net: sched: cls_rcvp, complete rcu conversion

This completes the cls_rsvp conversion to RCU safe
copy, update semantics.

As a result all cases of tcf_exts_change occur on
empty lists now.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/cls_rsvp.h b/net/sched/cls_rsvp.h
index 1c64a09..6bb55f2 100644 (file)
--- a/net/sched/cls_rsvp.h
+++ b/net/sched/cls_rsvp.h
@@ -222,6 +222,33 @@ matched:
        return -1;
 }
 
+static void rsvp_replace(struct tcf_proto *tp, struct rsvp_filter *n, u32 h)
+{
+       struct rsvp_head *head = rtnl_dereference(tp->root);
+       struct rsvp_session *s;
+       struct rsvp_filter __rcu **ins;
+       struct rsvp_filter *pins;
+       unsigned int h1 = h & 0xFF;
+       unsigned int h2 = (h >> 8) & 0xFF;
+
+       for (s = rtnl_dereference(head->ht[h1]); s;
+            s = rtnl_dereference(s->next)) {
+               for (ins = &s->ht[h2], pins = rtnl_dereference(*ins); ;
+                    ins = &pins->next, pins = rtnl_dereference(*ins)) {
+                       if (pins->handle == h) {
+                               RCU_INIT_POINTER(n->next, pins->next);
+                               rcu_assign_pointer(*ins, n);
+                               return;
+                       }
+               }
+       }
+
+       /* Something went wrong if we are trying to replace a non-existant
+        * node. Mind as well halt instead of silently failing.
+        */
+       BUG_ON(1);
+}
+
 static unsigned long rsvp_get(struct tcf_proto *tp, u32 handle)
 {
        struct rsvp_head *head = rtnl_dereference(tp->root);
@@ -454,15 +481,26 @@ static int rsvp_change(struct net *net, struct sk_buff *in_skb,
        f = (struct rsvp_filter *)*arg;
        if (f) {
                /* Node exists: adjust only classid */
+               struct rsvp_filter *n;
 
                if (f->handle != handle && handle)
                        goto errout2;
+
+               n = kmemdup(f, sizeof(*f), GFP_KERNEL);
+               if (!n) {
+                       err = -ENOMEM;
+                       goto errout2;
+               }
+
+               tcf_exts_init(&n->exts, TCA_RSVP_ACT, TCA_RSVP_POLICE);
+
                if (tb[TCA_RSVP_CLASSID]) {
-                       f->res.classid = nla_get_u32(tb[TCA_RSVP_CLASSID]);
-                       tcf_bind_filter(tp, &f->res, base);
+                       n->res.classid = nla_get_u32(tb[TCA_RSVP_CLASSID]);
+                       tcf_bind_filter(tp, &n->res, base);
                }
 
-               tcf_exts_change(tp, &f->exts, &e);
+               tcf_exts_change(tp, &n->exts, &e);
+               rsvp_replace(tp, n, handle);
                return 0;
        }