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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 2 | pj | 1 | |
| 2 | #include <fs/mutex.h> |
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| 3 | #include <fs/semaph.h> |
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| 4 | #include "mutex.h" |
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| 5 | #include "rwlock.h" |
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| 6 | |||
| 7 | void __rwlock_init(__rwlock_t *ptr) |
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| 8 | { |
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| 9 | __mutex_init(&ptr->mutex,fsmutexattr); |
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| 10 | __sem_init(&ptr->readers_semaph,0); |
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| 11 | __sem_init(&ptr->writers_semaph,0); |
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| 12 | ptr->active_readers=0; |
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| 13 | ptr->active_writers=0; |
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| 14 | ptr->blocked_readers=0; |
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| 15 | ptr->blocked_writers=0; |
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| 16 | } |
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| 17 | |||
| 18 | void __rwlock_rdlock(__rwlock_t *ptr) |
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| 19 | { |
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| 20 | __mutex_lock(&ptr->mutex); |
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| 21 | |||
| 22 | if (ptr->active_writers==0&&ptr->blocked_writers==0) { |
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| 23 | ptr->active_readers++; |
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| 24 | __sem_signal(&ptr->readers_semaph); |
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| 25 | } else |
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| 26 | ptr->blocked_readers++; |
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| 27 | |||
| 28 | __mutex_unlock(&ptr->mutex); |
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| 29 | |||
| 30 | __sem_wait(&ptr->readers_semaph); |
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| 31 | } |
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| 32 | |||
| 33 | int __rwlock_tryrdlock(__rwlock_t *ptr) |
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| 34 | { |
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| 35 | int ret; |
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| 36 | |||
| 37 | __mutex_lock(&ptr->mutex); |
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| 38 | |||
| 39 | ret=0; |
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| 40 | if (ptr->active_writers==0&&ptr->blocked_writers==0) { |
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| 41 | ptr->active_readers++; |
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| 42 | __sem_signal(&ptr->readers_semaph); |
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| 43 | } else |
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| 44 | ret=-1; |
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| 45 | |||
| 46 | __mutex_unlock(&ptr->mutex); |
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| 47 | |||
| 48 | if (ret==0) __sem_wait(&ptr->readers_semaph); |
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| 49 | return ret; |
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| 50 | } |
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| 51 | |||
| 52 | void __rwlock_wrlock(__rwlock_t *ptr) |
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| 53 | { |
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| 54 | __mutex_lock(&ptr->mutex); |
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| 55 | |||
| 56 | if (ptr->active_readers==0&&ptr->active_writers==0) { |
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| 57 | ptr->active_writers=1; |
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| 58 | __sem_signal(&ptr->writers_semaph); |
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| 59 | } |
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| 60 | else |
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| 61 | ptr->blocked_writers++; |
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| 62 | |||
| 63 | __mutex_unlock(&ptr->mutex); |
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| 64 | |||
| 65 | __sem_wait(&ptr->writers_semaph); |
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| 66 | } |
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| 67 | |||
| 68 | int __rwlock_trywrlock(__rwlock_t *ptr) |
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| 69 | { |
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| 70 | int ret; |
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| 71 | |||
| 72 | __mutex_lock(&ptr->mutex); |
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| 73 | |||
| 74 | ret=0; |
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| 75 | if (ptr->active_readers==0&&ptr->active_writers==0) { |
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| 76 | ptr->active_writers=1; |
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| 77 | __sem_signal(&ptr->writers_semaph); |
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| 78 | } |
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| 79 | else |
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| 80 | ret=-1; |
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| 81 | |||
| 82 | __mutex_unlock(&ptr->mutex); |
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| 83 | |||
| 84 | if (ret==0) __sem_wait(&ptr->writers_semaph); |
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| 85 | return ret; |
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| 86 | } |
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| 87 | |||
| 88 | void __rwlock_rdunlock(__rwlock_t *ptr) |
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| 89 | { |
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| 90 | __mutex_lock(&ptr->mutex); |
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| 91 | |||
| 92 | ptr->active_readers--; |
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| 93 | if (ptr->active_readers==0&&ptr->blocked_writers>0) { |
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| 94 | ptr->active_writers=1; |
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| 95 | ptr->blocked_writers--; |
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| 96 | __sem_signal(&ptr->writers_semaph); |
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| 97 | } |
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| 98 | |||
| 99 | __mutex_unlock(&ptr->mutex); |
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| 100 | } |
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| 101 | |||
| 102 | void __rwlock_wrunlock(__rwlock_t *ptr) |
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| 103 | { |
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| 104 | __mutex_lock(&ptr->mutex); |
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| 105 | |||
| 106 | ptr->active_writers=0; |
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| 107 | if (ptr->blocked_readers>0) { |
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| 108 | do { |
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| 109 | ptr->blocked_readers--; |
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| 110 | ptr->active_readers++; |
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| 111 | __sem_signal(&ptr->readers_semaph); |
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| 112 | } while(ptr->blocked_readers!=0); |
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| 113 | } else if (ptr->blocked_writers>0) { |
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| 114 | ptr->active_writers=1; |
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| 115 | ptr->blocked_writers--; |
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| 116 | __sem_signal(&ptr->writers_semaph); |
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| 117 | } |
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| 118 | |||
| 119 | __mutex_unlock(&ptr->mutex); |
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| 120 | } |