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Date: Wed, 13 Apr 2022 18:07:00 +0200
From: Christoph Hellwig <hch@lst.de>
To: Jason Gunthorpe <jgg@nvidia.com>
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References: <0-v1-a8faf768d202+125dd-vfio_mdev_no_group_jgg@nvidia.com>
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Subject: Re: [Intel-gfx] [PATCH 9/9] vfio: Remove calls to
 vfio_group_add_container_user()
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Cc: kvm@vger.kernel.org, linux-doc@vger.kernel.org,
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On Wed, Apr 13, 2022 at 11:03:05AM -0300, Jason Gunthorpe wrote:
> On Wed, Apr 13, 2022 at 08:11:05AM +0200, Christoph Hellwig wrote:
> > On Tue, Apr 12, 2022 at 12:53:36PM -0300, Jason Gunthorpe wrote:
> > > +	if (WARN_ON(!READ_ONCE(vdev->open_count)))
> > > +		return -EINVAL;
> > 
> > I think all the WARN_ON()s in this patch need to be WARN_ON_ONCE,
> > otherwise there will be too many backtraces to be useful if a driver
> > ever gets the API wrong.
> 
> Sure, I added a wrapper to make that have less overhead and merged it
> with the other 'driver is calling this correctly' checks:

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>