block/blk-cgroup.c: free per-blkcg data when freeing the blkcg
Currently, per-blkcg data is freed each time a policy is deactivated,
that is also upon scheduler switch. However, when switching from a
scheduler implementing a policy which requires per-blkcg data to
another one, that same policy might be active on other devices, and
therefore those same per-blkcg data could be still in use.
This commit lets per-blkcg data be freed when the blkcg is freed
instead of on policy deactivation.
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Reported-and-tested-by: Michael Kaminsky <kaminsky@cs.cmu.edu>
Fixes: e48453c3 ("block, cgroup: implement policy-specific per-blkcg data")
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 9f97da5..5e2723f 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -822,8 +822,13 @@
{
struct blkcg *blkcg = css_to_blkcg(css);
- if (blkcg != &blkcg_root)
+ if (blkcg != &blkcg_root) {
+ int i;
+
+ for (i = 0; i < BLKCG_MAX_POLS; i++)
+ kfree(blkcg->pd[i]);
kfree(blkcg);
+ }
}
static struct cgroup_subsys_state *
@@ -1162,8 +1167,6 @@
kfree(blkg->pd[pol->plid]);
blkg->pd[pol->plid] = NULL;
- kfree(blkg->blkcg->pd[pol->plid]);
- blkg->blkcg->pd[pol->plid] = NULL;
spin_unlock(&blkg->blkcg->lock);
}