text: /*
   * Copyright (C) 2013 Red Hat
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice (including the next
   * paragraph) shall be included in all copies or substantial portions of the
   * Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  
  #ifndef DRM_FLIP_WORK_H
  #define DRM_FLIP_WORK_H
  
  #include <linux/kfifo.h>
  #include <linux/workqueue.h>
  
  /**
   * DOC: flip utils
   *
   * Util to queue up work to run from work-queue context after flip/vblank.
   * Typically this can be used to defer unref of framebuffer's, cursor
   * bo's, etc until after vblank.  The APIs are all safe (and lockless)
   * for up to one producer and once consumer at a time.  The single-consumer
   * aspect is ensured by committing the queued work to a single work-queue.
   */
  
  struct drm_flip_work;
  
  /*
   * drm_flip_func_t - callback function
   *
   * @work: the flip work
   * @val: value queued via drm_flip_work_queue()
   *
   * Callback function to be called for each of the  queue'd work items after
   * drm_flip_work_commit() is called.
   */
  typedef void (*drm_flip_func_t)(struct drm_flip_work *work, void *val);
  
  /**
   * struct drm_flip_work - flip work queue
   * @name: debug name
   * @pending: number of queued but not committed items
   * @count: number of committed items
   * @func: callback fxn called for each committed item
   * @worker: worker which calls @func
   */
  struct drm_flip_work {
  	const char *name;
  	atomic_t pending, count;
  	drm_flip_func_t func;
  	struct work_struct worker;
  	DECLARE_KFIFO_PTR(fifo, void *);
  };
  
  void drm_flip_work_queue(struct drm_flip_work *work, void *val);
  void drm_flip_work_commit(struct drm_flip_work *work,
  		struct workqueue_struct *wq);
  int drm_flip_work_init(struct drm_flip_work *work, int size,
  		const char *name, drm_flip_func_t func);
  void drm_flip_work_cleanup(struct drm_flip_work *work);
  
  #endif  /* DRM_FLIP_WORK_H */
  