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-rw-r--r--arch/x86/include/asm/rwsem.h80
1 files changed, 9 insertions, 71 deletions
diff --git a/arch/x86/include/asm/rwsem.h b/arch/x86/include/asm/rwsem.h
index d1e41b0f9b60..df4cd32b4cc6 100644
--- a/arch/x86/include/asm/rwsem.h
+++ b/arch/x86/include/asm/rwsem.h
@@ -37,26 +37,9 @@
37#endif 37#endif
38 38
39#ifdef __KERNEL__ 39#ifdef __KERNEL__
40
41#include <linux/list.h>
42#include <linux/spinlock.h>
43#include <linux/lockdep.h>
44#include <asm/asm.h> 40#include <asm/asm.h>
45 41
46struct rwsem_waiter;
47
48extern asmregparm struct rw_semaphore *
49 rwsem_down_read_failed(struct rw_semaphore *sem);
50extern asmregparm struct rw_semaphore *
51 rwsem_down_write_failed(struct rw_semaphore *sem);
52extern asmregparm struct rw_semaphore *
53 rwsem_wake(struct rw_semaphore *);
54extern asmregparm struct rw_semaphore *
55 rwsem_downgrade_wake(struct rw_semaphore *sem);
56
57/* 42/*
58 * the semaphore definition
59 *
60 * The bias values and the counter type limits the number of 43 * The bias values and the counter type limits the number of
61 * potential readers/writers to 32767 for 32 bits and 2147483647 44 * potential readers/writers to 32767 for 32 bits and 2147483647
62 * for 64 bits. 45 * for 64 bits.
@@ -74,43 +57,6 @@ extern asmregparm struct rw_semaphore *
74#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS 57#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
75#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) 58#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
76 59
77typedef signed long rwsem_count_t;
78
79struct rw_semaphore {
80 rwsem_count_t count;
81 spinlock_t wait_lock;
82 struct list_head wait_list;
83#ifdef CONFIG_DEBUG_LOCK_ALLOC
84 struct lockdep_map dep_map;
85#endif
86};
87
88#ifdef CONFIG_DEBUG_LOCK_ALLOC
89# define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname }
90#else
91# define __RWSEM_DEP_MAP_INIT(lockname)
92#endif
93
94
95#define __RWSEM_INITIALIZER(name) \
96{ \
97 RWSEM_UNLOCKED_VALUE, __SPIN_LOCK_UNLOCKED((name).wait_lock), \
98 LIST_HEAD_INIT((name).wait_list) __RWSEM_DEP_MAP_INIT(name) \
99}
100
101#define DECLARE_RWSEM(name) \
102 struct rw_semaphore name = __RWSEM_INITIALIZER(name)
103
104extern void __init_rwsem(struct rw_semaphore *sem, const char *name,
105 struct lock_class_key *key);
106
107#define init_rwsem(sem) \
108do { \
109 static struct lock_class_key __key; \
110 \
111 __init_rwsem((sem), #sem, &__key); \
112} while (0)
113
114/* 60/*
115 * lock for reading 61 * lock for reading
116 */ 62 */
@@ -133,7 +79,7 @@ static inline void __down_read(struct rw_semaphore *sem)
133 */ 79 */
134static inline int __down_read_trylock(struct rw_semaphore *sem) 80static inline int __down_read_trylock(struct rw_semaphore *sem)
135{ 81{
136 rwsem_count_t result, tmp; 82 long result, tmp;
137 asm volatile("# beginning __down_read_trylock\n\t" 83 asm volatile("# beginning __down_read_trylock\n\t"
138 " mov %0,%1\n\t" 84 " mov %0,%1\n\t"
139 "1:\n\t" 85 "1:\n\t"
@@ -155,7 +101,7 @@ static inline int __down_read_trylock(struct rw_semaphore *sem)
155 */ 101 */
156static inline void __down_write_nested(struct rw_semaphore *sem, int subclass) 102static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
157{ 103{
158 rwsem_count_t tmp; 104 long tmp;
159 asm volatile("# beginning down_write\n\t" 105 asm volatile("# beginning down_write\n\t"
160 LOCK_PREFIX " xadd %1,(%2)\n\t" 106 LOCK_PREFIX " xadd %1,(%2)\n\t"
161 /* adds 0xffff0001, returns the old value */ 107 /* adds 0xffff0001, returns the old value */
@@ -180,9 +126,8 @@ static inline void __down_write(struct rw_semaphore *sem)
180 */ 126 */
181static inline int __down_write_trylock(struct rw_semaphore *sem) 127static inline int __down_write_trylock(struct rw_semaphore *sem)
182{ 128{
183 rwsem_count_t ret = cmpxchg(&sem->count, 129 long ret = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
184 RWSEM_UNLOCKED_VALUE, 130 RWSEM_ACTIVE_WRITE_BIAS);
185 RWSEM_ACTIVE_WRITE_BIAS);
186 if (ret == RWSEM_UNLOCKED_VALUE) 131 if (ret == RWSEM_UNLOCKED_VALUE)
187 return 1; 132 return 1;
188 return 0; 133 return 0;
@@ -193,7 +138,7 @@ static inline int __down_write_trylock(struct rw_semaphore *sem)
193 */ 138 */
194static inline void __up_read(struct rw_semaphore *sem) 139static inline void __up_read(struct rw_semaphore *sem)
195{ 140{
196 rwsem_count_t tmp; 141 long tmp;
197 asm volatile("# beginning __up_read\n\t" 142 asm volatile("# beginning __up_read\n\t"
198 LOCK_PREFIX " xadd %1,(%2)\n\t" 143 LOCK_PREFIX " xadd %1,(%2)\n\t"
199 /* subtracts 1, returns the old value */ 144 /* subtracts 1, returns the old value */
@@ -211,7 +156,7 @@ static inline void __up_read(struct rw_semaphore *sem)
211 */ 156 */
212static inline void __up_write(struct rw_semaphore *sem) 157static inline void __up_write(struct rw_semaphore *sem)
213{ 158{
214 rwsem_count_t tmp; 159 long tmp;
215 asm volatile("# beginning __up_write\n\t" 160 asm volatile("# beginning __up_write\n\t"
216 LOCK_PREFIX " xadd %1,(%2)\n\t" 161 LOCK_PREFIX " xadd %1,(%2)\n\t"
217 /* subtracts 0xffff0001, returns the old value */ 162 /* subtracts 0xffff0001, returns the old value */
@@ -247,8 +192,7 @@ static inline void __downgrade_write(struct rw_semaphore *sem)
247/* 192/*
248 * implement atomic add functionality 193 * implement atomic add functionality
249 */ 194 */
250static inline void rwsem_atomic_add(rwsem_count_t delta, 195static inline void rwsem_atomic_add(long delta, struct rw_semaphore *sem)
251 struct rw_semaphore *sem)
252{ 196{
253 asm volatile(LOCK_PREFIX _ASM_ADD "%1,%0" 197 asm volatile(LOCK_PREFIX _ASM_ADD "%1,%0"
254 : "+m" (sem->count) 198 : "+m" (sem->count)
@@ -258,10 +202,9 @@ static inline void rwsem_atomic_add(rwsem_count_t delta,
258/* 202/*
259 * implement exchange and add functionality 203 * implement exchange and add functionality
260 */ 204 */
261static inline rwsem_count_t rwsem_atomic_update(rwsem_count_t delta, 205static inline long rwsem_atomic_update(long delta, struct rw_semaphore *sem)
262 struct rw_semaphore *sem)
263{ 206{
264 rwsem_count_t tmp = delta; 207 long tmp = delta;
265 208
266 asm volatile(LOCK_PREFIX "xadd %0,%1" 209 asm volatile(LOCK_PREFIX "xadd %0,%1"
267 : "+r" (tmp), "+m" (sem->count) 210 : "+r" (tmp), "+m" (sem->count)
@@ -270,10 +213,5 @@ static inline rwsem_count_t rwsem_atomic_update(rwsem_count_t delta,
270 return tmp + delta; 213 return tmp + delta;
271} 214}
272 215
273static inline int rwsem_is_locked(struct rw_semaphore *sem)
274{
275 return (sem->count != 0);
276}
277
278#endif /* __KERNEL__ */ 216#endif /* __KERNEL__ */
279#endif /* _ASM_X86_RWSEM_H */ 217#endif /* _ASM_X86_RWSEM_H */