Virtualization - Aug 2021 - [PATCH v10 04/17] vdpa: Fail the vdpa_reset() if fail to set device status to zero

? 2021/7/29 ??3:34, Xie Yongji ??:
> Re-read the device status to ensure it's set to zero during
> resetting. Otherwise, fail the vdpa_reset() after timeout.
>
> Signed-off-by: Xie Yongji <xieyongji at bytedance.com>
> ---
>   include/linux/vdpa.h | 15 ++++++++++++++-
>   1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index 406d53a606ac..d1a80ef05089 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -6,6 +6,7 @@
>   #include <linux/device.h>
>   #include <linux/interrupt.h>
>   #include <linux/vhost_iotlb.h>
> +#include <linux/delay.h>
>   
>   /**
>    * struct vdpa_calllback - vDPA callback definition.
> @@ -340,12 +341,24 @@ static inline struct device *vdpa_get_dma_dev(struct
vdpa_device *vdev)
>   	return vdev->dma_dev;
>   }
>   
> -static inline void vdpa_reset(struct vdpa_device *vdev)
> +#define VDPA_RESET_TIMEOUT_MS 1000
> +
> +static inline int vdpa_reset(struct vdpa_device *vdev)
>   {
>   	const struct vdpa_config_ops *ops = vdev->config;
> +	int timeout = 0;
>   
>   	vdev->features_valid = false;
>   	ops->set_status(vdev, 0);
> +	while (ops->get_status(vdev)) {
> +		timeout += 20;
> +		if (timeout > VDPA_RESET_TIMEOUT_MS)
> +			return -EIO;
> +
> +		msleep(20);
> +	}

I wonder if it's better to do this in the vDPA parent?

Thanks

> +
> +	return 0;
>   }
>   
>   static inline int vdpa_set_features(struct vdpa_device *vdev, u64
features)