Turn the different ways of merging or issuing I/O into a series of if/else statements instead of the current maze of gotos. Note that this means we pin the CPU a little longer for some cases as the CTX put is moved to common code at the end of the function.
Signed-off-by: Christoph Hellwig <[email protected]> --- block/blk-mq.c | 67 +++++++++++++++++++++++----------------------------------- 1 file changed, 27 insertions(+), 40 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 48748cb799ed..18e449cc832f 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1534,16 +1534,17 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) cookie = request_to_qc_t(data.hctx, rq); + plug = current->plug; if (unlikely(is_flush_fua)) { - if (q->elevator) - goto elv_insert; blk_mq_bio_to_request(rq, bio); - blk_insert_flush(rq); - goto run_queue; - } - - plug = current->plug; - if (plug && q->nr_hw_queues == 1) { + if (q->elevator) { + blk_mq_sched_insert_request(rq, false, true, + !is_sync || is_flush_fua, true); + } else { + blk_insert_flush(rq); + blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua); + } + } else if (plug && q->nr_hw_queues == 1) { struct request *last = NULL; blk_mq_bio_to_request(rq, bio); @@ -1562,8 +1563,6 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) else last = list_entry_rq(plug->mq_list.prev); - blk_mq_put_ctx(data.ctx); - if (request_count >= BLK_MAX_REQUEST_COUNT || (last && blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) { blk_flush_plug_list(plug, false); @@ -1571,56 +1570,44 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) } list_add_tail(&rq->queuelist, &plug->mq_list); - goto done; - } else if (((plug && !blk_queue_nomerges(q)) || is_sync)) { - struct request *old_rq = NULL; - + } else if (plug && !blk_queue_nomerges(q)) { blk_mq_bio_to_request(rq, bio); /* * We do limited plugging. If the bio can be merged, do that. * Otherwise the existing request in the plug list will be * issued. So the plug list will have one request at most + * + * The plug list might get flushed before this. If that happens, + * the plug list is emptry and same_queue_rq is invalid. */ - if (plug) { - /* - * The plug list might get flushed before this. If that - * happens, same_queue_rq is invalid and plug list is - * empty - */ - if (same_queue_rq && !list_empty(&plug->mq_list)) { - old_rq = same_queue_rq; - list_del_init(&old_rq->queuelist); - } - list_add_tail(&rq->queuelist, &plug->mq_list); - } else /* is_sync */ - old_rq = rq; - blk_mq_put_ctx(data.ctx); - if (old_rq) - blk_mq_try_issue_directly(data.hctx, old_rq, &cookie); - goto done; - } + if (!list_empty(&plug->mq_list)) + list_del_init(&same_queue_rq->queuelist); + else + same_queue_rq = NULL; - if (q->elevator) { -elv_insert: - blk_mq_put_ctx(data.ctx); + list_add_tail(&rq->queuelist, &plug->mq_list); + if (same_queue_rq) + blk_mq_try_issue_directly(data.hctx, same_queue_rq, + &cookie); + } else if (is_sync) { + blk_mq_bio_to_request(rq, bio); + blk_mq_try_issue_directly(data.hctx, rq, &cookie); + } else if (q->elevator) { blk_mq_bio_to_request(rq, bio); blk_mq_sched_insert_request(rq, false, true, !is_sync || is_flush_fua, true); - goto done; - } - if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) { + } else if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) { /* * For a SYNC request, send it to the hardware immediately. For * an ASYNC request, just ensure that we run it later on. The * latter allows for merging opportunities and more efficient * dispatching. */ -run_queue: blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua); } + blk_mq_put_ctx(data.ctx); -done: return cookie; } -- 2.11.0
