From c329460af68ea733926a7cde460ea74ae8fd5c77 Mon Sep 17 00:00:00 2001
From: Xin Long <lucien.xin@gmail.com>
Date: Thu, 28 Oct 2021 05:36:04 -0400
Subject: [PATCH] sctp: return true only for pathmtu update in sctp_transport_pl_toobig
Git-commit: 75cf662c64dd8543f56c329c69eba18141c8fd9f
Patch-mainline: v5.16-rc1
References: stable-5.14.19

[ Upstream commit 75cf662c64dd8543f56c329c69eba18141c8fd9f ]

sctp_transport_pl_toobig() supposes to return true only if there's
pathmtu update, so that in sctp_icmp_frag_needed() it would call
sctp_assoc_sync_pmtu() and sctp_retransmit(). This patch is to fix
these return places in sctp_transport_pl_toobig().

Fixes: 836964083177 ("sctp: do state transition when receiving an icmp TOOBIG packet")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 net/sctp/transport.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 1f2dfad768d5..133f1719bf1b 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -368,6 +368,7 @@ static bool sctp_transport_pl_toobig(struct sctp_transport *t, u32 pmtu)
 
 			t->pl.pmtu = SCTP_BASE_PLPMTU;
 			t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t);
+			return true;
 		}
 	} else if (t->pl.state == SCTP_PL_SEARCH) {
 		if (pmtu >= SCTP_BASE_PLPMTU && pmtu < t->pl.pmtu) {
@@ -378,11 +379,10 @@ static bool sctp_transport_pl_toobig(struct sctp_transport *t, u32 pmtu)
 			t->pl.probe_high = 0;
 			t->pl.pmtu = SCTP_BASE_PLPMTU;
 			t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t);
+			return true;
 		} else if (pmtu > t->pl.pmtu && pmtu < t->pl.probe_size) {
 			t->pl.probe_size = pmtu;
 			t->pl.probe_count = 0;
-
-			return false;
 		}
 	} else if (t->pl.state == SCTP_PL_COMPLETE) {
 		if (pmtu >= SCTP_BASE_PLPMTU && pmtu < t->pl.pmtu) {
@@ -393,10 +393,11 @@ static bool sctp_transport_pl_toobig(struct sctp_transport *t, u32 pmtu)
 			t->pl.probe_high = 0;
 			t->pl.pmtu = SCTP_BASE_PLPMTU;
 			t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t);
+			return true;
 		}
 	}
 
-	return true;
+	return false;
 }
 
 bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu)
-- 
2.26.2