cgroup/blkio: Add deprecation messages to reset_stats

It is difficult to sync with stat updaters, stats are (should be)
monotonic so users can calculate differences from a reference.

Signed-off-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 45a395862fbc88f448fe281eeac620710bc1587d..b3e5184b10d5ff741feaef2f90f0281872be48de 100644 (file)
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -659,6 +659,7 @@ static int blkcg_reset_stats(struct cgroup_subsys_state *css,
        struct blkcg_gq *blkg;
        int i;
 
+       pr_info_once("blkio.%s is deprecated\n", cftype->name);
        mutex_lock(&blkcg_pol_mutex);
        spin_lock_irq(&blkcg->lock);