Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754197AbbLJRkm (ORCPT ); Thu, 10 Dec 2015 12:40:42 -0500 Received: from mail-vk0-f51.google.com ([209.85.213.51]:33038 "EHLO mail-vk0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751991AbbLJRkk (ORCPT ); Thu, 10 Dec 2015 12:40:40 -0500 MIME-Version: 1.0 In-Reply-To: <5669B5BB.6060608@cogentembedded.com> References: <1449700359-14262-1-git-send-email-geyslan@gmail.com> <1449700359-14262-4-git-send-email-geyslan@gmail.com> <5669680E.4070304@cogentembedded.com> <56698FB3.9030705@cogentembedded.com> <5669B5BB.6060608@cogentembedded.com> Date: Thu, 10 Dec 2015 14:40:39 -0300 Message-ID: Subject: Re: [PATCH 4/9v2] usb: host: ehci.h: fix single statement macros From: "Geyslan G. Bem" To: Sergei Shtylyov Cc: Peter Senna Tschudin , Alan Stern , Greg Kroah-Hartman , linux-usb@vger.kernel.org, LKML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2472 Lines: 91 2015-12-10 14:26 GMT-03:00 Sergei Shtylyov : > On 12/10/2015 05:56 PM, Geyslan G. Bem wrote: > >>>>>>> Don't use the 'do {} while (0)' wrapper in a single statement macro. >>>>>>> >>>>>>> Caught by checkpatch: "WARNING: Single statement macros should not >>>>>>> use a do {} while (0) loop" >>>>>>> >>>>>>> Signed-off-by: Geyslan G. Bem >>>>>>> --- >>>>>>> drivers/usb/host/ehci.h | 4 ++-- >>>>>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>>>>> >>>>>>> diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h >>>>>>> index cfeebd8..945000a 100644 >>>>>>> --- a/drivers/usb/host/ehci.h >>>>>>> +++ b/drivers/usb/host/ehci.h >>>>>>> @@ -244,9 +244,9 @@ struct ehci_hcd { /* one per >>>>>>> controller */ >>>>>>> /* irq statistics */ >>>>>>> #ifdef EHCI_STATS >>>>>>> struct ehci_stats stats; >>>>>>> -# define COUNT(x) do { (x)++; } while (0) >>>>>>> +# define COUNT(x) ((x)++) >>>>>>> #else >>>>>>> -# define COUNT(x) do {} while (0) >>>>>>> +# define COUNT(x) ((void) 0) >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> Why not just empty #define? >>>>> >>>>> >>>>> >>>>> Indeed. I'll change it. >>>>> Tks Sergei. >>>> >>>> >>>> >>>> Since COUNT is not used to return the empty #define is ok. Another way >>>> is to use #define COUNT(x) (0) to get a 0 when necessary to read >>>> returns. > > >>> Just 0, no parens please. > > >> Ok, no parens, since there's no evaluation. > > > It's because the literals don't need parens at all. > >> Then my change is: >> >> -# define COUNT(x) do { (x)++; } while (0) >> +# define COUNT(x) (++(x)) >> #else >> -# define COUNT(x) do {} while (0) >> +# define COUNT(x) 0 >> >> Pre-increment allowing to return the updated x. > > > Why if there was a post-increment before? There's nothing wrong with post-increment. The pre one would be necessary if using return. > > Anyway, this talk is quite pointless since the macro didn't return any > value anyway. You're sure, there's no use anywhere of the return of that macro indeed. Sending v2 soon. > > MBR, Sergei > -- Regards, Geyslan G. Bem hackingbits.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/