tcp: add tcp_sock_set_syncnt

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 4e4a750..2872584 100644 (file)
--- 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 2eaf832..6aa4ae5 100644 (file)
--- 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 27b5e7a..d2c67ae 100644 (file)
--- 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.
  */