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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0A49C433FE for ; Fri, 1 Apr 2022 16:32:43 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4C8CC8D0002; Fri, 1 Apr 2022 12:32:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4517C8D0001; Fri, 1 Apr 2022 12:32:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2F4668D0002; Fri, 1 Apr 2022 12:32:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0030.hostedemail.com [216.40.44.30]) by kanga.kvack.org (Postfix) with ESMTP id 1A90D8D0001 for ; Fri, 1 Apr 2022 12:32:33 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id B0518A5A8E for ; Fri, 1 Apr 2022 16:32:22 +0000 (UTC) X-FDA: 79308852924.30.7BA4FF3 Received: from mail-lf1-f51.google.com (mail-lf1-f51.google.com [209.85.167.51]) by imf01.hostedemail.com (Postfix) with ESMTP id 0FE9640019 for ; Fri, 1 Apr 2022 16:32:21 +0000 (UTC) Received: by mail-lf1-f51.google.com with SMTP id 5so5937487lfp.1 for ; Fri, 01 Apr 2022 09:32:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=jSn+1DlBmjF9liCFAObVEDkZuTzAiSQphLAr9mc3iek=; b=EMrbF6/FUCzz/mA9FTkStMXcBiPNQ3kZ6MlkbNvu29QIQOMkngWpkkZSDjJgw+o1Wn L39n6IqZYh2upzJE1VQ4bvuZj1k/YuRpwkL1xpensQ19FI//uyAsOog8d1vF1s+0Fy/7 c+Z3RRCNMyi3MKUUNQaDjDcza+QULvzb70HA4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=jSn+1DlBmjF9liCFAObVEDkZuTzAiSQphLAr9mc3iek=; b=1qraicK/lmxPnJcwRI8/t4WwjY2oOiD3uBgTrqeCXYhDLDaVQoZAa9z9KXoEppfEW4 LRpPMi2T83G0qUufeFONx14fUhzki10d/qEp7U3zDfVpKD/3xTE97otbJ0jysuQEppGn 4BXR+gcj4J6yhKh/xvbavfG2ueB+bpaaquE2yGP3gmjI+DTWE/fUqhaJacMePy0DlCNg OoxUBx5kl9DhhfK0ymvay9wyrd5phfyuiqKN9Nzbsx77WkSZyPcJm/6jw8ydB0/1mBsj Ot4nAHUSCNNtA9V5m8hmCitvmdGHWGsAaesF5Ow8W+77osFMTMmYSzRVQTVQoq5aqClU S86A== X-Gm-Message-State: AOAM531RJBQc1ii/q7uzgxCSjnzI8VtzEyekxJHTtzg+wcczpffR8enW lRbGQVeXyyoKTs6WAOG6s/dp6dlseUVTLq1v07Y= X-Google-Smtp-Source: ABdhPJyGSKj6A8U9nZ76+LQKRh8MOzRehMDCl6k2SKHG+R5AERqYanHuiG43PAxECnbBVTzhQYLnCw== X-Received: by 2002:a05:6512:1509:b0:443:e7fa:1c68 with SMTP id bq9-20020a056512150900b00443e7fa1c68mr14034914lfb.58.1648830740073; Fri, 01 Apr 2022 09:32:20 -0700 (PDT) Received: from mail-lf1-f41.google.com (mail-lf1-f41.google.com. [209.85.167.41]) by smtp.gmail.com with ESMTPSA id h12-20020ac24dac000000b0044a9a22cb5csm277749lfe.263.2022.04.01.09.32.15 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 01 Apr 2022 09:32:17 -0700 (PDT) Received: by mail-lf1-f41.google.com with SMTP id m3so5844073lfj.11 for ; Fri, 01 Apr 2022 09:32:15 -0700 (PDT) X-Received: by 2002:a05:6512:3ca1:b0:44a:93f1:45cf with SMTP id h33-20020a0565123ca100b0044a93f145cfmr14626698lfv.542.1648830735595; Fri, 01 Apr 2022 09:32:15 -0700 (PDT) MIME-Version: 1.0 References: <20220401135820.1453829-1-zi.yan@sent.com> <20220401135820.1453829-2-zi.yan@sent.com> In-Reply-To: <20220401135820.1453829-2-zi.yan@sent.com> From: Linus Torvalds Date: Fri, 1 Apr 2022 09:31:59 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 2/2] mm: wrap __find_buddy_pfn() with a necessary buddy page validation. To: Zi Yan Cc: Linux-MM , Steven Rostedt , David Hildenbrand , Vlastimil Babka , Mel Gorman , Mike Rapoport , Oscar Salvador , Andrew Morton , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: ijw39xx6c94njthgq3uw7ih4qtga9xqj Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b="EMrbF6/F"; dmarc=none; spf=pass (imf01.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.167.51 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org X-Rspamd-Queue-Id: 0FE9640019 X-HE-Tag: 1648830741-958259 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: On Fri, Apr 1, 2022 at 6:58 AM Zi Yan wrote: > > +extern bool find_buddy_page_pfn(struct page *page, unsigned int order, > + struct page **buddy, unsigned long *buddy_pfn); Wouldn't it make more sense to just return the 'struct page *buddy' here, instead of the 'bool'? So a NULL buddy means the obvious "no buddy found". I dislike those "pass return value by reference" in general, and the above has _two_ of them. We can get rid of at least one very obviously. Linus