tools headers UAPI: Sync files changed by new process_mrelease syscall and the remova...

[linux-2.6-microblaze.git] / block / blk-flush.c

diff --git a/block/blk-flush.c b/block/blk-flush.c
index 1002f6c..4201728 100644 (file)
--- 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);
 }