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 */ 26 static inline void mutex_set_owner(struct mutex *lock) 27 { 28 WRITE_ONCE(lock->owner, current); 29 } 30 31 static inline void mutex_clear_owner(struct mutex *lock) 32 { 33 WRITE_ONCE(lock->owner, NULL); 34 } 35 #else 36 static inline void mutex_set_owner(struct mutex *lock) 37 { 38 } 39 40 static 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 51 static inline void 52 debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter) 53 { 54 } 55