From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id 25DFA6B0003 for ; Fri, 23 Feb 2018 02:26:48 -0500 (EST) Received: by mail-pf0-f199.google.com with SMTP id z5so3791120pfe.16 for ; Thu, 22 Feb 2018 23:26:48 -0800 (PST) Received: from mga03.intel.com (mga03.intel.com. [134.134.136.65]) by mx.google.com with ESMTPS id o74si1403487pfj.75.2018.02.22.23.26.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 22 Feb 2018 23:26:47 -0800 (PST) Subject: [PATCH v2 0/5] vfio, dax: prevent long term filesystem-dax pins and other fixes From: Dan Williams Date: Thu, 22 Feb 2018 23:17:40 -0800 Message-ID: <151937026001.18973.12034171121582300402.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: linux-nvdimm@lists.01.org Cc: Haozhong Zhang , Michal Hocko , Jan Kara , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-mm@kvack.org, Alex Williamson , Gerd Rausch , Alexander Viro , linux-fsdevel@vger.kernel.org, kbuild test robot , Christoph Hellwig Changes since v1 [1]: * Fix the detection of device-dax file instances in vma_is_fsdax(). (Haozhong, Gerd) * Fix compile breakage in the FS_DAX=n and DEV_DAX=y case. (0day robot) [1]: https://lists.01.org/pipermail/linux-nvdimm/2018-February/014046.html --- The vfio interface, like RDMA, wants to setup long term (indefinite) pins of the pages backing an address range so that a guest or userspace driver can perform DMA to the with physical address. Given that this pinning may lead to filesystem operations deadlocking in the filesystem-dax case, the pinning request needs to be rejected. The longer term fix for vfio, RDMA, and any other long term pin user, is to provide a 'pin with lease' mechanism. Similar to the leases that are hold for pNFS RDMA layouts, this userspace lease gives the kernel a way to notify userspace that the block layout of the file is changing and the kernel is revoking access to pinned pages. --- Dan Williams (5): dax: fix vma_is_fsdax() helper dax: fix dax_mapping() definition in the FS_DAX=n + DEV_DAX=y case dax: fix S_DAX definition dax: short circuit vma_is_fsdax() in the CONFIG_FS_DAX=n case vfio: disable filesystem-dax page pinning drivers/vfio/vfio_iommu_type1.c | 18 +++++++++++++++--- include/linux/dax.h | 9 ++++++--- include/linux/fs.h | 6 ++++-- 3 files changed, 25 insertions(+), 8 deletions(-) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org