On 2/14/22 8:49 PM, Joerg Roedel wrote:
On Mon, Feb 14, 2022 at 09:55:35AM +0800, Lu Baolu wrote:+static inline const struct iommu_ops *dev_iommu_ops(struct device *dev) +{ + /* + * Assume that valid ops must be installed if iommu_probe_device() + * has succeeded. The device ops are essentially for internal use + * within the IOMMU subsystem itself, so we should be able to trust + * ourselves not to misuse the helper. + */ + WARN_ON(!dev || !dev->iommu || !dev->iommu->iommu_dev || + !dev->iommu->iommu_dev->ops);There is no need for this WARN_ON, the code will oops anyway when one of the pointers checked here is NULL.
We really don't need to WARN_ON intermediate null pointers. But I would argue that we could add a WARN() on null dev->iommu->iommu_dev->ops, so that callers have no need to check the returned ops. Best regards, baolu _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
