sctp: remove 'resent' bit from the chunk

The 'resent' bit is used to make sure that we don't update
rto estimate based on retransmitted chunks.  However, we already
have the 'rto_pending' bit that we test when need to update rto,
so 'resent' bit is just extra.  Additionally, we currently have
a bug in that we always set a 'resent' bit and thus rto estimate
is only updated by Heartbeats.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

include/net/sctp/structs.h

@@ -757,7 +757,6 @@ struct sctp_chunk {
 #define SCTP_NEED_FRTX 0x1
 #define SCTP_DONT_FRTX 0x2
 	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
-		resent:1,		/* Has this chunk ever been resent. */
 		has_tsn:1,		/* Does this chunk have a TSN yet? */
 		has_ssn:1,		/* Does this chunk have a SSN yet? */
 		singleton:1,		/* Only chunk in the packet? */
@@ -1065,7 +1064,7 @@ void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
 			  struct sctp_sock *);
 void sctp_transport_pmtu(struct sctp_transport *);
 void sctp_transport_free(struct sctp_transport *);
-void sctp_transport_reset_timers(struct sctp_transport *, int);
+void sctp_transport_reset_timers(struct sctp_transport *);
 void sctp_transport_hold(struct sctp_transport *);
 void sctp_transport_put(struct sctp_transport *);
 void sctp_transport_update_rto(struct sctp_transport *, __u32);

net/sctp/output.c

@@ -429,24 +429,17 @@ int sctp_packet_transmit(struct sctp_packet *packet)
 	list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
 		list_del_init(&chunk->list);
 		if (sctp_chunk_is_data(chunk)) {
+			/* 6.3.1 C4) When data is in flight and when allowed
+			 * by rule C5, a new RTT measurement MUST be made each
+			 * round trip.  Furthermore, new RTT measurements
+			 * SHOULD be made no more than once per round-trip
+			 * for a given destination transport address.
+			 */
 
-			if (!chunk->resent) {
-
-				/* 6.3.1 C4) When data is in flight and when allowed
-				 * by rule C5, a new RTT measurement MUST be made each
-				 * round trip.  Furthermore, new RTT measurements
-				 * SHOULD be made no more than once per round-trip
-				 * for a given destination transport address.
-				 */
-
-				if (!tp->rto_pending) {
-					chunk->rtt_in_progress = 1;
-					tp->rto_pending = 1;
-				}
+			if (!tp->rto_pending) {
+				chunk->rtt_in_progress = 1;
+				tp->rto_pending = 1;
 			}
-
-			chunk->resent = 1;
-
 			has_data = 1;
 		}
 

net/sctp/outqueue.c

@@ -1405,7 +1405,6 @@ static void sctp_check_transmitted(struct sctp_outq *q,
 				 * instance).
 				 */
 				if (!tchunk->tsn_gap_acked &&
-				    !tchunk->resent &&
 				    tchunk->rtt_in_progress) {
 					tchunk->rtt_in_progress = 0;
 					rtt = jiffies - tchunk->sent_at;

net/sctp/sm_make_chunk.c

@@ -1205,7 +1205,6 @@ struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
 	INIT_LIST_HEAD(&retval->list);
 	retval->skb		= skb;
 	retval->asoc		= (struct sctp_association *)asoc;
-	retval->resent  	= 0;
 	retval->has_tsn		= 0;
 	retval->has_ssn         = 0;
 	retval->rtt_in_progress	= 0;