netdev - Re: [PATCH V4 5/5] vdpasim: vDPA device simulator

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Date:   Wed, 26 Feb 2020 13:19:05 -0400
From:   Jason Gunthorpe <jgg@...lanox.com>
To:     Jason Wang <jasowang@...hat.com>
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Subject: Re: [PATCH V4 5/5] vdpasim: vDPA device simulator

On Wed, Feb 26, 2020 at 02:12:26PM +0800, Jason Wang wrote:
> > > It is a bit weird to be creating this dummy parent, couldn't this be
> > > done by just passing a NULL parent to vdpa_alloc_device, doing
> > > set_dma_ops() on the vdpasim->vdpa->dev and setting dma_device to
> > > vdpasim->vdpa->dev ?
> > 
> > 
> > I think it works.
> 
> 
> Rethink about this, since most hardware vDPA driver will have a parent and
> will use it to find the parent structure e.g
> 
> dev_get_drvdata(vdpa->dev->parent)

Oh that seems like a sketchy pattern

> So I keep this dummy parent in V5.

The dummy parent is visible in sysfs, I think you should remove it so
the syfs for this virtual device makes sense.

Jason