blk-mq: don't queue more if we get a busy return

[mirror_ubuntu-bionic-kernel.git] / block / blk-mq.c

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 0aa4a23cc6b1419ad27ec9f6f446dda85f077cb3..a522caa005a796c185571ca12b267ef591c83c7b 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1123,6 +1123,9 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx **hctx,
 
 #define BLK_MQ_RESOURCE_DELAY  3               /* ms units */
 
+/*
+ * Returns true if we did some work AND can potentially do more.
+ */
 bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
                             bool got_budget)
 {
@@ -1253,8 +1256,17 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
                        blk_mq_run_hw_queue(hctx, true);
                else if (needs_restart && (ret == BLK_STS_RESOURCE))
                        blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY);
+
+               return false;
        }
 
+       /*
+        * If the host/device is unable to accept more work, inform the
+        * caller of that.
+        */
+       if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE)
+               return false;
+
        return (queued + errors) != 0;
 }