drm/tegra: Protect IOMMU operations by mutex
IOMMU support is currently not thread-safe, which can cause crashes,
amongst other things, under certain workloads.
Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index 17e62ec..050ba78 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -128,12 +128,14 @@ static int tegra_bo_iommu_map(struct tegra_drm *tegra, struct tegra_bo *bo)
if (!bo->mm)
return -ENOMEM;
+ mutex_lock(&tegra->mm_lock);
+
err = drm_mm_insert_node_generic(&tegra->mm,
bo->mm, bo->gem.size, PAGE_SIZE, 0, 0);
if (err < 0) {
dev_err(tegra->drm->dev, "out of I/O virtual memory: %zd\n",
err);
- goto free;
+ goto unlock;
}
bo->paddr = bo->mm->start;
@@ -147,11 +149,14 @@ static int tegra_bo_iommu_map(struct tegra_drm *tegra, struct tegra_bo *bo)
bo->size = err;
+ mutex_unlock(&tegra->mm_lock);
+
return 0;
remove:
drm_mm_remove_node(bo->mm);
-free:
+unlock:
+ mutex_unlock(&tegra->mm_lock);
kfree(bo->mm);
return err;
}
@@ -161,8 +166,11 @@ static int tegra_bo_iommu_unmap(struct tegra_drm *tegra, struct tegra_bo *bo)
if (!bo->mm)
return 0;
+ mutex_lock(&tegra->mm_lock);
iommu_unmap(tegra->domain, bo->paddr, bo->size);
drm_mm_remove_node(bo->mm);
+ mutex_unlock(&tegra->mm_lock);
+
kfree(bo->mm);
return 0;