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=-5.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 75B0DC41514 for ; Mon, 12 Aug 2019 20:33:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 33432206C2 for ; Mon, 12 Aug 2019 20:33:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cmpxchg-org.20150623.gappssmtp.com header.i=@cmpxchg-org.20150623.gappssmtp.com header.b="Ns5tnFaX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726602AbfHLUdI (ORCPT ); Mon, 12 Aug 2019 16:33:08 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:36440 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726144AbfHLUdH (ORCPT ); Mon, 12 Aug 2019 16:33:07 -0400 Received: by mail-pg1-f195.google.com with SMTP id l21so50057719pgm.3 for ; Mon, 12 Aug 2019 13:33:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=opuTeOP019YiHjS7zgVGx1N/ZtI2m573pQ8Fm6DPedA=; b=Ns5tnFaXWDviA+GNTixFkO7AFl1W+l/Ald/kQO5BWa44a6ukvr1eWIfWjaWVDYUYDj hiAQT2HpufQzPthDGeB765CF3V6cCc9ECB9Nb9FumVOdvKyCv603isBx/5MPS6iHlrNj YgxsfNStteKFyfoyRgVQ7FztMMbz+A+7H9xCy4FP4N6hIP3FexB/hSxdWfnYZ5e8qxoO n8ijIrIRl4bVRGBQMRhePCuyMmbw7FhP1X3hyIp9VFPC+iRXtGEIKjnn3rnFwdAycubP 1wpdkQhN3+kVMZT8ywoPlKyHLiAEMXVoKcD7/Lr1NHmQ8oLt8qXpYTHauzLeviIHKc2M tWfg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=opuTeOP019YiHjS7zgVGx1N/ZtI2m573pQ8Fm6DPedA=; b=ojsyqzKzlAHRzJ6uIBrtzUBvoymi/pFYYpLMlfkNIz2u961Ce4Ve5L/d3u45NvoXe4 ZbxCfvOX3gBVgEmfTGwcmwItUaPCA8YVTg7jnzerv4K1hp+HqLtXtGm+UXKWsg8sR5jb hxje6e+4766VoFSQpT0gZ5+0L3sdqao2sy8M88H2qj/V/sb1U+8jlUk12gWU29/DCTRN en4MxAI48rQdDIFQO3DktX4wjToTz6gPaj43x4m0Y3tANKNa08+ne5pSTgiyjkRMsBdZ VThqRj9onyYvVvMI8U9Uar6YgYj/bpo0FoRNtHbyoHR5NjjhUVYjzulUm/5iQqFUe+8u joWg== X-Gm-Message-State: APjAAAXvhad9Ljo24LBQ2HbgZhOgsBOKlCazaLHSA5+mWp8GvDwtLklX lMUGhdqeGGF1k/vinLjbsAIzqw== X-Google-Smtp-Source: APXvYqzLso2VXLAcxk2gXZWzzA185FIPfyG4h7hY0rd/zhvtbW+18JphumXy+BZjj65b5PHnBueorA== X-Received: by 2002:a17:90a:d793:: with SMTP id z19mr1014808pju.36.1565641986978; Mon, 12 Aug 2019 13:33:06 -0700 (PDT) Received: from localhost ([2620:10d:c091:500::2:f08]) by smtp.gmail.com with ESMTPSA id b6sm93774090pgq.26.2019.08.12.13.33.05 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 12 Aug 2019 13:33:06 -0700 (PDT) Date: Mon, 12 Aug 2019 16:33:04 -0400 From: Johannes Weiner To: Song Liu Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, matthew.wilcox@oracle.com, kirill.shutemov@linux.intel.com, kernel-team@fb.com, william.kucharski@oracle.com, akpm@linux-foundation.org, hdanton@sina.com Subject: Re: [PATCH v10 2/7] filemap: check compound_head(page)->mapping in pagecache_get_page() Message-ID: <20190812203304.GA15498@cmpxchg.org> References: <20190801184244.3169074-1-songliubraving@fb.com> <20190801184244.3169074-3-songliubraving@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190801184244.3169074-3-songliubraving@fb.com> User-Agent: Mutt/1.12.0 (2019-05-25) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 01, 2019 at 11:42:39AM -0700, Song Liu wrote: > Similar to previous patch, pagecache_get_page() avoids race condition > with truncate by checking page->mapping == mapping. This does not work > for compound pages. This patch let it check compound_head(page)->mapping > instead. > > Suggested-by: Johannes Weiner > Signed-off-by: Song Liu Acked-by: Johannes Weiner