[PATCH 15/33] tcp: add tcp_sock_set_syncnt

Christoph Hellwig
2020-05-20T19:59:36Z

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

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
---
drivers/nvme/host/tcp.c | 9 +--------
include/linux/tcp.h | 1 +
net/ipv4/tcp.c | 12 ++++++++++++
3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 4e4a750ecdb97..2872584f52f63 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1336,14 +1336,7 @@ static int nvme_tcp_alloc_queue(struct nvme_ctrl *nctrl,
}

/* Single syn retry */
- opt = 1;
- ret = kernel_setsockopt(queue->sock, IPPROTO_TCP, TCP_SYNCNT,
- (char *)&opt, sizeof(opt));
- if (ret) {
- dev_err(nctrl->device,
- "failed to set TCP_SYNCNT sock opt %d\n", ret);
- goto err_sock;
- }
+ tcp_sock_set_syncnt(queue->sock->sk, 1);

/* Set TCP no delay */
tcp_sock_set_nodelay(queue->sock->sk);
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 2eaf8320b9db0..6aa4ae5ebf3d5 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -500,5 +500,6 @@ int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from, int pcount,
void tcp_sock_set_cork(struct sock *sk, bool on);
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);

#endif /* _LINUX_TCP_H */
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 27b5e7a4e2ef9..d2c67ae1da07a 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2881,6 +2881,18 @@ void tcp_sock_set_quickack(struct sock *sk, int val)
}
EXPORT_SYMBOL(tcp_sock_set_quickack);

+int tcp_sock_set_syncnt(struct sock *sk, int val)
+{
+ if (val < 1 || val > MAX_TCP_SYNCNT)
+ return -EINVAL;
+
+ lock_sock(sk);
+ inet_csk(sk)->icsk_syn_retries = val;
+ release_sock(sk);
+ return 0;
+}
+EXPORT_SYMBOL(tcp_sock_set_syncnt);
+
/*
* Socket option code for TCP.
*/
--
2.26.2