Commit ae8650b4 authored by Yu Kuai's avatar Yu Kuai Committed by Jens Axboe
Browse files

blk-cgroup: check for pd_(alloc|free)_fn in blkcg_activate_policy() 



Currently all policies implement pd_(alloc|free)_fn, however, this is
not necessary for ioprio that only works for blkcg, not blkg.

There are no functional changes, prepare to cleanup activating ioprio
policy.

Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20240719071506.158075-2-yukuai1@huaweicloud.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 8400291e

block/blk-cgroup.c

+13 −2
Original line number Diff line number Diff line
@@ -1554,6 +1554,14 @@ int blkcg_activate_policy(struct gendisk *disk, const struct blkcg_policy *pol) 
	if (blkcg_policy_enabled(q, pol))

		return 0;



	/*

	 * Policy is allowed to be registered without pd_alloc_fn/pd_free_fn,

	 * for example, ioprio. Such policy will work on blkcg level, not disk

	 * level, and don't need to be activated.

	 */

	if (WARN_ON_ONCE(!pol->pd_alloc_fn || !pol->pd_free_fn))

		return -EINVAL;



	if (queue_is_mq(q))

		blk_mq_freeze_queue(q);

retry:
@@ -1733,7 +1741,10 @@ int blkcg_policy_register(struct blkcg_policy *pol) 
		goto err_unlock;

	}



	/* Make sure cpd/pd_alloc_fn and cpd/pd_free_fn in pairs */

	/*

	 * Make sure cpd/pd_alloc_fn and cpd/pd_free_fn in pairs, and policy

	 * without pd_alloc_fn/pd_free_fn can't be activated.

	 */

	if ((!pol->cpd_alloc_fn ^ !pol->cpd_free_fn) ||

	    (!pol->pd_alloc_fn ^ !pol->pd_free_fn))

		goto err_unlock;