[PATCH 00/15] Retire dma_buf_k(un)map

Sumit Semwal sumit.semwal at linaro.org
Mon Nov 18 15:58:37 UTC 2019


Hello Daniel,

On Mon, 18 Nov 2019 at 16:05, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
>
> Hi all,
>
> Way back when we created the dma-buf spec it made sense to have kmap/unmap
> interfaces, since 32bit kernels with limited vmalloc space were still
> rather ubiquitous. But that idea (like many others) never caught on, was
> quickly replaced by vmaps covering the entire buffer for all real uses,
> and nowadays 64bit kernels rule the world. Currently merged upstream
> drivers (and we have a pile now) don't even bother to kmap for their
> private buffers, much less for anything shared.
>
> So since it was never used, and this idea's time is clearly over, let's
> remove it all.
As always, thanks for helping keep this code sane :)

Fwiw, for the series, please feel free to add my
Acked-by: Sumit Semwal <sumit.semwal at linaro.org>

>
> Only real change I had to do (aside from deleting lots of dead code) was
> in the tegra driver. But even there I suspect the dma-buf kmap path has
> never been run in anger anywhere, it just doesn't make sense to put relocs
> into a dma-buf (as opposed to using a dma-buf for the target address of a
> reloc).
>
> Comments, reviews and testing very much appreciated.
>
> Cheers, Daniel
>
> Daniel Vetter (15):
>   drm/tegra: Map cmdbuf once for reloc processing
>   drm/tegra: Delete host1x_bo_ops->k(un)map
>   drm/i915: Remove dma_buf_kmap selftest
>   staging/android/ion: delete dma_buf->kmap/unmap implemenation
>   drm/armada: Delete dma_buf->k(un)map implemenation
>   drm/i915: Drop dma_buf->k(un)map
>   drm/omapdrm: Drop dma_buf->k(un)map
>   drm/tegra: Remove dma_buf->k(un)map
>   dma-buf: Drop dma_buf_k(un)map
>   drm/vmwgfx: Delete mmaping functions
>   media/videobuf2: Drop dma_buf->k(un)map support
>   drm/tee_shm: Drop dma_buf_k(unmap) support
>   xen/gntdev-dmabuf: Ditch dummy map functions
>   sample/vfio-mdev/mbocs: Remove dma_buf_k(un)map support
>   dma-buf: Remove kernel map/unmap hooks
>
>  drivers/dma-buf/dma-buf.c                     |  63 +----------
>  drivers/gpu/drm/armada/armada_gem.c           |  12 ---
>  drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c    |  36 -------
>  .../drm/i915/gem/selftests/i915_gem_dmabuf.c  | 101 ------------------
>  .../gpu/drm/i915/gem/selftests/mock_dmabuf.c  |  16 ---
>  drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c     |  21 ----
>  drivers/gpu/drm/tegra/gem.c                   |  40 -------
>  drivers/gpu/drm/vmwgfx/vmwgfx_prime.c         |  33 ------
>  drivers/gpu/host1x/job.c                      |  21 ++--
>  .../common/videobuf2/videobuf2-dma-contig.c   |   8 --
>  .../media/common/videobuf2/videobuf2-dma-sg.c |   8 --
>  .../common/videobuf2/videobuf2-vmalloc.c      |   8 --
>  drivers/misc/fastrpc.c                        |   8 --
>  drivers/staging/android/ion/ion.c             |  14 ---
>  drivers/tee/tee_shm.c                         |   6 --
>  drivers/xen/gntdev-dmabuf.c                   |  23 ----
>  include/linux/dma-buf.h                       |  27 -----
>  include/linux/host1x.h                        |  13 ---
>  samples/vfio-mdev/mbochs.c                    |  16 ---
>  19 files changed, 10 insertions(+), 464 deletions(-)
>
> --
> 2.24.0
>
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Best,
Sumit.


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