blk-mq: fix for trace_block_plug()

The trace point is for tracing plug event of each request
queue instead of each task, so we should check the request
count in the plug list from current queue instead of
current task.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index d38371160019ca17468478d30a5c8f1792f5e109..24c528f182eaaccf0e9331b165a9df2755dee6b3 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1380,7 +1380,7 @@ static void blk_sq_make_request(struct request_queue *q, struct bio *bio)
        plug = current->plug;
        if (plug) {
                blk_mq_bio_to_request(rq, bio);
-               if (list_empty(&plug->mq_list))
+               if (!request_count)
                        trace_block_plug(q);
                else if (request_count >= BLK_MAX_REQUEST_COUNT) {
                        blk_flush_plug_list(plug, false);