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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Nathan Chancellor <nathan@kernel.org>,
	kernel test robot <lkp@intel.com>,
	Inki Dae <inki.dae@samsung.com>, Sasha Levin <sashal@kernel.org>,
	dri-devel@lists.freedesktop.org,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org,
	clang-built-linux@googlegroups.com
Subject: [PATCH AUTOSEL 5.14 183/252] drm/exynos: Always initialize mapping in exynos_drm_register_dma()
Date: Thu,  9 Sep 2021 07:39:57 -0400	[thread overview]
Message-ID: <20210909114106.141462-183-sashal@kernel.org> (raw)
In-Reply-To: <20210909114106.141462-1-sashal@kernel.org>

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


           reply	other threads:[~2021-09-09 11:56 UTC|newest]

Thread overview: expand[flat|nested]  mbox.gz  Atom feed
 [parent not found: <20210909114106.141462-1-sashal@kernel.org>]

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