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Message-ID: <de5b16cf3fdac1f783e291acc325b78368653ec5.camel@perches.com>
Subject: Re: [PATCH 072/141] can: peak_usb: Fix fall-through warnings for
 Clang
From:   Joe Perches <joe@perches.com>
To:     Marc Kleine-Budde <mkl@pengutronix.de>,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        Wolfgang Grandegger <wg@grandegger.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>
Cc:     linux-can@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Date:   Sat, 21 Nov 2020 11:50:17 -0800
In-Reply-To: <bf3dbc5c-c34e-b3ef-abb6-0c88d8a90332@pengutronix.de>
References: <cover.1605896059.git.gustavoars@kernel.org>
         <aab7cf16bf43cc7c3e9c9930d2dae850c1d07a3c.1605896059.git.gustavoars@kernel.org>
         <bf3dbc5c-c34e-b3ef-abb6-0c88d8a90332@pengutronix.de>
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On Sat, 2020-11-21 at 14:17 +0100, Marc Kleine-Budde wrote:
> On 11/20/20 7:34 PM, Gustavo A. R. Silva wrote:
> > In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
> > by explicitly adding a break statement instead of letting the code fall
> > through to the next case.
> > 
> > Link: https://github.com/KSPP/linux/issues/115
> > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
[]
> > diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_core.c b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
[]
> > @@ -299,6 +299,8 @@ static void peak_usb_write_bulk_callback(struct urb *urb)
> > ?		if (net_ratelimit())
> > ?			netdev_err(netdev, "Tx urb aborted (%d)\n",
> > ?				   urb->status);
> > +		break;
> > +
> > ?	case -EPROTO:
> > ?	case -ENOENT:
> > ?	case -ECONNRESET:
> > 
> 
> What about moving the default to the end if the case, which is more common anyways:
> 
> diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_core.c b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
[]
> @@ -295,16 +295,16 @@ static void peak_usb_write_bulk_callback(struct urb *urb)
> ????????????????netif_trans_update(netdev);
> ????????????????break;
> ?
> 
> -       default:
> -               if (net_ratelimit())
> -                       netdev_err(netdev, "Tx urb aborted (%d)\n",
> -                                  urb->status);
> ????????case -EPROTO:
> ????????case -ENOENT:
> ????????case -ECONNRESET:
> ????????case -ESHUTDOWN:
> -
> ????????????????break;
> +
> +       default:
> +               if (net_ratelimit())
> +                       netdev_err(netdev, "Tx urb aborted (%d)\n",
> +                                  urb->status);

That's fine and is more generally used style but this
default: case should IMO also end with a break;

+		break;

> ????????}