Re: [PATCH] usb: host: fhci-hcd: annotate PIPE_CONTROL switch case with fallthrough

[Rasmus Villemoes]

On 13/02/2020 13.56, Greg Kroah-Hartman wrote:

>> diff --git a/drivers/usb/host/fhci-hcd.c b/drivers/usb/host/fhci-hcd.c
>> index 04733876c9c6..a8e1048278d0 100644
>> --- a/drivers/usb/host/fhci-hcd.c
>> +++ b/drivers/usb/host/fhci-hcd.c
>> @@ -396,6 +396,7 @@ static int fhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
>>  	case PIPE_CONTROL:
>>  		/* 1 td fro setup,1 for ack */
>>  		size = 2;
>> +		fallthrough;
> 
> We have an attribute for that?
> 
> Shouldn't this be /* fall through */ instead?
> 
> Gustavo, what's the best practice here, I count only a few
> "fallthrough;" instances in the kernel, although one is in our coding
> style document, and thousands of the /* */ version.

Yes, I went with the attribute/macro due to that, and the history is
that Linus applied Joe's patches directly
(https://lore.kernel.org/lkml/CAHk-=whOF8heTGz5tfzYUBp_UQQzSWNJ_50M7-ECXkfFRDQWFA@xxxxxxxxxxxxxx/),
so I assumed that meant the Penguin decided that the attribute/macro is
the right thing to do for new code, while existing comment annotations
can be left alone or changed piecemeal as code gets refactored anyway.

Rasmus