Hi Christoph,

On Tue, Sep 15, 2020 at 05:51:05PM +0200, Christoph Hellwig wrote:

From: Sergey Senozhatsky <redacted>

The patch partially reverts some of the UAPI bits of the buffer
cache management hints. Namely, the queue consistency (memory
coherency) user-space hint because, as it turned out, the kernel
implementation of this feature was misusing DMA_ATTR_NON_CONSISTENT.

The patch revers both kernel and user space parts: removes the
DMA consistency attr functions, rollbacks changes to v4l2_requestbuffers,
v4l2_create_buffers structures and corresponding UAPI functions
(plus compat32 layer) and cleanups the documentation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sergey Senozhatsky <redacted>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 .../userspace-api/media/v4l/buffer.rst        | 17 -------
 .../media/v4l/vidioc-create-bufs.rst          |  6 +--
 .../media/v4l/vidioc-reqbufs.rst              | 12 +----
 .../media/common/videobuf2/videobuf2-core.c   | 46 +++----------------
 .../common/videobuf2/videobuf2-dma-contig.c   | 19 --------
 .../media/common/videobuf2/videobuf2-dma-sg.c |  3 +-
 .../media/common/videobuf2/videobuf2-v4l2.c   | 18 +-------
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 10 +---
 drivers/media/v4l2-core/v4l2-ioctl.c          |  5 +-
 include/media/videobuf2-core.h                |  7 +--
 include/uapi/linux/videodev2.h                | 13 +-----
 11 files changed, 22 insertions(+), 134 deletions(-)

Acked-by: Tomasz Figa <tfiga@chromium.org>

Best regards,
Tomasz