Commit b40f0130 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260130210303.3888261-7-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 8776c4ef

net/ipv6/ip6_gre.c

+1 −1
Original line number Diff line number Diff line
@@ -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,

net/ipv6/ip6_output.c

+3 −3
Original line number Diff line number Diff line
@@ -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)

net/ipv6/ip6_tunnel.c

+2 −2
Original line number Diff line number Diff line
@@ -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 @@ 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;

net/ipv6/ipv6_sockglue.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

net/ipv6/route.c

+6 −4
Original line number Diff line number Diff line
@@ -2049,6 +2049,8 @@ 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.
@@ -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);