From c117bac70133dbff9ed7fcbd91ef82b4ee518797 Mon Sep 17 00:00:00 2001 From: Damien Le Moal Date: Thu, 21 Dec 2017 15:43:41 +0900 Subject: [PATCH] deadline-iosched: 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 deadline_dispatch_requests() for zoned block devices. While at it, also remove the unnecessary forward declaration of the function deadline_move_request(). Signed-off-by: Damien Le Moal Reviewed-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Signed-off-by: Jens Axboe --- block/deadline-iosched.c | 47 +++++++++++++++++++++++++++++++--------- 1 file changed, 37 insertions(+), 10 deletions(-) diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c index b83f77460d28..81e3f0897457 100644 --- a/block/deadline-iosched.c +++ b/block/deadline-iosched.c @@ -50,8 +50,6 @@ struct deadline_data { int front_merges; }; -static void deadline_move_request(struct deadline_data *, struct request *); - static inline struct rb_root * deadline_rb_root(struct deadline_data *dd, struct request *rq) { @@ -230,6 +228,35 @@ 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 @@ -239,16 +266,15 @@ static int deadline_dispatch_requests(struct request_queue *q, int force) struct deadline_data *dd = q->elevator->elevator_data; const int reads = !list_empty(&dd->fifo_list[READ]); const int writes = !list_empty(&dd->fifo_list[WRITE]); - struct request *rq; + struct request *rq, *next_rq; int data_dir; /* * 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 */ @@ -291,19 +317,20 @@ dispatch_find_request: /* * 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; -- 2.30.2