When try to issue request directly, if the queue is stopped or quiesced, 'bypass' will be ignored and return BLK_STS_OK to caller to avoid it dispatch request again. Then the request will be inserted with blk_mq_sched_insert_request. This is not correct for dm-rq case where we should avoid to pass through the underlying path's io scheduler.
To fix it, use blk_mq_request_bypass_insert to insert the request to hctx->dispatch when we cannot pass through io scheduler but have to insert. Signed-off-by: Jianchao Wang <[email protected]> --- block/blk-mq.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 14b4d06..11c52bb 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1772,7 +1772,7 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, bool bypass) { struct request_queue *q = rq->q; - bool run_queue = true; + bool run_queue = true, force = false; blk_status_t ret = BLK_STS_RESOURCE; int srcu_idx; @@ -1786,7 +1786,7 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, */ if (unlikely(blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q))) { run_queue = false; - bypass = false; + force = true; goto out_unlock; } @@ -1817,6 +1817,9 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, if (!bypass) { blk_mq_sched_insert_request(rq, false, run_queue, false); ret = BLK_STS_OK; + } else if (force) { + blk_mq_request_bypass_insert(rq, run_queue); + ret = BLK_STS_OK; } break; default: -- 2.7.4
