[PATCH v14 4/4] RDMA/mlx5: Support dma-buf based userspace memory region

[Xiong, Jianxin]

> -----Original Message-----
> From: Leon Romanovsky <leon at kernel.org>
> Sent: Tuesday, December 08, 2020 10:45 PM
> To: Xiong, Jianxin <jianxin.xiong at intel.com>
> Cc: linux-rdma at vger.kernel.org; dri-devel at lists.freedesktop.org; Doug Ledford <dledford at redhat.com>; Jason Gunthorpe <jgg at ziepe.ca>;
> Sumit Semwal <sumit.semwal at linaro.org>; Christian Koenig <christian.koenig at amd.com>; Vetter, Daniel <daniel.vetter at intel.com>
> Subject: Re: [PATCH v14 4/4] RDMA/mlx5: Support dma-buf based userspace memory region
> 
> On Tue, Dec 08, 2020 at 02:39:15PM -0800, Jianxin Xiong wrote:
> > Implement the new driver method 'reg_user_mr_dmabuf'.  Utilize the
> > core functions to import dma-buf based memory region and update the mappings.
> >
> > Add code to handle dma-buf related page fault.
> >
> > Signed-off-by: Jianxin Xiong <jianxin.xiong at intel.com>
> > Reviewed-by: Sean Hefty <sean.hefty at intel.com>
> > Acked-by: Michael J. Ruhl <michael.j.ruhl at intel.com>
> > Acked-by: Christian Koenig <christian.koenig at amd.com>
> > Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> > ---
> >  drivers/infiniband/hw/mlx5/main.c    |   2 +
> >  drivers/infiniband/hw/mlx5/mlx5_ib.h |  18 +++++
> >  drivers/infiniband/hw/mlx5/mr.c      | 128 +++++++++++++++++++++++++++++++++--
> >  drivers/infiniband/hw/mlx5/odp.c     |  86 +++++++++++++++++++++--
> >  4 files changed, 225 insertions(+), 9 deletions(-)
> 
> <...>
> 
> >
> > +
> > +	umem = ib_umem_dmabuf_get(&dev->ib_dev, offset, length, fd, access_flags,
> > +				  &mlx5_ib_dmabuf_attach_ops);
> > +	if (IS_ERR(umem)) {
> > +		mlx5_ib_dbg(dev, "umem get failed (%ld)\n", PTR_ERR(umem));
> > +		return ERR_PTR(PTR_ERR(umem));
> 
> return ERR_CAST(umem);
> 
> > +	}
> 
> <...>
> 
> > +	dma_resv_lock(umem_dmabuf->attach->dmabuf->resv, NULL);
> > +	err = ib_umem_dmabuf_map_pages(umem_dmabuf);
> > +	if (!err) {
> > +		page_size = mlx5_umem_find_best_pgsz(&umem_dmabuf->umem, mkc,
> > +						     log_page_size, 0,
> > +						     umem_dmabuf->umem.iova);
> > +		if (unlikely(page_size < PAGE_SIZE)) {
> > +			ib_umem_dmabuf_unmap_pages(umem_dmabuf);
> > +			err = -EINVAL;
> > +		} else {
> > +			err = mlx5_ib_update_mr_pas(mr, xlt_flags);
> > +		}
> > +	}
> > +	dma_resv_unlock(umem_dmabuf->attach->dmabuf->resv);
> 
> Let's write this section in kernel coding style, please
> 
> dma_resv_lock(umem_dmabuf->attach->dmabuf->resv, NULL); err = ib_umem_dmabuf_map_pages(umem_dmabuf);
> if (err) {
>       dma_resv_unlock(umem_dmabuf->attach->dmabuf->resv);
>       return err;
> }
> .....
> 

Thanks a lot. Will fix these.