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 X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9C430C31E5B for ; Wed, 19 Jun 2019 00:21:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A44721479 for ; Wed, 19 Jun 2019 00:21:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="MXVd4PE5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729201AbfFSAVB (ORCPT ); Tue, 18 Jun 2019 20:21:01 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:45342 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726007AbfFSAVA (ORCPT ); Tue, 18 Jun 2019 20:21:00 -0400 Received: by mail-pl1-f195.google.com with SMTP id bi6so6372536plb.12; Tue, 18 Jun 2019 17:21:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=QKQ5dtYnqxmy6bgOfqdi46t1jOuoHpggM28BRKB8AQ8=; b=MXVd4PE57vRHp+k2WFV6t5QMzwcjpc2Cx5sWT5JMVgZSA/6sqNrHJ6MkXMCDejw1k9 5Nv/3cwpodbSEmrnvkK5R9k8kad/UqNjySudhE+pupt+Z47AKNVIfMT9aWdLNUjCKFW7 erbVlptf9+0sIrJN3Aj5WKZxILBfK31F0MsT2qTNTR/ZRBiRx2i1VanSDIYyBEvvOiA6 1d/UapBC7obDjxE5JVbqb8p+KtmBjK1isDQAGYHOz6FpEFTeM5et4zw94hoEmSb7ueWJ lTfecVYclMek/1DSs64Dwq29XuAHVUzWWeKaMoEvPlA7XcOAZMrGf/QXD81eZ5BtNXeT BiOA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=QKQ5dtYnqxmy6bgOfqdi46t1jOuoHpggM28BRKB8AQ8=; b=rKovPo27TacFCI3JtE38usojquGbWwc1ZJbNIdG6X0mYhRi3Mog8M0r/5guTpM9ONN ueMhG2kZBDQaYTfqCqtA+VpwqIzkKDachqbP41rcCMu/kgc0GeqcHNZ0zqIz1AwRC7jr HKwlP9cvNF949+RK6kFjir23Bugy/WlbBDFW2WTEd6A8alfTLRKjI1KnIPQm4+AYKMiK mxQG8F0a+qRZPXcdVsqy74LOzbtlV7BIEgBgIG1TyeTq5xZEO93lw8qhX6n8m7GDOYsy Y9krFS44Z4HxiBKB/lj24jflwV3gvcihI//A0/JBYbDZrOxl9lmvishvwGuYfX6JX2+o PqOg== X-Gm-Message-State: APjAAAUNAYWlTGv8DYarOJo43OSc73dGcgI8jEqmx1Q/EwYXHx3KVfb1 tguFXLNCt0xSwpdkYlLq5itNITo5 X-Google-Smtp-Source: APXvYqwhwHh60c7Jq2c+bmQdh2Jk4gQ/goBNU1RRwAbHB5SSvohsQhuh6iDSuJBe+EK2aHszyV2Giw== X-Received: by 2002:a17:902:24d:: with SMTP id 71mr119804933plc.166.1560903659966; Tue, 18 Jun 2019 17:20:59 -0700 (PDT) Received: from dtor-ws ([2620:15c:202:201:3adc:b08c:7acc:b325]) by smtp.gmail.com with ESMTPSA id g13sm15821370pfi.93.2019.06.18.17.20.59 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 18 Jun 2019 17:20:59 -0700 (PDT) Date: Tue, 18 Jun 2019 17:20:57 -0700 From: Dmitry Torokhov To: "Gustavo A. R. Silva" Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Input: gpio_keys - use struct_size() in devm_kzalloc() Message-ID: <20190619002057.GB62571@dtor-ws> References: <20190618152325.GA21504@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190618152325.GA21504@embeddedor> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 18, 2019 at 10:23:25AM -0500, Gustavo A. R. Silva wrote: > One of the more common cases of allocation size calculations is finding > the size of a structure that has a zero-sized array at the end, along > with memory for some number of elements for that array. For example: > > struct gpio_keys_drvdata { > ... > struct gpio_button_data data[0]; > }; > > > size = sizeof(struct gpio_keys_drvdata) + count * sizeof(struct gpio_button_data); > instance = devm_kzalloc(dev, size, GFP_KERNEL); > > Instead of leaving these open-coded and prone to type mistakes, we can > now use the new struct_size() helper: > > instance = devm_kzalloc(dev, struct_size(instance, data, count), GFP_KERNEL); > > Notice that, in this case, variable size is not necessary, hence it > is removed. > > This code was detected with the help of Coccinelle. > > Signed-off-by: Gustavo A. R. Silva Applied, thank you. > --- > drivers/input/keyboard/gpio_keys.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c > index 6cd199e8a370..c186c2552b04 100644 > --- a/drivers/input/keyboard/gpio_keys.c > +++ b/drivers/input/keyboard/gpio_keys.c > @@ -774,7 +774,6 @@ static int gpio_keys_probe(struct platform_device *pdev) > struct fwnode_handle *child = NULL; > struct gpio_keys_drvdata *ddata; > struct input_dev *input; > - size_t size; > int i, error; > int wakeup = 0; > > @@ -784,9 +783,8 @@ static int gpio_keys_probe(struct platform_device *pdev) > return PTR_ERR(pdata); > } > > - size = sizeof(struct gpio_keys_drvdata) + > - pdata->nbuttons * sizeof(struct gpio_button_data); > - ddata = devm_kzalloc(dev, size, GFP_KERNEL); > + ddata = devm_kzalloc(dev, struct_size(ddata, data, pdata->nbuttons), > + GFP_KERNEL); > if (!ddata) { > dev_err(dev, "failed to allocate state\n"); > return -ENOMEM; > -- > 2.21.0 > -- Dmitry