[PATCH v5 08/14] iommufd/viommu: Add iommufd_viommu_report_event helper

[Tian, Kevin]

> From: Nicolin Chen <nicolinc at nvidia.com>
> Sent: Wednesday, January 8, 2025 1:10 AM
> 
> +/*
> + * Typically called in driver's threaded IRQ handler.
> + * The @type and @event_data must be defined in
> include/uapi/linux/iommufd.h
> + */
> +int iommufd_viommu_report_event(struct iommufd_viommu *viommu,
> +				enum iommu_veventq_type type, void
> *event_data,
> +				size_t data_len)
> +{
> +	struct iommufd_veventq *veventq;
> +	struct iommufd_vevent *vevent;
> +	int rc = 0;
> +
> +	if (!viommu)
> +		return -ENODEV;
> +	if (WARN_ON_ONCE(!viommu->ops || !viommu->ops-
> >supports_veventq ||
> +			 !viommu->ops->supports_veventq(type)))
> +		return -EOPNOTSUPP;

Hmm the driver knows which type is supported by itself before
calling this helper. Why bother having the helper calling into
the driver again to verify?