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- /*
- * 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
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