[PATCH] helper function for retrieving scsi_cmd given host based block layer tag

This was necessitated by the need for a function to get back
to a scsi_cmnd, when an hba the posts its (corresponding) completion
interrupt with a block layer tag as its reference.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: David Somayajulu <david.somayajulu@qlogic.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 83425fb..c847e17 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -840,12 +840,7 @@
  **/
 struct request *blk_queue_find_tag(request_queue_t *q, int tag)
 {
-	struct blk_queue_tag *bqt = q->queue_tags;
-
-	if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
-		return NULL;
-
-	return bqt->tag_index[tag];
+	return blk_map_queue_find_tag(q->queue_tags, tag);
 }
 
 EXPORT_SYMBOL(blk_queue_find_tag);