03.10.2020 09:59, Nicolin Chen пишет: > static int tegra_smmu_of_xlate(struct device *dev, > struct of_phandle_args *args) > { > + struct platform_device *iommu_pdev = of_find_device_by_node(args->np); > + struct tegra_mc *mc = platform_get_drvdata(iommu_pdev); > u32 id = args->args[0]; > > + put_device(&iommu_pdev->dev); > + > + if (!mc || !mc->smmu) > + return -EPROBE_DEFER; I'm not very excited by seeing code in the patches that can't be explained by the patch authors and will appreciate if you could provide a detailed explanation about why this NULL checking is needed because I think it is unneeded, especially given that other IOMMU drivers don't have such check. I'm asking this question second time now, please don't ignore review comments next time.