Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161038AbbKEIs3 (ORCPT ); Thu, 5 Nov 2015 03:48:29 -0500 Received: from mail-yk0-f181.google.com ([209.85.160.181]:35126 "EHLO mail-yk0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030329AbbKEIs1 (ORCPT ); Thu, 5 Nov 2015 03:48:27 -0500 MIME-Version: 1.0 In-Reply-To: <1446698789-19308-3-git-send-email-okaya@codeaurora.org> References: <1446698789-19308-1-git-send-email-okaya@codeaurora.org> <1446698789-19308-3-git-send-email-okaya@codeaurora.org> Date: Thu, 5 Nov 2015 10:48:26 +0200 Message-ID: Subject: Re: [PATCH 3/4] scsi: fix compiler warning for sg From: Andy Shevchenko To: Sinan Kaya Cc: linux-scsi , timur@codeaurora.org, cov@codeaurora.org, jcm@redhat.com, Doug Gilbert , "James E.J. Bottomley" , "linux-kernel@vger.kernel.org" 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: 1970 Lines: 65 On Thu, Nov 5, 2015 at 6:46 AM, Sinan Kaya wrote: > The MULDIV macro has been designed for small > numbers. It emits an overflow warning on 64 bit > systems. This patch places type casts in the > parameters to fix the compiler warning. > > Signed-off-by: Sinan Kaya > --- > drivers/scsi/sg.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c > index 9d7b7db..eb2739d 100644 > --- a/drivers/scsi/sg.c > +++ b/drivers/scsi/sg.c > @@ -88,7 +88,10 @@ static void sg_proc_cleanup(void); > * Of course an overflow is inavoidable if the result of muldiv doesn't fit > * in 32 bits. > */ > -#define MULDIV(X,MUL,DIV) ((((X % DIV) * MUL) / DIV) + ((X / DIV) * MUL)) > +static inline u64 MULDIV(u64 X, u32 MUL, u32 DIV) > +{ > + return ((((X % DIV) * MUL) / DIV) + ((X / DIV) * MUL)); > +} Like kbuild bot already told you it would be nice to think of 32-bit architectures. Moreover we have mult_frac() macro already for 32-bit numbers. For 64 bit numbers you need to do do_div(). Like: static inline u64 mult_frac64(u64 x, u32 m, u32 n) { u64 ret; ret = do_div(x, n); return ret * m; } > > #define SG_DEFAULT_TIMEOUT MULDIV(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ) > > -- > Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc. > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project > > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- With Best Regards, Andy Shevchenko -- 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/