[PATCH v3] Add udmabuf misc device

[Gerd Hoffmann]

  Hi,

> > > qemu test branch:
> > >   https://git.kraxel.org/cgit/qemu/log/?h=sirius/udmabuf
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

> > > +	if (!shmem_mapping(file_inode(ubuf->filp)->i_mapping))
> > > +		goto err_free_ubuf;
> 
> Can/should we test here that the memfd has a locked down size here?

Makes sense.  Suggested way to check that?  unstatic memfd_get_seals()
function (mm/shmem.c)?  Or is there some better way?

Also which seals should we require?  Is F_SEAL_SHRINK enough?

> On that: Link to userspace patches/git tree using this would be nice.

See above.

cheers,
  Gerd