ipv6: use dst6_mtu() instead of dst_mtu()

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 <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260130210303.3888261-7-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index d19d86ed43766bbc8ec052113be02ab231a5272c..dafcc0dcd77a5394857d6f339d83370826a25109 100644 (file)
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -1057,7 +1057,7 @@ 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 4bb61265f1d8f870dbfd60bd22b8ab78828fb4cd..f110701d1eca1e5f763d9138a43e11e92c15412f 100644 (file)
--- 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);
 
@@ -1403,10 +1403,10 @@ 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 6fca0868b5a237417eb4c013f713952e8922696d..4c29aa94e86eb9439458e4b23426bfda8b3b8922 100644 (file)
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -638,7 +638,7 @@ 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);
@@ -1187,7 +1187,7 @@ route_lookup:
                                     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 a61e742794f9e67ff3743ddc31341d8647d5bcdc..d784a8644ff20e6008925b3d9b8e13c380318657 100644 (file)
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -1184,7 +1184,7 @@ 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;
@@ -1283,7 +1283,7 @@ 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 3cfa7ae1294b59d14e030fb7a4ceabd4e9b673a8..c0350d97307e1ef6a3b500db32a311891d3c6e72 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2049,6 +2049,8 @@ unlock:
 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.
@@ -2059,10 +2061,10 @@ 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;
@@ -2932,7 +2934,7 @@ 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)) {
@@ -3248,7 +3250,7 @@ EXPORT_SYMBOL_GPL(ip6_sk_redirect);
 
 static unsigned int ip6_default_advmss(const struct dst_entry *dst)
 {
-       unsigned int mtu = dst_mtu(dst);
+       unsigned int mtu = dst6_mtu(dst);
        struct net *net;
 
        mtu -= sizeof(struct ipv6hdr) + sizeof(struct tcphdr);

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 8bf29186c15f99dd2ab63d2b0b3890ed0c68d514..c65a5bfd322a1db5dc3fbc406e577f0ccb044c23 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -351,7 +351,7 @@ failure:
 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;
@@ -368,8 +368,9 @@ 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);
        }
 }
@@ -1467,7 +1468,7 @@ 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);