From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out4-smtp.messagingengine.com ([66.111.4.28]:42653 "EHLO out4-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753531AbdLDIT7 (ORCPT ); Mon, 4 Dec 2017 03:19:59 -0500 Subject: FAILED: patch "[PATCH] v4l2: disable filesystem-dax mapping support" failed to apply to 4.9-stable tree To: dan.j.williams@intel.com, akpm@linux-foundation.org, dledford@redhat.com, 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, stable@vger.kernel.org, sw0312.kim@samsung.com, torvalds@linux-foundation.org, vbabka@suse.cz Cc: From: Date: Mon, 04 Dec 2017 09:20:07 +0100 Message-ID: <151237560725494@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: The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From b70131de648c2b997d22f4653934438013f407a1 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 29 Nov 2017 16:10:43 -0800 Subject: [PATCH] v4l2: disable filesystem-dax mapping support 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 Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c index 0b5c43f7e020..f412429cf5ba 100644 --- 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(struct videobuf_dmabuf *dma, 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;