The implementation private sits right after the primary_key memory.
Signed-off-by: David S. Miller <davem@davemloft.net>
        struct pneigh_entry     **phash_buckets;
 };
 
+#define NEIGH_PRIV_ALIGN       sizeof(long long)
+
+static inline void *neighbour_priv(const struct neighbour *n)
+{
+       return (char *)n + ALIGN(sizeof(*n) + n->tbl->key_len, NEIGH_PRIV_ALIGN);
+}
+
 /* flags for neigh_update() */
 #define NEIGH_UPDATE_F_OVERRIDE                        0x00000001
 #define NEIGH_UPDATE_F_WEAK_OVERRIDE           0x00000002