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f1ca4da6 | 1 | #ifndef _SYS_LINUX_MUTEX_H |
2 | #define _SYS_LINUX_MUTEX_H | |
3 | ||
4 | #ifdef __cplusplus | |
5 | extern "C" { | |
6 | #endif | |
7 | ||
8 | /* See the "Big Theory Statement" in solaris mutex.c. | |
9 | * | |
10 | * Spin mutexes apparently aren't needed by zfs so we assert | |
11 | * if ibc is non-zero. | |
12 | * | |
13 | * Our impementation of adaptive mutexes aren't really adaptive. | |
14 | * They go to sleep every time. | |
15 | */ | |
16 | ||
17 | #define MUTEX_DEFAULT 0 | |
18 | #define MUTEX_HELD(x) (mutex_owned(x)) | |
19 | ||
20 | #define KM_MAGIC 0x42424242 | |
21 | #define KM_POISON 0x84 | |
22 | ||
23 | typedef struct { | |
24 | int km_magic; | |
25 | char *km_name; | |
26 | struct task_struct *km_owner; | |
27 | struct semaphore km_sem; | |
28 | } kmutex_t; | |
29 | ||
30 | #undef mutex_init | |
31 | static __inline__ void | |
32 | mutex_init(kmutex_t *mp, char *name, int type, void *ibc) | |
33 | { | |
34 | BUG_ON(ibc != NULL); /* XXX - Spin mutexes not needed? */ | |
35 | BUG_ON(type != MUTEX_DEFAULT); /* XXX - Only default type supported? */ | |
36 | ||
37 | mp->km_magic = KM_MAGIC; | |
38 | sema_init(&mp->km_sem, 1); | |
39 | mp->km_owner = NULL; | |
40 | mp->km_name = NULL; | |
41 | ||
42 | if (name) { | |
43 | mp->km_name = kmalloc(strlen(name) + 1, GFP_KERNEL); | |
44 | if (mp->km_name) | |
45 | strcpy(mp->km_name, name); | |
46 | } | |
47 | } | |
48 | ||
49 | #undef mutex_destroy | |
50 | static __inline__ void | |
51 | mutex_destroy(kmutex_t *mp) | |
52 | { | |
53 | BUG_ON(mp->km_magic != KM_MAGIC); | |
54 | ||
55 | if (mp->km_name) | |
56 | kfree(mp->km_name); | |
57 | ||
58 | memset(mp, KM_POISON, sizeof(*mp)); | |
59 | } | |
60 | ||
61 | static __inline__ void | |
62 | mutex_enter(kmutex_t *mp) | |
63 | { | |
64 | BUG_ON(mp->km_magic != KM_MAGIC); | |
65 | down(&mp->km_sem); /* Will check in_atomic() for us */ | |
66 | BUG_ON(mp->km_owner != NULL); | |
67 | mp->km_owner = current; | |
68 | } | |
69 | ||
70 | /* Return 1 if we acquired the mutex, else zero. | |
71 | */ | |
72 | static __inline__ int | |
73 | mutex_tryenter(kmutex_t *mp) | |
74 | { | |
75 | int result; | |
76 | ||
77 | BUG_ON(mp->km_magic != KM_MAGIC); | |
78 | result = down_trylock(&mp->km_sem); /* returns 0 if acquired */ | |
79 | if (result == 0) { | |
80 | BUG_ON(mp->km_owner != NULL); | |
81 | mp->km_owner = current; | |
82 | return 1; | |
83 | } | |
84 | return 0; | |
85 | } | |
86 | ||
87 | static __inline__ void | |
88 | mutex_exit(kmutex_t *mp) | |
89 | { | |
90 | BUG_ON(mp->km_magic != KM_MAGIC); | |
91 | BUG_ON(mp->km_owner != current); | |
92 | mp->km_owner = NULL; | |
93 | up(&mp->km_sem); | |
94 | } | |
95 | ||
96 | /* Return 1 if mutex is held by current process, else zero. | |
97 | */ | |
98 | static __inline__ int | |
99 | mutex_owned(kmutex_t *mp) | |
100 | { | |
101 | BUG_ON(mp->km_magic != KM_MAGIC); | |
102 | return (mp->km_owner == current); | |
103 | } | |
104 | ||
105 | /* Return owner if mutex is owned, else NULL. | |
106 | */ | |
107 | static __inline__ kthread_t * | |
108 | mutex_owner(kmutex_t *mp) | |
109 | { | |
110 | BUG_ON(mp->km_magic != KM_MAGIC); | |
111 | return mp->km_owner; | |
112 | } | |
113 | ||
114 | #ifdef __cplusplus | |
115 | } | |
116 | #endif | |
117 | ||
118 | #endif /* _SYS_LINUX_MUTEX_H */ |