tcp: add tcp_sock_set_cork

Add a helper to directly set the TCP_CORK sockopt from kernel space
without going through a fake uaccess. Cleanup the callers to avoid
pointless wrappers now that this is a simple function call.

Signed-off-by: Christoph Hellwig <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/block/drbd/drbd_int.h

···
 extern void _drbd_clear_done_ee(struct drbd_device *device, struct list_head *to_be_freed);
 extern int drbd_connected(struct drbd_peer_device *);
 
-static inline void drbd_tcp_cork(struct socket *sock)
-{
-	int val = 1;
-	(void) kernel_setsockopt(sock, SOL_TCP, TCP_CORK,
-			(char*)&val, sizeof(val));
-}
-
-static inline void drbd_tcp_uncork(struct socket *sock)
-{
-	int val = 0;
-	(void) kernel_setsockopt(sock, SOL_TCP, TCP_CORK,
-			(char*)&val, sizeof(val));
-}
-
 static inline void drbd_tcp_nodelay(struct socket *sock)
 {
 	int val = 1;

drivers/block/drbd/drbd_receiver.c

···
 	rcu_read_unlock();
 
 	if (tcp_cork)
-		drbd_tcp_cork(connection->meta.socket);
+		tcp_sock_set_cork(connection->meta.socket->sk, true);
 
 	err = drbd_finish_peer_reqs(device);
 	kref_put(&device->kref, drbd_destroy_device);
···
 	}
 
 	if (tcp_cork)
-		drbd_tcp_uncork(connection->meta.socket);
+		tcp_sock_set_cork(connection->meta.socket->sk, false);
 
 	return;
 }

drivers/block/drbd/drbd_worker.c

···
 	if (uncork) {
 		mutex_lock(&connection->data.mutex);
 		if (connection->data.socket)
-			drbd_tcp_uncork(connection->data.socket);
+			tcp_sock_set_cork(connection->data.socket->sk, false);
 		mutex_unlock(&connection->data.mutex);
 	}
 
···
 	mutex_lock(&connection->data.mutex);
 	if (connection->data.socket) {
 		if (cork)
-			drbd_tcp_cork(connection->data.socket);
+			tcp_sock_set_cork(connection->data.socket->sk, true);
 		else if (!uncork)
-			drbd_tcp_uncork(connection->data.socket);
+			tcp_sock_set_cork(connection->data.socket->sk, false);
 	}
 	mutex_unlock(&connection->data.mutex);
 }

fs/cifs/transport.c

···
 	size_t total_len = 0, sent, size;
 	struct socket *ssocket = server->ssocket;
 	struct msghdr smb_msg;
-	int val = 1;
 	__be32 rfc1002_marker;
 
 	if (cifs_rdma_enabled(server)) {
···
 	}
 
 	/* cork the socket */
-	kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,
-				(char *)&val, sizeof(val));
+	tcp_sock_set_cork(ssocket->sk, true);
 
 	for (j = 0; j < num_rqst; j++)
 		send_length += smb_rqst_len(server, &rqst[j]);
···
 	}
 
 	/* uncork it */
-	val = 0;
-	kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,
-				(char *)&val, sizeof(val));
+	tcp_sock_set_cork(ssocket->sk, false);
 
 	if ((total_len > 0) && (total_len != send_length)) {
 		cifs_dbg(FYI, "partial send (wanted=%u sent=%zu): terminating session\n",

include/linux/tcp.h

···
 int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from, int pcount,
 		  int shiftlen);
 
+void tcp_sock_set_cork(struct sock *sk, bool on);
+
 #endif	/* _LINUX_TCP_H */

net/ipv4/tcp.c

···
 	}
 }
 
+/* When set indicates to always queue non-full frames.  Later the user clears
+ * this option and we transmit any pending partial frames in the queue.  This is
+ * meant to be used alongside sendfile() to get properly filled frames when the
+ * user (for example) must write out headers with a write() call first and then
+ * use sendfile to send out the data parts.
+ *
+ * TCP_CORK can be set together with TCP_NODELAY and it is stronger than
+ * TCP_NODELAY.
+ */
+static void __tcp_sock_set_cork(struct sock *sk, bool on)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+
+	if (on) {
+		tp->nonagle |= TCP_NAGLE_CORK;
+	} else {
+		tp->nonagle &= ~TCP_NAGLE_CORK;
+		if (tp->nonagle & TCP_NAGLE_OFF)
+			tp->nonagle |= TCP_NAGLE_PUSH;
+		tcp_push_pending_frames(sk);
+	}
+}
+
+void tcp_sock_set_cork(struct sock *sk, bool on)
+{
+	lock_sock(sk);
+	__tcp_sock_set_cork(sk, on);
+	release_sock(sk);
+}
+EXPORT_SYMBOL(tcp_sock_set_cork);
+
 /*
  *	Socket option code for TCP.
  */
···
 		break;
 
 	case TCP_CORK:
-		/* When set indicates to always queue non-full frames.
-		 * Later the user clears this option and we transmit
-		 * any pending partial frames in the queue.  This is
-		 * meant to be used alongside sendfile() to get properly
-		 * filled frames when the user (for example) must write
-		 * out headers with a write() call first and then use
-		 * sendfile to send out the data parts.
-		 *
-		 * TCP_CORK can be set together with TCP_NODELAY and it is
-		 * stronger than TCP_NODELAY.
-		 */
-		if (val) {
-			tp->nonagle |= TCP_NAGLE_CORK;
-		} else {
-			tp->nonagle &= ~TCP_NAGLE_CORK;
-			if (tp->nonagle&TCP_NAGLE_OFF)
-				tp->nonagle |= TCP_NAGLE_PUSH;
-			tcp_push_pending_frames(sk);
-		}
+		__tcp_sock_set_cork(sk, val);
 		break;
 
 	case TCP_KEEPIDLE:

net/rds/tcp_send.c

···
 #include "rds.h"
 #include "tcp.h"
 
-static void rds_tcp_cork(struct socket *sock, int val)
-{
-	kernel_setsockopt(sock, SOL_TCP, TCP_CORK, (void *)&val, sizeof(val));
-}
-
 void rds_tcp_xmit_path_prepare(struct rds_conn_path *cp)
 {
 	struct rds_tcp_connection *tc = cp->cp_transport_data;
 
-	rds_tcp_cork(tc->t_sock, 1);
+	tcp_sock_set_cork(tc->t_sock->sk, true);
 }
 
 void rds_tcp_xmit_path_complete(struct rds_conn_path *cp)
 {
 	struct rds_tcp_connection *tc = cp->cp_transport_data;
 
-	rds_tcp_cork(tc->t_sock, 0);
+	tcp_sock_set_cork(tc->t_sock->sk, false);
 }
 
 /* the core send_sem serializes this with other xmit and shutdown */