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Commit c117bac7 authored by Damien Le Moal's avatar Damien Le Moal Committed by Jens Axboe
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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: default avatarDamien Le Moal <damien.lemoal@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 5700f691

block/deadline-iosched.c

+37 −10
Original line number Diff line number Diff line
@@ -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 @@ static int deadline_dispatch_requests(struct request_queue *q, int force) 
	/*

	 * 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;