ocfs2: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage()

Switch ocfs2 from using sendpage() to using sendmsg() + MSG_SPLICE_PAGES so
that sendpage can be phased out.

Signed-off-by: David Howells <dhowells@redhat.com>

cc: Mark Fasheh <mark@fasheh.com>
cc: Joel Becker <jlbec@evilplan.org>
cc: Joseph Qi <joseph.qi@linux.alibaba.com>
cc: ocfs2-devel@oss.oracle.com
Link: https://lore.kernel.org/r/20230623225513.2732256-15-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: dhowells

fs/ocfs2/cluster/tcp.c

@@ -930,19 +930,22 @@ static int o2net_send_tcp_msg(struct socket *sock, struct kvec *vec,
 }
 
 static void o2net_sendpage(struct o2net_sock_container *sc,
-			   void *kmalloced_virt,
-			   size_t size)
+			   void *virt, size_t size)
 {
 	struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
+	struct msghdr msg = {};
+	struct bio_vec bv;
 	ssize_t ret;
 
+	bvec_set_virt(&bv, virt, size);
+	iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bv, 1, size);
+
 	while (1) {
+		msg.msg_flags = MSG_DONTWAIT | MSG_SPLICE_PAGES;
 		mutex_lock(&sc->sc_send_lock);
-		ret = sc->sc_sock->ops->sendpage(sc->sc_sock,
-						 virt_to_page(kmalloced_virt),
-						 offset_in_page(kmalloced_virt),
-						 size, MSG_DONTWAIT);
+		ret = sock_sendmsg(sc->sc_sock, &msg);
 		mutex_unlock(&sc->sc_send_lock);
+
 		if (ret == size)
 			break;
 		if (ret == (ssize_t)-EAGAIN) {