From: Nathan Chancellor <nathan@kernel.org> stable inclusion from stable-5.10.67 commit 756924bc1804f0696fda8aeedd48a42152c0c7bf bugzilla: 182619 https://gitee.com/openeuler/kernel/issues/I4EWO7 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit c626f3864bbbb28bbe06476b0b497c1330aa4463 ] In certain randconfigs, clang warns: drivers/gpu/drm/exynos/exynos_drm_dma.c:121:19: warning: variable 'mapping' is uninitialized when used here [-Wuninitialized] priv->mapping = mapping; ^~~~~~~ drivers/gpu/drm/exynos/exynos_drm_dma.c:111:16: note: initialize the variable 'mapping' to silence this warning void *mapping; ^ = NULL 1 warning generated. This occurs when CONFIG_EXYNOS_IOMMU is enabled and both CONFIG_ARM_DMA_USE_IOMMU and CONFIG_IOMMU_DMA are disabled, which makes the code look like void *mapping; if (0) mapping = arm_iommu_create_mapping() else if (0) mapping = iommu_get_domain_for_dev() ... priv->mapping = mapping; Add an else branch that initializes mapping to the -ENODEV error pointer so that there is no more warning and the driver does not change during runtime. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Inki Dae <inki.dae@samsung.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> --- drivers/gpu/drm/exynos/exynos_drm_dma.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/exynos/exynos_drm_dma.c b/drivers/gpu/drm/exynos/exynos_drm_dma.c index 0644936afee2..bf33c3084cb4 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_dma.c +++ b/drivers/gpu/drm/exynos/exynos_drm_dma.c @@ -115,6 +115,8 @@ int exynos_drm_register_dma(struct drm_device *drm, struct device *dev, EXYNOS_DEV_ADDR_START, EXYNOS_DEV_ADDR_SIZE); else if (IS_ENABLED(CONFIG_IOMMU_DMA)) mapping = iommu_get_domain_for_dev(priv->dma_dev); + else + mapping = ERR_PTR(-ENODEV); if (IS_ERR(mapping)) return PTR_ERR(mapping); -- 2.20.1