Re: [PATCH 20/33] ipv4: add ip_sock_set_recverr

[Joe Perches]

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;