From: Tejun Heo Date: Wed, 14 May 2014 13:15:01 +0000 (-0400) Subject: cgroup: move cgroup->sibling unlinking to cgroup_put() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=4e4e28472365f8c7a7c55f6b5706f68bc40c5b13;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git cgroup: move cgroup->sibling unlinking to cgroup_put() Move cgroup->sibling unlinking from cgroup_destroy_css_killed() to cgroup_put(). This is later but still before the RCU grace period, so it doesn't break css_next_child() although there now is a larger window in which a dead cgroup is visible during css iteration. As css iteration always could have included offline csses, this doesn't affect correctness; however, it does make css_next_child() fall back to reiterting mode more often. This also makes cgroup_put() directly take cgroup_mutex, which limits where it can be called from. These are not immediately problematic and will be dealt with later. This change enables simplification of cgroup destruction path. Signed-off-by: Tejun Heo Acked-by: Li Zefan --- diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 061569fba245..e9aa2a51ca68 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1056,6 +1056,11 @@ static void cgroup_put(struct cgroup *cgrp) if (WARN_ON_ONCE(cgrp->parent && !cgroup_is_dead(cgrp))) return; + /* delete this cgroup from parent->children */ + mutex_lock(&cgroup_mutex); + list_del_rcu(&cgrp->sibling); + mutex_unlock(&cgroup_mutex); + cgroup_idr_remove(&cgrp->root->cgroup_idr, cgrp->id); cgrp->id = -1; @@ -4561,9 +4566,6 @@ static void cgroup_destroy_css_killed(struct cgroup *cgrp) { lockdep_assert_held(&cgroup_mutex); - /* delete this cgroup from parent->children */ - list_del_rcu(&cgrp->sibling); - cgroup_put(cgrp); }