Ocfs2 devel - May 2020 - [PATCH 20/33] ipv4: add ip_sock_set_recverr

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

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 include/net/ip.h         |  1 +
 net/ipv4/ip_sockglue.c   | 10 ++++++++++
 net/rxrpc/local_object.c |  8 +-------
 3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/include/net/ip.h b/include/net/ip.h
index 1e2feca8630d0..7ab8140b54429 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -767,5 +767,6 @@ static inline bool inetdev_valid_mtu(unsigned int mtu)
 
 void ip_sock_set_tos(struct sock *sk, int val);
 void ip_sock_set_freebind(struct sock *sk, bool val);
+void ip_sock_set_recverr(struct sock *sk, bool val);
 
 #endif	/* _IP_H */
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 0c40887a817f8..9abecc3195520 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -589,6 +589,16 @@ void ip_sock_set_freebind(struct sock *sk, bool val)
 }
 EXPORT_SYMBOL(ip_sock_set_freebind);
 
+void ip_sock_set_recverr(struct sock *sk, bool val)
+{
+	lock_sock(sk);
+	inet_sk(sk)->recverr = val;
+	if (!val)
+		skb_queue_purge(&sk->sk_error_queue);
+	release_sock(sk);
+}
+EXPORT_SYMBOL(ip_sock_set_recverr);
+
 /*
  *	Socket option code for IP. This is the end of the line after any
  *	TCP,UDP etc options on an IP socket.
diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c
index 562ea36c96b0f..1b87b8a9ff725 100644
--- a/net/rxrpc/local_object.c
+++ b/net/rxrpc/local_object.c
@@ -171,13 +171,7 @@ static int rxrpc_open_socket(struct rxrpc_local *local,
struct net *net)
 		/* Fall through */
 	case AF_INET:
 		/* we want to receive ICMP errors */
-		opt = 1;
-		ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
-					(char *) &opt, sizeof(opt));
-		if (ret < 0) {
-			_debug("setsockopt failed");
-			goto error;
-		}
+		ip_sock_set_recverr(local->socket->sk, true);
 
 		/* we want to set the don't fragment bit */
 		opt = IP_PMTUDISC_DO;
-- 
2.26.2

On Wed, 2020-05-13 at 08:26 +0200, Christoph Hellwig
wrote:
> Add a helper to directly set the IP_RECVERR sockopt from kernel space
> without going through a fake uaccess.
This seems used only with true as the second arg.
Is there reason to have that argument at all?
> diff --git a/include/net/ip.h b/include/net/ip.h
[]
> @@ -767,5 +767,6 @@ static inline bool inetdev_valid_mtu(unsigned int mtu)
>  
>  void ip_sock_set_tos(struct sock *sk, int val);
>  void ip_sock_set_freebind(struct sock *sk, bool val);
> +void ip_sock_set_recverr(struct sock *sk, bool val);
>  
>  #endif	/* _IP_H */
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index 0c40887a817f8..9abecc3195520 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -589,6 +589,16 @@ void ip_sock_set_freebind(struct sock *sk, bool val)
>  }
>  EXPORT_SYMBOL(ip_sock_set_freebind);
>  
> +void ip_sock_set_recverr(struct sock *sk, bool val)
> +{
> +	lock_sock(sk);
> +	inet_sk(sk)->recverr = val;
> +	if (!val)
> +		skb_queue_purge(&sk->sk_error_queue);
> +	release_sock(sk);
> +}
> +EXPORT_SYMBOL(ip_sock_set_recverr);
> +
>  /*
>   *	Socket option code for IP. This is the end of the line after any
>   *	TCP,UDP etc options on an IP socket.
> diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c
> index 562ea36c96b0f..1b87b8a9ff725 100644
> --- a/net/rxrpc/local_object.c
> +++ b/net/rxrpc/local_object.c
> @@ -171,13 +171,7 @@ static int rxrpc_open_socket(struct rxrpc_local
*local, struct net *net)
>  		/* Fall through */
>  	case AF_INET:
>  		/* we want to receive ICMP errors */
> -		opt = 1;
> -		ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
> -					(char *) &opt, sizeof(opt));
> -		if (ret < 0) {
> -			_debug("setsockopt failed");
> -			goto error;
> -		}
> +		ip_sock_set_recverr(local->socket->sk, true);
>  
>  		/* we want to set the don't fragment bit */
>  		opt = IP_PMTUDISC_DO;