1 files changed, 13 insertions, 5 deletions

diff --git a/block/blk-flush.c b/block/blk-flush.c
index a867e3f524f..0bd8c9c5d6e 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -212,9 +212,14 @@ static void flush_end_io(struct request *flush_rq, int error)
                 queued |= blk_flush_complete_seq(rq, seq, error);
         }
 
-        /* after populating an empty queue, kick it to avoid stall */
+        /*
+         * Moving a request silently to empty queue_head may stall the
+         * queue.  Kick the queue in those cases.  This function is called
+         * from request completion path and calling directly into
+         * request_fn may confuse the driver.  Always use kblockd.
+         */
         if (queued && was_empty)
-                __blk_run_queue(q);
+                __blk_run_queue(q, true);
 }
 
 /**
@@ -257,7 +262,7 @@ static bool blk_kick_flush(struct request_queue *q)
         q->flush_rq.end_io = flush_end_io;
 
         q->flush_pending_idx ^= 1;
-        elv_insert(q, &q->flush_rq, ELEVATOR_INSERT_FRONT);
+        elv_insert(q, &q->flush_rq, ELEVATOR_INSERT_REQUEUE);
         return true;
 }
 
@@ -266,9 +271,12 @@ static void flush_data_end_io(struct request *rq, int error)
         struct request_queue *q = rq->q;
         bool was_empty = elv_queue_empty(q);
 
-        /* after populating an empty queue, kick it to avoid stall */
+        /*
+         * After populating an empty queue, kick it to avoid stall.  Read
+         * the comment in flush_end_io().
+         */
         if (blk_flush_complete_seq(rq, REQ_FSEQ_DATA, error) && was_empty)
-                __blk_run_queue(q);
+                __blk_run_queue(q, true);
 }
 
 /**