drm/admgpu: add two shadow BO helper functions

Add amdgpu_bo_add_to_shadow_list() to handle shadow list
additions and amdgpu_bo_shadowed() to check if a BO is shadowed.
Signed-off-by: NNirmoy Das <nirmoy.das@amd.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_object.c

@@ -736,6 +736,22 @@ int amdgpu_bo_validate(struct amdgpu_bo *bo)
 	return r;
 }
 
+/**
+ * amdgpu_bo_add_to_shadow_list - add a BO to the shadow list
+ *
+ * @bo: BO that will be inserted into the shadow list
+ *
+ * Insert a BO to the shadow list.
+ */
+void amdgpu_bo_add_to_shadow_list(struct amdgpu_bo *bo)
+{
+	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
+
+	mutex_lock(&adev->shadow_list_lock);
+	list_add_tail(&bo->shadow_list, &adev->shadow_list);
+	mutex_unlock(&adev->shadow_list_lock);
+}
+
 /**
  * amdgpu_bo_restore_shadow - restore an &amdgpu_bo shadow
  *

drivers/gpu/drm/amd/amdgpu/amdgpu_object.h

@@ -259,6 +259,22 @@ static inline bool amdgpu_bo_encrypted(struct amdgpu_bo *bo)
 	return bo->flags & AMDGPU_GEM_CREATE_ENCRYPTED;
 }
 
+/**
+ * amdgpu_bo_shadowed - check if the BO is shadowed
+ *
+ * @bo: BO to be tested.
+ *
+ * Returns:
+ * NULL if not shadowed or else return a BO pointer.
+ */
+static inline struct amdgpu_bo *amdgpu_bo_shadowed(struct amdgpu_bo *bo)
+{
+	if (bo->tbo.type == ttm_bo_type_kernel)
+		return to_amdgpu_bo_vm(bo)->shadow;
+
+	return NULL;
+}
+
 bool amdgpu_bo_is_amdgpu_bo(struct ttm_buffer_object *bo);
 void amdgpu_bo_placement_from_domain(struct amdgpu_bo *abo, u32 domain);
 
@@ -322,6 +338,7 @@ u64 amdgpu_bo_gpu_offset_no_check(struct amdgpu_bo *bo);
 int amdgpu_bo_validate(struct amdgpu_bo *bo);
 void amdgpu_bo_get_memory(struct amdgpu_bo *bo, uint64_t *vram_mem,
 				uint64_t *gtt_mem, uint64_t *cpu_mem);
+void amdgpu_bo_add_to_shadow_list(struct amdgpu_bo *bo);
 int amdgpu_bo_restore_shadow(struct amdgpu_bo *shadow,
 			     struct dma_fence **fence);
 uint32_t amdgpu_bo_get_preferred_pin_domain(struct amdgpu_device *adev,