sctp: get sock from transport in sctp_transport_update_pmtu

This patch is almost to revert commit 02f3d4ce ("sctp: Adjust PMTU
updates to accomodate route invalidation."). As t->asoc can't be NULL
in sctp_transport_update_pmtu, it could get sk from asoc, and no need
to pass sk into that function.

It is also to remove some duplicated codes from that function.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sctp/sctp.h

@@ -448,10 +448,9 @@ static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
 	return frag;
 }
 
-static inline void sctp_assoc_pending_pmtu(struct sock *sk, struct sctp_association *asoc)
+static inline void sctp_assoc_pending_pmtu(struct sctp_association *asoc)
 {
-
-	sctp_assoc_sync_pmtu(sk, asoc);
+	sctp_assoc_sync_pmtu(asoc);
 	asoc->pmtu_pending = 0;
 }
 

include/net/sctp/structs.h

@@ -952,8 +952,8 @@ void sctp_transport_lower_cwnd(struct sctp_transport *, sctp_lower_cwnd_t);
 void sctp_transport_burst_limited(struct sctp_transport *);
 void sctp_transport_burst_reset(struct sctp_transport *);
 unsigned long sctp_transport_timeout(struct sctp_transport *);
-void sctp_transport_reset(struct sctp_transport *);
-void sctp_transport_update_pmtu(struct sock *, struct sctp_transport *, u32);
+void sctp_transport_reset(struct sctp_transport *t);
+void sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
 void sctp_transport_immediate_rtx(struct sctp_transport *);
 void sctp_transport_dst_release(struct sctp_transport *t);
 void sctp_transport_dst_confirm(struct sctp_transport *t);
@@ -1954,7 +1954,7 @@ void sctp_assoc_update(struct sctp_association *old,
 
 __u32 sctp_association_get_next_tsn(struct sctp_association *);
 
-void sctp_assoc_sync_pmtu(struct sock *, struct sctp_association *);
+void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
 void sctp_assoc_set_primary(struct sctp_association *,

net/sctp/associola.c

@@ -1412,7 +1412,7 @@ sctp_assoc_choose_alter_transport(struct sctp_association *asoc,
 /* Update the association's pmtu and frag_point by going through all the
  * transports. This routine is called when a transport's PMTU has changed.
  */
-void sctp_assoc_sync_pmtu(struct sock *sk, struct sctp_association *asoc)
+void sctp_assoc_sync_pmtu(struct sctp_association *asoc)
 {
 	struct sctp_transport *t;
 	__u32 pmtu = 0;
@@ -1424,8 +1424,8 @@ void sctp_assoc_sync_pmtu(struct sock *sk, struct sctp_association *asoc)
 	list_for_each_entry(t, &asoc->peer.transport_addr_list,
 				transports) {
 		if (t->pmtu_pending && t->dst) {
-			sctp_transport_update_pmtu(sk, t,
-						   SCTP_TRUNC4(dst_mtu(t->dst)));
+			sctp_transport_update_pmtu(
+					t, SCTP_TRUNC4(dst_mtu(t->dst)));
 			t->pmtu_pending = 0;
 		}
 		if (!pmtu || (t->pathmtu < pmtu))

net/sctp/input.c

@@ -401,10 +401,10 @@ void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
 
 	if (t->param_flags & SPP_PMTUD_ENABLE) {
 		/* Update transports view of the MTU */
-		sctp_transport_update_pmtu(sk, t, pmtu);
+		sctp_transport_update_pmtu(t, pmtu);
 
 		/* Update association pmtu. */
-		sctp_assoc_sync_pmtu(sk, asoc);
+		sctp_assoc_sync_pmtu(asoc);
 	}
 
 	/* Retransmit with the new pmtu setting.

net/sctp/output.c

@@ -105,10 +105,10 @@ void sctp_packet_config(struct sctp_packet *packet, __u32 vtag,
 	if (!sctp_transport_dst_check(tp)) {
 		sctp_transport_route(tp, NULL, sctp_sk(sk));
 		if (asoc->param_flags & SPP_PMTUD_ENABLE)
-			sctp_assoc_sync_pmtu(sk, asoc);
+			sctp_assoc_sync_pmtu(asoc);
 	} else if (!sctp_transport_pmtu_check(tp)) {
 		if (asoc->param_flags & SPP_PMTUD_ENABLE)
-			sctp_assoc_sync_pmtu(sk, asoc);
+			sctp_assoc_sync_pmtu(asoc);
 	}
 
 	/* If there a is a prepend chunk stick it on the list before

net/sctp/socket.c

@@ -1907,7 +1907,7 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
 	}
 
 	if (asoc->pmtu_pending)
-		sctp_assoc_pending_pmtu(sk, asoc);
+		sctp_assoc_pending_pmtu(asoc);
 
 	/* If fragmentation is disabled and the message length exceeds the
 	 * association fragmentation point, return EMSGSIZE.  The I-D
@@ -2435,7 +2435,7 @@ static int sctp_apply_peer_addr_params(struct sctp_paddrparams *params,
 	if ((params->spp_flags & SPP_PMTUD_DISABLE) && params->spp_pathmtu) {
 		if (trans) {
 			trans->pathmtu = params->spp_pathmtu;
-			sctp_assoc_sync_pmtu(sctp_opt2sk(sp), asoc);
+			sctp_assoc_sync_pmtu(asoc);
 		} else if (asoc) {
 			asoc->pathmtu = params->spp_pathmtu;
 		} else {
@@ -2451,7 +2451,7 @@ static int sctp_apply_peer_addr_params(struct sctp_paddrparams *params,
 				(trans->param_flags & ~SPP_PMTUD) | pmtud_change;
 			if (update) {
 				sctp_transport_pmtu(trans, sctp_opt2sk(sp));
-				sctp_assoc_sync_pmtu(sctp_opt2sk(sp), asoc);
+				sctp_assoc_sync_pmtu(asoc);
 			}
 		} else if (asoc) {
 			asoc->param_flags =

net/sctp/transport.c

@@ -251,14 +251,13 @@ void sctp_transport_pmtu(struct sctp_transport *transport, struct sock *sk)
 		transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
 }
 
-void sctp_transport_update_pmtu(struct sock *sk, struct sctp_transport *t, u32 pmtu)
+void sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu)
 {
-	struct dst_entry *dst;
+	struct dst_entry *dst = sctp_transport_dst_check(t);
 
 	if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) {
 		pr_warn("%s: Reported pmtu %d too low, using default minimum of %d\n",
-			__func__, pmtu,
-			SCTP_DEFAULT_MINSEGMENT);
+			__func__, pmtu, SCTP_DEFAULT_MINSEGMENT);
 		/* Use default minimum segment size and disable
 		 * pmtu discovery on this transport.
 		 */
@@ -267,17 +266,13 @@ void sctp_transport_update_pmtu(struct sock *sk, struct sctp_transport *t, u32 p
 		t->pathmtu = pmtu;
 	}
 
-	dst = sctp_transport_dst_check(t);
-	if (!dst)
-		t->af_specific->get_dst(t, &t->saddr, &t->fl, sk);
-
 	if (dst) {
-		dst->ops->update_pmtu(dst, sk, NULL, pmtu);
-
+		dst->ops->update_pmtu(dst, t->asoc->base.sk, NULL, pmtu);
 		dst = sctp_transport_dst_check(t);
-		if (!dst)
-			t->af_specific->get_dst(t, &t->saddr, &t->fl, sk);
 	}
+
+	if (!dst)
+		t->af_specific->get_dst(t, &t->saddr, &t->fl, t->asoc->base.sk);
 }
 
 /* Caches the dst entry and source address for a transport's destination