alistair23-linux/kernel/locking/rtmutex_common.h
Thomas Gleixner c051b21f71 rtmutex: Confine deadlock logic to futex
The deadlock logic is only required for futexes.

Remove the extra arguments for the public functions and also for the
futex specific ones which get always called with deadlock detection
enabled.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-21 22:05:30 +02:00

127 lines
3.4 KiB
C

/*
* 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>
/*
* The rtmutex in kernel tester is independent of rtmutex debugging. We
* call schedule_rt_mutex_test() instead of schedule() for the tasks which
* belong to the tester. That way we can delay the wakeup path of those
* threads to provoke lock stealing and testing of complex boosting scenarios.
*/
#ifdef CONFIG_RT_MUTEX_TESTER
extern void schedule_rt_mutex_test(struct rt_mutex *lock);
#define schedule_rt_mutex(_lock) \
do { \
if (!(current->flags & PF_MUTEX_TESTER)) \
schedule(); \
else \
schedule_rt_mutex_test(_lock); \
} while (0)
#else
# define schedule_rt_mutex(_lock) schedule()
#endif
/*
* 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
#define RT_MUTEX_OWNER_MASKALL 1UL
static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
{
return (struct task_struct *)
((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL);
}
/*
* 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);
#ifdef CONFIG_DEBUG_RT_MUTEXES
# include "rtmutex-debug.h"
#else
# include "rtmutex.h"
#endif
#endif