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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, 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 C3840C433DB for ; Wed, 13 Jan 2021 08:32:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 67E5323341 for ; Wed, 13 Jan 2021 08:32:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726743AbhAMIcg (ORCPT ); Wed, 13 Jan 2021 03:32:36 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:53219 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725747AbhAMIcg (ORCPT ); Wed, 13 Jan 2021 03:32:36 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610526669; 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=YLp4vxk+82Jz6Cr9tpUqUqEbN1T5xSL04lBhhKhpD84=; b=IE1PU57/qH5jbcEmhBJWIjPQXUYbF5lQ9VAcstTLwaeOoeqRz+KCM6vXTZiZgorakh2/r4 7Q5Jd3nl5m1GRIWuTtI2ZzRGnU2imuVMVoEfNDRQS89qZcg6t1l/jbn7vjkhgGz9tfXBVK u8RynaKb4L55fXZnyiq5cy0g61OTi4g= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-490-Iphjah_0POy8mBshrFSi2g-1; Wed, 13 Jan 2021 03:31:05 -0500 X-MC-Unique: Iphjah_0POy8mBshrFSi2g-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5D6238066E2; Wed, 13 Jan 2021 08:31:04 +0000 (UTC) Received: from [10.36.114.135] (ovpn-114-135.ams2.redhat.com [10.36.114.135]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9DAA45D9DD; Wed, 13 Jan 2021 08:31:02 +0000 (UTC) Subject: Re: [PATCH v3 5/6] mm: Fix memory_failure() handling of dax-namespace metadata To: Dan Williams , linux-mm@kvack.org Cc: Naoya Horiguchi , Andrew Morton , vishal.l.verma@intel.com, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org References: <161052331545.1805594.2356512831689786960.stgit@dwillia2-desk3.amr.corp.intel.com> <161052334425.1805594.17861842381807251887.stgit@dwillia2-desk3.amr.corp.intel.com> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: <4664e9f3-5c2d-4c51-2bcd-9d03ef9c4fed@redhat.com> Date: Wed, 13 Jan 2021 09:31:01 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <161052334425.1805594.17861842381807251887.stgit@dwillia2-desk3.amr.corp.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13.01.21 08:35, Dan Williams wrote: > Given 'struct dev_pagemap' spans both data pages and metadata pages be > careful to consult the altmap if present to delineate metadata. In fact > the pfn_first() helper already identifies the first valid data pfn, so > export that helper for other code paths via pgmap_pfn_valid(). > > Other usage of get_dev_pagemap() are not a concern because those are > operating on known data pfns having been looking up by get_user_pages(). > I.e. metadata pfns are never user mapped. > > Cc: Naoya Horiguchi > Cc: Andrew Morton > Reported-by: David Hildenbrand > Signed-off-by: Dan Williams > --- > include/linux/memremap.h | 6 ++++++ > mm/memory-failure.c | 6 ++++++ > mm/memremap.c | 15 +++++++++++++++ > 3 files changed, 27 insertions(+) > > diff --git a/include/linux/memremap.h b/include/linux/memremap.h > index 79c49e7f5c30..f5b464daeeca 100644 > --- a/include/linux/memremap.h > +++ b/include/linux/memremap.h > @@ -137,6 +137,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap); > void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap); > struct dev_pagemap *get_dev_pagemap(unsigned long pfn, > struct dev_pagemap *pgmap); > +bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn); > > unsigned long vmem_altmap_offset(struct vmem_altmap *altmap); > void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns); > @@ -165,6 +166,11 @@ static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn, > return NULL; > } > > +static inline bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn) > +{ > + return false; > +} > + > static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) > { > return 0; > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 78b173c7190c..541569cb4a99 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1308,6 +1308,12 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, > */ > put_page(page); > > + /* device metadata space is not recoverable */ > + if (!pgmap_pfn_valid(pgmap, pfn)) { > + rc = -ENXIO; > + goto out; > + } > + > /* > * Prevent the inode from being freed while we are interrogating > * the address_space, typically this would be handled by > diff --git a/mm/memremap.c b/mm/memremap.c > index 16b2fb482da1..2455bac89506 100644 > --- a/mm/memremap.c > +++ b/mm/memremap.c > @@ -80,6 +80,21 @@ static unsigned long pfn_first(struct dev_pagemap *pgmap, int range_id) > return pfn + vmem_altmap_offset(pgmap_altmap(pgmap)); > } > > +bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn) > +{ > + int i; > + > + for (i = 0; i < pgmap->nr_range; i++) { > + struct range *range = &pgmap->ranges[i]; > + > + if (pfn >= PHYS_PFN(range->start) && > + pfn <= PHYS_PFN(range->end)) > + return pfn >= pfn_first(pgmap, i); > + } > + > + return false; > +} > + > static unsigned long pfn_end(struct dev_pagemap *pgmap, int range_id) > { > const struct range *range = &pgmap->ranges[range_id]; > LGTM Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb