[Patch net 11/16] net_sched: use tcf_queue_work() in rsvp filter

[Cong Wang]

Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.

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_rsvp.h | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/net/sched/cls_rsvp.h b/net/sched/cls_rsvp.h
index b1f6ed48bc72..bdbc541787f8 100644
--- a/net/sched/cls_rsvp.h
+++ b/net/sched/cls_rsvp.h
@@ -97,7 +97,10 @@ struct rsvp_filter {
 
        u32                             handle;
        struct rsvp_session             *sess;
-       struct rcu_head                 rcu;
+       union {
+               struct work_struct              work;
+               struct rcu_head                 rcu;
+       };
 };
 
 static inline unsigned int hash_dst(__be32 *dst, u8 protocol, u8 tunnelid)
@@ -282,12 +285,22 @@ static int rsvp_init(struct tcf_proto *tp)
        return -ENOBUFS;
 }
 
-static void rsvp_delete_filter_rcu(struct rcu_head *head)
+static void rsvp_delete_filter_work(struct work_struct *work)
 {
-       struct rsvp_filter *f = container_of(head, struct rsvp_filter, rcu);
+       struct rsvp_filter *f = container_of(work, struct rsvp_filter, work);
 
+       rtnl_lock();
        tcf_exts_destroy(&f->exts);
        kfree(f);
+       rtnl_unlock();
+}
+
+static void rsvp_delete_filter_rcu(struct rcu_head *head)
+{
+       struct rsvp_filter *f = container_of(head, struct rsvp_filter, rcu);
+
+       INIT_WORK(&f->work, rsvp_delete_filter_work);
+       tcf_queue_work(&f->work);
 }
 
 static void rsvp_delete_filter(struct tcf_proto *tp, struct rsvp_filter *f)
-- 
2.13.0