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 <stable@xxxxxxxxxxxxxxx> know about it.
>From b70131de648c2b997d22f4653934438013f407a1 Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Date: Wed, 29 Nov 2017 16:10:43 -0800
Subject: v4l2: disable filesystem-dax mapping support
From: Dan Williams <dan.j.williams@xxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings")
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reported-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Doug Ledford <dledford@xxxxxxxxxx>
Cc: Hal Rosenstock <hal.rosenstock@xxxxxxxxx>
Cc: Inki Dae <inki.dae@xxxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: Joonyoung Shim <jy0922.shim@xxxxxxxxxxx>
Cc: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: Sean Hefty <sean.hefty@xxxxxxxxx>
Cc: Seung-Woo Kim <sw0312.kim@xxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxx 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