/*
   * 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;

  	struct pid		*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_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,
  				     int detect_deadlock);
  extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
  				      struct hrtimer_sleeper *to,
  				      struct rt_mutex_waiter *waiter,
  				      int detect_deadlock);

  
  #ifdef CONFIG_DEBUG_RT_MUTEXES
  # include "rtmutex-debug.h"
  #else
  # include "rtmutex.h"
  #endif

  #endif