[2/2] blk-mq: ensure a q_usage_counter reference is held when splitting bios

Message ID	20240111135705.2155518-3-hch@lst.de (mailing list archive)
State	New, archived
Headers	show Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 652F73C680 for <linux-block@vger.kernel.org>; Thu, 11 Jan 2024 13:57:19 +0000 (UTC) From: Christoph Hellwig <hch@lst.de> To: Jens Axboe <axboe@kernel.dk> Cc: Ming Lei <ming.lei@redhat.com>, linux-block@vger.kernel.org Subject: [PATCH 2/2] blk-mq: ensure a q_usage_counter reference is held when splitting bios Date: Thu, 11 Jan 2024 14:57:05 +0100 Message-Id: <20240111135705.2155518-3-hch@lst.de> In-Reply-To: <20240111135705.2155518-1-hch@lst.de> References: <20240111135705.2155518-1-hch@lst.de> Precedence: bulk MIME-Version: 1.0 Content-Transfer-Encoding: 8bit
Series	[1/2] blk-mq: rename blk_mq_can_use_cached_rq \| expand [1/2] blk-mq: rename blk_mq_can_use_cached_rq [2/2] blk-mq: ensure a q_usage_counter reference is held when splitting bios

diff --git a/block/blk-core.c b/block/blk-core.c index 9520ccab305007..885ba6bb58556f 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -592,17 +592,21 @@ static inline blk_status_t blk_check_zone_append(struct request_queue *q, static void __submit_bio(struct bio *bio) { + struct gendisk *disk = bio->bi_bdev->bd_disk; + if (unlikely(!blk_crypto_bio_prep(&bio))) return; + if (unlikely(bio_queue_enter(bio))) + return; if (!bio->bi_bdev->bd_has_submit_bio) { - blk_mq_submit_bio(bio); - } else if (likely(bio_queue_enter(bio) == 0)) { - struct gendisk *disk = bio->bi_bdev->bd_disk; - + if (blk_mq_submit_bio(bio)) + return; + } else { disk->fops->submit_bio(bio); - blk_queue_exit(disk->queue); } + + blk_queue_exit(disk->queue); } /* diff --git a/block/blk-mq.c b/block/blk-mq.c index a6731cacd0132c..421db29535ba50 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2936,14 +2936,17 @@ static void bio_set_ioprio(struct bio *bio) * * It will not queue the request if there is an error with the bio, or at the * request creation. + * + * Returns %true if the q_usage_counter usage is consumed, or %false if it + * isn't. */ -void blk_mq_submit_bio(struct bio *bio) +bool blk_mq_submit_bio(struct bio *bio) { struct request_queue *q = bdev_get_queue(bio->bi_bdev); struct blk_plug *plug = blk_mq_plug(bio); const int is_sync = op_is_sync(bio->bi_opf); struct blk_mq_hw_ctx *hctx; - struct request *rq = NULL; + struct request *rq; unsigned int nr_segs = 1; blk_status_t ret; @@ -2951,39 +2954,28 @@ void blk_mq_submit_bio(struct bio *bio) if (bio_may_exceed_limits(bio, &q->limits)) { bio = __bio_split_to_limits(bio, &q->limits, &nr_segs); if (!bio) - return; + return false; } bio_set_ioprio(bio); + if (!bio_integrity_prep(bio)) + return false; + if (plug) { rq = rq_list_peek(&plug->cached_rq); - if (rq && rq->q != q) - rq = NULL; - } - if (rq) { - if (!bio_integrity_prep(bio)) - return; - if (blk_mq_attempt_bio_merge(q, bio, nr_segs)) - return; - if (blk_mq_use_cached_rq(rq, plug, bio)) - goto done; - percpu_ref_get(&q->q_usage_counter); - } else { - if (unlikely(bio_queue_enter(bio))) - return; - if (!bio_integrity_prep(bio)) - goto fail; + if (rq && rq->q == q) { + if (blk_mq_attempt_bio_merge(q, bio, nr_segs)) + return false; + if (blk_mq_use_cached_rq(rq, plug, bio)) + goto has_rq; + } } rq = blk_mq_get_new_requests(q, plug, bio, nr_segs); - if (unlikely(!rq)) { -fail: - blk_queue_exit(q); - return; - } - -done: + if (unlikely(!rq)) + return false; +has_rq: trace_block_getrq(bio); rq_qos_track(q, rq, bio); @@ -2995,15 +2987,15 @@ void blk_mq_submit_bio(struct bio *bio) bio->bi_status = ret; bio_endio(bio); blk_mq_free_request(rq); - return; + return true; } if (op_is_flush(bio->bi_opf) && blk_insert_flush(rq)) - return; + return true; if (plug) { blk_add_rq_to_plug(plug, rq); - return; + return true; } hctx = rq->mq_hctx; @@ -3014,6 +3006,8 @@ void blk_mq_submit_bio(struct bio *bio) } else { blk_mq_run_dispatch_ops(q, blk_mq_try_issue_directly(hctx, rq)); } + + return true; } #ifdef CONFIG_BLK_MQ_STACKING diff --git a/block/blk-mq.h b/block/blk-mq.h index f75a9ecfebde1b..d45f222f117748 100644 --- a/block/blk-mq.h +++ b/block/blk-mq.h @@ -39,7 +39,7 @@ enum { typedef unsigned int __bitwise blk_insert_t; #define BLK_MQ_INSERT_AT_HEAD ((__force blk_insert_t)0x01) -void blk_mq_submit_bio(struct bio *bio); +bool blk_mq_submit_bio(struct bio *bio); int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, struct io_comp_batch *iob, unsigned int flags); void blk_mq_exit_queue(struct request_queue *q);

[2/2] blk-mq: ensure a q_usage_counter reference is held when splitting bios

Commit Message

Comments

Patch