Re: [RFC PATCH v2 1/1] misc: fgds: introduce GPU-File direct I/O via dma-buf

[Jens Axboe <axboe@kernel.dk>]

On 10/27/26 3:08 AM, Li Wang wrote:
> From: Mengmeng Zhao <zhaomengmeng@kylinos.cn>
> 
> This patch introduces a driver that allows moving data between a GPU
> dma-buf and a regular file on NVME without staging it through the page 
> cache. Userspace registers the GPU dma-buf with the device, then issues 
> read and write requests via the device's ioctls. Each transfer is direct 
> I/O: an ITER_DMABUF_MAP iterator is passed to the file's read_iter or
> write_iter, and the filesystem's iomap path submits REQ_DMABUF bios that
> already carry the dma addresses.
> 
> Signed-off-by: Mengmeng Zhao <zhaomengmeng@kylinos.cn>
> Signed-off-by: Li Wang <liwang@kylinos.cn>
> ---
>  .../userspace-api/ioctl/ioctl-number.rst      |   2 +
>  drivers/dma-buf/dma-buf-io.c                  |   3 +
>  drivers/misc/Kconfig                          |  16 +
>  drivers/misc/Makefile                         |   1 +
>  drivers/misc/fgds.c                           | 506 ++++++++++++++++++
>  fs/iomap/buffered-io.c                        |  11 +
>  fs/iomap/direct-io.c                          |  23 +-
>  fs/xfs/xfs_file.c                             |   4 +
>  include/linux/iov_iter.h                      |   4 +
>  include/uapi/linux/fgds.h                     | 124 +++++
>  lib/iov_iter.c                                |   1 +
>  mm/filemap.c                                  |  22 +-
>  12 files changed, 713 insertions(+), 4 deletions(-)
>  create mode 100644 drivers/misc/fgds.c
>  create mode 100644 include/uapi/linux/fgds.h

What's the point of this, when you can just use io_uring to do
the same?!

-- 
Jens Axboe