From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 74F7D21157FC2 for ; Mon, 27 May 2019 02:35:48 -0700 (PDT) Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4R9TfC1017744 for ; Mon, 27 May 2019 05:35:47 -0400 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2srbcwxj8m-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 27 May 2019 05:35:47 -0400 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 27 May 2019 10:35:45 +0100 From: "Aneesh Kumar K.V" Subject: Re: [PATCH] mm/nvdimm: Use correct alignment when looking at first pfn from a region In-Reply-To: <925e41ad-cc57-bc03-a2b6-6913c9e98abf@linux.ibm.com> References: <20190514025512.9670-1-aneesh.kumar@linux.ibm.com> <925e41ad-cc57-bc03-a2b6-6913c9e98abf@linux.ibm.com> Date: Mon, 27 May 2019 15:05:40 +0530 MIME-Version: 1.0 Message-Id: <87k1ecutn7.fsf@linux.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dan Williams Cc: Linux MM , linuxppc-dev , linux-nvdimm List-ID: "Aneesh Kumar K.V" writes: > On 5/14/19 9:59 AM, Dan Williams wrote: >> On Mon, May 13, 2019 at 7:55 PM Aneesh Kumar K.V >> wrote: >>> >>> We already add the start_pad to the resource->start but fails to section >>> align the start. This make sure with altmap we compute the right first >>> pfn when start_pad is zero and we are doing an align down of start address. >>> >>> Signed-off-by: Aneesh Kumar K.V >>> --- >>> kernel/memremap.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/kernel/memremap.c b/kernel/memremap.c >>> index a856cb5ff192..23d77b60e728 100644 >>> --- a/kernel/memremap.c >>> +++ b/kernel/memremap.c >>> @@ -59,9 +59,9 @@ static unsigned long pfn_first(struct dev_pagemap *pgmap) >>> { >>> const struct resource *res = &pgmap->res; >>> struct vmem_altmap *altmap = &pgmap->altmap; >>> - unsigned long pfn; >>> + unsigned long pfn = PHYS_PFN(res->start); >>> >>> - pfn = res->start >> PAGE_SHIFT; >>> + pfn = SECTION_ALIGN_DOWN(pfn); >> >> This does not seem right to me it breaks the assumptions of where the >> first expected valid pfn occurs in the passed in range. >> > > How do we define the first valid pfn? Isn't that at pfn_sb->dataoff ? for altmap the pfn_first should be pfn_first = altmap->base_pfn + vmem_altmap_offset(altmap); ? -aneesh _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm 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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 2C83DC07542 for ; Mon, 27 May 2019 09:35:51 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B7BC92173B for ; Mon, 27 May 2019 09:35:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B7BC92173B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 189D16B000C; Mon, 27 May 2019 05:35:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 13B0C6B0266; Mon, 27 May 2019 05:35:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 02A0D6B026B; Mon, 27 May 2019 05:35:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) by kanga.kvack.org (Postfix) with ESMTP id BFDD26B000C for ; Mon, 27 May 2019 05:35:49 -0400 (EDT) Received: by mail-pf1-f200.google.com with SMTP id 205so6464115pfx.2 for ; Mon, 27 May 2019 02:35:49 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:from:to:cc :subject:in-reply-to:references:date:mime-version:message-id; bh=+nFKZw1/3mrTKvNVIsRm9EX9HzlZYfPy7QXIUGdT7eA=; b=ktmF/d31zNHI8GB5cgL7ofBqePOpfdBNrYgLbSJPP2ip2dfnPxjZ2likVsAiDQ6wmF em/P1a04WViC/RK+zQUKA0mD63wepzg6z4GUVri6CUsoDD82VVhoku6j9jvxL1bTQsw4 amUolbcShLFQJ80y6+tbGJ+BpFIbUYo1uD5scRBOXnOD1xq88yMFrP2oJ+m4AE/QIS68 DZcfJp21k/RSs6YXoi77V3mv9/pL61My+1T6XG6T8SQz4YhB6mzvMJVLu4EctvZOsWRc V3EPgFhxYmg1EbeKHGu53COOnBQorQ8Sj4h9rEDkTH8WdsSjxD9qOqqZNXbMyIeRmb1g 5uxg== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of aneesh.kumar@linux.ibm.com designates 148.163.156.1 as permitted sender) smtp.mailfrom=aneesh.kumar@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com X-Gm-Message-State: APjAAAWo+rsPBtus+TsjcOCwtdTu/L22gMA2e4telwjQHW7yfOgTyUzC S78e8viGyMEsxpIn06qQychY4rbjRvpbtMvSTV3UZBekDj+s7Fe639cRx43Exp3AcWpRdukqZYC hcaEomvUTjpKduwL8vnPVjQBftvotVNfgxyXHSynOSDoZv0Pngekpl7ZusjdcsHYMfw== X-Received: by 2002:a17:90a:3442:: with SMTP id o60mr30360098pjb.5.1558949749347; Mon, 27 May 2019 02:35:49 -0700 (PDT) X-Google-Smtp-Source: APXvYqwB9bjr9tpxgcSicrTgwt88OJ9XOniUWICaGdVjKXqWMDdWnrk1fDL8miTtwfAx3TKB1cqY X-Received: by 2002:a17:90a:3442:: with SMTP id o60mr30359990pjb.5.1558949748425; Mon, 27 May 2019 02:35:48 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1558949748; cv=none; d=google.com; s=arc-20160816; b=PkdEGtd4jsucMfEgGxEk+JdcZjpAXuf88jqaagpN9TuXMMAbnEuphFfDJtuBr74RmJ ENleQyCyfo1c0o0X1O17ewSiboI3roxvjbms6UoxILFNYis3XmIFb59rCkwVyZfyj5nX zdkMs6JRy9EGtrTSYUuQMLiUBRM1roW7LNo1WrJyTINVOnsYATxqnANMPN7xTnzSNbNb ph8dWmfgJ0GaHQqiEnKu4X5SfYAGmlim4QJ4MC28pacYrldBXgAdNc2Xvy6ivqo2Azbb 0AEeW9LCRnG3zwrh02fYcJeqHM8trdpGPHHi93Yo4HB6kLURH1V/QpSuD9YGbmueQPe7 nF1w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:mime-version:date:references:in-reply-to:subject:cc:to :from; bh=+nFKZw1/3mrTKvNVIsRm9EX9HzlZYfPy7QXIUGdT7eA=; b=pJCbgM8BcVyseIUsQ1vRK5LbgS2tK+jTGCT1Mxq5dRMYU5i0kuLX88SZBFFu9nkogl CcYhDbeZe+aUhyLhRrUBWMHk59WtNuMfOWdZhr49tQKUjdRLBAUMEixhhSEt2l6bsZIc eG/ve8srCHo77Zw+fuDWbzKOMNTuX5pVFnnrpIhrIJlh4d/i79bfd62nqCu3yQ6atq9C hoTKSzdDm9Rg0QBAYCHcpXiD+ZEGdU3Y5y5OitpOxBZkHLSZ3BFwdjlOTAVpGkNaQbbS 7zEjF66j6iWB3UM3XeftLTBHZPyR/fe2pbNC1HJ72TWkD8Q1YPp/fM3wTpSoaviksIwt zlgg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of aneesh.kumar@linux.ibm.com designates 148.163.156.1 as permitted sender) smtp.mailfrom=aneesh.kumar@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id q43si16200342pjb.30.2019.05.27.02.35.48 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 27 May 2019 02:35:48 -0700 (PDT) Received-SPF: pass (google.com: domain of aneesh.kumar@linux.ibm.com designates 148.163.156.1 as permitted sender) client-ip=148.163.156.1; Authentication-Results: mx.google.com; spf=pass (google.com: domain of aneesh.kumar@linux.ibm.com designates 148.163.156.1 as permitted sender) smtp.mailfrom=aneesh.kumar@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4R9SG2f123078 for ; Mon, 27 May 2019 05:35:47 -0400 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2srcyq9kk7-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 27 May 2019 05:35:47 -0400 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 27 May 2019 10:35:43 +0100 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x4R9ZgFG51707976 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 27 May 2019 09:35:42 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AE9E4AE058; Mon, 27 May 2019 09:35:42 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C802BAE053; Mon, 27 May 2019 09:35:41 +0000 (GMT) Received: from skywalker.linux.ibm.com (unknown [9.124.31.115]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 27 May 2019 09:35:41 +0000 (GMT) X-Mailer: emacs 26.2 (via feedmail 11-beta-1 I) From: "Aneesh Kumar K.V" To: Dan Williams Cc: linux-nvdimm , Linux MM , linuxppc-dev Subject: Re: [PATCH] mm/nvdimm: Use correct alignment when looking at first pfn from a region In-Reply-To: <925e41ad-cc57-bc03-a2b6-6913c9e98abf@linux.ibm.com> References: <20190514025512.9670-1-aneesh.kumar@linux.ibm.com> <925e41ad-cc57-bc03-a2b6-6913c9e98abf@linux.ibm.com> Date: Mon, 27 May 2019 15:05:40 +0530 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 x-cbid: 19052709-0020-0000-0000-00000340DB7A X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19052709-0021-0000-0000-00002193D197 Message-Id: <87k1ecutn7.fsf@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-05-27_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=888 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905270067 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: "Aneesh Kumar K.V" writes: > On 5/14/19 9:59 AM, Dan Williams wrote: >> On Mon, May 13, 2019 at 7:55 PM Aneesh Kumar K.V >> wrote: >>> >>> We already add the start_pad to the resource->start but fails to section >>> align the start. This make sure with altmap we compute the right first >>> pfn when start_pad is zero and we are doing an align down of start address. >>> >>> Signed-off-by: Aneesh Kumar K.V >>> --- >>> kernel/memremap.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/kernel/memremap.c b/kernel/memremap.c >>> index a856cb5ff192..23d77b60e728 100644 >>> --- a/kernel/memremap.c >>> +++ b/kernel/memremap.c >>> @@ -59,9 +59,9 @@ static unsigned long pfn_first(struct dev_pagemap *pgmap) >>> { >>> const struct resource *res = &pgmap->res; >>> struct vmem_altmap *altmap = &pgmap->altmap; >>> - unsigned long pfn; >>> + unsigned long pfn = PHYS_PFN(res->start); >>> >>> - pfn = res->start >> PAGE_SHIFT; >>> + pfn = SECTION_ALIGN_DOWN(pfn); >> >> This does not seem right to me it breaks the assumptions of where the >> first expected valid pfn occurs in the passed in range. >> > > How do we define the first valid pfn? Isn't that at pfn_sb->dataoff ? for altmap the pfn_first should be pfn_first = altmap->base_pfn + vmem_altmap_offset(altmap); ? -aneesh 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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 95976C07542 for ; Mon, 27 May 2019 09:37:25 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CE684206C1 for ; Mon, 27 May 2019 09:37:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CE684206C1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 45CBhf01PFzDqLN for ; Mon, 27 May 2019 19:37:22 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=linux.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=aneesh.kumar@linux.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 45CBfy1Ry9zDqHk for ; Mon, 27 May 2019 19:35:52 +1000 (AEST) Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4R9Yb8H004284 for ; Mon, 27 May 2019 05:35:47 -0400 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2srdcrg2ck-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 27 May 2019 05:35:46 -0400 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 27 May 2019 10:35:45 +0100 Received: from b06cxnps4076.portsmouth.uk.ibm.com (9.149.109.198) by e06smtp05.uk.ibm.com (192.168.101.135) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 27 May 2019 10:35:43 +0100 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x4R9ZgFG51707976 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 27 May 2019 09:35:42 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AE9E4AE058; Mon, 27 May 2019 09:35:42 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C802BAE053; Mon, 27 May 2019 09:35:41 +0000 (GMT) Received: from skywalker.linux.ibm.com (unknown [9.124.31.115]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 27 May 2019 09:35:41 +0000 (GMT) X-Mailer: emacs 26.2 (via feedmail 11-beta-1 I) From: "Aneesh Kumar K.V" To: Dan Williams Subject: Re: [PATCH] mm/nvdimm: Use correct alignment when looking at first pfn from a region In-Reply-To: <925e41ad-cc57-bc03-a2b6-6913c9e98abf@linux.ibm.com> References: <20190514025512.9670-1-aneesh.kumar@linux.ibm.com> <925e41ad-cc57-bc03-a2b6-6913c9e98abf@linux.ibm.com> Date: Mon, 27 May 2019 15:05:40 +0530 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 x-cbid: 19052709-0020-0000-0000-00000340DB7A X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19052709-0021-0000-0000-00002193D197 Message-Id: <87k1ecutn7.fsf@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-05-27_07:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=894 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905270067 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Linux MM , linuxppc-dev , linux-nvdimm Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" "Aneesh Kumar K.V" writes: > On 5/14/19 9:59 AM, Dan Williams wrote: >> On Mon, May 13, 2019 at 7:55 PM Aneesh Kumar K.V >> wrote: >>> >>> We already add the start_pad to the resource->start but fails to section >>> align the start. This make sure with altmap we compute the right first >>> pfn when start_pad is zero and we are doing an align down of start address. >>> >>> Signed-off-by: Aneesh Kumar K.V >>> --- >>> kernel/memremap.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/kernel/memremap.c b/kernel/memremap.c >>> index a856cb5ff192..23d77b60e728 100644 >>> --- a/kernel/memremap.c >>> +++ b/kernel/memremap.c >>> @@ -59,9 +59,9 @@ static unsigned long pfn_first(struct dev_pagemap *pgmap) >>> { >>> const struct resource *res = &pgmap->res; >>> struct vmem_altmap *altmap = &pgmap->altmap; >>> - unsigned long pfn; >>> + unsigned long pfn = PHYS_PFN(res->start); >>> >>> - pfn = res->start >> PAGE_SHIFT; >>> + pfn = SECTION_ALIGN_DOWN(pfn); >> >> This does not seem right to me it breaks the assumptions of where the >> first expected valid pfn occurs in the passed in range. >> > > How do we define the first valid pfn? Isn't that at pfn_sb->dataoff ? for altmap the pfn_first should be pfn_first = altmap->base_pfn + vmem_altmap_offset(altmap); ? -aneesh