[NET]: Introduce union in struct dst_entry to hold 'next' pointer

This patch introduces an anonymous union to nicely express the fact that all
objects inherited from struct dst_entry should access to the generic 'next'
pointer but with appropriate type verification.

This patch is a prereq before following patches.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 1 deletions

diff --git a/include/net/dst.h b/include/net/dst.h
index 62b7e7598e9a..5d62342e8bc4 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -37,7 +37,12 @@ struct sk_buff;
 
 struct dst_entry
 {
-        struct dst_entry        *next;
+        union {
+                struct dst_entry *next;
+                struct rtable    *rt_next;
+                struct rt6_info   *rt6_next;
+                struct dn_route  *dn_next;
+        };
         atomic_t                __refcnt;       /* client references    */
         int                     __use;
         struct dst_entry        *child;