diff options
author | Damien Le Moal <damien.lemoal@wdc.com> | 2017-12-21 15:43:39 +0900 |
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committer | Jens Axboe <axboe@kernel.dk> | 2018-01-05 09:22:17 -0700 |
commit | bf09ce56f0e654b94d980b9aa89e3fce78887e01 (patch) | |
tree | 9ef99109ad0b7629d29be6d506013b6fa8072801 | |
parent | 6cc77e9cb08041627fe1d32ac3a743249deb8167 (diff) | |
download | linux-bf09ce56f0e654b94d980b9aa89e3fce78887e01.tar.bz2 |
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 <damien.lemoal@wdc.com>
Reviewed-by: Bart Van Assche <Bart.VanAssche@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r-- | block/mq-deadline.c | 45 |
1 files 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 @@ -192,13 +192,42 @@ static inline int deadline_check_fifo(struct deadline_data *dd, int ddir) } /* + * 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 */ 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 @@ 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; |