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=-5.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 D1345C433DF for ; Mon, 1 Jun 2020 08:46:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C18A206E2 for ; Mon, 1 Jun 2020 08:46:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Iq6Ri3LT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725967AbgFAIqy (ORCPT ); Mon, 1 Jun 2020 04:46:54 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:57027 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725290AbgFAIqx (ORCPT ); Mon, 1 Jun 2020 04:46:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591001212; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=C02MG+QK6H+u53KSuGOiYPyl9UBkarcNf8ZS3cPl7w4=; b=Iq6Ri3LTOeaX94iGhTm1zRdlgXLeDIyn6ohvxkr6dz4u0pRUEeOmHW/XM8XPOz9lHp6Tsq yBkKrDH/N3f1L7mZA9K7TJKDlMRIn6wfKqkAStRn40Kl5vqvAoB6j2G9ZWVpLm/ATGE5EP Q1qjSnrdOfBzqyigpAXbG51mFy/Z1Aw= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-477-UXHr-a8dNFWjCp-B5K1k2A-1; Mon, 01 Jun 2020 04:46:50 -0400 X-MC-Unique: UXHr-a8dNFWjCp-B5K1k2A-1 Received: by mail-wr1-f72.google.com with SMTP id c14so4600239wrm.15 for ; Mon, 01 Jun 2020 01:46:50 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=C02MG+QK6H+u53KSuGOiYPyl9UBkarcNf8ZS3cPl7w4=; b=XhCBWDmb+eh4xwRF6KuhuzhxzWPMn1cBS+Gr/0d7EU0CTqrMkkpCuKWMNie43MCs2n W5Zx8b690LutwFeDlc5cvLd2SnIqeHeULpR5SlPseYu6pHEXtqU+cVONy5qh9bt9lmTl 8QByMSya939fltNCIshaB5hRYuRjijW6oJ2i2gZdUad3GXdNwgGyDc/Foi+4a8gIXt0C 2faPpdDk8MopSR9aLWtn0SZluIYJ4VJethtiZZy0IgjtmfeRu8sbnKlR1v01xG0yf3Qa /gqFfkyu8yItSrp/RBJHQgfNQFplKUF/pOOIkwiJaWPOiNfDc1MJNTK6fUMyBOaiSB6Y S7SA== X-Gm-Message-State: AOAM530JkCek/TVrnImZ91phFXwZlYpZJSBgJJXqiSG2DhFRrPSdXFDv 8inmN5ZK8P+3lLQ8zC23HWcXUtSC0lkHLbj004g0gixyB5zHNuh4osca+rPL72uhNFSXcY78BnP dJukiTcb820kJej3XtT9cL/s9 X-Received: by 2002:a5d:6305:: with SMTP id i5mr13517768wru.268.1591001209376; Mon, 01 Jun 2020 01:46:49 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyEYY8mkL9Gi6Wprd77cQqEWyWHRjuAU8MMixFROUGrmjIE9m2xWDMlSexm+nSaLiFIQTBeWg== X-Received: by 2002:a5d:6305:: with SMTP id i5mr13517755wru.268.1591001209199; Mon, 01 Jun 2020 01:46:49 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:e044:3d2:1991:920c? ([2001:b07:6468:f312:e044:3d2:1991:920c]) by smtp.gmail.com with ESMTPSA id q1sm10003248wmc.12.2020.06.01.01.46.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 01 Jun 2020 01:46:48 -0700 (PDT) Subject: Re: [PATCH] KVM: Use previously computed array_size() To: Denis Efremov , Joe Perches , Sean Christopherson , Vitaly Kuznetsov Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200530143558.321449-1-efremov@linux.com> <0c00d96c46d34d69f5f459baebf3c89a507730fc.camel@perches.com> <6088fa0f-668a-f221-515b-413ca8c0c363@linux.com> From: Paolo Bonzini Message-ID: Date: Mon, 1 Jun 2020 10:46:47 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <6088fa0f-668a-f221-515b-413ca8c0c363@linux.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30/05/20 19:28, Denis Efremov wrote: >> On Sat, 2020-05-30 at 17:35 +0300, Denis Efremov wrote: >>> array_size() is used in alloc calls to compute the allocation >>> size. Next, "raw" multiplication is used to compute the size >>> for copy_from_user(). The patch removes duplicated computation >>> by saving the size in a var. No security concerns, just a small >>> optimization. >>> >>> Signed-off-by: Denis Efremov >> Perhaps use vmemdup_user? > vmemdup_user() uses kvmalloc internally. I think it will also require > changing vfree to kvfree. > Yes, it would be a good idea. Paolo