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| author |   Dan Williams <dan.j.williams@intel.com> | 2017-11-29 16:10:43 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-29 18:40:42 -0800 |
| commit | b70131de648c2b997d22f4653934438013f407a1 (patch) | |
| tree | db45b0f5cf76eb15173c3c485827912c0af6ff78 /drivers | |
| parent | mm: fail get_vaddr_frames() for filesystem-dax mappings (diff) | |
| download | wireguard-linux-b70131de648c2b997d22f4653934438013f407a1.tar.xz wireguard-linux-b70131de648c2b997d22f4653934438013f407a1.zip | |
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 <dan.j.williams@intel.com>
Reported-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/media/v4l2-core/videobuf-dma-sg.c | 5 |
1 files changed, 3 insertions, 2 deletions
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; |