net: Document dst->obsolete better.

Add a big comment explaining how the field works, and use defines
instead of magic constants for the values assigned to it.

Suggested by Joe Perches.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index 47de90d8fe94..23cc11dd4e40 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -1176,7 +1176,7 @@ make_route:
         if (dev_out->flags & IFF_LOOPBACK)
                 flags |= RTCF_LOCAL;
 
-        rt = dst_alloc(&dn_dst_ops, dev_out, 1, 0, DST_HOST);
+        rt = dst_alloc(&dn_dst_ops, dev_out, 1, DST_OBSOLETE_NONE, DST_HOST);
         if (rt == NULL)
                 goto e_nobufs;
 
@@ -1444,7 +1444,7 @@ static int dn_route_input_slow(struct sk_buff *skb)
         }
 
 make_route:
-        rt = dst_alloc(&dn_dst_ops, out_dev, 0, 0, DST_HOST);
+        rt = dst_alloc(&dn_dst_ops, out_dev, 0, DST_OBSOLETE_NONE, DST_HOST);
         if (rt == NULL)
                 goto e_nobufs;