From bf09ce56f0e654b94d980b9aa89e3fce78887e01 Mon Sep 17 00:00:00 2001 From: Damien Le Moal Date: Thu, 21 Dec 2017 15:43:39 +0900 Subject: [PATCH] mq-deadline: Introduce dispatch helpers Avoid directly referencing the next_rq and fifo_list arrays using the helper functions deadline_next_request() and deadline_fifo_request() to facilitate changes in the dispatch request selection in __dd_dispatch_request() for zoned block devices. Signed-off-by: Damien Le Moal Reviewed-by: Bart Van Assche Reviewed-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Signed-off-by: Jens Axboe --- block/mq-deadline.c | 45 +++++++++++++++++++++++++++++++++++++-------- 1 file changed, 37 insertions(+), 8 deletions(-) diff --git a/block/mq-deadline.c b/block/mq-deadline.c index 0179e484ec98..8bd6db9e69c7 100644 --- a/block/mq-deadline.c +++ b/block/mq-deadline.c @@ -191,6 +191,35 @@ static inline int deadline_check_fifo(struct deadline_data *dd, int ddir) return 0; } +/* + * For the specified data direction, return the next request to + * dispatch using arrival ordered lists. + */ +static struct request * +deadline_fifo_request(struct deadline_data *dd, int data_dir) +{ + if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE)) + return NULL; + + if (list_empty(&dd->fifo_list[data_dir])) + return NULL; + + return rq_entry_fifo(dd->fifo_list[data_dir].next); +} + +/* + * For the specified data direction, return the next request to + * dispatch using sector position sorted lists. + */ +static struct request * +deadline_next_request(struct deadline_data *dd, int data_dir) +{ + if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE)) + return NULL; + + return dd->next_rq[data_dir]; +} + /* * deadline_dispatch_requests selects the best request according to * read/write expire, fifo_batch, etc @@ -198,7 +227,7 @@ static inline int deadline_check_fifo(struct deadline_data *dd, int ddir) static struct request *__dd_dispatch_request(struct blk_mq_hw_ctx *hctx) { struct deadline_data *dd = hctx->queue->elevator->elevator_data; - struct request *rq; + struct request *rq, *next_rq; bool reads, writes; int data_dir; @@ -214,10 +243,9 @@ static struct request *__dd_dispatch_request(struct blk_mq_hw_ctx *hctx) /* * batches are currently reads XOR writes */ - if (dd->next_rq[WRITE]) - rq = dd->next_rq[WRITE]; - else - rq = dd->next_rq[READ]; + rq = deadline_next_request(dd, WRITE); + if (!rq) + rq = deadline_next_request(dd, READ); if (rq && dd->batching < dd->fifo_batch) /* we have a next request are still entitled to batch */ @@ -260,19 +288,20 @@ static struct request *__dd_dispatch_request(struct blk_mq_hw_ctx *hctx) /* * we are not running a batch, find best request for selected data_dir */ - if (deadline_check_fifo(dd, data_dir) || !dd->next_rq[data_dir]) { + next_rq = deadline_next_request(dd, data_dir); + if (deadline_check_fifo(dd, data_dir) || !next_rq) { /* * A deadline has expired, the last request was in the other * direction, or we have run out of higher-sectored requests. * Start again from the request with the earliest expiry time. */ - rq = rq_entry_fifo(dd->fifo_list[data_dir].next); + rq = deadline_fifo_request(dd, data_dir); } else { /* * The last req was the same dir and we have a next request in * sort order. No expired requests so continue on from here. */ - rq = dd->next_rq[data_dir]; + rq = next_rq; } dd->batching = 0;