From: Ming Lei <ming.lei@redhat.com> To: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org, Ming Lei <ming.lei@redhat.com>, Keith Busch <kbusch@kernel.org>, Sagi Grimberg <sagi@grimberg.me>, Bart Van Assche <bvanassche@acm.org>, James Smart <james.smart@broadcom.com>, Christoph Hellwig <hch@lst.de>, linux-nvme@lists.infradead.org Subject: [PATCH V3 1/2] blk-mq: introduce blk_mq_complete_request_sync() Date: Mon, 8 Apr 2019 17:40:46 +0800 [thread overview] Message-ID: <20190408094047.29150-2-ming.lei@redhat.com> (raw) In-Reply-To: <20190408094047.29150-1-ming.lei@redhat.com> In NVMe's error handler, follows the typical steps of tearing down hardware for recovering controller: 1) stop blk_mq hw queues 2) stop the real hw queues 3) cancel in-flight requests via blk_mq_tagset_busy_iter(tags, cancel_request, ...) cancel_request(): mark the request as abort blk_mq_complete_request(req); 4) destroy real hw queues However, there may be race between #3 and #4, because blk_mq_complete_request() may run q->mq_ops->complete(rq) remotelly and asynchronously, and ->complete(rq) may be run after #4. This patch introduces blk_mq_complete_request_sync() for fixing the above race. Cc: Keith Busch <kbusch@kernel.org> Cc: Sagi Grimberg <sagi@grimberg.me> Cc: Bart Van Assche <bvanassche@acm.org> Cc: James Smart <james.smart@broadcom.com> Cc: Christoph Hellwig <hch@lst.de> Cc: linux-nvme@lists.infradead.org Signed-off-by: Ming Lei <ming.lei@redhat.com> --- block/blk-mq.c | 11 +++++++++++ include/linux/blk-mq.h | 1 + 2 files changed, 12 insertions(+) diff --git a/block/blk-mq.c b/block/blk-mq.c index a9354835cf51..d8d89f3514ac 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -654,6 +654,17 @@ bool blk_mq_complete_request(struct request *rq) } EXPORT_SYMBOL(blk_mq_complete_request); +bool blk_mq_complete_request_sync(struct request *rq) +{ + if (unlikely(blk_should_fake_timeout(rq->q))) + return false; + + WRITE_ONCE(rq->state, MQ_RQ_COMPLETE); + rq->q->mq_ops->complete(rq); + return true; +} +EXPORT_SYMBOL_GPL(blk_mq_complete_request_sync); + int blk_mq_request_started(struct request *rq) { return blk_mq_rq_state(rq) != MQ_RQ_IDLE; diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index cb2aa7ecafff..1412c983e7b8 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -302,6 +302,7 @@ void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list); void blk_mq_kick_requeue_list(struct request_queue *q); void blk_mq_delay_kick_requeue_list(struct request_queue *q, unsigned long msecs); bool blk_mq_complete_request(struct request *rq); +bool blk_mq_complete_request_sync(struct request *rq); bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list, struct bio *bio); bool blk_mq_queue_stopped(struct request_queue *q); -- 2.9.5
WARNING: multiple messages have this Message-ID (diff)
From: ming.lei@redhat.com (Ming Lei) Subject: [PATCH V3 1/2] blk-mq: introduce blk_mq_complete_request_sync() Date: Mon, 8 Apr 2019 17:40:46 +0800 [thread overview] Message-ID: <20190408094047.29150-2-ming.lei@redhat.com> (raw) In-Reply-To: <20190408094047.29150-1-ming.lei@redhat.com> In NVMe's error handler, follows the typical steps of tearing down hardware for recovering controller: 1) stop blk_mq hw queues 2) stop the real hw queues 3) cancel in-flight requests via blk_mq_tagset_busy_iter(tags, cancel_request, ...) cancel_request(): mark the request as abort blk_mq_complete_request(req); 4) destroy real hw queues However, there may be race between #3 and #4, because blk_mq_complete_request() may run q->mq_ops->complete(rq) remotelly and asynchronously, and ->complete(rq) may be run after #4. This patch introduces blk_mq_complete_request_sync() for fixing the above race. Cc: Keith Busch <kbusch at kernel.org> Cc: Sagi Grimberg <sagi at grimberg.me> Cc: Bart Van Assche <bvanassche at acm.org> Cc: James Smart <james.smart at broadcom.com> Cc: Christoph Hellwig <hch at lst.de> Cc: linux-nvme at lists.infradead.org Signed-off-by: Ming Lei <ming.lei at redhat.com> --- block/blk-mq.c | 11 +++++++++++ include/linux/blk-mq.h | 1 + 2 files changed, 12 insertions(+) diff --git a/block/blk-mq.c b/block/blk-mq.c index a9354835cf51..d8d89f3514ac 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -654,6 +654,17 @@ bool blk_mq_complete_request(struct request *rq) } EXPORT_SYMBOL(blk_mq_complete_request); +bool blk_mq_complete_request_sync(struct request *rq) +{ + if (unlikely(blk_should_fake_timeout(rq->q))) + return false; + + WRITE_ONCE(rq->state, MQ_RQ_COMPLETE); + rq->q->mq_ops->complete(rq); + return true; +} +EXPORT_SYMBOL_GPL(blk_mq_complete_request_sync); + int blk_mq_request_started(struct request *rq) { return blk_mq_rq_state(rq) != MQ_RQ_IDLE; diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index cb2aa7ecafff..1412c983e7b8 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -302,6 +302,7 @@ void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list); void blk_mq_kick_requeue_list(struct request_queue *q); void blk_mq_delay_kick_requeue_list(struct request_queue *q, unsigned long msecs); bool blk_mq_complete_request(struct request *rq); +bool blk_mq_complete_request_sync(struct request *rq); bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list, struct bio *bio); bool blk_mq_queue_stopped(struct request_queue *q); -- 2.9.5
next prev parent reply other threads:[~2019-04-08 9:41 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-04-08 9:40 [PATCH V3 0/2] blk-mq/nvme: cancel request synchronously Ming Lei 2019-04-08 9:40 ` Ming Lei 2019-04-08 9:40 ` Ming Lei [this message] 2019-04-08 9:40 ` [PATCH V3 1/2] blk-mq: introduce blk_mq_complete_request_sync() Ming Lei 2019-04-08 16:15 ` Keith Busch 2019-04-08 16:15 ` Keith Busch 2019-04-08 16:16 ` Christoph Hellwig 2019-04-08 16:16 ` Christoph Hellwig 2019-04-08 9:40 ` [PATCH V3 2/2] nvme: cancel request synchronously Ming Lei 2019-04-08 9:40 ` Ming Lei
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