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Rev | Author | Line No. | Line |
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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 | } |