[mirror_ubuntu-zesty-kernel.git] / include / linux / kthread.h

#ifndef _LINUX_KTHREAD_H
#define _LINUX_KTHREAD_H
/* Simple interface for creating and stopping kernel threads without mess. */
#include <linux/err.h>
#include <linux/sched.h>

struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
					   void *data,
					   int node,
					   const char namefmt[], ...)
	__attribute__((format(printf, 4, 5)));

#define kthread_create(threadfn, data, namefmt, arg...) \
	kthread_create_on_node(threadfn, data, -1, namefmt, ##arg)


/**
 * kthread_run - create and wake a thread.
 * @threadfn: the function to run until signal_pending(current).
 * @data: data ptr for @threadfn.
 * @namefmt: printf-style name for the thread.
 *
 * Description: Convenient wrapper for kthread_create() followed by
 * wake_up_process().  Returns the kthread or ERR_PTR(-ENOMEM).
 */
#define kthread_run(threadfn, data, namefmt, ...)			   \
({									   \
	struct task_struct *__k						   \
		= kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
	if (!IS_ERR(__k))						   \
		wake_up_process(__k);					   \
	__k;								   \
})

void kthread_bind(struct task_struct *k, unsigned int cpu);
int kthread_stop(struct task_struct *k);
int kthread_should_stop(void);
void *kthread_data(struct task_struct *k);

int kthreadd(void *unused);
extern struct task_struct *kthreadd_task;
extern int tsk_fork_get_node(struct task_struct *tsk);

/*
 * Simple work processor based on kthread.
 *
 * This provides easier way to make use of kthreads.  A kthread_work
 * can be queued and flushed using queue/flush_kthread_work()
 * respectively.  Queued kthread_works are processed by a kthread
 * running kthread_worker_fn().
 *
 * A kthread_work can't be freed while it is executing.
 */
struct kthread_work;
typedef void (*kthread_work_func_t)(struct kthread_work *work);

struct kthread_worker {
	spinlock_t		lock;
	struct list_head	work_list;
	struct task_struct	*task;
};

struct kthread_work {
	struct list_head	node;
	kthread_work_func_t	func;
	wait_queue_head_t	done;
	atomic_t		flushing;
	int			queue_seq;
	int			done_seq;
};

#define KTHREAD_WORKER_INIT(worker)	{				\
	.lock = __SPIN_LOCK_UNLOCKED((worker).lock),			\
	.work_list = LIST_HEAD_INIT((worker).work_list),		\
	}

#define KTHREAD_WORK_INIT(work, fn)	{				\
	.node = LIST_HEAD_INIT((work).node),				\
	.func = (fn),							\
	.done = __WAIT_QUEUE_HEAD_INITIALIZER((work).done),		\
	.flushing = ATOMIC_INIT(0),					\
	}

#define DEFINE_KTHREAD_WORKER(worker)					\
	struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)

#define DEFINE_KTHREAD_WORK(work, fn)					\
	struct kthread_work work = KTHREAD_WORK_INIT(work, fn)

/*
 * kthread_worker.lock and kthread_work.done need their own lockdep class
 * keys if they are defined on stack with lockdep enabled.  Use the
 * following macros when defining them on stack.
 */
#ifdef CONFIG_LOCKDEP
# define KTHREAD_WORKER_INIT_ONSTACK(worker)				\
	({ init_kthread_worker(&worker); worker; })
# define DEFINE_KTHREAD_WORKER_ONSTACK(worker)				\
	struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
# define KTHREAD_WORK_INIT_ONSTACK(work, fn)				\
	({ init_kthread_work((&work), fn); work; })
# define DEFINE_KTHREAD_WORK_ONSTACK(work, fn)				\
	struct kthread_work work = KTHREAD_WORK_INIT_ONSTACK(work, fn)
#else
# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
# define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) DEFINE_KTHREAD_WORK(work, fn)
#endif

extern void __init_kthread_worker(struct kthread_worker *worker,
			const char *name, struct lock_class_key *key);

#define init_kthread_worker(worker)					\
	do {								\
		static struct lock_class_key __key;			\
		__init_kthread_worker((worker), "("#worker")->lock", &__key); \
	} while (0)

#define init_kthread_work(work, fn)					\
	do {								\
		memset((work), 0, sizeof(struct kthread_work));		\
		INIT_LIST_HEAD(&(work)->node);				\
		(work)->func = (fn);					\
		init_waitqueue_head(&(work)->done);			\
	} while (0)

int kthread_worker_fn(void *worker_ptr);

bool queue_kthread_work(struct kthread_worker *worker,
			struct kthread_work *work);
void flush_kthread_work(struct kthread_work *work);
void flush_kthread_worker(struct kthread_worker *worker);

#endif /* _LINUX_KTHREAD_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef _LINUX_KTHREAD_H
	2	#define _LINUX_KTHREAD_H
	3	/* Simple interface for creating and stopping kernel threads without mess. */
	4	#include <linux/err.h>
	5	#include <linux/sched.h>
	6
207205a2 ED	7	struct task_struct kthread_create_on_node(int (threadfn)(void *data),
	8	void *data,
	9	int node,
	10	const char namefmt[], ...)
	11	__attribute__((format(printf, 4, 5)));
	12
	13	#define kthread_create(threadfn, data, namefmt, arg...) \
	14	kthread_create_on_node(threadfn, data, -1, namefmt, ##arg)
	15
1da177e4 LT	16
1da177e4 LT	17	/**
9e37bd30	18	* kthread_run - create and wake a thread.
1da177e4 LT	19	* @threadfn: the function to run until signal_pending(current).
	20	* @data: data ptr for @threadfn.
	21	* @namefmt: printf-style name for the thread.
	22	*
	23	* Description: Convenient wrapper for kthread_create() followed by
9e37bd30 RD	24	* wake_up_process(). Returns the kthread or ERR_PTR(-ENOMEM).
9e37bd30 RD	25	*/
1da177e4 LT	26	#define kthread_run(threadfn, data, namefmt, ...) \
	27	({ \
	28	struct task_struct *__k \
	29	= kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
	30	if (!IS_ERR(__k)) \
	31	wake_up_process(__k); \
	32	__k; \
	33	})
	34
1da177e4	35	void kthread_bind(struct task_struct *k, unsigned int cpu);
1da177e4	36	int kthread_stop(struct task_struct *k);
1da177e4	37	int kthread_should_stop(void);
82805ab7	38	void kthread_data(struct task_struct k);
1da177e4	39
73c27992 EB	40	int kthreadd(void *unused);
73c27992 EB	41	extern struct task_struct *kthreadd_task;
207205a2	42	extern int tsk_fork_get_node(struct task_struct *tsk);
73c27992	43
b56c0d89 TH	44	/*
	45	* Simple work processor based on kthread.
	46	*
	47	* This provides easier way to make use of kthreads. A kthread_work
	48	* can be queued and flushed using queue/flush_kthread_work()
	49	* respectively. Queued kthread_works are processed by a kthread
	50	* running kthread_worker_fn().
	51	*
	52	* A kthread_work can't be freed while it is executing.
	53	*/
	54	struct kthread_work;
	55	typedef void (kthread_work_func_t)(struct kthread_work work);
	56
	57	struct kthread_worker {
	58	spinlock_t lock;
	59	struct list_head work_list;
	60	struct task_struct *task;
	61	};
	62
	63	struct kthread_work {
	64	struct list_head node;
	65	kthread_work_func_t func;
	66	wait_queue_head_t done;
	67	atomic_t flushing;
	68	int queue_seq;
	69	int done_seq;
	70	};
	71
	72	#define KTHREAD_WORKER_INIT(worker) { \
92578c0b	73	.lock = __SPIN_LOCK_UNLOCKED((worker).lock), \
b56c0d89 TH	74	.work_list = LIST_HEAD_INIT((worker).work_list), \
	75	}
	76
	77	#define KTHREAD_WORK_INIT(work, fn) { \
	78	.node = LIST_HEAD_INIT((work).node), \
	79	.func = (fn), \
	80	.done = __WAIT_QUEUE_HEAD_INITIALIZER((work).done), \
	81	.flushing = ATOMIC_INIT(0), \
	82	}
	83
	84	#define DEFINE_KTHREAD_WORKER(worker) \
	85	struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
	86
	87	#define DEFINE_KTHREAD_WORK(work, fn) \
	88	struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
	89
4f32e9b1 YZ	90	/*
	91	* kthread_worker.lock and kthread_work.done need their own lockdep class
	92	* keys if they are defined on stack with lockdep enabled. Use the
	93	* following macros when defining them on stack.
	94	*/
	95	#ifdef CONFIG_LOCKDEP
	96	# define KTHREAD_WORKER_INIT_ONSTACK(worker) \
	97	({ init_kthread_worker(&worker); worker; })
	98	# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) \
	99	struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
	100	# define KTHREAD_WORK_INIT_ONSTACK(work, fn) \
	101	({ init_kthread_work((&work), fn); work; })
	102	# define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) \
	103	struct kthread_work work = KTHREAD_WORK_INIT_ONSTACK(work, fn)
	104	#else
	105	# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
	106	# define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) DEFINE_KTHREAD_WORK(work, fn)
	107	#endif
	108
	109	extern void __init_kthread_worker(struct kthread_worker *worker,
	110	const char name, struct lock_class_key key);
	111
	112	#define init_kthread_worker(worker) \
	113	do { \
	114	static struct lock_class_key __key; \
	115	__init_kthread_worker((worker), "("#worker")->lock", &__key); \
	116	} while (0)
	117
	118	#define init_kthread_work(work, fn) \
	119	do { \
	120	memset((work), 0, sizeof(struct kthread_work)); \
	121	INIT_LIST_HEAD(&(work)->node); \
	122	(work)->func = (fn); \
	123	init_waitqueue_head(&(work)->done); \
	124	} while (0)
b56c0d89 TH	125
	126	int kthread_worker_fn(void *worker_ptr);
	127
	128	bool queue_kthread_work(struct kthread_worker *worker,
	129	struct kthread_work *work);
	130	void flush_kthread_work(struct kthread_work *work);
	131	void flush_kthread_worker(struct kthread_worker *worker);
	132
1da177e4	133	#endif /* _LINUX_KTHREAD_H */