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, 1 insertions, 1 deletions

diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index a6b7ee9ce28a..ec3a12b9b802 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -216,7 +216,7 @@ void sctp_transport_set_owner(struct sctp_transport *transport,
 void sctp_transport_pmtu(struct sctp_transport *transport, struct sock *sk)
 {
         /* If we don't have a fresh route, look one up */
-        if (!transport->dst || transport->dst->obsolete > 1) {
+        if (!transport->dst || transport->dst->obsolete) {
                 dst_release(transport->dst);
                 transport->af_specific->get_dst(transport, &transport->saddr,
                                                 &transport->fl, sk);