From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1D8EC433EF for ; Thu, 10 Feb 2022 10:17:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239523AbiBJKQ6 (ORCPT ); Thu, 10 Feb 2022 05:16:58 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:37354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239557AbiBJKQx (ORCPT ); Thu, 10 Feb 2022 05:16:53 -0500 Received: from mail-lj1-x236.google.com (mail-lj1-x236.google.com [IPv6:2a00:1450:4864:20::236]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8494DFFB for ; Thu, 10 Feb 2022 02:16:50 -0800 (PST) Received: by mail-lj1-x236.google.com with SMTP id j14so7265911lja.3 for ; Thu, 10 Feb 2022 02:16:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=message-id:date:mime-version:user-agent:subject:content-language:to :references:from:in-reply-to:content-transfer-encoding; bh=3ne9afkcEMUgeoGNnWkV++QClTAUsFhKUiDokSSK4gs=; b=cpwqd0ostl/K+0LDjp2O6emA6OJVYcuj390GkHObcgJdcYkRtqUketq5yz81ZW1ECl XNHUYvbLv6X9XrwkTOPMd0aj8dFeJivC7rqhA/EwEwFsHu/2/2VYqiP4gmU1vK1v5bgH 0r1SH59cy3GO/YFDMyrJ90Z9jcifx/DZvIZ+Smo8syz3lY5yQByFDE+P5EK0qRWKKzVc 6D17AWW2PEHr/FfcoztmL0216RO4PipqiK8X08Zedwbl90LI3Dkv5sTl0B5SJr2o9ONs JgS3JxvDgP0iqwaryvvqtf8raA7fGcBKOV9bXpANRbVytEfgzOPqqB4852ysoRhjbuN+ NDkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:references:from:in-reply-to :content-transfer-encoding; bh=3ne9afkcEMUgeoGNnWkV++QClTAUsFhKUiDokSSK4gs=; b=sP61b+ofPP5ZcIkwSdzjX7B7+dPxmlpw2YWlO58Pn7i5uhVEEFlSgJZSgY4Mo4UxzC 8WLSIFhENqH3sVNAjha8gOwg1bJ2BHLYGV9tELivX6h1mW8Avyvlc9P4vS3chu8TND3D Ug2+pTM97PPX5Ehk1A7tpaTdkGlAdBU0XOR4T8HzciZ5HYEeFSnGByh8nNNO855aPq/S aVnqjoERHZIclMxIgDX3nl/ugkPobHg4HqyImoLamvL3GdJnn+co75P4C7GotY5tFvnW Lm687mxLOT3ibVqKII0sNiEPo2SJFm5oO8GSeYlvaZpLiUzEfbCOBoM8a0LYqIisCdhl eYbA== X-Gm-Message-State: AOAM531kRBVXQoOAfdDwqUs1xV1BSsr9lj5NhIySSliQUjT9lKRPpT50 l13KxqhL4MOmmR2+v5TKNUF1rQ== X-Google-Smtp-Source: ABdhPJxjobzeo5yzVqpZ1edrDcbPHOwnY2/Az6fBOhCPktWcPtktCsDi7eYsUWXornR+W6Dt96frYg== X-Received: by 2002:a05:651c:1413:: with SMTP id u19mr4516534lje.240.1644488208827; Thu, 10 Feb 2022 02:16:48 -0800 (PST) Received: from [192.168.1.211] ([37.153.55.125]) by smtp.gmail.com with ESMTPSA id a6sm2841646ljb.93.2022.02.10.02.16.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 10 Feb 2022 02:16:48 -0800 (PST) Message-ID: <19b96972-cee7-937f-21ce-c78982ed2048@linaro.org> Date: Thu, 10 Feb 2022 13:16:46 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.1 Subject: Re: [PATCH] media: qcom: use div64_u64() instead of do_div() Content-Language: en-GB To: Qing Wang , Stanimir Varbanov , Andy Gross , Bjorn Andersson , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org References: <1644395913-4091-1-git-send-email-wangqing@vivo.com> From: Dmitry Baryshkov In-Reply-To: <1644395913-4091-1-git-send-email-wangqing@vivo.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/02/2022 11:38, Qing Wang wrote: > From: Wang Qing > > do_div() does a 64-by-32 division. > When the divisor is u64, do_div() truncates it to 32 bits, this means it > can test non-zero and be truncated to zero for division. > > fix do_div.cocci warning: > do_div() does a 64-by-32 division, please consider using div64_u64 instead. NAK The div64_u64 is not equivalent to do_div. It returns the quotient rather than modifying the first arg. Moreover it is unoptimal on 32-bit arches. > > Signed-off-by: Wang Qing > --- > drivers/media/platform/qcom/venus/vdec.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/media/platform/qcom/venus/vdec.c b/drivers/media/platform/qcom/venus/vdec.c > index 91da3f5..941a904 > --- a/drivers/media/platform/qcom/venus/vdec.c > +++ b/drivers/media/platform/qcom/venus/vdec.c > @@ -435,7 +435,7 @@ static int vdec_s_parm(struct file *file, void *fh, struct v4l2_streamparm *a) > return -EINVAL; > > fps = (u64)USEC_PER_SEC; > - do_div(fps, us_per_frame); > + div64_u64(fps, us_per_frame); > > inst->fps = fps; > inst->timeperframe = *timeperframe; -- With best wishes Dmitry