[PATCH 19/33] tcp: add tcp_sock_set_keepcnt

Christoph Hellwig
2020-05-20T19:59:23Z

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

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
include/linux/tcp.h | 1 +
net/ipv4/tcp.c | 12 ++++++++++++
net/rds/tcp.h | 2 +-
net/rds/tcp_listen.c | 17 +++--------------
net/sunrpc/xprtsock.c | 3 +--
5 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 1f9bada00faab..9aac824c523cf 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -498,6 +498,7 @@ 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);
+int tcp_sock_set_keepcnt(struct sock *sk, int val);
int tcp_sock_set_keepidle(struct sock *sk, int val);
int tcp_sock_set_keepintvl(struct sock *sk, int val);
void tcp_sock_set_nodelay(struct sock *sk);
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 7eb083e09786a..15d47d5e79510 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2946,6 +2946,18 @@ int tcp_sock_set_keepintvl(struct sock *sk, int val)
}
EXPORT_SYMBOL(tcp_sock_set_keepintvl);

+int tcp_sock_set_keepcnt(struct sock *sk, int val)
+{
+ if (val < 1 || val > MAX_TCP_KEEPCNT)
+ return -EINVAL;
+
+ lock_sock(sk);
+ tcp_sk(sk)->keepalive_probes = val;
+ release_sock(sk);
+ return 0;
+}
+EXPORT_SYMBOL(tcp_sock_set_keepcnt);
+
/*
* Socket option code for TCP.
*/
diff --git a/net/rds/tcp.h b/net/rds/tcp.h
index f6d75d8cb167a..bad9cf49d5657 100644
--- a/net/rds/tcp.h
+++ b/net/rds/tcp.h
@@ -70,7 +70,7 @@ struct socket *rds_tcp_listen_init(struct net *net, bool isv6);
void rds_tcp_listen_stop(struct socket *sock, struct work_struct *acceptor);
void rds_tcp_listen_data_ready(struct sock *sk);
int rds_tcp_accept_one(struct socket *sock);
-int rds_tcp_keepalive(struct socket *sock);
+void rds_tcp_keepalive(struct socket *sock);
void *rds_tcp_listen_sock_def_readable(struct net *net);

/* tcp_recv.c */
diff --git a/net/rds/tcp_listen.c b/net/rds/tcp_listen.c
index 9ad555c48d15d..101cf14215a0b 100644
--- a/net/rds/tcp_listen.c
+++ b/net/rds/tcp_listen.c
@@ -38,27 +38,19 @@
#include "rds.h"
#include "tcp.h"

-int rds_tcp_keepalive(struct socket *sock)
+void rds_tcp_keepalive(struct socket *sock)
{
/* values below based on xs_udp_default_timeout */
int keepidle = 5; /* send a probe 'keepidle' secs after last data */
int keepcnt = 5; /* number of unack'ed probes before declaring dead */
- int ret = 0;

sock_set_keepalive(sock->sk);
-
- ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPCNT,
- (char *)&keepcnt, sizeof(keepcnt));
- if (ret < 0)
- goto bail;
-
+ tcp_sock_set_keepcnt(sock->sk, keepcnt);
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.
*/
tcp_sock_set_keepintvl(sock->sk, keepidle);
-bail:
- return ret;
}

/* rds_tcp_accept_one_path(): if accepting on cp_index > 0, make sure the
@@ -140,10 +132,7 @@ int rds_tcp_accept_one(struct socket *sock)
new_sock->ops = sock->ops;
__module_get(new_sock->ops->owner);

- ret = rds_tcp_keepalive(new_sock);
- if (ret < 0)
- goto out;
-
+ rds_tcp_keepalive(new_sock);
rds_tcp_tune(new_sock);

inet = inet_sk(new_sock->sk);
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 5ca64e12af0c5..0d3ec055bc12f 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2109,8 +2109,7 @@ static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
sock_set_keepalive(sock->sk);
tcp_sock_set_keepidle(sock->sk, keepidle);
tcp_sock_set_keepintvl(sock->sk, keepidle);
- kernel_setsockopt(sock, SOL_TCP, TCP_KEEPCNT,
- (char *)&keepcnt, sizeof(keepcnt));
+ tcp_sock_set_keepcnt(sock->sk, keepcnt);

/* TCP user timeout (see RFC5482) */
tcp_sock_set_user_timeout(sock->sk, timeo);
--
2.26.2