1 | /** |
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2 | * @file |
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3 | * |
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4 | * @ingroup rtems_bsd_rtems |
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5 | * |
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6 | * @brief TODO. |
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7 | */ |
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8 | |
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9 | /* |
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10 | * Copyright (c) 2011 OPTI Medical. All rights reserved. |
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11 | * |
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12 | * OPTI Medical |
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13 | * 235 Hembree Park Drive |
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14 | * Roswell, GA 30076 |
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15 | * USA |
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16 | * <kevin.kirspel@optimedical.com> |
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17 | * |
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18 | * Redistribution and use in source and binary forms, with or without |
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19 | * modification, are permitted provided that the following conditions |
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20 | * are met: |
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21 | * 1. Redistributions of source code must retain the above copyright |
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22 | * notice, this list of conditions and the following disclaimer. |
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23 | * 2. Redistributions in binary form must reproduce the above copyright |
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24 | * notice, this list of conditions and the following disclaimer in the |
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25 | * documentation and/or other materials provided with the distribution. |
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26 | * |
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27 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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28 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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29 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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30 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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31 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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32 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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33 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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34 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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35 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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36 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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37 | * SUCH DAMAGE. |
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38 | */ |
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39 | |
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40 | #include <machine/rtems-bsd-config.h> |
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41 | |
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42 | #include <rtems/score/objectimpl.h> |
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43 | #include <rtems/posix/rwlockimpl.h> |
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44 | |
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45 | #include <rtems/bsd/sys/param.h> |
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46 | #include <rtems/bsd/sys/types.h> |
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47 | #include <sys/systm.h> |
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48 | #include <rtems/bsd/sys/lock.h> |
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49 | #include <sys/rwlock.h> |
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50 | |
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51 | #ifndef INVARIANTS |
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52 | #define _rw_assert(rw, what, file, line) |
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53 | #endif |
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54 | |
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55 | static void assert_rw(struct lock_object *lock, int what); |
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56 | static void lock_rw(struct lock_object *lock, int how); |
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57 | #ifdef KDTRACE_HOOKS |
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58 | static int owner_rw(struct lock_object *lock, struct thread **owner); |
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59 | #endif |
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60 | static int unlock_rw(struct lock_object *lock); |
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61 | |
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62 | struct lock_class lock_class_rw = { |
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63 | .lc_name = "rw", |
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64 | .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE | LC_UPGRADABLE, |
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65 | .lc_assert = assert_rw, |
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66 | #ifdef DDB |
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67 | .lc_ddb_show = db_show_rwlock, |
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68 | #endif |
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69 | .lc_lock = lock_rw, |
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70 | .lc_unlock = unlock_rw, |
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71 | #ifdef KDTRACE_HOOKS |
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72 | .lc_owner = owner_rw, |
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73 | #endif |
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74 | }; |
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75 | |
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76 | RTEMS_CHAIN_DEFINE_EMPTY(rtems_bsd_rwlock_chain); |
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77 | |
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78 | void |
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79 | assert_rw(struct lock_object *lock, int what) |
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80 | { |
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81 | rw_assert((struct rwlock *)lock, what); |
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82 | } |
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83 | |
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84 | void |
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85 | lock_rw(struct lock_object *lock, int how) |
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86 | { |
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87 | struct rwlock *rw; |
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88 | |
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89 | rw = (struct rwlock *)lock; |
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90 | if (how) |
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91 | rw_wlock(rw); |
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92 | else |
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93 | rw_rlock(rw); |
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94 | } |
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95 | |
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96 | int |
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97 | unlock_rw(struct lock_object *lock) |
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98 | { |
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99 | struct rwlock *rw; |
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100 | |
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101 | rw = (struct rwlock *)lock; |
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102 | rw_assert(rw, RA_LOCKED | LA_NOTRECURSED); |
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103 | if (rw->rw_lock & RW_LOCK_READ) { |
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104 | rw_runlock(rw); |
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105 | return (0); |
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106 | } else { |
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107 | rw_wunlock(rw); |
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108 | return (1); |
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109 | } |
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110 | } |
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111 | |
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112 | #ifdef KDTRACE_HOOKS |
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113 | int |
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114 | owner_rw(struct lock_object *lock, struct thread **owner) |
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115 | { |
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116 | struct rwlock *rw = (struct rwlock *)lock; |
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117 | uintptr_t x = rw->rw_lock; |
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118 | |
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119 | *owner = rw_wowner(rw); |
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120 | return ((x & RW_LOCK_READ) != 0 ? (RW_READERS(x) != 0) : |
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121 | (*owner != NULL)); |
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122 | } |
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123 | #endif |
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124 | |
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125 | void |
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126 | rw_init_flags(struct rwlock *rw, const char *name, int opts) |
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127 | { |
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128 | struct lock_class *class; |
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129 | int i; |
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130 | pthread_rwlock_t lock; |
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131 | int iret; |
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132 | |
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133 | if ((opts & RW_RECURSE) != 0) { |
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134 | /* FIXME */ |
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135 | } |
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136 | |
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137 | class = &lock_class_rw; |
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138 | |
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139 | /* Check for double-init and zero object. */ |
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140 | KASSERT(!lock_initalized(&rw->lock_object), ("lock \"%s\" %p already initialized", name, rw->lock_object)); |
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141 | |
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142 | /* Look up lock class to find its index. */ |
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143 | for (i = 0; i < LOCK_CLASS_MAX; i++) |
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144 | { |
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145 | if (lock_classes[i] == class) |
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146 | { |
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147 | rw->lock_object.lo_flags = i << LO_CLASSSHIFT; |
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148 | break; |
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149 | } |
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150 | } |
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151 | KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class)); |
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152 | |
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153 | iret = pthread_rwlock_init( &lock, NULL ); |
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154 | BSD_ASSERT( iret == 0 ); |
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155 | |
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156 | rw->lock_object.lo_name = name; |
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157 | rw->lock_object.lo_flags |= LO_INITIALIZED; |
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158 | rw->lock_object.lo_id = lock; |
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159 | |
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160 | rtems_chain_append(&rtems_bsd_rwlock_chain, &rw->lock_object.lo_node); |
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161 | } |
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162 | |
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163 | void |
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164 | rw_destroy(struct rwlock *rw) |
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165 | { |
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166 | int iret; |
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167 | pthread_rwlock_destroy( rw->lock_object.lo_id ); |
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168 | BSD_ASSERT( iret == 0 ); |
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169 | rtems_chain_extract( &rw->lock_object.lo_node ); |
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170 | rw->lock_object.lo_id = 0; |
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171 | rw->lock_object.lo_flags &= ~LO_INITIALIZED; |
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172 | } |
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173 | |
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174 | void |
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175 | rw_sysinit(void *arg) |
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176 | { |
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177 | struct rw_args *args = arg; |
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178 | |
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179 | rw_init(args->ra_rw, args->ra_desc); |
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180 | } |
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181 | |
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182 | void |
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183 | rw_sysinit_flags(void *arg) |
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184 | { |
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185 | struct rw_args_flags *args = arg; |
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186 | |
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187 | rw_init_flags(args->ra_rw, args->ra_desc, args->ra_flags); |
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188 | } |
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189 | |
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190 | /* XXX add pthread_rwlock_is_wlocked_np( id, &wlocked ) |
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191 | * XXX returns 0 or -1 w/error |
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192 | * XXX wlocked = 1 if write locked |
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193 | * XXX |
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194 | /* XXX add pthread_rwlock_is_rlocked_np( id, &wlocked ) |
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195 | * XXX similar behavior |
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196 | * XXX probably want to add "unlocked" state to RTEMS SuperCore rwlock |
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197 | * XXX |
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198 | * XXX Rationale: This violates the API layering BADLY!!!!! |
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199 | * XXX Consider: Adding pthread_np.h to hold np methods like FreeBSD |
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200 | * XXX This would avoid polluting pthread.h |
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201 | */ |
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202 | int |
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203 | rw_wowned(struct rwlock *rw) |
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204 | { |
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205 | int is_locked_for_write = 0; |
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206 | Objects_Locations location; |
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207 | POSIX_RWLock_Control *the_rwlock; |
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208 | |
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209 | the_rwlock = _POSIX_RWLock_Get(&rw->lock_object.lo_id, &location); |
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210 | switch ( location ) { |
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211 | |
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212 | case OBJECTS_LOCAL: |
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213 | if (the_rwlock->RWLock.current_state == CORE_RWLOCK_LOCKED_FOR_WRITING) |
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214 | is_locked_for_write = 1; |
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215 | _Thread_Enable_dispatch(); |
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216 | return is_locked_for_write; |
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217 | |
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218 | #if defined(RTEMS_MULTIPROCESSING) |
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219 | case OBJECTS_REMOTE: |
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220 | #endif |
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221 | case OBJECTS_ERROR: |
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222 | break; |
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223 | } |
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224 | _Thread_Enable_dispatch(); |
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225 | |
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226 | BSD_PANIC("unexpected semaphore location or attributes"); |
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227 | } |
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228 | |
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229 | void |
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230 | _rw_wlock(struct rwlock *rw, const char *file, int line) |
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231 | { |
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232 | int iret; |
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233 | |
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234 | iret = pthread_rwlock_wrlock( &rw->lock_object.lo_id ); |
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235 | BSD_ASSERT( iret == 0 ); |
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236 | |
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237 | return 0; |
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238 | } |
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239 | |
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240 | int |
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241 | _rw_try_wlock(struct rwlock *rw, const char *file, int line) |
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242 | { |
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243 | int iret; |
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244 | |
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245 | iret = pthread_rwlock_trywrlock( &rw->lock_object.lo_id ); |
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246 | if (iret == 0) { |
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247 | return 1; |
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248 | } else { |
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249 | return 0; |
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250 | } |
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251 | } |
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252 | |
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253 | void |
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254 | _rw_wunlock(struct rwlock *rw, const char *file, int line) |
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255 | { |
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256 | int iret; |
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257 | |
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258 | iret = pthread_rwlock_unlock( &rw->lock_object.lo_id ); |
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259 | BSD_ASSERT( iret == 0 ); |
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260 | } |
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261 | |
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262 | void |
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263 | _rw_rlock(struct rwlock *rw, const char *file, int line) |
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264 | { |
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265 | int iret; |
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266 | |
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267 | iret = pthread_rwlock_rdlock( &rw->lock_object.lo_id ); |
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268 | BSD_ASSERT( iret == 0 ); |
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269 | } |
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270 | |
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271 | int |
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272 | _rw_try_rlock(struct rwlock *rw, const char *file, int line) |
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273 | { |
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274 | int iret; |
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275 | |
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276 | iret = pthread_rwlock_tryrdlock( &rw->lock_object.lo_id ); |
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277 | if (iret == 0) { |
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278 | return 1; |
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279 | } else { |
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280 | return 0; |
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281 | } |
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282 | } |
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283 | |
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284 | void |
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285 | _rw_runlock(struct rwlock *rw, const char *file, int line) |
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286 | { |
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287 | int iret; |
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288 | |
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289 | iret = pthread_rwlock_unlock( &rw->lock_object.lo_id ); |
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290 | BSD_ASSERT( iret == 0 ); |
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291 | } |
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292 | |
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293 | /* |
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294 | * Attempt to do a non-blocking upgrade from a read lock to a write |
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295 | * lock. This will only succeed if this thread holds a single read |
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296 | * lock. Returns true if the upgrade succeeded and false otherwise. |
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297 | */ |
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298 | int |
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299 | _rw_try_upgrade(struct rwlock *rw, const char *file, int line) |
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300 | { |
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301 | return 0; /* XXX */ |
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302 | } |
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303 | |
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304 | /* |
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305 | * Downgrade a write lock into a single read lock. |
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306 | */ |
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307 | void |
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308 | _rw_downgrade(struct rwlock *rw, const char *file, int line) |
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309 | { |
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310 | /* XXX */ |
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311 | } |
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312 | |
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313 | #ifdef INVARIANT_SUPPORT |
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314 | #ifndef INVARIANTS |
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315 | #undef _rw_assert |
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316 | #endif |
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317 | |
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318 | /* |
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319 | * In the non-WITNESS case, rw_assert() can only detect that at least |
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320 | * *some* thread owns an rlock, but it cannot guarantee that *this* |
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321 | * thread owns an rlock. |
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322 | */ |
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323 | void |
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324 | _rw_assert(struct rwlock *rw, int what, const char *file, int line) |
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325 | { |
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326 | |
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327 | if (panicstr != NULL) |
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328 | return; |
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329 | switch (what) { |
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330 | case RA_LOCKED: |
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331 | case RA_LOCKED | RA_RECURSED: |
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332 | case RA_LOCKED | RA_NOTRECURSED: |
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333 | case RA_RLOCKED: |
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334 | #ifdef WITNESS |
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335 | witness_assert(&rw->lock_object, what, file, line); |
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336 | #else |
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337 | /* |
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338 | * If some other thread has a write lock or we have one |
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339 | * and are asserting a read lock, fail. Also, if no one |
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340 | * has a lock at all, fail. |
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341 | */ |
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342 | if (rw->rw_lock == RW_UNLOCKED || |
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343 | (!(rw->rw_lock & RW_LOCK_READ) && (what == RA_RLOCKED || |
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344 | rw_wowner(rw) != curthread))) |
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345 | panic("Lock %s not %slocked @ %s:%d\n", |
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346 | rw->lock_object.lo_name, (what == RA_RLOCKED) ? |
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347 | "read " : "", file, line); |
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348 | |
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349 | if (!(rw->rw_lock & RW_LOCK_READ)) { |
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350 | if (rw_recursed(rw)) { |
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351 | if (what & RA_NOTRECURSED) |
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352 | panic("Lock %s recursed @ %s:%d\n", |
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353 | rw->lock_object.lo_name, file, |
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354 | line); |
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355 | } else if (what & RA_RECURSED) |
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356 | panic("Lock %s not recursed @ %s:%d\n", |
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357 | rw->lock_object.lo_name, file, line); |
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358 | } |
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359 | #endif |
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360 | break; |
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361 | case RA_WLOCKED: |
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362 | case RA_WLOCKED | RA_RECURSED: |
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363 | case RA_WLOCKED | RA_NOTRECURSED: |
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364 | if (rw_wowner(rw) != curthread) |
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365 | panic("Lock %s not exclusively locked @ %s:%d\n", |
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366 | rw->lock_object.lo_name, file, line); |
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367 | if (rw_recursed(rw)) { |
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368 | if (what & RA_NOTRECURSED) |
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369 | panic("Lock %s recursed @ %s:%d\n", |
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370 | rw->lock_object.lo_name, file, line); |
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371 | } else if (what & RA_RECURSED) |
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372 | panic("Lock %s not recursed @ %s:%d\n", |
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373 | rw->lock_object.lo_name, file, line); |
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374 | break; |
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375 | case RA_UNLOCKED: |
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376 | #ifdef WITNESS |
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377 | witness_assert(&rw->lock_object, what, file, line); |
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378 | #else |
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379 | /* |
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380 | * If we hold a write lock fail. We can't reliably check |
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381 | * to see if we hold a read lock or not. |
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382 | */ |
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383 | if (rw_wowner(rw) == curthread) |
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384 | panic("Lock %s exclusively locked @ %s:%d\n", |
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385 | rw->lock_object.lo_name, file, line); |
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386 | #endif |
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387 | break; |
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388 | default: |
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389 | panic("Unknown rw lock assertion: %d @ %s:%d", what, file, |
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390 | line); |
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391 | } |
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392 | } |
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393 | #endif /* INVARIANT_SUPPORT */ |
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