Re: [PATCH v3 7/8] virtio/s390: use DMA memory for ccw I/O and classic notifiers

Halil Pasic
2019-06-04T14:29:22Z

On Tue, 4 Jun 2019 15:36:25 +0200
Cornelia Huck <cohuck@redhat.com> wrote:

> On Tue, 4 Jun 2019 15:08:19 +0200
> Halil Pasic <pasic@linux.ibm.com> wrote:
>

[..]

>
> Two things:
> - The call path goes from the vcdev to the vdev, then back to the vcdev
> and then to the cdev. Going from the vcdev to the cdev directly
> eliminates the roundtrip via the vdev, which I think does not add
> anything.
> - I prefer
> variable = function_returning_a_pointer(...);
> over
> function_setting_a_variable(..., variable);
> The latter obscures the fact that we change the value of the
> variable, unless named very obviously.
>

I understand. Here it's especially bad because what looks like a
function is actually a macro so it ain't even fn(..., &variable) but
just fn(..., variable). I guess I'm a bit desensitized towards the latter
because of my c++ background.

> >
> > I will change this for v4 as you requested. Again sorry for missing it!
>
> np, can happen.

Thanks for the explanation. I will use

ccw_device_dma_zalloc() directly in v4.

Regards,
Halil