165 lines
4.7 KiB
C
165 lines
4.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* 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/debug_locks.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
|
|
* @lock: Pointer to the rt_mutex on which the waiter blocks
|
|
* @prio: Priority of the waiter
|
|
* @deadline: Deadline of the waiter if applicable
|
|
*/
|
|
struct rt_mutex_waiter {
|
|
struct rb_node tree_entry;
|
|
struct rb_node pi_tree_entry;
|
|
struct task_struct *task;
|
|
struct rt_mutex *lock;
|
|
int prio;
|
|
u64 deadline;
|
|
};
|
|
|
|
/*
|
|
* Must be guarded because this header is included from rcu/tree_plugin.h
|
|
* unconditionally.
|
|
*/
|
|
#ifdef CONFIG_RT_MUTEXES
|
|
static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
|
|
{
|
|
return !RB_EMPTY_ROOT(&lock->waiters.rb_root);
|
|
}
|
|
|
|
static inline struct rt_mutex_waiter *rt_mutex_top_waiter(struct rt_mutex *lock)
|
|
{
|
|
struct rb_node *leftmost = rb_first_cached(&lock->waiters);
|
|
struct rt_mutex_waiter *w = NULL;
|
|
|
|
if (leftmost) {
|
|
w = rb_entry(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.rb_root);
|
|
}
|
|
|
|
static inline struct rt_mutex_waiter *task_top_pi_waiter(struct task_struct *p)
|
|
{
|
|
return rb_entry(p->pi_waiters.rb_leftmost, struct rt_mutex_waiter,
|
|
pi_tree_entry);
|
|
}
|
|
|
|
#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);
|
|
}
|
|
#else /* CONFIG_RT_MUTEXES */
|
|
/* Used in rcu/tree_plugin.h */
|
|
static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
|
|
{
|
|
return NULL;
|
|
}
|
|
#endif /* !CONFIG_RT_MUTEXES */
|
|
|
|
/*
|
|
* 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,
|
|
};
|
|
|
|
static inline void __rt_mutex_basic_init(struct rt_mutex *lock)
|
|
{
|
|
lock->owner = NULL;
|
|
raw_spin_lock_init(&lock->wait_lock);
|
|
lock->waiters = RB_ROOT_CACHED;
|
|
}
|
|
|
|
/*
|
|
* PI-futex support (proxy locking functions, etc.):
|
|
*/
|
|
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);
|
|
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 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);
|
|
|
|
/* Debug functions */
|
|
static inline void debug_rt_mutex_unlock(struct rt_mutex *lock)
|
|
{
|
|
if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
|
|
DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
|
|
}
|
|
|
|
static inline void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
|
|
{
|
|
if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
|
|
DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));
|
|
}
|
|
|
|
static inline void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
|
|
{
|
|
if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
|
|
memset(waiter, 0x11, sizeof(*waiter));
|
|
}
|
|
|
|
static inline void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
|
|
{
|
|
if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
|
|
memset(waiter, 0x22, sizeof(*waiter));
|
|
}
|
|
|
|
#endif
|