ipv6: Teach tree walker to skip multipath routes

As explained in previous patch, fib6_ifdown() needs to consider the
state of all the sibling routes when a multipath route is traversed.

This is done by evaluating all the siblings when the first sibling in a
multipath route is traversed. If the multipath route does not need to be
flushed (e.g., not all siblings are dead), then we should just skip the
multipath route as our work is done.

Have the tree walker jump to the last sibling when it is determined that
the multipath route needs to be skipped.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 3bbb89d8187d22fb9853068de9553acad12e0496..5e4b5eef0ddd345d926cbf3a84e2d1970c0ba938 100644 (file)
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1887,7 +1887,7 @@ static int fib6_clean_node(struct fib6_walker *w)
 
        for_each_fib6_walker_rt(w) {
                res = c->func(rt, c->arg);
-               if (res < 0) {
+               if (res == -1) {
                        w->leaf = rt;
                        res = fib6_del(rt, &info);
                        if (res) {
@@ -1900,6 +1900,12 @@ static int fib6_clean_node(struct fib6_walker *w)
                                continue;
                        }
                        return 0;
+               } else if (res == -2) {
+                       if (WARN_ON(!rt->rt6i_nsiblings))
+                               continue;
+                       rt = list_last_entry(&rt->rt6i_siblings,
+                                            struct rt6_info, rt6i_siblings);
+                       continue;
                }
                WARN_ON(res != 0);
        }
@@ -1911,7 +1917,8 @@ static int fib6_clean_node(struct fib6_walker *w)
  *     Convenient frontend to tree walker.
  *
  *     func is called on each route.
- *             It may return -1 -> delete this route.
+ *             It may return -2 -> skip multipath route.
+ *                           -1 -> delete this route.
  *                           0  -> continue walking
  */