linux-kernel - [PATCH v2 net-next 02/11] udp/ipv6: refactor udpv6

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Message-Id: <33dfdf2119c86e35062f783d405bedec2fde2b4c.1651153920.git.asml.silence@gmail.com>
Date:   Thu, 28 Apr 2022 14:57:57 +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 v2 net-next 02/11] udp/ipv6: refactor udpv6_sendmsg udplite checks

Don't save a IS_UDPLITE() result in advance but do when it's really
needed, so it doesn't store/load it from the stack. Same for resolving
the getfrag callback pointer.

Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
---
 net/ipv6/udp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index de8382930910..705eea080f5e 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1310,7 +1310,6 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	int ulen = len;
 	int corkreq = READ_ONCE(up->corkflag) || msg->msg_flags&MSG_MORE;
 	int err;
-	int is_udplite = IS_UDPLITE(sk);
 	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
 
 	ipcm6_init_sk(&ipc6, np);
@@ -1371,7 +1370,6 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	if (len > INT_MAX - sizeof(struct udphdr))
 		return -EMSGSIZE;
 
-	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
 	if (up->pending) {
 		if (up->pending == AF_INET)
 			return udp_sendmsg(sk, msg, len);
@@ -1538,6 +1536,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	if (!corkreq) {
 		struct sk_buff *skb;
 
+		getfrag = IS_UDPLITE(sk) ? udplite_getfrag : ip_generic_getfrag;
 		skb = ip6_make_skb(sk, getfrag, msg, ulen,
 				   sizeof(struct udphdr), &ipc6,
 				   (struct rt6_info *)dst,
@@ -1564,6 +1563,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 do_append_data:
 	up->len += ulen;
+	getfrag = IS_UDPLITE(sk) ? udplite_getfrag : ip_generic_getfrag;
 	err = ip6_append_data(sk, getfrag, msg, ulen, sizeof(struct udphdr),
 			      &ipc6, fl6, (struct rt6_info *)dst,
 			      corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
@@ -1594,7 +1594,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	 */
 	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
 		UDP6_INC_STATS(sock_net(sk),
-			       UDP_MIB_SNDBUFERRORS, is_udplite);
+			       UDP_MIB_SNDBUFERRORS, IS_UDPLITE(sk));
 	}
 	return err;
 
-- 
2.36.0