From 600c3b0cea784aaba77df3ed4a6b4f2ebfa935ce Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 29 May 2020 15:53:13 +0200 Subject: [PATCH] blk-mq: open code __blk_mq_alloc_request in blk_mq_alloc_request_hctx blk_mq_alloc_request_hctx is only used for NVMeoF connect commands, so tailor it to the specific requirements, and don't bother the general fast path code with its special twinkles. Signed-off-by: Christoph Hellwig Reviewed-by: Ming Lei Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe --- block/blk-mq.c | 44 +++++++++++++++++++++++--------------------- 1 file changed, 23 insertions(+), 21 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index dcc52859a92c..560ef5df8993 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -351,21 +351,13 @@ static struct request *__blk_mq_alloc_request(struct blk_mq_alloc_data *data) { struct request_queue *q = data->q; struct elevator_queue *e = q->elevator; - unsigned int tag; - bool clear_ctx_on_error = false; u64 alloc_time_ns = 0; + unsigned int tag; /* alloc_time includes depth and tag waits */ if (blk_queue_rq_alloc_time(q)) alloc_time_ns = ktime_get_ns(); - if (likely(!data->ctx)) { - data->ctx = blk_mq_get_ctx(q); - clear_ctx_on_error = true; - } - if (likely(!data->hctx)) - data->hctx = blk_mq_map_queue(q, data->cmd_flags, - data->ctx); if (data->cmd_flags & REQ_NOWAIT) data->flags |= BLK_MQ_REQ_NOWAIT; @@ -381,17 +373,16 @@ static struct request *__blk_mq_alloc_request(struct blk_mq_alloc_data *data) e->type->ops.limit_depth && !(data->flags & BLK_MQ_REQ_RESERVED)) e->type->ops.limit_depth(data->cmd_flags, data); - } else { - blk_mq_tag_busy(data->hctx); } + data->ctx = blk_mq_get_ctx(q); + data->hctx = blk_mq_map_queue(q, data->cmd_flags, data->ctx); + if (!(data->flags & BLK_MQ_REQ_INTERNAL)) + blk_mq_tag_busy(data->hctx); + tag = blk_mq_get_tag(data); - if (tag == BLK_MQ_NO_TAG) { - if (clear_ctx_on_error) - data->ctx = NULL; + if (tag == BLK_MQ_NO_TAG) return NULL; - } - return blk_mq_rq_ctx_init(data, tag, alloc_time_ns); } @@ -431,17 +422,22 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q, .flags = flags, .cmd_flags = op, }; - struct request *rq; + u64 alloc_time_ns = 0; unsigned int cpu; + unsigned int tag; int ret; + /* alloc_time includes depth and tag waits */ + if (blk_queue_rq_alloc_time(q)) + alloc_time_ns = ktime_get_ns(); + /* * If the tag allocator sleeps we could get an allocation for a * different hardware context. No need to complicate the low level * allocator for this for the rare use case of a command tied to * a specific queue. */ - if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT))) + if (WARN_ON_ONCE(!(flags & (BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_RESERVED)))) return ERR_PTR(-EINVAL); if (hctx_idx >= q->nr_hw_queues) @@ -462,11 +458,17 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q, cpu = cpumask_first_and(data.hctx->cpumask, cpu_online_mask); data.ctx = __blk_mq_get_ctx(q, cpu); + if (q->elevator) + data.flags |= BLK_MQ_REQ_INTERNAL; + else + blk_mq_tag_busy(data.hctx); + ret = -EWOULDBLOCK; - rq = __blk_mq_alloc_request(&data); - if (!rq) + tag = blk_mq_get_tag(&data); + if (tag == BLK_MQ_NO_TAG) goto out_queue_exit; - return rq; + return blk_mq_rq_ctx_init(&data, tag, alloc_time_ns); + out_queue_exit: blk_queue_exit(q); return ERR_PTR(ret);