1 /* SPDX-License-Identifier: MIT */ 2 /* 3 * Copyright © 2023 Intel Corporation 4 */ 5 6 #ifndef __I915_GEM_OBJECT_FRONTBUFFER_H__ 7 #define __I915_GEM_OBJECT_FRONTBUFFER_H__ 8 9 #include <linux/kref.h> 10 #include <linux/rcupdate.h> 11 12 #include "display/intel_frontbuffer.h" 13 #include "i915_gem_object_types.h" 14 15 struct i915_frontbuffer { 16 struct intel_frontbuffer base; 17 struct drm_i915_gem_object *obj; 18 struct i915_active write; 19 struct rcu_head rcu; 20 struct kref ref; 21 }; 22 23 void __i915_gem_object_flush_frontbuffer(struct drm_i915_gem_object *obj, 24 enum fb_op_origin origin); 25 void __i915_gem_object_invalidate_frontbuffer(struct drm_i915_gem_object *obj, 26 enum fb_op_origin origin); 27 28 static inline void 29 i915_gem_object_flush_frontbuffer(struct drm_i915_gem_object *obj, 30 enum fb_op_origin origin) 31 { 32 if (unlikely(rcu_access_pointer(obj->frontbuffer))) 33 __i915_gem_object_flush_frontbuffer(obj, origin); 34 } 35 36 static inline void 37 i915_gem_object_invalidate_frontbuffer(struct drm_i915_gem_object *obj, 38 enum fb_op_origin origin) 39 { 40 if (unlikely(rcu_access_pointer(obj->frontbuffer))) 41 __i915_gem_object_invalidate_frontbuffer(obj, origin); 42 } 43 44 struct i915_frontbuffer *i915_gem_object_frontbuffer_get(struct drm_i915_gem_object *obj); 45 void i915_gem_object_frontbuffer_ref(struct i915_frontbuffer *front); 46 void i915_gem_object_frontbuffer_put(struct i915_frontbuffer *front); 47 48 /** 49 * i915_gem_object_frontbuffer_lookup - Look up the object's frontbuffer 50 * @obj: The object whose frontbuffer to look up. 51 * 52 * Get pointer to object's frontbuffer if such exists. Please note that RCU 53 * mechanism is used to handle e.g. ongoing removal of frontbuffer pointer. 54 * 55 * Return: pointer to object's frontbuffer is such exists or NULL 56 */ 57 static inline struct i915_frontbuffer * 58 i915_gem_object_frontbuffer_lookup(const struct drm_i915_gem_object *obj) 59 { 60 struct i915_frontbuffer *front; 61 62 if (likely(!rcu_access_pointer(obj->frontbuffer))) 63 return NULL; 64 65 rcu_read_lock(); 66 do { 67 front = rcu_dereference(obj->frontbuffer); 68 if (!front) 69 break; 70 71 if (unlikely(!kref_get_unless_zero(&front->ref))) 72 continue; 73 74 if (likely(front == rcu_access_pointer(obj->frontbuffer))) 75 break; 76 77 i915_gem_object_frontbuffer_put(front); 78 } while (1); 79 rcu_read_unlock(); 80 81 return front; 82 } 83 84 #endif 85