[PATCH AUTOSEL 6.6 42/47] drm/exynos: fix a wrong error checking

Sasha Levin
2023-12-11T13:57:17Z

From: Inki Dae <inki.dae@samsung.com>

[ Upstream commit 8d1b7809684c688005706125b804e1f9792d2b1b ]

Fix a wrong error checking in exynos_drm_dma.c module.

In the exynos_drm_register_dma function, both arm_iommu_create_mapping()
and iommu_get_domain_for_dev() functions are expected to return NULL as
an error.

However, the error checking is performed using the statement
if(IS_ERR(mapping)), which doesn't provide a suitable error value.
So check if 'mapping' is NULL, and if it is, return -ENODEV.

This issue[1] was reported by Dan.

Changelog v1:
- fix build warning.

[1] https://lore.kernel.org/all/33e52277-1349-472b-a55b-ab5c3462bfcf@moroto.mountain/

Reported-by : Dan Carpenter <dan.carpenter@linaro.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 | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_dma.c b/drivers/gpu/drm/exynos/exynos_drm_dma.c
index a971590b81323..e2c7373f20c6b 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dma.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dma.c
@@ -107,18 +107,16 @@ int exynos_drm_register_dma(struct drm_device *drm, struct device *dev,
return 0;

if (!priv->mapping) {
- void *mapping;
+ void *mapping = NULL;

if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
mapping = arm_iommu_create_mapping(&platform_bus_type,
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);
+ if (!mapping)
+ return -ENODEV;
priv->mapping = mapping;
}

--
2.42.0