From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752916AbdK2SPF (ORCPT ); Wed, 29 Nov 2017 13:15:05 -0500 Received: from mga04.intel.com ([192.55.52.120]:48797 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752062AbdK2SNz (ORCPT ); Wed, 29 Nov 2017 13:13:55 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.45,338,1508828400"; d="scan'208";a="1249976060" Subject: [PATCH v3 2/4] mm: fail get_vaddr_frames() for filesystem-dax mappings From: Dan Williams To: akpm@linux-foundation.org Cc: Jan Kara , Joonyoung Shim , linux-nvdimm@lists.01.org, Seung-Woo Kim , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Inki Dae , linux-mm@kvack.org, Kyungmin Park , Mel Gorman , Mauro Carvalho Chehab , hch@lst.de, Vlastimil Babka , linux-media@vger.kernel.org Date: Wed, 29 Nov 2017 10:05:40 -0800 Message-ID: <151197874035.26211.4061781453123083667.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151197872943.26211.6551382719053304996.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151197872943.26211.6551382719053304996.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Until there is a solution to the dma-to-dax vs truncate problem it is not safe to allow V4L2, Exynos, and other frame vector users to create long standing / irrevocable memory registrations against filesytem-dax vmas. Cc: Inki Dae Cc: Seung-Woo Kim Cc: Joonyoung Shim Cc: Kyungmin Park Cc: Mauro Carvalho Chehab Cc: linux-media@vger.kernel.org Cc: Mel Gorman Cc: Vlastimil Babka Cc: Andrew Morton Cc: Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings") Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- mm/frame_vector.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/mm/frame_vector.c b/mm/frame_vector.c index 2f98df0d460e..297c7238f7d4 100644 --- a/mm/frame_vector.c +++ b/mm/frame_vector.c @@ -53,6 +53,18 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, ret = -EFAULT; goto out; } + + /* + * While get_vaddr_frames() could be used for transient (kernel + * controlled lifetime) pinning of memory pages all current + * users establish long term (userspace controlled lifetime) + * page pinning. Treat get_vaddr_frames() like + * get_user_pages_longterm() and disallow it for filesystem-dax + * mappings. + */ + if (vma_is_fsdax(vma)) + return -EOPNOTSUPP; + if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) { vec->got_ref = true; vec->is_pfns = false;