1 files changed, 72 insertions, 4 deletions
diff --git a/drivers/gpu/drm/i915/i915_scatterlist.h b/drivers/gpu/drm/i915/i915_scatterlist.h
index b8bd5925b03f..12c6a1684081 100644
--- a/drivers/gpu/drm/i915/i915_scatterlist.h
+++ b/drivers/gpu/drm/i915/i915_scatterlist.h
@@ -144,10 +144,78 @@ static inline unsigned int i915_sg_segment_size(void)
 
 bool i915_sg_trim(struct sg_table *orig_st);
 
-struct sg_table *i915_sg_from_mm_node(const struct drm_mm_node *node,
-				      u64 region_start);
+/**
+ * struct i915_refct_sgt_ops - Operations structure for struct i915_refct_sgt
+ */
+struct i915_refct_sgt_ops {
+	/**
+	 * release() - Free the memory of the struct i915_refct_sgt
+	 * @ref: struct kref that is embedded in the struct i915_refct_sgt
+	 */
+	void (*release)(struct kref *ref);
+};
+
+/**
+ * struct i915_refct_sgt - A refcounted scatter-gather table
+ * @kref: struct kref for refcounting
+ * @table: struct sg_table holding the scatter-gather table itself. Note that
+ * @table->sgl = NULL can be used to determine whether a scatter-gather table
+ * is present or not.
+ * @size: The size in bytes of the underlying memory buffer
+ * @ops: The operations structure.
+ */
+struct i915_refct_sgt {
+	struct kref kref;
+	struct sg_table table;
+	size_t size;
+	const struct i915_refct_sgt_ops *ops;
+};
+
+/**
+ * i915_refct_sgt_put - Put a refcounted sg-table
+ * @rsgt the struct i915_refct_sgt to put.
+ */
+static inline void i915_refct_sgt_put(struct i915_refct_sgt *rsgt)
+{
+	if (rsgt)
+		kref_put(&rsgt->kref, rsgt->ops->release);
+}
+
+/**
+ * i915_refct_sgt_get - Get a refcounted sg-table
+ * @rsgt the struct i915_refct_sgt to get.
+ */
+static inline struct i915_refct_sgt *
+i915_refct_sgt_get(struct i915_refct_sgt *rsgt)
+{
+	kref_get(&rsgt->kref);
+	return rsgt;
+}
+
+/**
+ * __i915_refct_sgt_init - Initialize a refcounted sg-list with a custom
+ * operations structure
+ * @rsgt The struct i915_refct_sgt to initialize.
+ * @size: Size in bytes of the underlying memory buffer.
+ * @ops: A customized operations structure in case the refcounted sg-list
+ * is embedded into another structure.
+ */
+static inline void __i915_refct_sgt_init(struct i915_refct_sgt *rsgt,
+					 size_t size,
+					 const struct i915_refct_sgt_ops *ops)
+{
+	kref_init(&rsgt->kref);
+	rsgt->table.sgl = NULL;
+	rsgt->size = size;
+	rsgt->ops = ops;
+}
+
+void i915_refct_sgt_init(struct i915_refct_sgt *rsgt, size_t size);
+
+struct i915_refct_sgt *i915_rsgt_from_mm_node(const struct drm_mm_node *node,
+					      u64 region_start);
 
-struct sg_table *i915_sg_from_buddy_resource(struct ttm_resource *res,
-					     u64 region_start);
+struct i915_refct_sgt *i915_rsgt_from_buddy_resource(struct ttm_resource *res,
+						     u64 region_start);
 
 #endif