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=-10.1 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_GIT 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 ACD5CC5ACAE for ; Wed, 11 Sep 2019 22:28:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7DE9E2087E for ; Wed, 11 Sep 2019 22:28:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="EHV8pR7V" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728529AbfIKW2x (ORCPT ); Wed, 11 Sep 2019 18:28:53 -0400 Received: from hqemgate14.nvidia.com ([216.228.121.143]:1596 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728061AbfIKW2u (ORCPT ); Wed, 11 Sep 2019 18:28:50 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Wed, 11 Sep 2019 15:28:51 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Wed, 11 Sep 2019 15:28:49 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Wed, 11 Sep 2019 15:28:49 -0700 Received: from HQMAIL109.nvidia.com (172.20.187.15) by HQMAIL111.nvidia.com (172.20.187.18) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 11 Sep 2019 22:28:46 +0000 Received: from hqnvemgw01.nvidia.com (172.20.150.20) by HQMAIL109.nvidia.com (172.20.187.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Wed, 11 Sep 2019 22:28:46 +0000 Received: from rcampbell-dev.nvidia.com (Not Verified[10.110.48.66]) by hqnvemgw01.nvidia.com with Trustwave SEG (v7,5,8,10121) id ; Wed, 11 Sep 2019 15:28:46 -0700 From: Ralph Campbell To: CC: , , , , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Jason Gunthorpe , Andrew Morton , "Christoph Hellwig" , Ralph Campbell Subject: [PATCH 3/4] mm/hmm: allow hmm_range_fault() of mmap(PROT_NONE) Date: Wed, 11 Sep 2019 15:28:28 -0700 Message-ID: <20190911222829.28874-4-rcampbell@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190911222829.28874-1-rcampbell@nvidia.com> References: <20190911222829.28874-1-rcampbell@nvidia.com> MIME-Version: 1.0 X-NVConfidentiality: public Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1568240931; bh=F20+CtE96DKxf8E9hC0a2S8wRPS9i4pdaXNv/ANnE1k=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:X-NVConfidentiality: Content-Type:Content-Transfer-Encoding; b=EHV8pR7Vx2o54VOBe9IiUlPWtdqX1Bc/1/UKUEx3gpEMFs7hfOIwd/89RCnmdNqV/ JxxnSfJKv+Lv+A9hv5TtPCiEQ7UeRyHgPP165+7aebwpPZ/iuE5m1lagJtleznsAgb RHcAoxNlxawV83OHZC8z8vwpSD7eV3fSD9HWbJry61FPhtIbRFOvFpre4bIrcVubvC GxD2YwE9TkX0WYagYzw0Ma0JO1W415YxmhSJPW4Tmhkep2I5j2pnJF1VDhbJCdi4RH Y6nNbO/Sh8DurJ3DJPCtvHqf0hRlvIlYyO3ePZLlK2KWMZB9DFAUWRK0HXg3ozACcV KiOoYgiwY9dHQ== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Allow hmm_range_fault() to return success (0) when the range has no access (!(vma->vm_flags & VM_READ)). The range->pfns[] array will be filled with range->values[HMM_PFN_NONE] in this case. This allows the caller to get a snapshot of a range without having to lookup the vma before calling hmm_range_fault(). If the call to hmm_range_fault() is not a snapshot, the caller can still check that pfns have the desired access permissions. Signed-off-by: Ralph Campbell Cc: "J=C3=A9r=C3=B4me Glisse" Cc: Jason Gunthorpe Cc: Christoph Hellwig --- mm/hmm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/hmm.c b/mm/hmm.c index 7217912bef13..16c834e5d1c0 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -795,7 +795,9 @@ static int hmm_vma_walk_test(unsigned long start, */ if (!(vma->vm_flags & VM_READ)) { (void) hmm_pfns_fill(start, end, range, HMM_PFN_NONE); - return -EPERM; + + /* Skip this vma and continue processing the next vma. */ + return 1; } =20 return 0; --=20 2.20.1