dh_dev_list);
 
 static struct scsi_device_handler *get_device_handler(const char *name)
 {
@@ -50,43 +44,29 @@ static struct scsi_device_handler *get_device_handler(const char *name)
 	return found;
 }
 
-
+/*
+ * 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 *
-scsi_dh_cache_lookup(struct scsi_device *sdev)
+device_handler_match_function(struct scsi_device *sdev)
 {
-	struct scsi_dh_devinfo_list *tmp;
-	struct scsi_device_handler *found_dh = NULL;
+	struct scsi_device_handler *tmp_dh, *found_dh = NULL;
 
 	spin_lock(&list_lock);
-	list_for_each_entry(tmp, &scsi_dh_dev_list, node) {
-		if (!strncmp(sdev->vendor, tmp->vendor, strlen(tmp->vendor)) &&
-		    !strncmp(sdev->model, tmp->model, strlen(tmp->model))) {
-			found_dh = tmp->handler;
+	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;
 }
 
-static int scsi_dh_handler_lookup(struct scsi_device_handler *scsi_dh,
-				  struct scsi_device *sdev)
-{
-	int i, found = 0;
-
-	for(i = 0; scsi_dh->devlist[i].vendor; i++) {
-		if (!strncmp(sdev->vendor, scsi_dh->devlist[i].vendor,
-			     strlen(scsi_dh->devlist[i].vendor)) &&
-		    !strncmp(sdev->model, scsi_dh->devlist[i].model,
-			     strlen(scsi_dh->devlist[i].model))) {
-			found = 1;
-			break;
-		}
-	}
-	return found;
-}
-
 /*
  * device_handler_match - Attach a device handler to a device
  * @scsi_dh - The device handler to match against or NULL
@@ -100,42 +80,12 @@ static struct scsi_device_handler *
 device_handler_match(struct scsi_device_handler *scsi_dh,
 		     struct scsi_device *sdev)
 {
-	struct scsi_device_handler *found_dh = NULL;
-	struct scsi_dh_devinfo_list *tmp;
-
-	found_dh = scsi_dh_cache_lookup(sdev);
-	if (found_dh)
-		return found_dh;
+	struct scsi_device_handler *found_dh;
 
-	if (scsi_dh) {
-		if (scsi_dh_handler_lookup(scsi_dh, sdev))
-			found_dh = scsi_dh;
-	} else {
-		struct scsi_device_handler *tmp_dh;
+	found_dh = device_handler_match_function(sdev);
 
-		spin_lock(&list_lock);
-		list_for_each_entry(tmp_dh, &scsi_dh_list, list) {
-			if (scsi_dh_handler_lookup(tmp_dh, sdev))
-				found_dh = tmp_dh;
-		}
-		spin_unlock(&list_lock);
-	}
-
-	if (found_dh) { /* If device is found, add it to the cache */
-		tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
-		if (tmp) {
-			strncpy(tmp->vendor, sdev->vendor, 8);
-			strncpy(tmp->model, sdev->model, 16);
-			tmp->vendor[8] = '\0';
-			tmp->model[16] = '\0';
-			tmp->handler = found_dh;
-			spin_lock(&list_lock);
-			list_add(&tmp->node, &scsi_dh_dev_list);
-			spin_unlock(&list_lock);
-		} else {
-			found_dh = NULL;
-		}
-	}
+	if (scsi_dh && found_dh != scsi_dh)
+		found_dh = NULL;
 
 	return found_dh;
 }
@@ -153,12 +103,24 @@ static int scsi_dh_handler_attach(struct scsi_device *sdev,
 	if (sdev->scsi_dh_data) {
 		if (sdev->scsi_dh_data->scsi_dh != scsi_dh)
 			err = -EBUSY;
-	} else if (scsi_dh->attach)
+		else
+			kref_get(&sdev->scsi_dh_data->kref);
+	} else if (scsi_dh->attach) {
 		err = scsi_dh->attach(sdev);
-
+		if (!err) {
+			kref_init(&sdev->scsi_dh_data->kref);
+			sdev->scsi_dh_data->sdev = sdev;
+		}
+	}
 	return err;
 }
 
+static void __detach_handler (struct kref *kref)
+{
+	struct scsi_dh_data *scsi_dh_data = container_of(kref, struct scsi_dh_data, kref);
+	scsi_dh_data->scsi_dh->detach(scsi_dh_data->sdev);
+}
+
 /*
  * scsi_dh_handler_detach - Detach a device handler from a device
  * @sdev - SCSI device the device handler should be detached from
@@ -180,7 +142,7 @@ static void scsi_dh_handler_detach(struct scsi_device *sdev,
 		scsi_dh = sdev->scsi_dh_data->scsi_dh;
 
 	if (scsi_dh && scsi_dh->detach)
-		scsi_dh->detach(sdev);
+		kref_put(&sdev->scsi_dh_data->kref, __detach_handler);
 }
 
 /*
@@ -194,6 +156,10 @@ store_dh_state(struct device *dev, struct device_attribute *attr,
 	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
@@ -214,7 +180,7 @@ store_dh_state(struct device *dev, struct device_attribute *attr,
 			 * Activate a device handler
 			 */
 			if (scsi_dh->activate)
-				err = scsi_dh->activate(sdev);
+				err = scsi_dh->activate(sdev, NULL, NULL);
 			else
 				err = 0;
 		}
@@ -292,18 +258,15 @@ static int scsi_dh_notifier(struct notifier_block *nb,
 	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)
-			goto out;
-
-		err = scsi_dh_handler_attach(sdev, devinfo);
-		if (!err)
-			err = device_create_file(dev, &scsi_dh_state_attr);
+		if (devinfo)
+			err = scsi_dh_handler_attach(sdev, devinfo);
 	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
 		device_remove_file(dev, &scsi_dh_state_attr);
 		scsi_dh_handler_detach(sdev, NULL);
 	}
-out:
 	return err;
 }
 
@@ -363,12 +326,14 @@ static int scsi_dh_notifier_remove(struct device *dev, void *data)
  */
 int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
 {
+
 	if (get_device_handler(scsi_dh->name))
 		return -EBUSY;
 
 	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);
 
@@ -385,7 +350,6 @@ EXPORT_SYMBOL_GPL(scsi_register_device_handler);
  */
 int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
 {
-	struct scsi_dh_devinfo_list *tmp, *pos;
 
 	if (!get_device_handler(scsi_dh->name))
 		return -ENODEV;
@@ -395,12 +359,6 @@ int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
 
 	spin_lock(&list_lock);
 	list_del(&scsi_dh->list);
-	list_for_each_entry_safe(pos, tmp, &scsi_dh_dev_list, node) {
-		if (pos->handler == scsi_dh) {
-			list_del(&pos->node);
-			kfree(pos);
-		}
-	}
 	spin_unlock(&list_lock);
 	printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
 
@@ -411,35 +369,93 @@ EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
 /*
  * scsi_dh_activate - activate the path associated with the scsi_device
  *      corresponding to the given request queue.
- * @q - Request queue that is associated with the scsi_device to be
- *      activated.
+ *     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)
+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 && sdev->scsi_dh_data)
+	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;
-	if (!scsi_dh || !get_device(&sdev->sdev_gendev))
+	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)
-		return err;
+	if (err) {
+		if (fn)
+			fn(data, err);
+		goto out;
+	}
 
 	if (scsi_dh->activate)
-		err = scsi_dh->activate(sdev);
-	put_device(&sdev->sdev_gendev);
+		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_handler_exist - Return TRUE(1) if a device handler exists for
  *	the given name. FALSE(0) otherwise.
  * @name - name of the device handler.
@@ -451,8 +467,9 @@ int scsi_dh_handler_exist(const char *name)
 EXPORT_SYMBOL_GPL(scsi_dh_handler_exist);
 
 /*
- * scsi_dh_handler_attach - Attach device handler
- * @sdev - sdev the handler should be attached to
+ * 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)
@@ -474,7 +491,6 @@ int scsi_dh_attach(struct request_queue *q, const char *name)
 
 	if (!err) {
 		err = scsi_dh_handler_attach(sdev, scsi_dh);
-
 		put_device(&sdev->sdev_gendev);
 	}
 	return err;
@@ -482,8 +498,9 @@ int scsi_dh_attach(struct request_queue *q, const char *name)
 EXPORT_SYMBOL_GPL(scsi_dh_attach);
 
 /*
- * scsi_dh_handler_detach - Detach device handler
- * @sdev - sdev the handler should be detached from
+ * scsi_dh_detach - Detach device handler
+ * @q - Request queue that is associated with the scsi_device
+ *      the handler should be detached from
  *
  * This function will detach the device handler only
  * if the sdev is not part of the internal list, ie
@@ -505,15 +522,45 @@ void scsi_dh_detach(struct request_queue *q)
 		return;
 
 	if (sdev->scsi_dh_data) {
-		/* if sdev is not on internal list, detach */
 		scsi_dh = sdev->scsi_dh_data->scsi_dh;
-		if (!device_handler_match(scsi_dh, sdev))
-			scsi_dh_handler_detach(sdev, scsi_dh);
+		scsi_dh_handler_detach(sdev, scsi_dh);
 	}
 	put_device(&sdev->sdev_gendev);
 }
 EXPORT_SYMBOL_GPL(scsi_dh_detach);
 
+/*
+ * 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
 };