[PATCH AUTOSEL 5.14 183/252] drm/exynos: Always initialize mapping in exynos_drm_register_dma()

Sasha Levin
2021-09-09T11:57:37Z

From: Nathan Chancellor <nathan@kernel.org>

[ 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>
---
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);
--
2.30.2