From: Yu Kuai <yukuai3@xxxxxxxxxx> 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: Yu Kuai <yukuai3@xxxxxxxxxx> --- block/blk-cgroup.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 37e6cc91d576..dcd5e857650a 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -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; -- 2.39.2
