X-Git-Url: http://git.monstr.eu/?a=blobdiff_plain;f=block%2Fblk-flush.c;h=4201728bf3a5a8144e9c0bf76c87d69898f1bf37;hb=81b0b29bf70bb8b459cf1f0b4a6a4898be457850;hp=1002f6c581816d111f28b085fb647931d591b32d;hpb=96dcb97d0a40a60b9aee9f2c7a44ce8a1b6704bc;p=linux-2.6-microblaze.git

diff --git a/block/blk-flush.c b/block/blk-flush.c
index 1002f6c58181..4201728bf3a5 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -262,6 +262,11 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
 	spin_unlock_irqrestore(&fq->mq_flush_lock, flags);
 }
 
+bool is_flush_rq(struct request *rq)
+{
+	return rq->end_io == flush_end_io;
+}
+
 /**
  * blk_kick_flush - consider issuing flush request
  * @q: request_queue being kicked
@@ -329,6 +334,14 @@ static void blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq,
 	flush_rq->rq_flags |= RQF_FLUSH_SEQ;
 	flush_rq->rq_disk = first_rq->rq_disk;
 	flush_rq->end_io = flush_end_io;
+	/*
+	 * Order WRITE ->end_io and WRITE rq->ref, and its pair is the one
+	 * implied in refcount_inc_not_zero() called from
+	 * blk_mq_find_and_get_req(), which orders WRITE/READ flush_rq->ref
+	 * and READ flush_rq->end_io
+	 */
+	smp_wmb();
+	refcount_set(&flush_rq->ref, 1);
 
 	blk_flush_queue_rq(flush_rq, false);
 }