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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 37CABC352A2 for ; Fri, 7 Feb 2020 04:11:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 08B962064C for ; Fri, 7 Feb 2020 04:11:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KoeCHPmg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727309AbgBGELr (ORCPT ); Thu, 6 Feb 2020 23:11:47 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:25624 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726674AbgBGELq (ORCPT ); Thu, 6 Feb 2020 23:11:46 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581048705; 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: in-reply-to:in-reply-to:references:references; bh=akgcBFyOF/SJfU2Z94L9VSjtKLSXA2U9TSAHH+wmN5c=; b=KoeCHPmgnwtOK0xwMjS2uQy+N2CLfkPQZRHF1CTNSt6++4zuu12GXXBig0uPFjZ75Vj2RZ 3GXX3xiZTDfCzOou/qYEgd5gAmMM5U5tHbc+fZOGhhdFZUVCjYcaEoMw2zE2krtMMyT+YL PV85C8+QcTpAflTTCcJMzkkhDHeyvhs= 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-205-Cw8G6ibaM4CZqgLJh8wlFw-1; Thu, 06 Feb 2020 23:11:41 -0500 X-MC-Unique: Cw8G6ibaM4CZqgLJh8wlFw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0E9101088389; Fri, 7 Feb 2020 04:11:40 +0000 (UTC) Received: from localhost (ovpn-12-30.pek2.redhat.com [10.72.12.30]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DE3FA60BEC; Fri, 7 Feb 2020 04:11:36 +0000 (UTC) Date: Fri, 7 Feb 2020 12:11:34 +0800 From: Baoquan He To: Wei Yang Cc: akpm@linux-foundation.org, osalvador@suse.de, dan.j.williams@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, david@redhat.com Subject: Re: [PATCH 2/3] mm/sparsemem: get physical address to page struct instead of virtual address to pfn Message-ID: <20200207041134.GC25537@MiWiFi-R3L-srv> References: <20200206231629.14151-1-richardw.yang@linux.intel.com> <20200206231629.14151-3-richardw.yang@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200206231629.14151-3-richardw.yang@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/07/20 at 07:16am, Wei Yang wrote: > memmap should be the physical address to page struct instead of virtual > address to pfn. Maybe not, memmap stores a virtual address. > > Since we call this only for SPARSEMEM_VMEMMAP, pfn_to_page() is valid at > this point. > > Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug") > Signed-off-by: Wei Yang > CC: Dan Williams > --- > mm/sparse.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/sparse.c b/mm/sparse.c > index b5da121bdd6e..56816f653588 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -888,7 +888,7 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn, > /* Align memmap to section boundary in the subsection case */ > if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP) && > section_nr_to_pfn(section_nr) != start_pfn) > - memmap = pfn_to_kaddr(section_nr_to_pfn(section_nr)); > + memmap = pfn_to_page(section_nr_to_pfn(section_nr)); With Dan's confirmation, sub-section is only valid in vmemmap case. I think the old if (section_nr_to_pfn(section_nr) != start_pfn) is enough to filter out non vmemmap case. So only below code is good: + memmap = pfn_to_page(section_nr_to_pfn(section_nr)); > sparse_init_one_section(ms, section_nr, memmap, ms->usage, 0); > > return 0; > -- > 2.17.1 >