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blk-mq-sched: refactor scheduler initialization

Browse source 
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: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Omar Sandoval 2017-04-05 12:01:30 -07:00 committed by Jens Axboe
parent 81380ca107
commit 6917ff0b5b
3 changed files with 59 additions and 61 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

84
block/blk-mq-sched.c
View file

@ -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;
/*
* 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);
if (ret)
break;
}
/*
* If we failed, free what we did allocate
*/
if (ret) {
queue_for_each_hw_ctx(q, hctx, i) {
hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests,
set->reserved_tags);
if (!hctx->sched_tags)
continue;
blk_mq_sched_free_tags(set, hctx, i);
}
return -ENOMEM;
ret = blk_mq_alloc_rqs(set, hctx->sched_tags, hctx_idx, q->nr_requests);
if (ret)
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;

2
block/blk-mq-sched.h
View file

@ -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);

26
block/elevator.c
View file

@ -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) {