1 files changed, 84 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_frontbuffer.h b/drivers/gpu/drm/i915/gem/i915_gem_object_frontbuffer.h
new file mode 100644
index 000000000000..2133e29047c5
--- /dev/null
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_frontbuffer.h
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2023 Intel Corporation
+ */
+
+#ifndef __I915_GEM_OBJECT_FRONTBUFFER_H__
+#define __I915_GEM_OBJECT_FRONTBUFFER_H__
+
+#include <linux/kref.h>
+#include <linux/rcupdate.h>
+
+#include "display/intel_frontbuffer.h"
+#include "i915_gem_object_types.h"
+
+struct i915_frontbuffer {
+	struct intel_frontbuffer base;
+	struct drm_i915_gem_object *obj;
+	struct i915_active write;
+	struct rcu_head rcu;
+	struct kref ref;
+};
+
+void __i915_gem_object_flush_frontbuffer(struct drm_i915_gem_object *obj,
+					 enum fb_op_origin origin);
+void __i915_gem_object_invalidate_frontbuffer(struct drm_i915_gem_object *obj,
+					      enum fb_op_origin origin);
+
+static inline void
+i915_gem_object_flush_frontbuffer(struct drm_i915_gem_object *obj,
+				  enum fb_op_origin origin)
+{
+	if (unlikely(rcu_access_pointer(obj->frontbuffer)))
+		__i915_gem_object_flush_frontbuffer(obj, origin);
+}
+
+static inline void
+i915_gem_object_invalidate_frontbuffer(struct drm_i915_gem_object *obj,
+				       enum fb_op_origin origin)
+{
+	if (unlikely(rcu_access_pointer(obj->frontbuffer)))
+		__i915_gem_object_invalidate_frontbuffer(obj, origin);
+}
+
+struct i915_frontbuffer *i915_gem_object_frontbuffer_get(struct drm_i915_gem_object *obj);
+void i915_gem_object_frontbuffer_ref(struct i915_frontbuffer *front);
+void i915_gem_object_frontbuffer_put(struct i915_frontbuffer *front);
+
+/**
+ * i915_gem_object_frontbuffer_lookup - Look up the object's frontbuffer
+ * @obj: The object whose frontbuffer to look up.
+ *
+ * Get pointer to object's frontbuffer if such exists. Please note that RCU
+ * mechanism is used to handle e.g. ongoing removal of frontbuffer pointer.
+ *
+ * Return: pointer to object's frontbuffer is such exists or NULL
+ */
+static inline struct i915_frontbuffer *
+i915_gem_object_frontbuffer_lookup(const struct drm_i915_gem_object *obj)
+{
+	struct i915_frontbuffer *front;
+
+	if (likely(!rcu_access_pointer(obj->frontbuffer)))
+		return NULL;
+
+	rcu_read_lock();
+	do {
+		front = rcu_dereference(obj->frontbuffer);
+		if (!front)
+			break;
+
+		if (unlikely(!kref_get_unless_zero(&front->ref)))
+			continue;
+
+		if (likely(front == rcu_access_pointer(obj->frontbuffer)))
+			break;
+
+		i915_gem_object_frontbuffer_put(front);
+	} while (1);
+	rcu_read_unlock();
+
+	return front;
+}
+
+#endif