Commit bf09ce56 authored by Damien Le Moal's avatar Damien Le Moal Committed by Jens Axboe
Browse files

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: default avatarDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: default avatarBart Van Assche <Bart.VanAssche@wdc.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 6cc77e9c

block/mq-deadline.c

+37 −8
Original line number Diff line number Diff line
@@ -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 @@ 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;

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