block: add missed trace_block_plug

After flush plug list, the list has no request, so we need to add a
trace_block_plug().

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-core.c b/block/blk-core.c
index 6403c12..ea70e6c 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1387,8 +1387,10 @@ get_rq:
                                if (__rq->q != q)
                                        plug->should_sort = 1;
                        }
                                if (__rq->q != q)
                                        plug->should_sort = 1;
                        }

-                       if (request_count >= BLK_MAX_REQUEST_COUNT)
+                       if (request_count >= BLK_MAX_REQUEST_COUNT) {

                                blk_flush_plug_list(plug, false);
                                blk_flush_plug_list(plug, false);

+                               trace_block_plug(q);
+                       }

                }
                list_add_tail(&req->queuelist, &plug->list);
                drive_stat_acct(req, 1);
                }
                list_add_tail(&req->queuelist, &plug->list);
                drive_stat_acct(req, 1);