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Commit 6917ff0b authored by Omar Sandoval's avatar Omar Sandoval Committed by Jens Axboe
Browse files

blk-mq-sched: refactor scheduler initialization 



Preparation cleanup for the next couple of fixes, push
blk_mq_sched_setup() and e->ops.mq.init_sched() into a helper.

Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 81380ca1

block/blk-mq-sched.c

+44 −38
Original line number Diff line number Diff line
@@ -432,53 +432,25 @@ static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set, 
	}

}



int blk_mq_sched_setup(struct request_queue *q)

static int blk_mq_sched_alloc_tags(struct request_queue *q,

				   struct blk_mq_hw_ctx *hctx,

				   unsigned int hctx_idx)

{

	struct blk_mq_tag_set *set = q->tag_set;

	struct blk_mq_hw_ctx *hctx;

	int ret, i;

	int ret;



	/*

	 * Default to 256, since we don't split into sync/async like the

	 * old code did. Additionally, this is a per-hw queue depth.

	 */

	q->nr_requests = 2 * BLKDEV_MAX_RQ;

	hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests,

					       set->reserved_tags);

	if (!hctx->sched_tags)

		return -ENOMEM;



	/*

	 * We're switching to using an IO scheduler, so setup the hctx

	 * scheduler tags and switch the request map from the regular

	 * tags to scheduler tags. First allocate what we need, so we

	 * can safely fail and fallback, if needed.

	 */

	ret = 0;

	queue_for_each_hw_ctx(q, hctx, i) {

		hctx->sched_tags = blk_mq_alloc_rq_map(set, i,

				q->nr_requests, set->reserved_tags);

		if (!hctx->sched_tags) {

			ret = -ENOMEM;

			break;

		}

		ret = blk_mq_alloc_rqs(set, hctx->sched_tags, i, q->nr_requests);

	ret = blk_mq_alloc_rqs(set, hctx->sched_tags, hctx_idx, q->nr_requests);

	if (ret)

			break;

	}



	/*

	 * If we failed, free what we did allocate

	 */

	if (ret) {

		queue_for_each_hw_ctx(q, hctx, i) {

			if (!hctx->sched_tags)

				continue;

			blk_mq_sched_free_tags(set, hctx, i);

		}

		blk_mq_sched_free_tags(set, hctx, hctx_idx);



	return ret;

}



	return 0;

}



void blk_mq_sched_teardown(struct request_queue *q)

{

	struct blk_mq_tag_set *set = q->tag_set;
@@ -489,6 +461,40 @@ void blk_mq_sched_teardown(struct request_queue *q) 
		blk_mq_sched_free_tags(set, hctx, i);

}



int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)

{

	struct blk_mq_hw_ctx *hctx;

	unsigned int i;

	int ret;



	if (!e) {

		q->elevator = NULL;

		return 0;

	}



	/*

	 * Default to 256, since we don't split into sync/async like the

	 * old code did. Additionally, this is a per-hw queue depth.

	 */

	q->nr_requests = 2 * BLKDEV_MAX_RQ;



	queue_for_each_hw_ctx(q, hctx, i) {

		ret = blk_mq_sched_alloc_tags(q, hctx, i);

		if (ret)

			goto err;

	}



	ret = e->ops.mq.init_sched(q, e);

	if (ret)

		goto err;



	return 0;



err:

	blk_mq_sched_teardown(q);

	return ret;

}



int blk_mq_sched_init(struct request_queue *q)

{

	int ret;

block/blk-mq-sched.h

+1 −1
Original line number Diff line number Diff line
@@ -32,7 +32,7 @@ void blk_mq_sched_move_to_dispatch(struct blk_mq_hw_ctx *hctx, 
			struct list_head *rq_list,

			struct request *(*get_rq)(struct blk_mq_hw_ctx *));



int blk_mq_sched_setup(struct request_queue *q);

int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e);

void blk_mq_sched_teardown(struct request_queue *q);



int blk_mq_sched_init(struct request_queue *q);

block/elevator.c

+12 −20
Original line number Diff line number Diff line
@@ -242,17 +242,12 @@ int elevator_init(struct request_queue *q, char *name) 
		}

	}



	if (e->uses_mq) {

		err = blk_mq_sched_setup(q);

		if (!err)

			err = e->ops.mq.init_sched(q, e);

	} else

		err = e->ops.sq.elevator_init_fn(q, e);

	if (err) {

	if (e->uses_mq)

			blk_mq_sched_teardown(q);

		err = blk_mq_init_sched(q, e);

	else

		err = e->ops.sq.elevator_init_fn(q, e);

	if (err)

		elevator_put(e);

	}

	return err;

}

EXPORT_SYMBOL(elevator_init);
@@ -987,21 +982,18 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) 
	}



	/* allocate, init and register new elevator */

	if (new_e) {

		if (new_e->uses_mq) {

			err = blk_mq_sched_setup(q);

			if (!err)

				err = new_e->ops.mq.init_sched(q, new_e);

		} else

	if (q->mq_ops)

		err = blk_mq_init_sched(q, new_e);

	else

		err = new_e->ops.sq.elevator_init_fn(q, new_e);

	if (err)

		goto fail_init;



	if (new_e) {

		err = elv_register_queue(q);

		if (err)

			goto fail_register;

	} else

		q->elevator = NULL;

	}



	/* done, kill the old one and finish */

	if (old) {