[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;
};

/*
 * 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 int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
				     struct rt_mutex_waiter *waiter,
				     struct task_struct *task);
extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
				      struct hrtimer_sleeper *to,
				      struct rt_mutex_waiter *waiter);
extern int rt_mutex_timed_futex_lock(struct rt_mutex *l, struct hrtimer_sleeper *to);
extern bool rt_mutex_futex_unlock(struct rt_mutex *lock,
				  struct wake_q_head *wqh);
extern void rt_mutex_adjust_prio(struct task_struct *task);

#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;
23f78d4a IM	37	};
	38
	39	/*
fb00aca4	40	* Various helpers to access the waiters-tree:
23f78d4a IM	41	*/
	42	static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
	43	{
fb00aca4	44	return !RB_EMPTY_ROOT(&lock->waiters);
23f78d4a IM	45	}
	46
	47	static inline struct rt_mutex_waiter *
	48	rt_mutex_top_waiter(struct rt_mutex *lock)
	49	{
	50	struct rt_mutex_waiter *w;
	51
fb00aca4 PZ	52	w = rb_entry(lock->waiters_leftmost, struct rt_mutex_waiter,
fb00aca4 PZ	53	tree_entry);
23f78d4a IM	54	BUG_ON(w->lock != lock);
	55
	56	return w;
	57	}
	58
	59	static inline int task_has_pi_waiters(struct task_struct *p)
	60	{
fb00aca4	61	return !RB_EMPTY_ROOT(&p->pi_waiters);
23f78d4a IM	62	}
	63
	64	static inline struct rt_mutex_waiter *
	65	task_top_pi_waiter(struct task_struct *p)
	66	{
fb00aca4 PZ	67	return rb_entry(p->pi_waiters_leftmost, struct rt_mutex_waiter,
fb00aca4 PZ	68	pi_tree_entry);
23f78d4a IM	69	}
	70
	71	/*
	72	* lock->owner state tracking:
	73	*/
8161239a	74	#define RT_MUTEX_HAS_WAITERS 1UL
23f78d4a IM	75
	76	static inline struct task_struct rt_mutex_owner(struct rt_mutex lock)
	77	{
1be5d4fa TG	78	unsigned long owner = (unsigned long) READ_ONCE(lock->owner);
1be5d4fa TG	79
b5016e82	80	return (struct task_struct *) (owner & ~RT_MUTEX_HAS_WAITERS);
23f78d4a IM	81	}
23f78d4a IM	82
8930ed80 TG	83	/*
	84	* Constants for rt mutex functions which have a selectable deadlock
	85	* detection.
	86	*
	87	* RT_MUTEX_MIN_CHAINWALK: Stops the lock chain walk when there are
	88	* no further PI adjustments to be made.
	89	*
	90	* RT_MUTEX_FULL_CHAINWALK: Invoke deadlock detection with a full
	91	* walk of the lock chain.
	92	*/
	93	enum rtmutex_chainwalk {
	94	RT_MUTEX_MIN_CHAINWALK,
	95	RT_MUTEX_FULL_CHAINWALK,
	96	};
	97
c87e2837 IM	98	/*
	99	* PI-futex support (proxy locking functions, etc.):
	100	*/
	101	extern struct task_struct rt_mutex_next_owner(struct rt_mutex lock);
	102	extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
	103	struct task_struct *proxy_owner);
	104	extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
	105	struct task_struct *proxy_owner);
8dac456a DH	106	extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
8dac456a DH	107	struct rt_mutex_waiter *waiter,
c051b21f	108	struct task_struct *task);
8dac456a DH	109	extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
8dac456a DH	110	struct hrtimer_sleeper *to,
c051b21f TG	111	struct rt_mutex_waiter *waiter);
c051b21f TG	112	extern int rt_mutex_timed_futex_lock(struct rt_mutex l, struct hrtimer_sleeper to);
802ab58d SAS	113	extern bool rt_mutex_futex_unlock(struct rt_mutex *lock,
	114	struct wake_q_head *wqh);
	115	extern void rt_mutex_adjust_prio(struct task_struct *task);
36cf3b5c TG	116
	117	#ifdef CONFIG_DEBUG_RT_MUTEXES
	118	# include "rtmutex-debug.h"
	119	#else
	120	# include "rtmutex.h"
	121	#endif
	122
23f78d4a	123	#endif