/* SPDX-License-Identifier: GPL-2.0 */

  /*
   * 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>

  #include <linux/cpumask.h>

  #include <linux/rcupdate.h>

  
  struct workqueue_struct;

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

  void delayed_work_timer_fn(struct timer_list *t);

  /*
   * 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_PWQ_BIT	= 2,	/* data points to pwq */

  	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_PWQ		= 1 << WORK_STRUCT_PWQ_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,

  	/* not bound to any CPU, prefer the local CPU */

  	WORK_CPU_UNBOUND	= NR_CPUS,

  	/*

  	 * Reserve 8 bits off of pwq pointer w/ debugobjects turned off.

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

  	 */
  	WORK_STRUCT_FLAG_BITS	= WORK_STRUCT_COLOR_SHIFT +
  				  WORK_STRUCT_COLOR_BITS,

  	/* data contains off-queue information when !WORK_STRUCT_PWQ */

  	WORK_OFFQ_FLAG_BASE	= WORK_STRUCT_COLOR_SHIFT,

  	__WORK_OFFQ_CANCELING	= WORK_OFFQ_FLAG_BASE,
  	WORK_OFFQ_CANCELING	= (1 << __WORK_OFFQ_CANCELING),

  	/*
  	 * When a work item is off queue, its high bits point to the last

  	 * pool it was on.  Cap at 31 bits and use the highest number to
  	 * indicate that no pool is associated.

  	 */

  	WORK_OFFQ_FLAG_BITS	= 1,

  	WORK_OFFQ_POOL_SHIFT	= WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
  	WORK_OFFQ_LEFT		= BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
  	WORK_OFFQ_POOL_BITS	= WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
  	WORK_OFFQ_POOL_NONE	= (1LU << WORK_OFFQ_POOL_BITS) - 1,

  
  	/* convenience constants */

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

  	WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,

  	WORK_STRUCT_NO_POOL	= (unsigned long)WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT,

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

  
  	/* maximum string length for set_worker_desc() */
  	WORKER_DESC_LEN		= 24,

  };

  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((unsigned long)WORK_STRUCT_NO_POOL)

  #define WORK_DATA_STATIC_INIT()	\

  	ATOMIC_LONG_INIT((unsigned long)(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC))

  struct delayed_work {
  	struct work_struct work;

  	struct timer_list timer;

  
  	/* target workqueue and CPU ->timer uses to queue ->work */
  	struct workqueue_struct *wq;

  	int cpu;

  };

  struct rcu_work {
  	struct work_struct work;
  	struct rcu_head rcu;
  
  	/* target workqueue ->rcu uses to queue ->work */
  	struct workqueue_struct *wq;
  };

  /**
   * struct workqueue_attrs - A struct for workqueue attributes.

   *

   * This can be used to change attributes of an unbound workqueue.

   */
  struct workqueue_attrs {

  	/**
  	 * @nice: nice level
  	 */
  	int nice;
  
  	/**
  	 * @cpumask: allowed CPUs
  	 */
  	cpumask_var_t cpumask;
  
  	/**
  	 * @no_numa: disable NUMA affinity
  	 *
  	 * Unlike other fields, ``no_numa`` isn't a property of a worker_pool. It
  	 * only modifies how :c:func:`apply_workqueue_attrs` select pools and thus
  	 * doesn't participate in pool hash calculations or equality comparisons.
  	 */
  	bool no_numa;

  };

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

  static inline struct rcu_work *to_rcu_work(struct work_struct *work)
  {
  	return container_of(work, struct rcu_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, tflags) {			\

  	.work = __WORK_INITIALIZER((n).work, (f)),			\

  	.timer = __TIMER_INITIALIZER(delayed_work_timer_fn,\

  				     (tflags) | TIMER_IRQSAFE),		\

  	}

  #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, 0)

  #define DECLARE_DEFERRABLE_WORK(n, f)					\

  	struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)

  #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);

  extern void destroy_delayed_work_on_stack(struct delayed_work *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 void destroy_delayed_work_on_stack(struct delayed_work *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_completion)"#_work, &__key, 0); \

  		INIT_LIST_HEAD(&(_work)->entry);			\

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

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

  	} while (0)
  #endif

  #define INIT_WORK(_work, _func)						\

  	__INIT_WORK((_work), (_func), 0)

  #define INIT_WORK_ONSTACK(_work, _func)					\

  	__INIT_WORK((_work), (_func), 1)

  #define __INIT_DELAYED_WORK(_work, _func, _tflags)			\

  	do {								\
  		INIT_WORK(&(_work)->work, (_func));			\

  		__init_timer(&(_work)->timer,				\
  			     delayed_work_timer_fn,			\
  			     (_tflags) | TIMER_IRQSAFE);		\

  	} while (0)

  #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags)		\

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

  		__init_timer_on_stack(&(_work)->timer,			\
  				      delayed_work_timer_fn,		\
  				      (_tflags) | TIMER_IRQSAFE);	\

  	} while (0)

  #define INIT_DELAYED_WORK(_work, _func)					\
  	__INIT_DELAYED_WORK(_work, _func, 0)
  
  #define INIT_DELAYED_WORK_ONSTACK(_work, _func)				\
  	__INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)

  #define INIT_DEFERRABLE_WORK(_work, _func)				\

  	__INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
  
  #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func)			\
  	__INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)

  #define INIT_RCU_WORK(_work, _func)					\
  	INIT_WORK(&(_work)->work, (_func))
  
  #define INIT_RCU_WORK_ONSTACK(_work, _func)				\
  	INIT_WORK_ONSTACK(&(_work)->work, (_func))

  /**
   * 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

   * @w: The work item in question

   */

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

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

   * Documentation/core-api/workqueue.rst.

   */

  enum {

  	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 intensive workqueue */

  	WQ_SYSFS		= 1 << 6, /* visible in sysfs, see wq_sysfs_register() */

  	/*
  	 * Per-cpu workqueues are generally preferred because they tend to
  	 * show better performance thanks to cache locality.  Per-cpu
  	 * workqueues exclude the scheduler from choosing the CPU to
  	 * execute the worker threads, which has an unfortunate side effect
  	 * of increasing power consumption.
  	 *
  	 * The scheduler considers a CPU idle if it doesn't have any task
  	 * to execute and tries to keep idle cores idle to conserve power;
  	 * however, for example, a per-cpu work item scheduled from an
  	 * interrupt handler on an idle CPU will force the scheduler to
  	 * excute the work item on that CPU breaking the idleness, which in
  	 * turn may lead to more scheduling choices which are sub-optimal
  	 * in terms of power consumption.
  	 *
  	 * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
  	 * but become unbound if workqueue.power_efficient kernel param is
  	 * specified.  Per-cpu workqueues which are identified to
  	 * contribute significantly to power-consumption are identified and
  	 * marked with this flag and enabling the power_efficient mode
  	 * leads to noticeable power saving at the cost of small
  	 * performance disadvantage.
  	 *
  	 * http://thread.gmane.org/gmane.linux.kernel/1480396
  	 */
  	WQ_POWER_EFFICIENT	= 1 << 7,

  	__WQ_DRAINING		= 1 << 16, /* internal: workqueue is draining */

  	__WQ_ORDERED		= 1 << 17, /* internal: workqueue is ordered */

  	__WQ_LEGACY		= 1 << 18, /* internal: create*_workqueue() */

  	__WQ_ORDERED_EXPLICIT	= 1 << 19, /* internal: alloc_ordered_workqueue() */

  	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_highpri_wq is similar to system_wq but for work items which
   * require WQ_HIGHPRI.
   *

   * system_long_wq is similar to system_wq but may host long running
   * works.  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.

   *
   * *_power_efficient_wq are inclined towards saving power and converted
   * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
   * they are same as their non-power-efficient counterparts - e.g.
   * system_power_efficient_wq is identical to system_wq if
   * 'wq_power_efficient' is disabled.  See WQ_POWER_EFFICIENT for more info.

   */
  extern struct workqueue_struct *system_wq;

  extern struct workqueue_struct *system_highpri_wq;

  extern struct workqueue_struct *system_long_wq;

  extern struct workqueue_struct *system_unbound_wq;

  extern struct workqueue_struct *system_freezable_wq;

  extern struct workqueue_struct *system_power_efficient_wq;
  extern struct workqueue_struct *system_freezable_power_efficient_wq;

  /**
   * alloc_workqueue - allocate a workqueue
   * @fmt: printf format for the name of the workqueue
   * @flags: WQ_* flags
   * @max_active: max in-flight work items, 0 for default

   * remaining args: args for @fmt

   *
   * Allocate a workqueue with the specified parameters.  For detailed

   * information on WQ_* flags, please refer to
   * Documentation/core-api/workqueue.rst.

   *

   * RETURNS:
   * Pointer to the allocated workqueue on success, %NULL on failure.
   */

  struct workqueue_struct *alloc_workqueue(const char *fmt,
  					 unsigned int flags,
  					 int max_active, ...);

  /**
   * alloc_ordered_workqueue - allocate an ordered workqueue

   * @fmt: printf format for the name of the workqueue

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

   * @args...: args for @fmt

   *
   * 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.
   */

  #define alloc_ordered_workqueue(fmt, flags, args...)			\

  	alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED |		\
  			__WQ_ORDERED_EXPLICIT | (flags), 1, ##args)

  #define create_workqueue(name)						\

  	alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name))

  #define create_freezable_workqueue(name)				\

  	alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND |	\
  			WQ_MEM_RECLAIM, 1, (name))

  #define create_singlethread_workqueue(name)				\

  	alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name)

  
  extern void destroy_workqueue(struct workqueue_struct *wq);

  struct workqueue_attrs *alloc_workqueue_attrs(void);
  void free_workqueue_attrs(struct workqueue_attrs *attrs);
  int apply_workqueue_attrs(struct workqueue_struct *wq,
  			  const struct workqueue_attrs *attrs);

  int workqueue_set_unbound_cpumask(cpumask_var_t cpumask);

  extern bool queue_work_on(int cpu, struct workqueue_struct *wq,

  			struct work_struct *work);

  extern bool queue_work_node(int node, struct workqueue_struct *wq,
  			    struct work_struct *work);

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

  			struct delayed_work *work, unsigned long delay);

  extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
  			struct delayed_work *dwork, unsigned long delay);

  extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork);

  extern void flush_workqueue(struct workqueue_struct *wq);

  extern void drain_workqueue(struct workqueue_struct *wq);

  extern int schedule_on_each_cpu(work_func_t func);

  int execute_in_process_context(work_func_t fn, struct execute_work *);

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

  extern bool cancel_delayed_work(struct delayed_work *dwork);

  extern bool cancel_delayed_work_sync(struct delayed_work *dwork);

  extern bool flush_rcu_work(struct rcu_work *rwork);

  extern void workqueue_set_max_active(struct workqueue_struct *wq,
  				     int max_active);

  extern struct work_struct *current_work(void);

  extern bool current_is_workqueue_rescuer(void);

  extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);

  extern unsigned int work_busy(struct work_struct *work);

  extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
  extern void print_worker_info(const char *log_lvl, struct task_struct *task);

  extern void show_workqueue_state(void);

  extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task);

  /**
   * queue_work - queue work on a workqueue
   * @wq: workqueue to use
   * @work: work to queue
   *
   * Returns %false if @work was already on a queue, %true otherwise.
   *
   * We queue the work to the CPU on which it was submitted, but if the CPU dies
   * it can be processed by another CPU.

   *
   * Memory-ordering properties:  If it returns %true, guarantees that all stores
   * preceding the call to queue_work() in the program order will be visible from
   * the CPU which will execute @work by the time such work executes, e.g.,
   *
   * { x is initially 0 }
   *
   *   CPU0				CPU1
   *
   *   WRITE_ONCE(x, 1);			[ @work is being executed ]
   *   r0 = queue_work(wq, work);		  r1 = READ_ONCE(x);
   *
   * Forbids: r0 == true && r1 == 0

   */
  static inline bool queue_work(struct workqueue_struct *wq,
  			      struct work_struct *work)
  {
  	return queue_work_on(WORK_CPU_UNBOUND, wq, work);
  }
  
  /**
   * queue_delayed_work - queue work on a workqueue after delay
   * @wq: workqueue to use
   * @dwork: delayable work to queue
   * @delay: number of jiffies to wait before queueing
   *
   * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
   */
  static inline bool queue_delayed_work(struct workqueue_struct *wq,
  				      struct delayed_work *dwork,
  				      unsigned long delay)
  {
  	return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
  }
  
  /**
   * mod_delayed_work - modify delay of or queue a delayed work
   * @wq: workqueue to use
   * @dwork: work to queue
   * @delay: number of jiffies to wait before queueing
   *
   * mod_delayed_work_on() on local CPU.
   */
  static inline bool mod_delayed_work(struct workqueue_struct *wq,
  				    struct delayed_work *dwork,
  				    unsigned long delay)
  {
  	return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
  }
  
  /**
   * schedule_work_on - put work task on a specific cpu
   * @cpu: cpu to put the work task on
   * @work: job to be done
   *
   * This puts a job on a specific cpu
   */
  static inline bool schedule_work_on(int cpu, struct work_struct *work)
  {
  	return queue_work_on(cpu, system_wq, work);
  }
  
  /**
   * schedule_work - put work task in global workqueue
   * @work: job to be done
   *
   * Returns %false if @work was already on the kernel-global workqueue and
   * %true otherwise.
   *
   * This puts a job in the kernel-global workqueue if it was not already
   * queued and leaves it in the same position on the kernel-global
   * workqueue otherwise.

   *
   * Shares the same memory-ordering properties of queue_work(), cf. the
   * DocBook header of queue_work().

   */
  static inline bool schedule_work(struct work_struct *work)
  {
  	return queue_work(system_wq, work);
  }
  
  /**

   * flush_scheduled_work - ensure that any scheduled work has run to completion.
   *
   * Forces execution of the kernel-global workqueue and blocks until its
   * completion.
   *
   * Think twice before calling this function!  It's very easy to get into
   * trouble if you don't take great care.  Either of the following situations
   * will lead to deadlock:
   *
   *	One of the work items currently on the workqueue needs to acquire
   *	a lock held by your code or its caller.
   *
   *	Your code is running in the context of a work routine.
   *
   * They will be detected by lockdep when they occur, but the first might not
   * occur very often.  It depends on what work items are on the workqueue and
   * what locks they need, which you have no control over.
   *
   * In most situations flushing the entire workqueue is overkill; you merely
   * need to know that a particular work item isn't queued and isn't running.
   * In such cases you should use cancel_delayed_work_sync() or
   * cancel_work_sync() instead.
   */
  static inline void flush_scheduled_work(void)
  {
  	flush_workqueue(system_wq);
  }
  
  /**

   * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
   * @cpu: cpu to use
   * @dwork: job to be done
   * @delay: number of jiffies to wait
   *
   * After waiting for a given time this puts a job in the kernel-global
   * workqueue on the specified CPU.
   */
  static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
  					    unsigned long delay)
  {
  	return queue_delayed_work_on(cpu, system_wq, dwork, delay);
  }
  
  /**
   * schedule_delayed_work - put work task in global workqueue after delay
   * @dwork: job to be done
   * @delay: number of jiffies to wait or 0 for immediate execution
   *
   * After waiting for a given time this puts a job in the kernel-global
   * workqueue.
   */
  static inline bool schedule_delayed_work(struct delayed_work *dwork,
  					 unsigned long delay)
  {
  	return queue_delayed_work(system_wq, dwork, delay);
  }

  #ifndef CONFIG_SMP

  static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)

  {
  	return fn(arg);
  }

  static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
  {
  	return fn(arg);
  }

  #else

  long work_on_cpu(int cpu, long (*fn)(void *), void *arg);

  long work_on_cpu_safe(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 */

  #ifdef CONFIG_SYSFS
  int workqueue_sysfs_register(struct workqueue_struct *wq);
  #else	/* CONFIG_SYSFS */
  static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
  { return 0; }
  #endif	/* CONFIG_SYSFS */

  #ifdef CONFIG_WQ_WATCHDOG
  void wq_watchdog_touch(int cpu);
  #else	/* CONFIG_WQ_WATCHDOG */
  static inline void wq_watchdog_touch(int cpu) { }
  #endif	/* CONFIG_WQ_WATCHDOG */

  #ifdef CONFIG_SMP
  int workqueue_prepare_cpu(unsigned int cpu);
  int workqueue_online_cpu(unsigned int cpu);
  int workqueue_offline_cpu(unsigned int cpu);
  #endif

  void __init workqueue_init_early(void);
  void __init workqueue_init(void);

  #endif