From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:37018 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753416AbdLDItD (ORCPT ); Mon, 4 Dec 2017 03:49:03 -0500 Subject: Patch "v4l2: disable filesystem-dax mapping support" has been added to the 4.14-stable tree To: dan.j.williams@intel.com, akpm@linux-foundation.org, dledford@redhat.com, gregkh@linuxfoundation.org, hal.rosenstock@gmail.com, hch@lst.de, inki.dae@samsung.com, jack@suse.cz, jgg@mellanox.com, jmoyer@redhat.com, jy0922.shim@samsung.com, kyungmin.park@samsung.com, mchehab@kernel.org, mgorman@suse.de, ross.zwisler@linux.intel.com, sean.hefty@intel.com, sw0312.kim@samsung.com, torvalds@linux-foundation.org, vbabka@suse.cz Cc: , From: Date: Mon, 04 Dec 2017 09:48:58 +0100 Message-ID: <151237733819092@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled v4l2: disable filesystem-dax mapping support to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: v4l2-disable-filesystem-dax-mapping-support.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From b70131de648c2b997d22f4653934438013f407a1 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 29 Nov 2017 16:10:43 -0800 Subject: v4l2: disable filesystem-dax mapping support From: Dan Williams commit b70131de648c2b997d22f4653934438013f407a1 upstream. V4L2 memory registrations are incompatible with filesystem-dax that needs the ability to revoke dma access to a mapping at will, or otherwise allow the kernel to wait for completion of DMA. The filesystem-dax implementation breaks the traditional solution of truncate of active file backed mappings since there is no page-cache page we can orphan to sustain ongoing DMA. If v4l2 wants to support long lived DMA mappings it needs to arrange to hold a file lease or use some other mechanism so that the kernel can coordinate revoking DMA access when the filesystem needs to truncate mappings. Link: http://lkml.kernel.org/r/151068940499.7446.12846708245365671207.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings") Signed-off-by: Dan Williams Reported-by: Jan Kara Reviewed-by: Jan Kara Cc: Mauro Carvalho Chehab Cc: Christoph Hellwig Cc: Doug Ledford Cc: Hal Rosenstock Cc: Inki Dae Cc: Jason Gunthorpe Cc: Jeff Moyer Cc: Joonyoung Shim Cc: Kyungmin Park Cc: Mel Gorman Cc: Ross Zwisler Cc: Sean Hefty Cc: Seung-Woo Kim Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- drivers/media/v4l2-core/videobuf-dma-sg.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/media/v4l2-core/videobuf-dma-sg.c +++ b/drivers/media/v4l2-core/videobuf-dma-sg.c @@ -185,12 +185,13 @@ static int videobuf_dma_init_user_locked dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n", data, size, dma->nr_pages); - err = get_user_pages(data & PAGE_MASK, dma->nr_pages, + err = get_user_pages_longterm(data & PAGE_MASK, dma->nr_pages, flags, dma->pages, NULL); if (err != dma->nr_pages) { dma->nr_pages = (err >= 0) ? err : 0; - dprintk(1, "get_user_pages: err=%d [%d]\n", err, dma->nr_pages); + dprintk(1, "get_user_pages_longterm: err=%d [%d]\n", err, + dma->nr_pages); return err < 0 ? err : -EINVAL; } return 0; Patches currently in stable-queue which might be from dan.j.williams@intel.com are queue-4.14/mm-hugetlbfs-introduce-split-to-vm_operations_struct.patch queue-4.14/ib-core-disable-memory-registration-of-filesystem-dax-vmas.patch queue-4.14/mm-introduce-get_user_pages_longterm.patch queue-4.14/mm-fail-get_vaddr_frames-for-filesystem-dax-mappings.patch queue-4.14/device-dax-implement-split-to-catch-invalid-munmap-attempts.patch queue-4.14/v4l2-disable-filesystem-dax-mapping-support.patch queue-4.14/mm-fix-device-dax-pud-write-faults-triggered-by-get_user_pages.patch queue-4.14/mm-madvise.c-fix-madvise-infinite-loop-under-special-circumstances.patch