[PATCH 1/5] NET : Introduce union in struct dst_entry to hold 'next' pointer

[Eric Dumazet]

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 <[EMAIL PROTECTED]>
--- linux-2.6.20/include/net/dst.h      2007-02-08 21:06:15.000000000 +0100
+++ linux-2.6.20-ed/include/net/dst.h   2007-02-08 21:07:21.000000000 +0100
@@ -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;