From 04ced159cec863f9bc27015d6b970bb13cfa6176 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 9 Jan 2018 08:29:46 -0800 Subject: [PATCH] blk-mq: move hctx lock/unlock into a helper Move the RCU vs SRCU logic into lock/unlock helpers, which makes the actual functional bits within the locked region much easier to read. tj: Reordered in front of timeout revamp patches and added the missing blk_mq_run_hw_queue() conversion. Signed-off-by: Jens Axboe Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- block/blk-mq.c | 66 ++++++++++++++++++++++++-------------------------- 1 file changed, 32 insertions(+), 34 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index e258ad8dc171..bd7c47eb2923 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -557,6 +557,22 @@ static void __blk_mq_complete_request(struct request *rq) put_cpu(); } +static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx) +{ + if (!(hctx->flags & BLK_MQ_F_BLOCKING)) + rcu_read_unlock(); + else + srcu_read_unlock(hctx->queue_rq_srcu, srcu_idx); +} + +static void hctx_lock(struct blk_mq_hw_ctx *hctx, int *srcu_idx) +{ + if (!(hctx->flags & BLK_MQ_F_BLOCKING)) + rcu_read_lock(); + else + *srcu_idx = srcu_read_lock(hctx->queue_rq_srcu); +} + /** * blk_mq_complete_request - end I/O on a request * @rq: the request being processed @@ -1214,17 +1230,11 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) */ WARN_ON_ONCE(in_interrupt()); - if (!(hctx->flags & BLK_MQ_F_BLOCKING)) { - rcu_read_lock(); - blk_mq_sched_dispatch_requests(hctx); - rcu_read_unlock(); - } else { - might_sleep(); + might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); - srcu_idx = srcu_read_lock(hctx->queue_rq_srcu); - blk_mq_sched_dispatch_requests(hctx); - srcu_read_unlock(hctx->queue_rq_srcu, srcu_idx); - } + hctx_lock(hctx, &srcu_idx); + blk_mq_sched_dispatch_requests(hctx); + hctx_unlock(hctx, srcu_idx); } /* @@ -1296,17 +1306,10 @@ bool blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) * And queue will be rerun in blk_mq_unquiesce_queue() if it is * quiesced. */ - if (!(hctx->flags & BLK_MQ_F_BLOCKING)) { - rcu_read_lock(); - need_run = !blk_queue_quiesced(hctx->queue) && - blk_mq_hctx_has_pending(hctx); - rcu_read_unlock(); - } else { - srcu_idx = srcu_read_lock(hctx->queue_rq_srcu); - need_run = !blk_queue_quiesced(hctx->queue) && - blk_mq_hctx_has_pending(hctx); - srcu_read_unlock(hctx->queue_rq_srcu, srcu_idx); - } + hctx_lock(hctx, &srcu_idx); + need_run = !blk_queue_quiesced(hctx->queue) && + blk_mq_hctx_has_pending(hctx); + hctx_unlock(hctx, srcu_idx); if (need_run) { __blk_mq_delay_run_hw_queue(hctx, async, 0); @@ -1618,7 +1621,7 @@ static blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx, struct request *rq) static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, struct request *rq, - blk_qc_t *cookie, bool may_sleep) + blk_qc_t *cookie) { struct request_queue *q = rq->q; struct blk_mq_queue_data bd = { @@ -1668,25 +1671,20 @@ static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, } insert: - blk_mq_sched_insert_request(rq, false, run_queue, false, may_sleep); + blk_mq_sched_insert_request(rq, false, run_queue, false, + hctx->flags & BLK_MQ_F_BLOCKING); } static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, struct request *rq, blk_qc_t *cookie) { - if (!(hctx->flags & BLK_MQ_F_BLOCKING)) { - rcu_read_lock(); - __blk_mq_try_issue_directly(hctx, rq, cookie, false); - rcu_read_unlock(); - } else { - unsigned int srcu_idx; + int srcu_idx; - might_sleep(); + might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); - srcu_idx = srcu_read_lock(hctx->queue_rq_srcu); - __blk_mq_try_issue_directly(hctx, rq, cookie, true); - srcu_read_unlock(hctx->queue_rq_srcu, srcu_idx); - } + hctx_lock(hctx, &srcu_idx); + __blk_mq_try_issue_directly(hctx, rq, cookie); + hctx_unlock(hctx, srcu_idx); } static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)