[Patch net 11/13] cls_rsvp: use tcf_exts_get_net() before call_rcu()

[Cong Wang]

Hold netns refcnt before call_rcu() and release it after
the tcf_exts_destroy() is done.

Note, on ->destroy() path we have to respect the return value
of tcf_exts_get_net(), on other paths it should always return
true, so we don't need to care.

Cc: Lucas Bates <luc...@mojatatu.com>
Cc: Jamal Hadi Salim <j...@mojatatu.com>
Cc: Jiri Pirko <j...@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangc...@gmail.com>
---
 net/sched/cls_rsvp.h | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/net/sched/cls_rsvp.h b/net/sched/cls_rsvp.h
index bdbc541787f8..cf325625c99d 100644
--- a/net/sched/cls_rsvp.h
+++ b/net/sched/cls_rsvp.h
@@ -285,13 +285,19 @@ static int rsvp_init(struct tcf_proto *tp)
        return -ENOBUFS;
 }
 
+static void __rsvp_delete_filter(struct rsvp_filter *f)
+{
+       tcf_exts_destroy(&f->exts);
+       tcf_exts_put_net(&f->exts);
+       kfree(f);
+}
+
 static void rsvp_delete_filter_work(struct work_struct *work)
 {
        struct rsvp_filter *f = container_of(work, struct rsvp_filter, work);
 
        rtnl_lock();
-       tcf_exts_destroy(&f->exts);
-       kfree(f);
+       __rsvp_delete_filter(f);
        rtnl_unlock();
 }
 
@@ -310,7 +316,10 @@ static void rsvp_delete_filter(struct tcf_proto *tp, 
struct rsvp_filter *f)
         * grace period, since converted-to-rcu actions are relying on that
         * in cleanup() callback
         */
-       call_rcu(&f->rcu, rsvp_delete_filter_rcu);
+       if (tcf_exts_get_net(&f->exts))
+               call_rcu(&f->rcu, rsvp_delete_filter_rcu);
+       else
+               __rsvp_delete_filter(f);
 }
 
 static void rsvp_destroy(struct tcf_proto *tp)
-- 
2.13.0