socket: Remove unused kernel_sendmsg_locked

The last use of kernel_sendmsg_locked() was removed in 2023 by
commit dc97391 ("sock: Remove ->sendpage*() in favour of
sendmsg(MSG_SPLICE_PAGES)")

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Joe Damato <jdamato@fastly.com>
Link: https://patch.msgid.link/20250112131318.63753-1-linux@treblig.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/net.h

@@ -343,8 +343,6 @@ static inline bool sendpages_ok(struct page *page, size_t len, size_t offset)
 
 int kernel_sendmsg(struct socket *sock, struct msghdr *msg, struct kvec *vec,
 		   size_t num, size_t len);
-int kernel_sendmsg_locked(struct sock *sk, struct msghdr *msg,
-			  struct kvec *vec, size_t num, size_t len);
 int kernel_recvmsg(struct socket *sock, struct msghdr *msg, struct kvec *vec,
 		   size_t num, size_t len, int flags);
 

net/socket.c

@@ -776,34 +776,6 @@ int kernel_sendmsg(struct socket *sock, struct msghdr *msg,
 }
 EXPORT_SYMBOL(kernel_sendmsg);
 
-/**
- *	kernel_sendmsg_locked - send a message through @sock (kernel-space)
- *	@sk: sock
- *	@msg: message header
- *	@vec: output s/g array
- *	@num: output s/g array length
- *	@size: total message data size
- *
- *	Builds the message data with @vec and sends it through @sock.
- *	Returns the number of bytes sent, or an error code.
- *	Caller must hold @sk.
- */
-
-int kernel_sendmsg_locked(struct sock *sk, struct msghdr *msg,
-			  struct kvec *vec, size_t num, size_t size)
-{
-	struct socket *sock = sk->sk_socket;
-	const struct proto_ops *ops = READ_ONCE(sock->ops);
-
-	if (!ops->sendmsg_locked)
-		return sock_no_sendmsg_locked(sk, msg, size);
-
-	iov_iter_kvec(&msg->msg_iter, ITER_SOURCE, vec, num, size);
-
-	return ops->sendmsg_locked(sk, msg, msg_data_left(msg));
-}
-EXPORT_SYMBOL(kernel_sendmsg_locked);
-
 static bool skb_is_err_queue(const struct sk_buff *skb)
 {
 	/* pkt_type of skbs enqueued on the error queue are set to