From patchwork Thu Mar 19 18:48:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 11447849 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B5B41913 for ; Thu, 19 Mar 2020 18:48:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 948772078C for ; Thu, 19 Mar 2020 18:48:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=embeddedor.com header.i=@embeddedor.com header.b="QwtrUKuo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727417AbgCSSso (ORCPT ); Thu, 19 Mar 2020 14:48:44 -0400 Received: from gateway32.websitewelcome.com ([192.185.145.123]:24102 "EHLO gateway32.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726867AbgCSSso (ORCPT ); Thu, 19 Mar 2020 14:48:44 -0400 Received: from cm16.websitewelcome.com (cm16.websitewelcome.com [100.42.49.19]) by gateway32.websitewelcome.com (Postfix) with ESMTP id B0DCF80989 for ; Thu, 19 Mar 2020 13:48:40 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id F0DgjUMqa8vkBF0DgjLQGg; Thu, 19 Mar 2020 13:48:40 -0500 X-Authority-Reason: nr=8 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=embeddedor.com; s=default; h=Content-Type:MIME-Version:Message-ID:Subject: Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=salDAP8ehHVtnoEEty5Lr7QuUQoBYqHUOZ9uNY3e1ZY=; b=QwtrUKuoVfkrES4TwRleFDy94M aJ+tp9jr48joTJd7HG7UVcgVKan0i4lpwYXgJwGeGTcQ7OjColOH7y4UmQ+M0fqY+hFAHnxI21cZF fe6Gn/BrMbtq/RjHIeKxorufNWKHE0psCAHvzo7E56VvIYal0JmyFttYgsMe0cON2FMNnY2kfW6tD MvyKLNrso7A20RyREcX1ug3bbdBHhalPL3iYaGdmrjLWF+Emwp6jI+sHeqkXQbqfYGWU3ZAueTJSJ PWlrePfL66XsmFAF6sDHlHIVYVDCGpCykzuVwpuPmRKvdo3UuUYtiYZ23qVgGgdEch0QnGghSc85M qOasqU0w==; Received: from cablelink-189-218-116-241.hosts.intercable.net ([189.218.116.241]:51748 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1jF0De-000G3A-Om; Thu, 19 Mar 2020 13:48:38 -0500 Date: Thu, 19 Mar 2020 13:48:38 -0500 From: "Gustavo A. R. Silva" To: Andy Gross , Bjorn Andersson , Amit Kucheria , Zhang Rui , Daniel Lezcano Cc: linux-arm-msm@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] thermal: qcom: tsens.h: Replace zero-length array with flexible-array member Message-ID: <20200319184838.GA25767@embeddedor.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.218.116.241 X-Source-L: No X-Exim-ID: 1jF0De-000G3A-Om X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: cablelink-189-218-116-241.hosts.intercable.net (embeddedor) [189.218.116.241]:51748 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 6 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva Reviewed-by: Amit Kucheria --- drivers/thermal/qcom/tsens.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/thermal/qcom/tsens.h b/drivers/thermal/qcom/tsens.h index e24a865fbc34..92503712596a 100644 --- a/drivers/thermal/qcom/tsens.h +++ b/drivers/thermal/qcom/tsens.h @@ -488,7 +488,7 @@ struct tsens_priv { struct dentry *debug_root; struct dentry *debug; - struct tsens_sensor sensor[0]; + struct tsens_sensor sensor[]; }; char *qfprom_read(struct device *dev, const char *cname);