Re: [PATCH rdma-next v5 03/15] RDMA/core: Introduce generic buffer descriptor infrastructure for umem

[Jason Gunthorpe <jgg@ziepe.ca>]

On Mon, May 18, 2026 at 09:04:06AM -0400, Jacob Moroni wrote:
> Hi,
> 
> > +struct ib_umem *ib_umem_get_desc(struct ib_device *device,
> > +                                const struct ib_uverbs_buffer_desc *desc,
> > +                                int access)
> > +{
> > +       struct ib_umem_dmabuf *umem_dmabuf;
> > +
> > +       if (desc->reserved[0] || desc->reserved[1])
> > +               return ERR_PTR(-EINVAL);
> > +
> > +       switch (desc->type) {
> > +       case IB_UVERBS_BUFFER_TYPE_DMABUF:
> > +               umem_dmabuf = ib_umem_dmabuf_get_pinned(device, desc->addr,
> > +                                                       desc->length, desc->fd,
> > +                                                       access);
> 
> This all looks good to me. Just thinking out loud...
> 
> Is there a longer term plan to handle revocable dmabufs on this path and
> get rid of the separate ib_umem_dmabuf_get methods?

We probably will need a more general _revocable variation that adds in
an ops struct from the driver to be able to do the revoke.. So far
no driver supports revoke outside of MR so...

Jason