From patchwork Thu May 7 19:22:28 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: 11535823 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 F387E14B4 for ; Fri, 8 May 2020 07:36:29 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8AB0E206D5 for ; Fri, 8 May 2020 07:36:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="C4zJUiUI"; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="KJ7s41EA" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8AB0E206D5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-devel-bounces@alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id D0468185F; Fri, 8 May 2020 09:35:41 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz D0468185F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1588923387; bh=6u2Zjd4cCAJplBkIJArkC26yIzl29BGwwVH3o2xHtus=; h=Date:From:To:Subject:Cc:List-Id:List-Unsubscribe:List-Archive: List-Post:List-Help:List-Subscribe:From; b=C4zJUiUIaBCvs0H3FKjycom5Qy6acMeKG0QFn5KyiBJprKd/f7XDNy0LgymHET9fd ChlJPbOuUoZP13m0hakEdh7NOUJvUcKDlIs96Ac9u7I/XAMiwSFM1pNCOnDNL/V9dJ Bxpc1DzNkjmIJZFER62C2t8AbOhqrWfyONgutoFs= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 09388F8029B; Fri, 8 May 2020 09:33:15 +0200 (CEST) X-Original-To: alsa-devel@alsa-project.org Delivered-To: alsa-devel@alsa-project.org Received: by alsa1.perex.cz (Postfix, from userid 50401) id 461E0F8015F; Thu, 7 May 2020 21:18:06 +0200 (CEST) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on alsa1.perex.cz X-Spam-Level: X-Spam-Status: No, score=0.9 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,PRX_BODY_30,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=disabled version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 6EC5EF800AD for ; Thu, 7 May 2020 21:18:03 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 6EC5EF800AD Authentication-Results: alsa1.perex.cz; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="KJ7s41EA" Received: from embeddedor (unknown [189.207.59.248]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B0CF821835; Thu, 7 May 2020 19:18:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588879082; bh=6u2Zjd4cCAJplBkIJArkC26yIzl29BGwwVH3o2xHtus=; h=Date:From:To:Cc:Subject:From; b=KJ7s41EA/KoUExDhcHun9qGSDWEpgm/fTIP9T9CzHUw4Jhqsz64KiFgt9cTc+tzQ2 a/1gXi4RyMPG7UC9ubhXx19jnsIbGpm6KoDr//HwybVANQgxObEtbnMIVvhgeq4bRF Al/JgIZkn/n4NLqevOxa/qXJnx9tV+tHjHLz/VFI= Date: Thu, 7 May 2020 14:22:28 -0500 From: "Gustavo A. R. Silva" To: Liam Girdwood , Mark Brown Subject: [PATCH] ASoC: soc-core: Replace zero-length array with flexible-array Message-ID: <20200507192228.GA16355@embeddedor> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) X-Mailman-Approved-At: Fri, 08 May 2020 09:33:05 +0200 Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" 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] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. 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 --- include/sound/soc-dapm.h | 2 +- include/sound/soc.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/include/sound/soc-dapm.h b/include/sound/soc-dapm.h index 08495f8d86dc..cc3dcb815282 100644 --- a/include/sound/soc-dapm.h +++ b/include/sound/soc-dapm.h @@ -689,7 +689,7 @@ struct snd_soc_dapm_context { /* A list of widgets associated with an object, typically a snd_kcontrol */ struct snd_soc_dapm_widget_list { int num_widgets; - struct snd_soc_dapm_widget *widgets[0]; + struct snd_soc_dapm_widget *widgets[]; }; #define for_each_dapm_widgets(list, i, widget) \ diff --git a/include/sound/soc.h b/include/sound/soc.h index 13458e4fbb13..3e14442de2ec 100644 --- a/include/sound/soc.h +++ b/include/sound/soc.h @@ -1167,7 +1167,7 @@ struct snd_soc_pcm_runtime { unsigned int fe_compr:1; /* for Dynamic PCM */ int num_components; - struct snd_soc_component *components[0]; /* CPU/Codec/Platform */ + struct snd_soc_component *components[]; /* CPU/Codec/Platform */ }; /* see soc_new_pcm_runtime() */ #define asoc_rtd_to_cpu(rtd, n) (rtd)->dais[n]