From patchwork Tue Apr 7 03:10:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11477393 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 2D31C92A for ; Tue, 7 Apr 2020 03:10:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EEBF720716 for ; Tue, 7 Apr 2020 03:10:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="xHAbWkaE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EEBF720716 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B8A148E0076; Mon, 6 Apr 2020 23:10:02 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id B3A9A8E0062; Mon, 6 Apr 2020 23:10:02 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A7A8C8E0076; Mon, 6 Apr 2020 23:10:02 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0229.hostedemail.com [216.40.44.229]) by kanga.kvack.org (Postfix) with ESMTP id 8D34D8E0062 for ; Mon, 6 Apr 2020 23:10:02 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 5844F181AEF31 for ; Tue, 7 Apr 2020 03:10:02 +0000 (UTC) X-FDA: 76679579844.30.spade83_491f1a0a242 X-Spam-Summary: 2,0,0,95a3f7981f377e13,d41d8cd98f00b204,akpm@linux-foundation.org,,RULES_HIT:41:355:379:800:960:967:973:988:989:1260:1263:1345:1359:1381:1431:1437:1534:1541:1711:1730:1747:1777:1792:2194:2198:2199:2200:2393:2525:2559:2565:2682:2685:2693:2859:2902:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3352:3865:3866:3867:3870:3871:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4321:4605:5007:6117:6261:6653:7576:8599:9025:9545:10004:10913:11658:11914:12043:12048:12296:12297:12517:12519:12555:12679:12696:12737:12783:12986:13069:13161:13229:13255:13311:13357:14094:14181:14384:14721:14849:21080:21451:21627:21939:21972:30045:30054,0,RBL:198.145.29.99:@linux-foundation.org:.lbl8.mailshell.net-64.100.201.201 62.2.0.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:1,LUA_SUMMARY:none X-HE-Tag: spade83_491f1a0a242 X-Filterd-Recvd-Size: 2903 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Tue, 7 Apr 2020 03:10:01 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 EBCBB2083E; Tue, 7 Apr 2020 03:10:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586229001; bh=9NikmecMkDrlmkfd8d2Ci5GNE3ph1xjdhNTbk0gK5xA=; h=Date:From:To:Subject:In-Reply-To:From; b=xHAbWkaECClC51HkgF84g/5haI8xZe2ky68MR7numxP5/gjHazTokXX176ViAE0So lyauaW9dPV5vJzJiYXl9w87jfErXIVKinE8U+jIX+8YwQUhgRyBM9NgZcE8Nsc86n+ Mcm6RlwIimIYdlOnek58cei3oH4lZwFJ9UynhZM8= Date: Mon, 06 Apr 2020 20:10:00 -0700 From: Andrew Morton To: akpm@linux-foundation.org, gustavo@embeddedor.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 112/166] lib/ts_bm.c: replace zero-length array with flexible-array member Message-ID: <20200407031000.oYeSSqjYZ%akpm@linux-foundation.org> In-Reply-To: <20200406200254.a69ebd9e08c4074e41ddebaf@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: "Gustavo A. R. Silva" Subject: lib/ts_bm.c: replace zero-length array with flexible-array member 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 inadvertenly introduced[3] to the codebase from now on. 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") Link: http://lkml.kernel.org/r/20200211205620.GA24694@embeddedor Signed-off-by: Gustavo A. R. Silva Signed-off-by: Andrew Morton --- lib/ts_bm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/lib/ts_bm.c~lib-ts_bm-replace-zero-length-array-with-flexible-array-member +++ a/lib/ts_bm.c @@ -52,7 +52,7 @@ struct ts_bm u8 * pattern; unsigned int patlen; unsigned int bad_shift[ASIZE]; - unsigned int good_shift[0]; + unsigned int good_shift[]; }; static unsigned int bm_find(struct ts_config *conf, struct ts_state *state)