From: Christoph Hellwig <hch@lst.de>
Date: Thu, 28 May 2020 07:12:23 +0200
Subject: tcp: add tcp_sock_set_keepidle
Patch-mainline: v5.8-rc1
Git-commit: 71c48eb81c9ecb6fed49dc33e7c9b621fdcb7bf8
References: bsc#1177028

Add a helper to directly set the TCP_KEEP_IDLE 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>
Acked-by: Gary Lin <glin@suse.com>
---
 include/linux/tcp.h   |    1 +
 net/ipv4/tcp.c        |   49 ++++++++++++++++++++++++++++++++++---------------
 net/rds/tcp_listen.c  |    5 +----
 net/sunrpc/xprtsock.c |    3 +--
 4 files changed, 37 insertions(+), 21 deletions(-)

--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -488,6 +488,7 @@ int tcp_skb_shift(struct sk_buff *to, st
 		  int shiftlen);
 
 void tcp_sock_set_cork(struct sock *sk, bool on);
+int tcp_sock_set_keepidle(struct sock *sk, int val);
 void tcp_sock_set_nodelay(struct sock *sk);
 void tcp_sock_set_quickack(struct sock *sk, int val);
 int tcp_sock_set_syncnt(struct sock *sk, int val);
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2895,6 +2895,39 @@ void tcp_sock_set_user_timeout(struct so
 }
 EXPORT_SYMBOL(tcp_sock_set_user_timeout);
 
+static int __tcp_sock_set_keepidle(struct sock *sk, int val)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+
+	if (val < 1 || val > MAX_TCP_KEEPIDLE)
+		return -EINVAL;
+
+	tp->keepalive_time = val * HZ;
+	if (sock_flag(sk, SOCK_KEEPOPEN) &&
+	    !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
+		u32 elapsed = keepalive_time_elapsed(tp);
+
+		if (tp->keepalive_time > elapsed)
+			elapsed = tp->keepalive_time - elapsed;
+		else
+			elapsed = 0;
+		inet_csk_reset_keepalive_timer(sk, elapsed);
+	}
+
+	return 0;
+}
+
+int tcp_sock_set_keepidle(struct sock *sk, int val)
+{
+	int err;
+
+	lock_sock(sk);
+	err = __tcp_sock_set_keepidle(sk, val);
+	release_sock(sk);
+	return err;
+}
+EXPORT_SYMBOL(tcp_sock_set_keepidle);
+
 /*
  *	Socket option code for TCP.
  */
@@ -3064,21 +3097,7 @@ static int do_tcp_setsockopt(struct sock
 		break;
 
 	case TCP_KEEPIDLE:
-		if (val < 1 || val > MAX_TCP_KEEPIDLE)
-			err = -EINVAL;
-		else {
-			tp->keepalive_time = val * HZ;
-			if (sock_flag(sk, SOCK_KEEPOPEN) &&
-			    !((1 << sk->sk_state) &
-			      (TCPF_CLOSE | TCPF_LISTEN))) {
-				u32 elapsed = keepalive_time_elapsed(tp);
-				if (tp->keepalive_time > elapsed)
-					elapsed = tp->keepalive_time - elapsed;
-				else
-					elapsed = 0;
-				inet_csk_reset_keepalive_timer(sk, elapsed);
-			}
-		}
+		err = __tcp_sock_set_keepidle(sk, val);
 		break;
 	case TCP_KEEPINTVL:
 		if (val < 1 || val > MAX_TCP_KEEPINTVL)
--- a/net/rds/tcp_listen.c
+++ b/net/rds/tcp_listen.c
@@ -52,10 +52,7 @@ int rds_tcp_keepalive(struct socket *soc
 	if (ret < 0)
 		goto bail;
 
-	ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPIDLE,
-				(char *)&keepidle, sizeof(keepidle));
-	if (ret < 0)
-		goto bail;
+	tcp_sock_set_keepidle(sock->sk, keepidle);
 
 	/* KEEPINTVL is the interval between successive probes. We follow
 	 * the model in xs_tcp_finish_connecting() and re-use keepidle.
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2231,8 +2231,7 @@ static void xs_tcp_set_socket_timeouts(s
 
 	/* TCP Keepalive options */
 	sock_set_keepalive(sock->sk);
-	kernel_setsockopt(sock, SOL_TCP, TCP_KEEPIDLE,
-			(char *)&keepidle, sizeof(keepidle));
+	tcp_sock_set_keepidle(sock->sk, keepidle);
 	kernel_setsockopt(sock, SOL_TCP, TCP_KEEPINTVL,
 			(char *)&keepidle, sizeof(keepidle));
 	kernel_setsockopt(sock, SOL_TCP, TCP_KEEPCNT,