From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C204259B56 for ; Tue, 1 Sep 2026 11:11:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788261082; cv=none; b=e+1B5DJHF/p1SMqHhgU4eRjDZZYPEZeMyurshRo8mawsltZ8D49cmCxryk+7dxw9FUDL00ruQJPvy+QCQ16FVxJrymbDaMID1/JmOinhgbdPYHmVY48JYuPqlEKHthBHuZ1+IPNgo8Emvxt7pW01DuWs8v/TpNXfEWaq1fF2iHI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788261082; c=relaxed/simple; bh=w71MILykEuIG0TQw0X6JC7Rh7MLia/ZSvcQ4o9ym4MM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tV0RtQpLI33iJQ9CgBE40/S97Ji3azjadQqyFmIYS2IL6R/024bK08Ol+0E6mGwq0BjeZT3kYs+r+5uIoXrEH2lVjlF8gF7HjEHMDdz4pZYFrFfv7Z/f1P2IpDbmCS2/QqLSuDJzvIPrwIE/tz//ZFc+BdJjLr92sKmI4oU5ci0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gAHlWrT7; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gAHlWrT7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D8D761F00A3E; Tue, 1 Sep 2026 11:11:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788261080; bh=Rhw8gyfK61/TEM194+4i0Kxq9WfAv8+sko0Oy3umWrQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gAHlWrT7Xxqo4U2bZEISfb0PioSdSrQVWOb2kkAN746hQTlQTG27IsIc0DxZ4KyAO YvdlI3jpWXFfkdvtO2c+ZonhUSuHP2854kUTTTahAymU5ZdLcRBA/5ri+3OVSdP4US uBegeeVK7LOxAE3JGvhER88a9j6eT6Q/TbmIUOlSOC+MO2suAxP2qM3xVdEcdsKJ8g CMCUmlDJYMEolqs0/nQ7bCuaiTjR5mIBIuK6yJXaBZRci5isEDWwm9H5T1g0tbJp0t YpzztCPy8+iotfqD7qS+Uxkton3NTzip76RbkOrqp1TqPx7eFDzhOiIAAeU+NJDmTE ASk4/yVO/hYpg== From: Sasha Levin To: stable@vger.kernel.org Cc: Eric Dumazet , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12.y 4/5] ipv6: use dst6_mtu() instead of dst_mtu() Date: Tue, 1 Sep 2026 07:11:14 -0400 Message-ID: <20260901111115.4175900-4-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260901111115.4175900-1-sashal@kernel.org> References: <2026083114-maturing-resize-d958@gregkh> <20260901111115.4175900-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Eric Dumazet [ Upstream commit b40f0130a23b6bab8b359e158a40af81f11f14be ] When we expect an IPv6 dst, use dst6_mtu() instead of dst_mtu() to save some code space. Due to current dst6_mtu() implementation, only convert users in IPv6 stack. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260130210303.3888261-7-edumazet@google.com Signed-off-by: Jakub Kicinski Stable-dep-of: 2640e6419594 ("net: advertise TCP MSS from the configured MTU, not the learned PMTU") Signed-off-by: Sasha Levin --- net/ipv6/ip6_gre.c | 2 +- net/ipv6/ip6_output.c | 6 +++--- net/ipv6/ip6_tunnel.c | 4 ++-- net/ipv6/ipv6_sockglue.c | 4 ++-- net/ipv6/route.c | 8 +++++--- net/ipv6/tcp_ipv6.c | 9 +++++---- 6 files changed, 18 insertions(+), 15 deletions(-) diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index dac2e589849df..cf7e5d1046672 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -1086,7 +1086,7 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb, /* TooBig packet may have updated dst->dev's mtu */ if (!t->parms.collect_md && dst) { mtu = READ_ONCE(dst_dev(dst)->mtu); - if (dst_mtu(dst) > mtu) + if (dst6_mtu(dst) > mtu) dst->ops->update_pmtu(dst, NULL, skb, mtu, false); } err = ip6_tnl_xmit(skb, dev, dsfield, &fl6, encap_limit, &mtu, diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index c1227bfeb8496..e483ea209fb76 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -353,7 +353,7 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6, skb->priority = priority; skb->mark = mark; - mtu = dst_mtu(dst); + mtu = dst6_mtu(dst); if (likely((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb))) { IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTREQUESTS); @@ -1400,10 +1400,10 @@ static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork, v6_cork->dontfrag = ipc6->dontfrag; if (rt->dst.flags & DST_XFRM_TUNNEL) mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ? - READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst); + READ_ONCE(rt->dst.dev->mtu) : dst6_mtu(&rt->dst); else mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ? - READ_ONCE(rt->dst.dev->mtu) : dst_mtu(xfrm_dst_path(&rt->dst)); + READ_ONCE(rt->dst.dev->mtu) : dst6_mtu(xfrm_dst_path(&rt->dst)); frag_size = READ_ONCE(np->frag_size); if (frag_size && frag_size < mtu) diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index 43ccc1a0a0d04..60b2583a8b2b4 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -643,7 +643,7 @@ ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, /* change mtu on this route */ if (rel_type == ICMP_DEST_UNREACH && rel_code == ICMP_FRAG_NEEDED) { - if (rel_info > dst_mtu(skb_dst(skb2))) + if (rel_info > dst6_mtu(skb_dst(skb2))) goto out; skb_dst_update_pmtu_no_confirm(skb2, rel_info); @@ -1195,7 +1195,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield, t->parms.name); goto tx_err_dst_release; } - mtu = dst_mtu(dst) - eth_hlen - psh_hlen - t->tun_hlen; + mtu = dst6_mtu(dst) - eth_hlen - psh_hlen - t->tun_hlen; if (encap_limit >= 0) { max_headroom += 8; mtu -= 8; diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 1e225e6489ea1..c2ea92c0f9166 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -1204,7 +1204,7 @@ int do_ipv6_getsockopt(struct sock *sk, int level, int optname, rcu_read_lock(); dst = __sk_dst_get(sk); if (dst) - val = dst_mtu(dst); + val = dst6_mtu(dst); rcu_read_unlock(); if (!val) return -ENOTCONN; @@ -1303,7 +1303,7 @@ int do_ipv6_getsockopt(struct sock *sk, int level, int optname, rcu_read_lock(); dst = __sk_dst_get(sk); if (dst) - mtuinfo.ip6m_mtu = dst_mtu(dst); + mtuinfo.ip6m_mtu = dst6_mtu(dst); rcu_read_unlock(); if (!mtuinfo.ip6m_mtu) return -ENOTCONN; diff --git a/net/ipv6/route.c b/net/ipv6/route.c index eb2ba7c34f6f8..f7a138e317bad 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2051,6 +2051,8 @@ static void rt6_update_exception_stamp_rt(struct rt6_info *rt) static bool rt6_mtu_change_route_allowed(struct inet6_dev *idev, struct rt6_info *rt, int mtu) { + u32 dmtu = dst6_mtu(&rt->dst); + /* If the new MTU is lower than the route PMTU, this new MTU will be the * lowest MTU in the path: always allow updating the route PMTU to * reflect PMTU decreases. @@ -2061,10 +2063,10 @@ static bool rt6_mtu_change_route_allowed(struct inet6_dev *idev, * handle this. */ - if (dst_mtu(&rt->dst) >= mtu) + if (dmtu >= mtu) return true; - if (dst_mtu(&rt->dst) == idev->cnf.mtu6) + if (dmtu == idev->cnf.mtu6) return true; return false; @@ -2927,7 +2929,7 @@ static void __ip6_rt_update_pmtu(struct dst_entry *dst, const struct sock *sk, if (mtu < IPV6_MIN_MTU) return; - if (mtu >= dst_mtu(dst)) + if (mtu >= dst6_mtu(dst)) return; if (!rt6_cache_allowed_for_pmtu(rt6)) { diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 085fc97c5a5b3..b6190f09551d5 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -347,7 +347,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr, static void tcp_v6_mtu_reduced(struct sock *sk) { struct dst_entry *dst; - u32 mtu; + u32 mtu, dmtu; if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) return; @@ -364,8 +364,9 @@ static void tcp_v6_mtu_reduced(struct sock *sk) if (!dst) return; - if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) { - tcp_sync_mss(sk, dst_mtu(dst)); + dmtu = dst6_mtu(dst); + if (inet_csk(sk)->icsk_pmtu_cookie > dmtu) { + tcp_sync_mss(sk, dmtu); tcp_simple_retransmit(sk); } } @@ -1500,7 +1501,7 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff * tcp_ca_openreq_child(newsk, dst); - tcp_sync_mss(newsk, dst_mtu(dst)); + tcp_sync_mss(newsk, dst6_mtu(dst)); newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst)); tcp_initialize_rcv_mss(newsk); -- 2.53.0