diff options
| author | Christoph Hellwig <hch@lst.de> | 2020-05-16 20:28:01 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-05-19 17:34:29 +0200 |
| commit | ac7c5675fa45a372fab27d78a72d2e10e4734959 (patch) | |
| tree | 7add7a513b2d64e636acf3d3912f8cf292253ad7 /block/blk-mq.c | |
| parent | blk-mq: remove a pointless queue enter pair in blk_mq_alloc_request_hctx (diff) | |
| download | linux-ac7c5675fa45a372fab27d78a72d2e10e4734959.tar.xz linux-ac7c5675fa45a372fab27d78a72d2e10e4734959.zip | |
blk-mq: allow blk_mq_make_request to consume the q_usage_counter reference
blk_mq_make_request currently needs to grab an q_usage_counter
reference when allocating a request. This is because the block layer
grabs one before calling blk_mq_make_request, but also releases it as
soon as blk_mq_make_request returns. Remove the blk_queue_exit call
after blk_mq_make_request returns, and instead let it consume the
reference. This works perfectly fine for the block layer caller, just
device mapper needs an extra reference as the old problem still
persists there. Open code blk_queue_enter_live in device mapper,
as there should be no other callers and this allows better documenting
why we do a non-try get.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq.c')
| -rw-r--r-- | block/blk-mq.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index b1c12de8926e..cac11945f602 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2028,26 +2028,24 @@ blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) __blk_queue_split(q, &bio, &nr_segs); if (!bio_integrity_prep(bio)) - return BLK_QC_T_NONE; + goto queue_exit; if (!is_flush_fua && !blk_queue_nomerges(q) && blk_attempt_plug_merge(q, bio, nr_segs, &same_queue_rq)) - return BLK_QC_T_NONE; + goto queue_exit; if (blk_mq_sched_bio_merge(q, bio, nr_segs)) - return BLK_QC_T_NONE; + goto queue_exit; rq_qos_throttle(q, bio); data.cmd_flags = bio->bi_opf; - blk_queue_enter_live(q); rq = blk_mq_get_request(q, bio, &data); if (unlikely(!rq)) { - blk_queue_exit(q); rq_qos_cleanup(q, bio); if (bio->bi_opf & REQ_NOWAIT) bio_wouldblock_error(bio); - return BLK_QC_T_NONE; + goto queue_exit; } trace_block_getrq(q, bio, bio->bi_opf); @@ -2134,6 +2132,9 @@ blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) } return cookie; +queue_exit: + blk_queue_exit(q); + return BLK_QC_T_NONE; } EXPORT_SYMBOL_GPL(blk_mq_make_request); /* only for request based dm */ |