Merge commit 'c039c332f23e794deb6d6f37b9f07ff3b27fb2cf' into md

Pull in pre-requisites for adding raid10 support to dm-raid.

1 files changed, 36 insertions, 2 deletions

diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index 48e46f5b77cc..33e422e75835 100644
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -468,7 +468,8 @@ EXPORT_SYMBOL_GPL(scsi_dh_handler_exist);
 
 /*
  * scsi_dh_attach - Attach device handler
- * @sdev - sdev the handler should be attached to
+ * @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)
@@ -498,7 +499,8 @@ EXPORT_SYMBOL_GPL(scsi_dh_attach);
 
 /*
  * scsi_dh_detach - Detach device handler
- * @sdev - sdev the handler should be detached from
+ * @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
@@ -527,6 +529,38 @@ void scsi_dh_detach(struct request_queue *q)
 }
 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
 };