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 57A97C761A6 for ; Mon, 20 Mar 2023 19:33:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229601AbjCTTdE (ORCPT ); Mon, 20 Mar 2023 15:33:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44784 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230305AbjCTTck (ORCPT ); Mon, 20 Mar 2023 15:32:40 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 84EA23B212; Mon, 20 Mar 2023 12:26:21 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2550E617C3; Mon, 20 Mar 2023 19:26:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F3712C4339E; Mon, 20 Mar 2023 19:26:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1679340380; bh=p3nfI37uSD2HaSJ85GLFWgl7AfpzPINmlDeM97COr3g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LSbRdbY4kd9P9uxj3pLqomRsxEQw1KI3sfqU0vaasQo9/aJGViFhNiqlTlb9eHYa5 vubwALccOL5I2YMNuYB7Lb14Lq6C6B0aId2DQd5MdfuzSwEjkX5UzU+fqajqUeKcZ3 uGGNojiVjiXlAE7nE9ejACNKX4zYxJI+ongZew5BJfrglx6gIuhdlm9cuSdxlkmNiZ hWlH5higqWB6ImYOJ3SA/TgQ7Um8r3fOTd5RHpHBnuiUyUCtQvLZwQj9SJZ9BGq0hi atVLKDonKz2bJunCnZjifinF8cuYuUUQN74EZ4X48UrWrgP95n8keaRzwGnFMdwT+r NUUBaQk/smCrQ== Date: Mon, 20 Mar 2023 13:26:49 -0600 From: "Gustavo A. R. Silva" To: Simon Horman Cc: Felix Fietkau , Lorenzo Bianconi , Ryder Lee , Shayne Chen , Sean Wang , Kalle Valo , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Matthias Brugger , AngeloGioacchino Del Regno , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH][next] wifi: mt76: mt7921: Replace fake flex-arrays with flexible-array members Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Mar 20, 2023 at 03:56:54PM +0100, Simon Horman wrote: > > struct mt7921_asar_cl { > > @@ -85,7 +85,7 @@ struct mt7921_asar_fg { > > u8 rsvd; > > u8 nr_flag; > > u8 rsvd1; > > - u8 flag[0]; > > + u8 flag[]; > > I am curious to know why DECLARE_FLEX_ARRAY isn't used here. In contrast to the other structs, there is no object of type struct mt7921_asar_fg declared in a union: 91 struct mt7921_acpi_sar { 92 u8 ver; 93 union { 94 struct mt7921_asar_dyn *dyn; 95 struct mt7921_asar_dyn_v2 *dyn_v2; 96 }; 97 union { 98 struct mt7921_asar_geo *geo; 99 struct mt7921_asar_geo_v2 *geo_v2; 100 }; 101 struct mt7921_asar_cl *countrylist; 102 struct mt7921_asar_fg *fg; 103 }; The DECLARE_FLEX_ARRAY() helper was created to declare flex-array members in unions or alone in structs[1]. -- Gustavo [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays