linux-kernel - RE: [PATCH] usb: gadget: goku_udc: mark expected switch fall-throughs

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Date:   Tue, 24 Oct 2017 14:21:21 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     "'Gustavo A. R. Silva'" <garsilva@...eddedor.com>,
        Felipe Balbi <balbi@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
CC:     "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] usb: gadget: goku_udc: mark expected switch
 fall-throughs

From: Gustavo A. R. Silva
> Sent: 24 October 2017 04:46
> In preparation to enabling -Wimplicit-fallthrough, mark switch cases
> where we are expecting to fall through.
> 
> Addresses-Coverity-ID: 145713
> Signed-off-by: Gustavo A. R. Silva <garsilva@...eddedor.com>
> ---
>  drivers/usb/gadget/udc/goku_udc.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/usb/gadget/udc/goku_udc.c b/drivers/usb/gadget/udc/goku_udc.c
> index 8433c22..a85407e 100644
> --- a/drivers/usb/gadget/udc/goku_udc.c
> +++ b/drivers/usb/gadget/udc/goku_udc.c
> @@ -127,11 +127,15 @@ goku_ep_enable(struct usb_ep *_ep, const struct usb_endpoint_descriptor *desc)
>  	mode = 0;
>  	max = get_unaligned_le16(&desc->wMaxPacketSize);
>  	switch (max) {
> -	case 64:	mode++;
> -	case 32:	mode++;
> -	case 16:	mode++;
> -	case 8:		mode <<= 3;
> -			break;
> +	case 64:
> +		mode++; /* fall through */
> +	case 32:
> +		mode++; /* fall through */
> +	case 16:
> +		mode++; /* fall through */
> +	case 8:
> +		mode <<= 3;
> +		break;
>  	default:
>  		return -EINVAL;

I can't help feeling this could be the more obvious:
	switch (max) {
	case  8: mode =  0; break;
	case 16: mode =  8; break;
	case 32: mode = 16; break;
	case 64: mode = 24; break;
	default: return -EINVAL;
	}
(with a few more blank lines)

	David