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 8C52359481F; Wed, 9 Sep 2026 14:40:38 +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=1788964839; cv=none; b=qw/trnkqQ8yGbdGTtygPX2hiRaro4dU5TQf0y6M77CAjf6CXsUWGz9d39vUuxoCaiook40La2Q/v1jRGR3zWpMcA83QdNx1SFvM9bUdqhBoXyKlDaMwhbdFAyUNNwYZzoQCW+R+rwVqSBd9+CTGzNLbKfVpZXIW2KBTMQ3zYuWo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788964839; c=relaxed/simple; bh=bTShbVn9yziL55heb+49HuCbKj8ieH8IxKwQG+i1lno=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=d8ZTepCgjz2XT1Ca2Qfhp53JQ8jqIDhyWBsUxgSNaBeuGGIlg51/BPafdfUFaD0jTlsv3ZSx5eQogTyWuBoeACFFqjhr7/ibHPWYAWbWYIQJljOblkm3xw9iiW+9g+o8c4aMyEaEStEzmZ39MZ+thRHoUWnebCvIqraEn9hoq6E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=bA6b80dX; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="bA6b80dX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3D961F00A3F; Wed, 9 Sep 2026 14:40:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788964838; bh=Z0VjPPLKylGy+SM1xLEpLlH3YFAk1RxPOYIdXTGHnvk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=bA6b80dXnax/KkO3pC1ns1gWyJeDj12yw7NXiSx4kXD9hPzlIqkPBTbk8cw1N+oht PtemCgPbkqwXRUkCzeQjJ1/9yZqsBtB033ZDWYPgf7kgM/zY6nsW4bO9bdfAW1oOlX RW5gX+c204KYod2Nyk/SWU1T+oQk3Qh3HsUYzX7o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 522/583] ipv6: add some unlikely()/likely() clauses in ip6_output.c Date: Wed, 9 Sep 2026 15:43:27 +0200 Message-ID: <20260909134255.792202910@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260909134237.773280130@linuxfoundation.org> References: <20260909134237.773280130@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 2855e4925416c5900a9c6cece11f4a2e56bf6e63 ] 1) daddr is unlikely a multicast in ip6_finish_output2(). 2) ip6_finish_output_gso_slowpath_drop() should not be called often. 3) ip6_fragment() should not be called often. 4) opt is unlikely to be set. 5) ip6_xmit() and ip6_forward() mostly sends not too big packets. 6) Most __ip6_make_skb() calls are for UDP packets, not ICMPV6 ones. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260130210303.3888261-3-edumazet@google.com Signed-off-by: Jakub Kicinski Stable-dep-of: 870a9e42ecc6 ("tcp: clamp route advmss to TCP_MIN_MSS") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ip6_output.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -80,7 +80,7 @@ static int ip6_finish_output2(struct net hdr = ipv6_hdr(skb); daddr = &hdr->daddr; - if (ipv6_addr_is_multicast(daddr)) { + if (unlikely(ipv6_addr_is_multicast(daddr))) { if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(sk) && ((mroute6_is_socket(net, skb) && !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) || @@ -181,8 +181,8 @@ ip6_finish_output_gso_slowpath_drop(stru static int ip6_finish_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb, unsigned int mtu) { - if (!(IP6CB(skb)->flags & IP6SKB_FAKEJUMBO) && - !skb_gso_validate_network_len(skb, mtu)) + if (unlikely(!(IP6CB(skb)->flags & IP6SKB_FAKEJUMBO) && + !skb_gso_validate_network_len(skb, mtu))) return ip6_finish_output_gso_slowpath_drop(net, sk, skb, mtu); return ip6_finish_output2(net, sk, skb); @@ -204,8 +204,8 @@ static int __ip6_finish_output(struct ne if (skb_is_gso(skb)) return ip6_finish_output_gso(net, sk, skb, mtu); - if (skb->len > mtu || - (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size)) + if (unlikely(skb->len > mtu || + (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size))) return ip6_fragment(net, sk, skb, ip6_finish_output2); return ip6_finish_output2(net, sk, skb); @@ -303,7 +303,7 @@ int ip6_xmit(const struct sock *sk, stru } } - if (opt) { + if (unlikely(opt)) { seg_len += opt->opt_nflen + opt->opt_flen; if (opt->opt_flen) @@ -356,7 +356,7 @@ int ip6_xmit(const struct sock *sk, stru skb->mark = mark; mtu = dst_mtu(dst); - if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) { + if (likely((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb))) { IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTREQUESTS); /* if egress device is enslaved to an L3 master device pass the @@ -656,7 +656,7 @@ int ip6_forward(struct sk_buff *skb) if (mtu < IPV6_MIN_MTU) mtu = IPV6_MIN_MTU; - if (ip6_pkt_too_big(skb, mtu)) { + if (unlikely(ip6_pkt_too_big(skb, mtu))) { /* Again, force OUTPUT device used as source address */ skb->dev = dev; icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); @@ -1370,7 +1370,7 @@ static int ip6_setup_cork(struct sock *s /* * setup for corking */ - if (opt) { + if (unlikely(opt)) { if (WARN_ON(v6_cork->opt)) return -EINVAL; @@ -1886,7 +1886,7 @@ static void ip6_cork_steal_dst(struct sk static void ip6_cork_release(struct inet_cork_full *cork, struct inet6_cork *v6_cork) { - if (v6_cork->opt) { + if (unlikely(v6_cork->opt)) { struct ipv6_txoptions *opt = v6_cork->opt; kfree(opt->dst0opt); @@ -1942,7 +1942,7 @@ struct sk_buff *__ip6_make_skb(struct so __skb_pull(skb, skb_network_header_len(skb)); final_dst = &fl6->daddr; - if (opt) { + if (unlikely(opt)) { if (opt->opt_flen) proto = ipv6_push_frag_opts(skb, opt, proto); if (opt->opt_nflen) @@ -1970,7 +1970,7 @@ struct sk_buff *__ip6_make_skb(struct so ip6_cork_steal_dst(skb, cork); IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTREQUESTS); - if (proto == IPPROTO_ICMPV6) { + if (unlikely(proto == IPPROTO_ICMPV6)) { struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); u8 icmp6_type;