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 X-Spam-Level: X-Spam-Status: No, score=-17.8 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 88B15C433DF for ; Wed, 29 Jul 2020 14:50:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 48A3520809 for ; Wed, 29 Jul 2020 14:50:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Uekz1hDH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 48A3520809 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CE8C96B000C; Wed, 29 Jul 2020 10:50:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C97726B000D; Wed, 29 Jul 2020 10:50:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B3B746B000E; Wed, 29 Jul 2020 10:50:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0209.hostedemail.com [216.40.44.209]) by kanga.kvack.org (Postfix) with ESMTP id 97C1B6B000C for ; Wed, 29 Jul 2020 10:50:22 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 60C5D1802EABD for ; Wed, 29 Jul 2020 14:50:22 +0000 (UTC) X-FDA: 77091399084.05.bells22_380362526f73 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin05.hostedemail.com (Postfix) with ESMTP id 3CDFB18479694 for ; Wed, 29 Jul 2020 14:50:22 +0000 (UTC) X-HE-Tag: bells22_380362526f73 X-Filterd-Recvd-Size: 4830 Received: from mail-pl1-f194.google.com (mail-pl1-f194.google.com [209.85.214.194]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Wed, 29 Jul 2020 14:50:21 +0000 (UTC) Received: by mail-pl1-f194.google.com with SMTP id t6so11898187plo.3 for ; Wed, 29 Jul 2020 07:50:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=XgDzWs5LYt7Mkx0UdbPr7BFgEZ8N/ZoZ6ADwKcHkW84=; b=Uekz1hDHFE/A9esJhBdVFwm8ohWCgO/OY+8PRW1Bp2rQOpEMNN1vlmW+8ay2DT91cC 7eD39VYxARUX7FoPwiGCEGuKIqd7uzQ0yuRdRsUhVuy+XVqUoytulRJDXGOkjnpk4WIQ /F5R0wumaXINUq/XwS3HWxK+YZttG/FXg/eyuOPSQXavDsp4DE6hVWijJQRb/+g8uEm+ L8z4RGzDZwAonZa3lTaSb5tla73JNC4esECyEUnIvyakAruIZnKlTUP1hUtcwhuosDWz 7kVUbvMUh33slesyNHfEwPykMehktJmKvc8qgzggibg4jyM5K4SDzXd5fhQXDd+zKHKL MG3Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=XgDzWs5LYt7Mkx0UdbPr7BFgEZ8N/ZoZ6ADwKcHkW84=; b=J798e8CCg8rVYJLpy6E8e9oYHYpJFWF94kArLqnLOus9Xsfj+oac5yIoei5jrsnIS/ cywOPeQ75qb6DdkAMqb72wlx0/HtvD6Jr0YI0BiUSVRta4W3PE9hv7MOaWxzOaCQjmBR GevbWbkyMMQwG/CXm+1Y2PLxXFAAnAyuMj/OEMha6AsHVPEPUwog7VpkR5dvhpFGJOP2 IpO8IRGQHc0h9fGqr+8K7Z+JrZbhKPyhVlPH4QTdSWeRjWw9yctA+tA/yqTq80ZEVuSR OlUSsdbnQ69T/eMmxe6HdCv3BP2VECI895ImP5MjBm9Nwu8fJiNj3Sl4jqJP2LG2zkVS 23Jw== X-Gm-Message-State: AOAM533AhBFpoFVGLUIAArQ40aic7rrUxLqLhxdVdWyXtXATFIqCS1Ae gveeIAQsmOibvDgaDb4lmBg= X-Google-Smtp-Source: ABdhPJxsckiyS9HZ6KWrI4D+jRealIDAmq6K3fsnqkoDoBrRPnfto+1PgdXkVPNlSwxO859eW7X4jQ== X-Received: by 2002:a17:902:d303:: with SMTP id b3mr13162508plc.101.1596034220591; Wed, 29 Jul 2020 07:50:20 -0700 (PDT) Received: from builder-PowerEdge-R730xd.mioffice.cn ([43.224.245.179]) by smtp.gmail.com with ESMTPSA id o190sm1251827pfd.194.2020.07.29.07.50.17 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 29 Jul 2020 07:50:20 -0700 (PDT) From: Qianli Zhao To: cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, zhaoqianli@xiaomi.com Subject: [PATCH] mm: slab: Avoid the use of one-element array and use struct_size() helper Date: Wed, 29 Jul 2020 22:50:14 +0800 Message-Id: <1596034214-15010-1-git-send-email-zhaoqianligood@gmail.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Rspamd-Queue-Id: 3CDFB18479694 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000002, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Qianli Zhao There is a regular need in the kernel to provide a way to declare having = a dynamically sized set of trailing elements in a structure. Kernel code sh= ould always use =E2=80=9Cflexible array members=E2=80=9D[1] for these cases. T= he older style of one-element or zero-length arrays should no longer be used[2]. Make use of the struct_size() helper instead of an open-coded version in order to avoid any potential type mistakes. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://github.com/KSPP/linux/issues/21 Signed-off-by: Qianli Zhao --- mm/slab.h | 2 +- mm/slab_common.c | 7 ++----- 2 files changed, 3 insertions(+), 6 deletions(-) diff --git a/mm/slab.h b/mm/slab.h index 74f7e09..c12fb65 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -34,7 +34,7 @@ struct kmem_cache { =20 struct memcg_cache_array { struct rcu_head rcu; - struct kmem_cache *entries[0]; + struct kmem_cache *entries[]; }; =20 /* diff --git a/mm/slab_common.c b/mm/slab_common.c index fe8b684..56f4818 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -166,9 +166,7 @@ static int init_memcg_params(struct kmem_cache *s, if (!memcg_nr_cache_ids) return 0; =20 - arr =3D kvzalloc(sizeof(struct memcg_cache_array) + - memcg_nr_cache_ids * sizeof(void *), - GFP_KERNEL); + arr =3D kvzalloc(struct_size(arr, entries, memcg_nr_cache_ids), GFP_KER= NEL); if (!arr) return -ENOMEM; =20 @@ -199,8 +197,7 @@ static int update_memcg_params(struct kmem_cache *s, = int new_array_size) { struct memcg_cache_array *old, *new; =20 - new =3D kvzalloc(sizeof(struct memcg_cache_array) + - new_array_size * sizeof(void *), GFP_KERNEL); + new =3D kvzalloc(struct_size(new, entries, new_array_size), GFP_KERNEL)= ; if (!new) return -ENOMEM; =20 --=20 2.7.4