[PATCH net-next 02/11] udp/ipv6: refactor udpv6_sendmsg udplite checks

From: Pavel Begunkov
Date: Thu Apr 28 2022 - 06:57:44 EST


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@xxxxxxxxx>
---
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