Re: [PATCH] net/af_iucv: mark expected switch fall-throughs

[Kees Cook <keescook@chromium.org>]

On Mon, Jul 29, 2019 at 09:59:47AM -0500, Gustavo A. R. Silva wrote:
> Mark switch cases where we are expecting to fall through.
> 
> This patch fixes the following warnings:
> 
> net/iucv/af_iucv.c: warning: this statement may fall
> through [-Wimplicit-fallthrough=]:  => 537:3, 519:6, 2246:6, 510:6
> 
> Notice that, in this particular case, the code comment is
> modified in accordance with what GCC is expecting to find.
> 
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> ---
>  net/iucv/af_iucv.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
> index 09e1694b6d34..ebb62a4ebe30 100644
> --- a/net/iucv/af_iucv.c
> +++ b/net/iucv/af_iucv.c
> @@ -512,7 +512,9 @@ static void iucv_sock_close(struct sock *sk)
>  			sk->sk_state = IUCV_DISCONN;
>  			sk->sk_state_change(sk);
>  		}
> -	case IUCV_DISCONN:   /* fall through */
> +		/* fall through */
> +
> +	case IUCV_DISCONN:
>  		sk->sk_state = IUCV_CLOSING;
>  		sk->sk_state_change(sk);
>  
> @@ -525,8 +527,9 @@ static void iucv_sock_close(struct sock *sk)
>  					iucv_sock_in_state(sk, IUCV_CLOSED, 0),
>  					timeo);
>  		}
> +		/* fall through */
>  
> -	case IUCV_CLOSING:   /* fall through */
> +	case IUCV_CLOSING:
>  		sk->sk_state = IUCV_CLOSED;
>  		sk->sk_state_change(sk);
>  
> @@ -535,8 +538,9 @@ static void iucv_sock_close(struct sock *sk)
>  
>  		skb_queue_purge(&iucv->send_skb_q);
>  		skb_queue_purge(&iucv->backlog_skb_q);
> +		/* fall through */
>  
> -	default:   /* fall through */
> +	default:
>  		iucv_sever_path(sk, 1);
>  	}
>  
> @@ -2247,10 +2251,10 @@ static int afiucv_hs_rcv(struct sk_buff *skb, struct net_device *dev,
>  			kfree_skb(skb);
>  			break;
>  		}
> -		/* fall through and receive non-zero length data */
> +		/* fall through - and receive non-zero length data */
>  	case (AF_IUCV_FLAG_SHT):
>  		/* shutdown request */
> -		/* fall through and receive zero length data */
> +		/* fall through - and receive zero length data */
>  	case 0:
>  		/* plain data frame */
>  		IUCV_SKB_CB(skb)->class = trans_hdr->iucv_hdr.class;
> -- 
> 2.22.0
> 

-- 
Kees Cook