[Patch net 05/15] net_sched: remove RCU callbacks in cgroup filter

[Cong Wang]

Replace call_rcu() with synchronize_rcu().

Reported-by: Chris Mi <chr...@mellanox.com>
Cc: Daniel Borkmann <dan...@iogearbox.net>
Cc: Jiri Pirko <j...@resnulli.us>
Cc: John Fastabend <john.fastab...@gmail.com>
Cc: Jamal Hadi Salim <j...@mojatatu.com>
Cc: "Paul E. McKenney" <paul...@linux.vnet.ibm.com>
Signed-off-by: Cong Wang <xiyou.wangc...@gmail.com>
---
 net/sched/cls_cgroup.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c
index d48452f87975..fb001799eca6 100644
--- a/net/sched/cls_cgroup.c
+++ b/net/sched/cls_cgroup.c
@@ -23,7 +23,6 @@ struct cls_cgroup_head {
        struct tcf_exts         exts;
        struct tcf_ematch_tree  ematches;
        struct tcf_proto        *tp;
-       struct rcu_head         rcu;
 };
 
 static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp,
@@ -57,11 +56,8 @@ static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX 
+ 1] = {
        [TCA_CGROUP_EMATCHES]   = { .type = NLA_NESTED },
 };
 
-static void cls_cgroup_destroy_rcu(struct rcu_head *root)
+static void __cls_cgroup_destroy(struct cls_cgroup_head *head)
 {
-       struct cls_cgroup_head *head = container_of(root,
-                                                   struct cls_cgroup_head,
-                                                   rcu);
 
        tcf_exts_destroy(&head->exts);
        tcf_em_tree_destroy(&head->ematches);
@@ -110,8 +106,10 @@ static int cls_cgroup_change(struct net *net, struct 
sk_buff *in_skb,
                goto errout;
 
        rcu_assign_pointer(tp->root, new);
-       if (head)
-               call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
+       if (head) {
+               synchronize_rcu();
+               __cls_cgroup_destroy(head);
+       }
        return 0;
 errout:
        tcf_exts_destroy(&new->exts);
@@ -124,8 +122,10 @@ static void cls_cgroup_destroy(struct tcf_proto *tp)
        struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 
        /* Head can still be NULL due to cls_cgroup_init(). */
-       if (head)
-               call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
+       if (head) {
+               synchronize_rcu();
+               __cls_cgroup_destroy(head);
+       }
 }
 
 static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last)
-- 
2.13.0