c87e2837be
This adds the actual pi-futex implementation, based on rt-mutexes. [dino@in.ibm.com: fix an oops-causing race] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Dinakar Guniguntala <dino@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
123 lines
3.2 KiB
C
123 lines
3.2 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.
|
|
*
|
|
* @list_entry: pi node to enqueue into the mutex waiters list
|
|
* @pi_list_entry: pi node to enqueue into the mutex owner waiters list
|
|
* @task: task reference to the blocked task
|
|
*/
|
|
struct rt_mutex_waiter {
|
|
struct plist_node list_entry;
|
|
struct plist_node pi_list_entry;
|
|
struct task_struct *task;
|
|
struct rt_mutex *lock;
|
|
#ifdef CONFIG_DEBUG_RT_MUTEXES
|
|
unsigned long ip;
|
|
pid_t deadlock_task_pid;
|
|
struct rt_mutex *deadlock_lock;
|
|
#endif
|
|
};
|
|
|
|
/*
|
|
* Various helpers to access the waiters-plist:
|
|
*/
|
|
static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
|
|
{
|
|
return !plist_head_empty(&lock->wait_list);
|
|
}
|
|
|
|
static inline struct rt_mutex_waiter *
|
|
rt_mutex_top_waiter(struct rt_mutex *lock)
|
|
{
|
|
struct rt_mutex_waiter *w;
|
|
|
|
w = plist_first_entry(&lock->wait_list, struct rt_mutex_waiter,
|
|
list_entry);
|
|
BUG_ON(w->lock != lock);
|
|
|
|
return w;
|
|
}
|
|
|
|
static inline int task_has_pi_waiters(struct task_struct *p)
|
|
{
|
|
return !plist_head_empty(&p->pi_waiters);
|
|
}
|
|
|
|
static inline struct rt_mutex_waiter *
|
|
task_top_pi_waiter(struct task_struct *p)
|
|
{
|
|
return plist_first_entry(&p->pi_waiters, struct rt_mutex_waiter,
|
|
pi_list_entry);
|
|
}
|
|
|
|
/*
|
|
* lock->owner state tracking:
|
|
*/
|
|
#define RT_MUTEX_OWNER_PENDING 1UL
|
|
#define RT_MUTEX_HAS_WAITERS 2UL
|
|
#define RT_MUTEX_OWNER_MASKALL 3UL
|
|
|
|
static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
|
|
{
|
|
return (struct task_struct *)
|
|
((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL);
|
|
}
|
|
|
|
static inline struct task_struct *rt_mutex_real_owner(struct rt_mutex *lock)
|
|
{
|
|
return (struct task_struct *)
|
|
((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS);
|
|
}
|
|
|
|
static inline unsigned long rt_mutex_owner_pending(struct rt_mutex *lock)
|
|
{
|
|
return (unsigned long)lock->owner & RT_MUTEX_OWNER_PENDING;
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
#endif
|