Re: [PATCH RESEND] rpmsg: virtio_rpmsg_bus: fix rpmsg_probe() for virtio-mmio transport

On Mon, Mar 19, 2018 at 4:17 AM, Bjorn Andersson bjorn.andersson@linaro.org wrote:

On Wed 10 Jan 05:16 PST 2018, Anup Patel wrote:

...

diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c

[..]

...

@@ -924,9 +925,16 @@ static int rpmsg_probe(struct virtio_device *vdev) total_buf_space, &vrp->bufs_dma, GFP_KERNEL); if (!bufs_va) {

•         err = -ENOMEM;
  

•         goto vqs_del;
  

• }
  

•         bufs_va = dma_alloc_coherent(vdev->dev.parent,
  

•                                      total_buf_space, &vrp->bufs_dma,
  

•                                      GFP_KERNEL);
  

•         if (!bufs_va) {
  

•                 err = -ENOMEM;
  

•                 goto vqs_del;
  

•         } else
  

•                 vrp->bufs_dev = vdev->dev.parent;
  

• } else
  

•         vrp->bufs_dev = vdev->dev.parent->parent;
  

I really don't fancy the idea of us allocating on behalf of our grandparent here, as you show it's not certain that our grandparent is what someone originally expected it to be.

With the purpose of being able to control these allocations there is an ongoing discussion related to this, which I believe will result in this being changed to at least vdev->dev.parent..

I do expect that this discussion will be brought up during Linaro Connect the coming week.

Currently, rpmsg_probe() is broken for virtio-mmio transport hence I send this patch as a stable fix.

In general, I am fine if we are eventually going towards vdev->dev.parent usage.

Regards, Anup