proto_ops: Add locked held versions of sendmsg and sendpage

Add new proto_ops sendmsg_locked and sendpage_locked that can be
called when the socket lock is already held. Correspondingly, add
kernel_sendmsg_locked and kernel_sendpage_locked as front end
functions.

These functions will be used in zero proxy so that we can take
the socket lock in a ULP sendmsg/sendpage and then directly call the
backend transport proto_ops functions.

Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 0 deletions

diff --git a/net/core/sock.c b/net/core/sock.c
index ac2a404c73eb..742f68c9c84a 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2500,6 +2500,12 @@ int sock_no_sendmsg(struct socket *sock, struct msghdr *m, size_t len)
 }
 EXPORT_SYMBOL(sock_no_sendmsg);
 
+int sock_no_sendmsg_locked(struct sock *sk, struct msghdr *m, size_t len)
+{
+	return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL(sock_no_sendmsg_locked);
+
 int sock_no_recvmsg(struct socket *sock, struct msghdr *m, size_t len,
 		    int flags)
 {
@@ -2528,6 +2534,22 @@ ssize_t sock_no_sendpage(struct socket *sock, struct page *page, int offset, siz
 }
 EXPORT_SYMBOL(sock_no_sendpage);
 
+ssize_t sock_no_sendpage_locked(struct sock *sk, struct page *page,
+				int offset, size_t size, int flags)
+{
+	ssize_t res;
+	struct msghdr msg = {.msg_flags = flags};
+	struct kvec iov;
+	char *kaddr = kmap(page);
+
+	iov.iov_base = kaddr + offset;
+	iov.iov_len = size;
+	res = kernel_sendmsg_locked(sk, &msg, &iov, 1, size);
+	kunmap(page);
+	return res;
+}
+EXPORT_SYMBOL(sock_no_sendpage_locked);
+
 /*
  *	Default Socket Callbacks
  */