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authorMadhuparna Bhowmik <madhuparnabhowmik10@gmail.com>2020-01-18 08:40:51 +0530
committerTejun Heo <tj@kernel.org>2020-02-12 17:12:22 -0500
commit3010c5b9f5f476b35b24955f08a3a6c06ec8e878 (patch)
tree93d94005cefb24a84c181b2fa940d2b8c56117f0
parent04189382c0be4e045d63a38b47f012a8f6c35edc (diff)
downloadlinux-3010c5b9f5f476b35b24955f08a3a6c06ec8e878.tar.bz2
cgroup.c: Use built-in RCU list checking
list_for_each_entry_rcu has built-in RCU and lock checking. Pass cond argument to list_for_each_entry_rcu() to silence false lockdep warning when CONFIG_PROVE_RCU_LIST is enabled by default. Even though the function css_next_child() already checks if cgroup_mutex or rcu_read_lock() is held using cgroup_assert_mutex_or_rcu_locked(), there is a need to pass cond to list_for_each_entry_rcu() to avoid false positive lockdep warning. Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com> Acked-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
-rw-r--r--kernel/cgroup/cgroup.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index b4c4c4fbd6de..7a310db6c807 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -4148,7 +4148,8 @@ struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,
} else if (likely(!(pos->flags & CSS_RELEASED))) {
next = list_entry_rcu(pos->sibling.next, struct cgroup_subsys_state, sibling);
} else {
- list_for_each_entry_rcu(next, &parent->children, sibling)
+ list_for_each_entry_rcu(next, &parent->children, sibling,
+ lockdep_is_held(&cgroup_mutex))
if (next->serial_nr > pos->serial_nr)
break;
}