/*
   * workqueue.h --- work queue handling for Linux.
   */
  
  #ifndef _LINUX_WORKQUEUE_H
  #define _LINUX_WORKQUEUE_H
  
  #include <linux/timer.h>
  #include <linux/linkage.h>
  #include <linux/bitops.h>

  #include <linux/lockdep.h>

  #include <linux/threads.h>

  #include <linux/atomic.h>

  
  struct workqueue_struct;

  struct work_struct;
  typedef void (*work_func_t)(struct work_struct *work);

  /*
   * The first word is the work queue pointer and the flags rolled into
   * one
   */
  #define work_data_bits(work) ((unsigned long *)(&(work)->data))

  enum {
  	WORK_STRUCT_PENDING_BIT	= 0,	/* work item is pending execution */

  	WORK_STRUCT_DELAYED_BIT	= 1,	/* work item is delayed */
  	WORK_STRUCT_CWQ_BIT	= 2,	/* data points to cwq */
  	WORK_STRUCT_LINKED_BIT	= 3,	/* next work is linked to this one */

  #ifdef CONFIG_DEBUG_OBJECTS_WORK

  	WORK_STRUCT_STATIC_BIT	= 4,	/* static initializer (debugobjects) */
  	WORK_STRUCT_COLOR_SHIFT	= 5,	/* color for workqueue flushing */

  #else

  	WORK_STRUCT_COLOR_SHIFT	= 4,	/* color for workqueue flushing */

  #endif

  	WORK_STRUCT_COLOR_BITS	= 4,

  	WORK_STRUCT_PENDING	= 1 << WORK_STRUCT_PENDING_BIT,

  	WORK_STRUCT_DELAYED	= 1 << WORK_STRUCT_DELAYED_BIT,

  	WORK_STRUCT_CWQ		= 1 << WORK_STRUCT_CWQ_BIT,

  	WORK_STRUCT_LINKED	= 1 << WORK_STRUCT_LINKED_BIT,

  #ifdef CONFIG_DEBUG_OBJECTS_WORK
  	WORK_STRUCT_STATIC	= 1 << WORK_STRUCT_STATIC_BIT,
  #else
  	WORK_STRUCT_STATIC	= 0,
  #endif

  	/*
  	 * The last color is no color used for works which don't
  	 * participate in workqueue flushing.
  	 */
  	WORK_NR_COLORS		= (1 << WORK_STRUCT_COLOR_BITS) - 1,
  	WORK_NO_COLOR		= WORK_NR_COLORS,

  	/* special cpu IDs */

  	WORK_CPU_UNBOUND	= NR_CPUS,
  	WORK_CPU_NONE		= NR_CPUS + 1,

  	WORK_CPU_LAST		= WORK_CPU_NONE,

  	/*

  	 * Reserve 7 bits off of cwq pointer w/ debugobjects turned

  	 * off.  This makes cwqs aligned to 256 bytes and allows 15
  	 * workqueue flush colors.

  	 */
  	WORK_STRUCT_FLAG_BITS	= WORK_STRUCT_COLOR_SHIFT +
  				  WORK_STRUCT_COLOR_BITS,

  	WORK_STRUCT_FLAG_MASK	= (1UL << WORK_STRUCT_FLAG_BITS) - 1,

  	WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,

  	WORK_STRUCT_NO_CPU	= WORK_CPU_NONE << WORK_STRUCT_FLAG_BITS,

  
  	/* bit mask for work_busy() return values */
  	WORK_BUSY_PENDING	= 1 << 0,
  	WORK_BUSY_RUNNING	= 1 << 1,

  };

  struct work_struct {

  	atomic_long_t data;

  	struct list_head entry;

  	work_func_t func;

  #ifdef CONFIG_LOCKDEP
  	struct lockdep_map lockdep_map;
  #endif

  };

  #define WORK_DATA_INIT()	ATOMIC_LONG_INIT(WORK_STRUCT_NO_CPU)
  #define WORK_DATA_STATIC_INIT()	\
  	ATOMIC_LONG_INIT(WORK_STRUCT_NO_CPU | WORK_STRUCT_STATIC)

  struct delayed_work {
  	struct work_struct work;

  	struct timer_list timer;
  };

  static inline struct delayed_work *to_delayed_work(struct work_struct *work)
  {
  	return container_of(work, struct delayed_work, work);
  }

  struct execute_work {
  	struct work_struct work;
  };

  #ifdef CONFIG_LOCKDEP
  /*
   * NB: because we have to copy the lockdep_map, setting _key
   * here is required, otherwise it could get initialised to the
   * copy of the lockdep_map!
   */
  #define __WORK_INIT_LOCKDEP_MAP(n, k) \
  	.lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
  #else
  #define __WORK_INIT_LOCKDEP_MAP(n, k)
  #endif

  #define __WORK_INITIALIZER(n, f) {				\

  	.data = WORK_DATA_STATIC_INIT(),			\

  	.entry	= { &(n).entry, &(n).entry },			\

  	.func = (f),						\

  	__WORK_INIT_LOCKDEP_MAP(#n, &(n))			\

  	}
  
  #define __DELAYED_WORK_INITIALIZER(n, f) {			\
  	.work = __WORK_INITIALIZER((n).work, (f)),		\
  	.timer = TIMER_INITIALIZER(NULL, 0, 0),			\
  	}

  #define __DEFERRED_WORK_INITIALIZER(n, f) {			\
  	.work = __WORK_INITIALIZER((n).work, (f)),		\
  	.timer = TIMER_DEFERRED_INITIALIZER(NULL, 0, 0),	\
  	}

  #define DECLARE_WORK(n, f)					\
  	struct work_struct n = __WORK_INITIALIZER(n, f)

  #define DECLARE_DELAYED_WORK(n, f)				\
  	struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f)

  #define DECLARE_DEFERRED_WORK(n, f)				\
  	struct delayed_work n = __DEFERRED_WORK_INITIALIZER(n, f)

  /*

   * initialize a work item's function pointer

   */

  #define PREPARE_WORK(_work, _func)				\

  	do {							\

  		(_work)->func = (_func);			\

  	} while (0)

  #define PREPARE_DELAYED_WORK(_work, _func)			\
  	PREPARE_WORK(&(_work)->work, (_func))

  #ifdef CONFIG_DEBUG_OBJECTS_WORK
  extern void __init_work(struct work_struct *work, int onstack);
  extern void destroy_work_on_stack(struct work_struct *work);

  static inline unsigned int work_static(struct work_struct *work)
  {

  	return *work_data_bits(work) & WORK_STRUCT_STATIC;

  }

  #else
  static inline void __init_work(struct work_struct *work, int onstack) { }
  static inline void destroy_work_on_stack(struct work_struct *work) { }

  static inline unsigned int work_static(struct work_struct *work) { return 0; }

  #endif

  /*

   * initialize all of a work item in one go

   *

   * NOTE! No point in using "atomic_long_set()": using a direct

   * assignment of the work data initializer allows the compiler
   * to generate better code.

   */

  #ifdef CONFIG_LOCKDEP

  #define __INIT_WORK(_work, _func, _onstack)				\

  	do {								\

  		static struct lock_class_key __key;			\
  									\

  		__init_work((_work), _onstack);				\

  		(_work)->data = (atomic_long_t) WORK_DATA_INIT();	\

  		lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0);\

  		INIT_LIST_HEAD(&(_work)->entry);			\
  		PREPARE_WORK((_work), (_func));				\
  	} while (0)

  #else

  #define __INIT_WORK(_work, _func, _onstack)				\

  	do {								\

  		__init_work((_work), _onstack);				\

  		(_work)->data = (atomic_long_t) WORK_DATA_INIT();	\
  		INIT_LIST_HEAD(&(_work)->entry);			\
  		PREPARE_WORK((_work), (_func));				\
  	} while (0)
  #endif

  #define INIT_WORK(_work, _func)					\
  	do {							\
  		__INIT_WORK((_work), (_func), 0);		\
  	} while (0)

  #define INIT_WORK_ONSTACK(_work, _func)				\

  	do {							\
  		__INIT_WORK((_work), (_func), 1);		\
  	} while (0)

  #define INIT_DELAYED_WORK(_work, _func)				\
  	do {							\
  		INIT_WORK(&(_work)->work, (_func));		\
  		init_timer(&(_work)->timer);			\

  	} while (0)

  #define INIT_DELAYED_WORK_ONSTACK(_work, _func)			\

  	do {							\

  		INIT_WORK_ONSTACK(&(_work)->work, (_func));	\

  		init_timer_on_stack(&(_work)->timer);		\
  	} while (0)

  #define INIT_DELAYED_WORK_DEFERRABLE(_work, _func)		\

  	do {							\
  		INIT_WORK(&(_work)->work, (_func));		\
  		init_timer_deferrable(&(_work)->timer);		\
  	} while (0)

  /**
   * work_pending - Find out whether a work item is currently pending
   * @work: The work item in question
   */
  #define work_pending(work) \

  	test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))

  
  /**
   * delayed_work_pending - Find out whether a delayable work item is currently
   * pending
   * @work: The work item in question
   */

  #define delayed_work_pending(w) \
  	work_pending(&(w)->work)

  /**

   * work_clear_pending - for internal use only, mark a work item as not pending
   * @work: The work item in question

   */

  #define work_clear_pending(work) \

  	clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))

  /*
   * Workqueue flags and constants.  For details, please refer to
   * Documentation/workqueue.txt.
   */

  enum {

  	WQ_NON_REENTRANT	= 1 << 0, /* guarantee non-reentrance */

  	WQ_UNBOUND		= 1 << 1, /* not bound to any cpu */

  	WQ_FREEZABLE		= 1 << 2, /* freeze during suspend */

  	WQ_MEM_RECLAIM		= 1 << 3, /* may be used for memory reclaim */

  	WQ_HIGHPRI		= 1 << 4, /* high priority */

  	WQ_CPU_INTENSIVE	= 1 << 5, /* cpu instensive workqueue */

  	WQ_DRAINING		= 1 << 6, /* internal: workqueue is draining */

  	WQ_RESCUER		= 1 << 7, /* internal: workqueue has rescuer */

  	WQ_MAX_ACTIVE		= 512,	  /* I like 512, better ideas? */

  	WQ_MAX_UNBOUND_PER_CPU	= 4,	  /* 4 * #cpus for unbound wq */

  	WQ_DFL_ACTIVE		= WQ_MAX_ACTIVE / 2,

  };

  /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
  #define WQ_UNBOUND_MAX_ACTIVE	\
  	max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)

  /*
   * System-wide workqueues which are always present.
   *
   * system_wq is the one used by schedule[_delayed]_work[_on]().
   * Multi-CPU multi-threaded.  There are users which expect relatively
   * short queue flush time.  Don't queue works which can run for too
   * long.
   *
   * system_long_wq is similar to system_wq but may host long running
   * works.  Queue flushing might take relatively long.
   *
   * system_nrt_wq is non-reentrant and guarantees that any given work
   * item is never executed in parallel by multiple CPUs.  Queue
   * flushing might take relatively long.

   *
   * system_unbound_wq is unbound workqueue.  Workers are not bound to
   * any specific CPU, not concurrency managed, and all queued works are
   * executed immediately as long as max_active limit is not reached and
   * resources are available.

   *

   * system_freezable_wq is equivalent to system_wq except that it's
   * freezable.

   */
  extern struct workqueue_struct *system_wq;
  extern struct workqueue_struct *system_long_wq;
  extern struct workqueue_struct *system_nrt_wq;

  extern struct workqueue_struct *system_unbound_wq;

  extern struct workqueue_struct *system_freezable_wq;

  extern struct workqueue_struct *

  __alloc_workqueue_key(const char *name, unsigned int flags, int max_active,
  		      struct lock_class_key *key, const char *lock_name);

  
  #ifdef CONFIG_LOCKDEP

  #define alloc_workqueue(name, flags, max_active)		\

  ({								\
  	static struct lock_class_key __key;			\

  	const char *__lock_name;				\
  								\
  	if (__builtin_constant_p(name))				\
  		__lock_name = (name);				\
  	else							\
  		__lock_name = #name;				\

  								\

  	__alloc_workqueue_key((name), (flags), (max_active),	\
  			      &__key, __lock_name);		\

  })
  #else

  #define alloc_workqueue(name, flags, max_active)		\
  	__alloc_workqueue_key((name), (flags), (max_active), NULL, NULL)

  #endif

  /**
   * alloc_ordered_workqueue - allocate an ordered workqueue
   * @name: name of the workqueue

   * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)

   *
   * Allocate an ordered workqueue.  An ordered workqueue executes at
   * most one work item at any given time in the queued order.  They are
   * implemented as unbound workqueues with @max_active of one.
   *
   * RETURNS:
   * Pointer to the allocated workqueue on success, %NULL on failure.
   */
  static inline struct workqueue_struct *
  alloc_ordered_workqueue(const char *name, unsigned int flags)
  {
  	return alloc_workqueue(name, WQ_UNBOUND | flags, 1);
  }

  #define create_workqueue(name)					\

  	alloc_workqueue((name), WQ_MEM_RECLAIM, 1)

  #define create_freezable_workqueue(name)			\
  	alloc_workqueue((name), WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, 1)

  #define create_singlethread_workqueue(name)			\

  	alloc_workqueue((name), WQ_UNBOUND | WQ_MEM_RECLAIM, 1)

  
  extern void destroy_workqueue(struct workqueue_struct *wq);

  extern int queue_work(struct workqueue_struct *wq, struct work_struct *work);

  extern int queue_work_on(int cpu, struct workqueue_struct *wq,
  			struct work_struct *work);

  extern int queue_delayed_work(struct workqueue_struct *wq,
  			struct delayed_work *work, unsigned long delay);

  extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,

  			struct delayed_work *work, unsigned long delay);

  extern void flush_workqueue(struct workqueue_struct *wq);

  extern void drain_workqueue(struct workqueue_struct *wq);

  extern void flush_scheduled_work(void);

  extern int schedule_work(struct work_struct *work);

  extern int schedule_work_on(int cpu, struct work_struct *work);

  extern int schedule_delayed_work(struct delayed_work *work, unsigned long delay);

  extern int schedule_delayed_work_on(int cpu, struct delayed_work *work,
  					unsigned long delay);

  extern int schedule_on_each_cpu(work_func_t func);

  extern int keventd_up(void);

  int execute_in_process_context(work_func_t fn, struct execute_work *);

  extern bool flush_work(struct work_struct *work);

  extern bool flush_work_sync(struct work_struct *work);

  extern bool cancel_work_sync(struct work_struct *work);
  
  extern bool flush_delayed_work(struct delayed_work *dwork);

  extern bool flush_delayed_work_sync(struct delayed_work *work);

  extern bool cancel_delayed_work_sync(struct delayed_work *dwork);

  extern void workqueue_set_max_active(struct workqueue_struct *wq,
  				     int max_active);
  extern bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq);
  extern unsigned int work_cpu(struct work_struct *work);
  extern unsigned int work_busy(struct work_struct *work);

  /*
   * Kill off a pending schedule_delayed_work().  Note that the work callback

   * function may still be running on return from cancel_delayed_work(), unless
   * it returns 1 and the work doesn't re-arm itself. Run flush_workqueue() or

   * cancel_work_sync() to wait on it.

   */

  static inline bool cancel_delayed_work(struct delayed_work *work)

  {

  	bool ret;

  	ret = del_timer_sync(&work->timer);

  	if (ret)

  		work_clear_pending(&work->work);

  	return ret;
  }

  /*
   * Like above, but uses del_timer() instead of del_timer_sync(). This means,
   * if it returns 0 the timer function may be running and the queueing is in
   * progress.
   */

  static inline bool __cancel_delayed_work(struct delayed_work *work)

  {

  	bool ret;

  
  	ret = del_timer(&work->timer);
  	if (ret)
  		work_clear_pending(&work->work);
  	return ret;
  }

  #ifndef CONFIG_SMP
  static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
  {
  	return fn(arg);
  }
  #else
  long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg);
  #endif /* CONFIG_SMP */

  #ifdef CONFIG_FREEZER
  extern void freeze_workqueues_begin(void);
  extern bool freeze_workqueues_busy(void);
  extern void thaw_workqueues(void);
  #endif /* CONFIG_FREEZER */

  #endif