net: add sock_set_rcvbuf

Add a helper to directly set the SO_RCVBUFFORCE sockopt from kernel space
without going through a fake uaccess.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index b6e6dba..2822a43 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -1180,7 +1180,6 @@ static int sctp_listen_for_all(void)
 	struct socket *sock = NULL;
 	int result = -EINVAL;
 	struct connection *con = nodeid2con(0, GFP_NOFS);
-	int bufsize = NEEDED_RMEM;
 	int one = 1;
 
 	if (!con)
@@ -1195,11 +1194,7 @@ static int sctp_listen_for_all(void)
 		goto out;
 	}
 
-	result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE,
-				 (char *)&bufsize, sizeof(bufsize));
-	if (result)
-		log_print("Error increasing buffer space on socket %d", result);
-
+	sock_set_rcvbuf(sock->sk, NEEDED_RMEM);
 	result = kernel_setsockopt(sock, SOL_SCTP, SCTP_NODELAY, (char *)&one,
 				   sizeof(one));
 	if (result < 0)