diff options
Diffstat (limited to 'include/asm-generic/mutex-dec.h')
-rw-r--r-- | include/asm-generic/mutex-dec.h | 88 |
1 files changed, 0 insertions, 88 deletions
diff --git a/include/asm-generic/mutex-dec.h b/include/asm-generic/mutex-dec.h deleted file mode 100644 index c54829d3de37..000000000000 --- a/include/asm-generic/mutex-dec.h +++ /dev/null | |||
@@ -1,88 +0,0 @@ | |||
1 | /* | ||
2 | * include/asm-generic/mutex-dec.h | ||
3 | * | ||
4 | * Generic implementation of the mutex fastpath, based on atomic | ||
5 | * decrement/increment. | ||
6 | */ | ||
7 | #ifndef _ASM_GENERIC_MUTEX_DEC_H | ||
8 | #define _ASM_GENERIC_MUTEX_DEC_H | ||
9 | |||
10 | /** | ||
11 | * __mutex_fastpath_lock - try to take the lock by moving the count | ||
12 | * from 1 to a 0 value | ||
13 | * @count: pointer of type atomic_t | ||
14 | * @fail_fn: function to call if the original value was not 1 | ||
15 | * | ||
16 | * Change the count from 1 to a value lower than 1, and call <fail_fn> if | ||
17 | * it wasn't 1 originally. This function MUST leave the value lower than | ||
18 | * 1 even when the "1" assertion wasn't true. | ||
19 | */ | ||
20 | static inline void | ||
21 | __mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *)) | ||
22 | { | ||
23 | if (unlikely(atomic_dec_return_acquire(count) < 0)) | ||
24 | fail_fn(count); | ||
25 | } | ||
26 | |||
27 | /** | ||
28 | * __mutex_fastpath_lock_retval - try to take the lock by moving the count | ||
29 | * from 1 to a 0 value | ||
30 | * @count: pointer of type atomic_t | ||
31 | * | ||
32 | * Change the count from 1 to a value lower than 1. This function returns 0 | ||
33 | * if the fastpath succeeds, or -1 otherwise. | ||
34 | */ | ||
35 | static inline int | ||
36 | __mutex_fastpath_lock_retval(atomic_t *count) | ||
37 | { | ||
38 | if (unlikely(atomic_dec_return_acquire(count) < 0)) | ||
39 | return -1; | ||
40 | return 0; | ||
41 | } | ||
42 | |||
43 | /** | ||
44 | * __mutex_fastpath_unlock - try to promote the count from 0 to 1 | ||
45 | * @count: pointer of type atomic_t | ||
46 | * @fail_fn: function to call if the original value was not 0 | ||
47 | * | ||
48 | * Try to promote the count from 0 to 1. If it wasn't 0, call <fail_fn>. | ||
49 | * In the failure case, this function is allowed to either set the value to | ||
50 | * 1, or to set it to a value lower than 1. | ||
51 | * | ||
52 | * If the implementation sets it to a value of lower than 1, then the | ||
53 | * __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs | ||
54 | * to return 0 otherwise. | ||
55 | */ | ||
56 | static inline void | ||
57 | __mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *)) | ||
58 | { | ||
59 | if (unlikely(atomic_inc_return_release(count) <= 0)) | ||
60 | fail_fn(count); | ||
61 | } | ||
62 | |||
63 | #define __mutex_slowpath_needs_to_unlock() 1 | ||
64 | |||
65 | /** | ||
66 | * __mutex_fastpath_trylock - try to acquire the mutex, without waiting | ||
67 | * | ||
68 | * @count: pointer of type atomic_t | ||
69 | * @fail_fn: fallback function | ||
70 | * | ||
71 | * Change the count from 1 to a value lower than 1, and return 0 (failure) | ||
72 | * if it wasn't 1 originally, or return 1 (success) otherwise. This function | ||
73 | * MUST leave the value lower than 1 even when the "1" assertion wasn't true. | ||
74 | * Additionally, if the value was < 0 originally, this function must not leave | ||
75 | * it to 0 on failure. | ||
76 | * | ||
77 | * If the architecture has no effective trylock variant, it should call the | ||
78 | * <fail_fn> spinlock-based trylock variant unconditionally. | ||
79 | */ | ||
80 | static inline int | ||
81 | __mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *)) | ||
82 | { | ||
83 | if (likely(atomic_read(count) == 1 && atomic_cmpxchg_acquire(count, 1, 0) == 1)) | ||
84 | return 1; | ||
85 | return 0; | ||
86 | } | ||
87 | |||
88 | #endif | ||