[mirror_ubuntu-artful-kernel.git] / kernel / locking / rtmutex_common.h

/*
 * RT Mutexes: blocking mutual exclusion locks with PI support
 *
 * started by Ingo Molnar and Thomas Gleixner:
 *
 *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
 *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
 *
 * This file contains the private data structure and API definitions.
 */

#ifndef __KERNEL_RTMUTEX_COMMON_H
#define __KERNEL_RTMUTEX_COMMON_H

#include <linux/rtmutex.h>
#include <linux/sched/wake_q.h>

/*
 * This is the control structure for tasks blocked on a rt_mutex,
 * which is allocated on the kernel stack on of the blocked task.
 *
 * @tree_entry:		pi node to enqueue into the mutex waiters tree
 * @pi_tree_entry:	pi node to enqueue into the mutex owner waiters tree
 * @task:		task reference to the blocked task
 */
struct rt_mutex_waiter {
	struct rb_node          tree_entry;
	struct rb_node          pi_tree_entry;
	struct task_struct	*task;
	struct rt_mutex		*lock;
#ifdef CONFIG_DEBUG_RT_MUTEXES
	unsigned long		ip;
	struct pid		*deadlock_task_pid;
	struct rt_mutex		*deadlock_lock;
#endif
	int prio;
	u64 deadline;
};

/*
 * Various helpers to access the waiters-tree:
 */
static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
{
	return !RB_EMPTY_ROOT(&lock->waiters);
}

static inline struct rt_mutex_waiter *
rt_mutex_top_waiter(struct rt_mutex *lock)
{
	struct rt_mutex_waiter *w;

	w = rb_entry(lock->waiters_leftmost, struct rt_mutex_waiter,
		     tree_entry);
	BUG_ON(w->lock != lock);

	return w;
}

static inline int task_has_pi_waiters(struct task_struct *p)
{
	return !RB_EMPTY_ROOT(&p->pi_waiters);
}

static inline struct rt_mutex_waiter *
task_top_pi_waiter(struct task_struct *p)
{
	return rb_entry(p->pi_waiters_leftmost, struct rt_mutex_waiter,
			pi_tree_entry);
}

/*
 * lock->owner state tracking:
 */
#define RT_MUTEX_HAS_WAITERS	1UL

static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
{
	unsigned long owner = (unsigned long) READ_ONCE(lock->owner);

	return (struct task_struct *) (owner & ~RT_MUTEX_HAS_WAITERS);
}

/*
 * Constants for rt mutex functions which have a selectable deadlock
 * detection.
 *
 * RT_MUTEX_MIN_CHAINWALK:	Stops the lock chain walk when there are
 *				no further PI adjustments to be made.
 *
 * RT_MUTEX_FULL_CHAINWALK:	Invoke deadlock detection with a full
 *				walk of the lock chain.
 */
enum rtmutex_chainwalk {
	RT_MUTEX_MIN_CHAINWALK,
	RT_MUTEX_FULL_CHAINWALK,
};

/*
 * PI-futex support (proxy locking functions, etc.):
 */
extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
				       struct task_struct *proxy_owner);
extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
				  struct task_struct *proxy_owner);
extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
extern int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
				     struct rt_mutex_waiter *waiter,
				     struct task_struct *task);
extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
				     struct rt_mutex_waiter *waiter,
				     struct task_struct *task);
extern int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
			       struct hrtimer_sleeper *to,
			       struct rt_mutex_waiter *waiter);
extern bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
				 struct rt_mutex_waiter *waiter);

extern int rt_mutex_futex_trylock(struct rt_mutex *l);

extern void rt_mutex_futex_unlock(struct rt_mutex *lock);
extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
				 struct wake_q_head *wqh);

extern void rt_mutex_postunlock(struct wake_q_head *wake_q);

#ifdef CONFIG_DEBUG_RT_MUTEXES
# include "rtmutex-debug.h"
#else
# include "rtmutex.h"
#endif

#endif
Commit	Line	Data
23f78d4a IM	1	/*
	2	* RT Mutexes: blocking mutual exclusion locks with PI support
	3	*
	4	* started by Ingo Molnar and Thomas Gleixner:
	5	*
	6	* Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
	7	* Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
	8	*
	9	* This file contains the private data structure and API definitions.
	10	*/
	11
	12	#ifndef __KERNEL_RTMUTEX_COMMON_H
	13	#define __KERNEL_RTMUTEX_COMMON_H
	14
	15	#include <linux/rtmutex.h>
84f001e1	16	#include <linux/sched/wake_q.h>
23f78d4a IM	17
	18	/*
	19	* This is the control structure for tasks blocked on a rt_mutex,
	20	* which is allocated on the kernel stack on of the blocked task.
	21	*
fb00aca4 PZ	22	* @tree_entry: pi node to enqueue into the mutex waiters tree
fb00aca4 PZ	23	* @pi_tree_entry: pi node to enqueue into the mutex owner waiters tree
23f78d4a IM	24	* @task: task reference to the blocked task
	25	*/
	26	struct rt_mutex_waiter {
fb00aca4 PZ	27	struct rb_node tree_entry;
fb00aca4 PZ	28	struct rb_node pi_tree_entry;
23f78d4a IM	29	struct task_struct *task;
	30	struct rt_mutex *lock;
	31	#ifdef CONFIG_DEBUG_RT_MUTEXES
	32	unsigned long ip;
48d13e48	33	struct pid *deadlock_task_pid;
23f78d4a IM	34	struct rt_mutex *deadlock_lock;
23f78d4a IM	35	#endif
2d3d891d	36	int prio;
e0aad5b4	37	u64 deadline;
23f78d4a IM	38	};
	39
	40	/*
fb00aca4	41	* Various helpers to access the waiters-tree:
23f78d4a IM	42	*/
	43	static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
	44	{
fb00aca4	45	return !RB_EMPTY_ROOT(&lock->waiters);
23f78d4a IM	46	}
	47
	48	static inline struct rt_mutex_waiter *
	49	rt_mutex_top_waiter(struct rt_mutex *lock)
	50	{
	51	struct rt_mutex_waiter *w;
	52
fb00aca4 PZ	53	w = rb_entry(lock->waiters_leftmost, struct rt_mutex_waiter,
fb00aca4 PZ	54	tree_entry);
23f78d4a IM	55	BUG_ON(w->lock != lock);
	56
	57	return w;
	58	}
	59
	60	static inline int task_has_pi_waiters(struct task_struct *p)
	61	{
fb00aca4	62	return !RB_EMPTY_ROOT(&p->pi_waiters);
23f78d4a IM	63	}
	64
	65	static inline struct rt_mutex_waiter *
	66	task_top_pi_waiter(struct task_struct *p)
	67	{
fb00aca4 PZ	68	return rb_entry(p->pi_waiters_leftmost, struct rt_mutex_waiter,
fb00aca4 PZ	69	pi_tree_entry);
23f78d4a IM	70	}
	71
	72	/*
	73	* lock->owner state tracking:
	74	*/
8161239a	75	#define RT_MUTEX_HAS_WAITERS 1UL
23f78d4a IM	76
	77	static inline struct task_struct rt_mutex_owner(struct rt_mutex lock)
	78	{
1be5d4fa TG	79	unsigned long owner = (unsigned long) READ_ONCE(lock->owner);
1be5d4fa TG	80
b5016e82	81	return (struct task_struct *) (owner & ~RT_MUTEX_HAS_WAITERS);
23f78d4a IM	82	}
23f78d4a IM	83
8930ed80 TG	84	/*
	85	* Constants for rt mutex functions which have a selectable deadlock
	86	* detection.
	87	*
	88	* RT_MUTEX_MIN_CHAINWALK: Stops the lock chain walk when there are
	89	* no further PI adjustments to be made.
	90	*
	91	* RT_MUTEX_FULL_CHAINWALK: Invoke deadlock detection with a full
	92	* walk of the lock chain.
	93	*/
	94	enum rtmutex_chainwalk {
	95	RT_MUTEX_MIN_CHAINWALK,
	96	RT_MUTEX_FULL_CHAINWALK,
	97	};
	98
c87e2837 IM	99	/*
	100	* PI-futex support (proxy locking functions, etc.):
	101	*/
	102	extern struct task_struct rt_mutex_next_owner(struct rt_mutex lock);
	103	extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
	104	struct task_struct *proxy_owner);
	105	extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
	106	struct task_struct *proxy_owner);
50809358	107	extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
56222b21 PZ	108	extern int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
	109	struct rt_mutex_waiter *waiter,
	110	struct task_struct *task);
8dac456a DH	111	extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
8dac456a DH	112	struct rt_mutex_waiter *waiter,
c051b21f	113	struct task_struct *task);
38d589f2 PZ	114	extern int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
	115	struct hrtimer_sleeper *to,
	116	struct rt_mutex_waiter *waiter);
	117	extern bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
	118	struct rt_mutex_waiter *waiter);
5293c2ef	119
5293c2ef PZ	120	extern int rt_mutex_futex_trylock(struct rt_mutex *l);
	121
	122	extern void rt_mutex_futex_unlock(struct rt_mutex *lock);
	123	extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
	124	struct wake_q_head *wqh);
	125
aa2bfe55	126	extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
36cf3b5c TG	127
	128	#ifdef CONFIG_DEBUG_RT_MUTEXES
	129	# include "rtmutex-debug.h"
	130	#else
	131	# include "rtmutex.h"
	132	#endif
	133
23f78d4a	134	#endif