[PATCH rdma-core v3 4/6] pyverbs: Add dma-buf based MR support

[Xiong, Jianxin]

> -----Original Message-----
> From: Daniel Vetter <daniel at ffwll.ch>
> Sent: Monday, November 30, 2020 6:58 AM
> To: Xiong, Jianxin <jianxin.xiong at intel.com>
> Cc: linux-rdma at vger.kernel.org; dri-devel at lists.freedesktop.org; Leon Romanovsky <leon at kernel.org>; Jason Gunthorpe <jgg at ziepe.ca>;
> Doug Ledford <dledford at redhat.com>; Vetter, Daniel <daniel.vetter at intel.com>; Christian Koenig <christian.koenig at amd.com>
> Subject: Re: [PATCH rdma-core v3 4/6] pyverbs: Add dma-buf based MR support
> 
> > +cdef class DmaBuf:
> > +    def __init__(self, size, unit=0):
> > +        """
> > +        Allocate DmaBuf object from a GPU device. This is done through the
> > +        DRI device interface. Usually this requires the effective user id
> > +        being a member of the 'render' group.
> > +        :param size: The size (in number of bytes) of the buffer.
> > +        :param unit: The unit number of the GPU to allocate the buffer from.
> > +        :return: The newly created DmaBuf object on success.
> > +        """
> > +        self.dmabuf_mrs = weakref.WeakSet()
> > +        self.dmabuf = dmabuf_alloc(size, unit)
> > +        if self.dmabuf == NULL:
> > +            raise PyverbsRDMAErrno(f'Failed to allocate dmabuf of size {size} on unit {unit}')
> > +        self.dri_fd = dmabuf_get_dri_fd(<dmabuf *>self.dmabuf)
> 
> dri_fd seems unused by the tests

It's used by the read/write methods of the DmaBufMR class for performing mmap.