Re: [PATCH net-next] tcp: tcp_sendmsg() wrong access to sk_route_caps

[Joe Perches <joe@perches.com>]

On Mon, 2011-11-28 at 11:27 +0100, Eric Dumazet wrote:
> Now sk_route_caps is u64, its dangerous to use an integer to store
> result of an AND operator. It wont work if NETIF_F_SG is moved on the
> upper part of u64.

trivial comment below.

> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
[]
> @@ -917,9 +917,9 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
>  	struct iovec *iov;
>  	struct tcp_sock *tp = tcp_sk(sk);
>  	struct sk_buff *skb;
> -	int iovlen, flags;
> +	int iovlen, flags, err, copied;
>  	int mss_now, size_goal;
> -	int sg, err, copied;
> +	bool sg;
>  	long timeo;
>  
>  	lock_sock(sk);
> @@ -946,7 +946,7 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
>  	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
>  		goto out_err;
>  
> -	sg = sk->sk_route_caps & NETIF_F_SG;
> +	sg = !!(sk->sk_route_caps & NETIF_F_SG);

As sg is now bool, using !! is unnecessary.

A commit was done recently to remove one.
3ad9b358e03fd9dbf6705721490c811b666b0fe2