blk-mq: don't dispatch request in blk_mq_request_direct_issue if queue is busy
If we run into blk_mq_request_direct_issue(), when queue is busy, we
don't want to dispatch this request into hctx->dispatch_list, and
what we need to do is to return the queue busy info to caller, so
that caller can deal with it well.
Fixes: 396eaf21ee
("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback")
Reported-by: Laurence Oberman <loberman@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
parent
de99a34688
commit
23d4ee19e7
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@ -1773,15 +1773,6 @@ static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
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return ret;
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}
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static void __blk_mq_fallback_to_insert(struct request *rq,
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bool run_queue, bool bypass_insert)
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{
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if (!bypass_insert)
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blk_mq_sched_insert_request(rq, false, run_queue, false);
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else
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blk_mq_request_bypass_insert(rq, run_queue);
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}
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static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
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struct request *rq,
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blk_qc_t *cookie,
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@ -1790,9 +1781,16 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
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struct request_queue *q = rq->q;
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bool run_queue = true;
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/* RCU or SRCU read lock is needed before checking quiesced flag */
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/*
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* RCU or SRCU read lock is needed before checking quiesced flag.
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*
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* When queue is stopped or quiesced, ignore 'bypass_insert' from
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* blk_mq_request_direct_issue(), and return BLK_STS_OK to caller,
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* and avoid driver to try to dispatch again.
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*/
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if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) {
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run_queue = false;
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bypass_insert = false;
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goto insert;
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}
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@ -1809,10 +1807,10 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
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return __blk_mq_issue_directly(hctx, rq, cookie);
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insert:
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__blk_mq_fallback_to_insert(rq, run_queue, bypass_insert);
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if (bypass_insert)
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return BLK_STS_RESOURCE;
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blk_mq_sched_insert_request(rq, false, run_queue, false);
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return BLK_STS_OK;
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}
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@ -1828,7 +1826,7 @@ static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
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ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false);
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if (ret == BLK_STS_RESOURCE)
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__blk_mq_fallback_to_insert(rq, true, false);
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blk_mq_sched_insert_request(rq, false, true, false);
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else if (ret != BLK_STS_OK)
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blk_mq_end_request(rq, ret);
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