From patchwork Wed Feb 26 22:31:25 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: 11407393 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 9B65A1580 for ; Wed, 26 Feb 2020 22:28:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 701C024670 for ; Wed, 26 Feb 2020 22:28:39 +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="lnt9fUCw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727763AbgBZW2j (ORCPT ); Wed, 26 Feb 2020 17:28:39 -0500 Received: from gateway24.websitewelcome.com ([192.185.51.202]:11957 "EHLO gateway24.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727740AbgBZW2i (ORCPT ); Wed, 26 Feb 2020 17:28:38 -0500 Received: from cm16.websitewelcome.com (cm16.websitewelcome.com [100.42.49.19]) by gateway24.websitewelcome.com (Postfix) with ESMTP id 562C6A503D for ; Wed, 26 Feb 2020 16:28:37 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 75ATjUI348vkB75ATjPNGk; Wed, 26 Feb 2020 16:28:37 -0600 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=PtyODivJUtDP9MgCyxcSsityaCmUVDZg/RBEFKBCll0=; b=lnt9fUCwwhD2j8AXOE+QPdVwS0 rf4kr3sau6HQ7AUq/27TIk4qcQyE7uPX51BjsM7bdgZn0DDb7sjspoANUu7XYfS+eSDzlYragd+6G KRq+/zSzjZCqbisZbLoPR/NKuLg3xt394GWv4TWUJHsgpSSgBLRsGYhzw1Atwc5SfsVkD4OSdDDVc h4L2TbMYUH5hNB0Db/QqV7G9l+zjZIH3rrl2hDQMnERqZVHiNmkzm5NmiFlipNLh0PzYnOwK9RI48 6JhzsfVg1/DExj501hZsfpO4WGdrrLEw4fvMn1zKk30UjJkuGdAQqaFGA4sjNXVUWxJ618dF6SpCV OyWMwCyQ==; Received: from [201.162.161.208] (port=50608 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j75AP-001MIy-8J; Wed, 26 Feb 2020 16:28:35 -0600 Date: Wed, 26 Feb 2020 16:31:25 -0600 From: "Gustavo A. R. Silva" To: Adrian Hunter , Ulf Hansson Cc: linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] mmc: Replace zero-length array with flexible-array member Message-ID: <20200226223125.GA20630@embeddedor> 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: 201.162.161.208 X-Source-L: No X-Exim-ID: 1j75AP-001MIy-8J X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [201.162.161.208]:50608 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 28 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mmc@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 Acked-by: Adrian Hunter --- drivers/mmc/host/sdhci-acpi.c | 2 +- drivers/mmc/host/sdhci-cadence.c | 2 +- drivers/mmc/host/sdhci-pci.h | 2 +- drivers/mmc/host/sdhci-pltfm.h | 2 +- drivers/mmc/host/sdhci.h | 2 +- drivers/mmc/host/vub300.c | 2 +- include/linux/mmc/host.h | 2 +- include/linux/mmc/sdio_func.h | 2 +- include/uapi/linux/mmc/ioctl.h | 2 +- 9 files changed, 9 insertions(+), 9 deletions(-) diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c index 9651dca6863e..ea0e4fda3a9e 100644 --- a/drivers/mmc/host/sdhci-acpi.c +++ b/drivers/mmc/host/sdhci-acpi.c @@ -72,7 +72,7 @@ struct sdhci_acpi_host { const struct sdhci_acpi_slot *slot; struct platform_device *pdev; bool use_runtime_pm; - unsigned long private[0] ____cacheline_aligned; + unsigned long private[] ____cacheline_aligned; }; static inline void *sdhci_acpi_priv(struct sdhci_acpi_host *c) diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c index 5827d3751b81..9af3fe48d62f 100644 --- a/drivers/mmc/host/sdhci-cadence.c +++ b/drivers/mmc/host/sdhci-cadence.c @@ -67,7 +67,7 @@ struct sdhci_cdns_priv { void __iomem *hrs_addr; bool enhanced_strobe; unsigned int nr_phy_params; - struct sdhci_cdns_phy_param phy_params[0]; + struct sdhci_cdns_phy_param phy_params[]; }; struct sdhci_cdns_phy_cfg { diff --git a/drivers/mmc/host/sdhci-pci.h b/drivers/mmc/host/sdhci-pci.h index 981bbbe63aff..42ccd123b046 100644 --- a/drivers/mmc/host/sdhci-pci.h +++ b/drivers/mmc/host/sdhci-pci.h @@ -163,7 +163,7 @@ struct sdhci_pci_slot { bool cd_override_level; void (*hw_reset)(struct sdhci_host *host); - unsigned long private[0] ____cacheline_aligned; + unsigned long private[] ____cacheline_aligned; }; struct sdhci_pci_chip { diff --git a/drivers/mmc/host/sdhci-pltfm.h b/drivers/mmc/host/sdhci-pltfm.h index 2af445b8c325..6301b81cf573 100644 --- a/drivers/mmc/host/sdhci-pltfm.h +++ b/drivers/mmc/host/sdhci-pltfm.h @@ -25,7 +25,7 @@ struct sdhci_pltfm_host { unsigned int clock; u16 xfer_mode_shadow; - unsigned long private[0] ____cacheline_aligned; + unsigned long private[] ____cacheline_aligned; }; #ifdef CONFIG_MMC_SDHCI_BIG_ENDIAN_32BIT_BYTE_SWAPPER diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index cac2d97782e6..249635692112 100644 --- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h @@ -614,7 +614,7 @@ struct sdhci_host { u64 data_timeout; - unsigned long private[0] ____cacheline_aligned; + unsigned long private[] ____cacheline_aligned; }; struct sdhci_ops { diff --git a/drivers/mmc/host/vub300.c b/drivers/mmc/host/vub300.c index 6ced1b7f642f..a5a90d133f1f 100644 --- a/drivers/mmc/host/vub300.c +++ b/drivers/mmc/host/vub300.c @@ -95,7 +95,7 @@ struct sd_response_header { u8 port_number; u8 command_type; u8 command_index; - u8 command_response[0]; + u8 command_response[]; } __packed; struct sd_status_header { diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 562ed06881b0..2629329ab9f2 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -465,7 +465,7 @@ struct mmc_host { /* Host Software Queue support */ bool hsq_enabled; - unsigned long private[0] ____cacheline_aligned; + unsigned long private[] ____cacheline_aligned; }; struct device_node; diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h index 5a177f7a83c3..fa2aaab5e57a 100644 --- a/include/linux/mmc/sdio_func.h +++ b/include/linux/mmc/sdio_func.h @@ -25,7 +25,7 @@ struct sdio_func_tuple { struct sdio_func_tuple *next; unsigned char code; unsigned char size; - unsigned char data[0]; + unsigned char data[]; }; /* diff --git a/include/uapi/linux/mmc/ioctl.h b/include/uapi/linux/mmc/ioctl.h index 00c08120f3ba..98e29e7f54ac 100644 --- a/include/uapi/linux/mmc/ioctl.h +++ b/include/uapi/linux/mmc/ioctl.h @@ -57,7 +57,7 @@ struct mmc_ioc_cmd { */ struct mmc_ioc_multi_cmd { __u64 num_of_cmds; - struct mmc_ioc_cmd cmds[0]; + struct mmc_ioc_cmd cmds[]; }; #define MMC_IOC_CMD _IOWR(MMC_BLOCK_MAJOR, 0, struct mmc_ioc_cmd)