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From:   Cornelia Huck <cohuck@redhat.com>
To:     Christoph Hellwig <hch@lst.de>,
        Kirti Wankhede <kwankhede@nvidia.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        Jason Gunthorpe <jgg@nvidia.com>
Cc:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] vfio/mdev: don't warn if ->request is not set
In-Reply-To: <20210726143524.155779-3-hch@lst.de>
Organization: Red Hat GmbH
References: <20210726143524.155779-1-hch@lst.de>
 <20210726143524.155779-3-hch@lst.de>
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Date:   Mon, 26 Jul 2021 19:07:04 +0200
Message-ID: <87zgu93sxz.fsf@redhat.com>
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On Mon, Jul 26 2021, Christoph Hellwig <hch@lst.de> wrote:

> Only a single driver actually sets the ->request method, so don't print
> a scary warning if it isn't.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/vfio/mdev/mdev_core.c | 4 ----
>  1 file changed, 4 deletions(-)
>
> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
> index b16606ebafa1..b314101237fe 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -138,10 +138,6 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
>  	if (!dev)
>  		return -EINVAL;
>  
> -	/* Not mandatory, but its absence could be a problem */
> -	if (!ops->request)
> -		dev_info(dev, "Driver cannot be asked to release device\n");
> -
>  	mutex_lock(&parent_list_lock);
>  
>  	/* Check for duplicate */

We also log a warning if we would like to call ->request() but none was
provided, so I think that's fine.

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

But I wonder why nobody else implements this? Lack of surprise removal?