projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| a00736e9 SR |
1 | /* |
| 2 | * rwsem.h: R/W semaphores implemented using CAS | |
| 3 | * | |
| 4 | * Written by David S. Miller (davem@redhat.com), 2001. | |
| 5 | * Derived from asm-i386/rwsem.h | |
| 6 | */ | |
| 7 | #ifndef _SPARC64_RWSEM_H | |
| 8 | #define _SPARC64_RWSEM_H | |
| 9 | ||
| 10 | #ifndef _LINUX_RWSEM_H | |
| 11 | #error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead" | |
| 12 | #endif | |
| 13 | ||
| 14 | #ifdef __KERNEL__ | |
| 15 | ||
| 16 | #include <linux/list.h> | |
| 17 | #include <linux/spinlock.h> | |
| 18 | #include <asm/rwsem-const.h> | |
| 19 | ||
| 20 | struct rwsem_waiter; | |
| 21 | ||
| 22 | struct rw_semaphore { | |
| 23 | signed int count; | |
| 24 | spinlock_t wait_lock; | |
| 25 | struct list_head wait_list; | |
| 26 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
| 27 | struct lockdep_map dep_map; | |
| 28 | #endif | |
| 29 | }; | |
| 30 | ||
| 31 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
| 32 | # define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname } | |
| 33 | #else | |
| 34 | # define __RWSEM_DEP_MAP_INIT(lockname) | |
| 35 | #endif | |
| 36 | ||
| 37 | #define __RWSEM_INITIALIZER(name) \ | |
| 38 | { RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) \ | |
| 39 | __RWSEM_DEP_MAP_INIT(name) } | |
| 40 | ||
| 41 | #define DECLARE_RWSEM(name) \ | |
| 42 | struct rw_semaphore name = __RWSEM_INITIALIZER(name) | |
| 43 | ||
| 44 | extern void __init_rwsem(struct rw_semaphore *sem, const char *name, | |
| 45 | struct lock_class_key *key); | |
| 46 | ||
| 47 | #define init_rwsem(sem) \ | |
| 48 | do { \ | |
| 49 | static struct lock_class_key __key; \ | |
| 50 | \ | |
| 51 | __init_rwsem((sem), #sem, &__key); \ | |
| 52 | } while (0) | |
| 53 | ||
| 54 | extern void __down_read(struct rw_semaphore *sem); | |
| 55 | extern int __down_read_trylock(struct rw_semaphore *sem); | |
| 56 | extern void __down_write(struct rw_semaphore *sem); | |
| 57 | extern int __down_write_trylock(struct rw_semaphore *sem); | |
| 58 | extern void __up_read(struct rw_semaphore *sem); | |
| 59 | extern void __up_write(struct rw_semaphore *sem); | |
| 60 | extern void __downgrade_write(struct rw_semaphore *sem); | |
| 61 | ||
| 62 | static inline void __down_write_nested(struct rw_semaphore *sem, int subclass) | |
| 63 | { | |
| 64 | __down_write(sem); | |
| 65 | } | |
| 66 | ||
| 67 | static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem) | |
| 68 | { | |
| 69 | return atomic_add_return(delta, (atomic_t *)(&sem->count)); | |
| 70 | } | |
| 71 | ||
| 72 | static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem) | |
| 73 | { | |
| 74 | atomic_add(delta, (atomic_t *)(&sem->count)); | |
| 75 | } | |
| 76 | ||
| 77 | static inline int rwsem_is_locked(struct rw_semaphore *sem) | |
| 78 | { | |
| 79 | return (sem->count != 0); | |
| 80 | } | |
| 81 | ||
| 82 | #endif /* __KERNEL__ */ | |
| 83 | ||
| 84 | #endif /* _SPARC64_RWSEM_H */ |