1 files changed, 49 insertions, 7 deletions

diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index a518f2eff19a..3ee1cbc89479 100644
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -153,12 +153,24 @@ 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 +192,7 @@ 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);
 }
 
 /*
@@ -440,6 +452,39 @@ int scsi_dh_activate(struct request_queue *q)
 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.
@@ -474,7 +519,6 @@ 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;
@@ -505,10 +549,8 @@ 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);
 }