netdev - [PATCH net-next v3 04/10] udp/ipv6: optimise udpv6

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Message-Id: <96848ef2c22f73cd819c719fec0ce7a608d1c93e.1652368648.git.asml.silence@gmail.com>
Date:   Fri, 13 May 2022 16:26:09 +0100
From:   Pavel Begunkov <asml.silence@...il.com>
To:     netdev@...r.kernel.org, "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     David Ahern <dsahern@...nel.org>,
        Eric Dumazet <edumazet@...gle.com>,
        linux-kernel@...r.kernel.org,
        Pavel Begunkov <asml.silence@...il.com>
Subject: [PATCH net-next v3 04/10] udp/ipv6: optimise udpv6_sendmsg() daddr checks

All paths taking udpv6_sendmsg() to the ipv6_addr_v4mapped() check set a
non zero daddr, we can safely kill the NULL check just before it.

Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
---
 net/ipv6/udp.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index e0b1bea998ce..8a37e2d7b14b 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1386,19 +1386,18 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		daddr = &sk->sk_v6_daddr;
 	}
 
-	if (daddr) {
-		if (ipv6_addr_v4mapped(daddr)) {
-			struct sockaddr_in sin;
-			sin.sin_family = AF_INET;
-			sin.sin_port = sin6 ? sin6->sin6_port : inet->inet_dport;
-			sin.sin_addr.s_addr = daddr->s6_addr32[3];
-			msg->msg_name = &sin;
-			msg->msg_namelen = sizeof(sin);
+	if (ipv6_addr_v4mapped(daddr)) {
+		struct sockaddr_in sin;
+
+		sin.sin_family = AF_INET;
+		sin.sin_port = sin6 ? sin6->sin6_port : inet->inet_dport;
+		sin.sin_addr.s_addr = daddr->s6_addr32[3];
+		msg->msg_name = &sin;
+		msg->msg_namelen = sizeof(sin);
 do_udp_sendmsg:
-			if (ipv6_only_sock(sk))
-				return -ENETUNREACH;
-			return udp_sendmsg(sk, msg, len);
-		}
+		if (ipv6_only_sock(sk))
+			return -ENETUNREACH;
+		return udp_sendmsg(sk, msg, len);
 	}
 
 	ulen += sizeof(struct udphdr);
-- 
2.36.0