[SCSI] rework scsi_target allocation

The current target allocation code registeres each possible target
with sysfs; it will be deleted again if no useable LUN on this target
was found. This results in a string of 'target add/target remove' uevents.

Based on a patch by Hannes Reinecke <hare@suse.de> this patch reworks
the target allocation code so that only uevents for existing targets
are sent. The sysfs registration is split off from the existing
scsi_target_alloc() into a in a new scsi_add_target() function, which
should be called whenever an existing target is found. Only then a
uevent is sent, so we'll be generating events for existing targets
only.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 84e2a8a..198aa45 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -809,6 +809,27 @@
 	return count;
 }
 
+static int scsi_target_add(struct scsi_target *starget)
+{
+	int error;
+
+	if (starget->state != STARGET_CREATED)
+		return 0;
+
+	error = device_add(&starget->dev);
+	if (error) {
+		dev_err(&starget->dev, "target device_add failed, error %d\n", error);
+		get_device(&starget->dev);
+		scsi_target_reap(starget);
+		put_device(&starget->dev);
+		return error;
+	}
+	transport_add_device(&starget->dev);
+	starget->state = STARGET_RUNNING;
+
+	return 0;
+}
+
 static struct device_attribute sdev_attr_queue_type_rw =
 	__ATTR(queue_type, S_IRUGO | S_IWUSR, show_queue_type_field,
 	       sdev_store_queue_type_rw);
@@ -824,10 +845,16 @@
 {
 	int error, i;
 	struct request_queue *rq = sdev->request_queue;
+	struct scsi_target *starget = sdev->sdev_target;
 
 	if ((error = scsi_device_set_state(sdev, SDEV_RUNNING)) != 0)
 		return error;
 
+	error = scsi_target_add(starget);
+	if (error)
+		return error;
+
+	transport_configure_device(&starget->dev);
 	error = device_add(&sdev->sdev_gendev);
 	if (error) {
 		put_device(sdev->sdev_gendev.parent);