blk-mq: don't fail allocating driver tag for stopped hw queue

We rely on blk_mq_get_driver_tag() not failing if 'wait' is true,
but it currently fails in that case if the queue happens to be
stopped at the time of the call.

We don't need to check for stopped here, it's just assigning
the tag. If the queue is stopped, we'll handle it when
attempting to run the queue.

This fixes a stall/crash on flush intensive workloads, where
we proceed to process a flush that doesn't have a valid tag
assigned.

Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 60dac10228fe0fc410921b176415c57c3c6a6b11..489076e7ae15988bd1678fd3080f8186c78669c8 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -856,9 +856,6 @@ bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx,
                .flags = wait ? 0 : BLK_MQ_REQ_NOWAIT,
        };
 
-       if (blk_mq_hctx_stopped(data.hctx))
-               return false;
-
        if (rq->tag != -1) {
 done:
                if (hctx)