LXR linux/kernel/locking/mutex.h

   1/*
   2 * Mutexes: blocking mutual exclusion locks
   3 *
   4 * started by Ingo Molnar:
   5 *
   6 *  Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
   7 *
   8 * This file contains mutex debugging related internal prototypes, for the
   9 * !CONFIG_DEBUG_MUTEXES case. Most of them are NOPs:
  10 */
  11
  12#define spin_lock_mutex(lock, flags) \
  13                do { spin_lock(lock); (void)(flags); } while (0)
  14#define spin_unlock_mutex(lock, flags) \
  15                do { spin_unlock(lock); (void)(flags); } while (0)
  16#define mutex_remove_waiter(lock, waiter, task) \
  17                __list_del((waiter)->list.prev, (waiter)->list.next)
  18
  19#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
  20/*
  21 * The mutex owner can get read and written to locklessly.
  22 * We should use WRITE_ONCE when writing the owner value to
  23 * avoid store tearing, otherwise, a thread could potentially
  24 * read a partially written and incomplete owner value.
  25 */
  26static inline void mutex_set_owner(struct mutex *lock)
  27{
  28        WRITE_ONCE(lock->owner, current);
  29}
  30
  31static inline void mutex_clear_owner(struct mutex *lock)
  32{
  33        WRITE_ONCE(lock->owner, NULL);
  34}
  35#else
  36static inline void mutex_set_owner(struct mutex *lock)
  37{
  38}
  39
  40static inline void mutex_clear_owner(struct mutex *lock)
  41{
  42}
  43#endif
  44
  45#define debug_mutex_wake_waiter(lock, waiter)           do { } while (0)
  46#define debug_mutex_free_waiter(waiter)                 do { } while (0)
  47#define debug_mutex_add_waiter(lock, waiter, ti)        do { } while (0)
  48#define debug_mutex_unlock(lock)                        do { } while (0)
  49#define debug_mutex_init(lock, name, key)               do { } while (0)
  50
  51static inline void
  52debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
  53{
  54}
  55