From f7c72773de88fa3d4b51d4eb2bd2a89b746aaf54 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Fri, 17 Jun 2016 09:54:23 +0200 Subject: [PATCH] drm/exynos: iommu: move dma_params configuration code to separate functions Move code for managing DMA max segment size parameter to separate functions. This patch also replaces devm_kzalloc() with kzalloc() and adds proper kfree call. devm_kzalloc() cannot be used for dma_params structure, because it will be freed on driver remove not on device release. This means in case of Exynos DRM being compiled as module and loaded 2 times, a user-after-free issue will happen. Signed-off-by: Marek Szyprowski Signed-off-by: Inki Dae --- drivers/gpu/drm/exynos/exynos_drm_iommu.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/exynos/exynos_drm_iommu.c b/drivers/gpu/drm/exynos/exynos_drm_iommu.c index 7ca09ee..1e82529 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_iommu.c +++ b/drivers/gpu/drm/exynos/exynos_drm_iommu.c @@ -21,6 +21,23 @@ #include "exynos_drm_drv.h" #include "exynos_drm_iommu.h" +static inline int configure_dma_max_seg_size(struct device *dev) +{ + if (!dev->dma_parms) + dev->dma_parms = kzalloc(sizeof(*dev->dma_parms), GFP_KERNEL); + if (!dev->dma_parms) + return -ENOMEM; + + dma_set_max_seg_size(dev, DMA_BIT_MASK(32)); + return 0; +} + +static inline void clear_dma_max_seg_size(struct device *dev) +{ + kfree(dev->dma_parms); + dev->dma_parms = NULL; +} + /* * drm_create_iommu_mapping - create a mapping structure * @@ -80,13 +97,10 @@ int drm_iommu_attach_device(struct drm_device *drm_dev, if (!priv->mapping) return 0; - subdrv_dev->dma_parms = devm_kzalloc(subdrv_dev, - sizeof(*subdrv_dev->dma_parms), - GFP_KERNEL); - if (!subdrv_dev->dma_parms) - return -ENOMEM; - dma_set_max_seg_size(subdrv_dev, 0xffffffffu); + ret = configure_dma_max_seg_size(subdrv_dev); + if (ret) + return ret; if (subdrv_dev->archdata.mapping) arm_iommu_detach_device(subdrv_dev); @@ -94,6 +108,7 @@ int drm_iommu_attach_device(struct drm_device *drm_dev, ret = arm_iommu_attach_device(subdrv_dev, priv->mapping); if (ret < 0) { DRM_DEBUG_KMS("failed iommu attach.\n"); + clear_dma_max_seg_size(subdrv_dev); return ret; } @@ -119,4 +134,5 @@ void drm_iommu_detach_device(struct drm_device *drm_dev, return; arm_iommu_detach_device(subdrv_dev); + clear_dma_max_seg_size(subdrv_dev); } -- 2.7.4