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5078 | serge | 1 | /************************************************************************** |
2 | * |
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3 | * Copyright (c) 2007-2009 VMware, Inc., Palo Alto, CA., USA |
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4 | * All Rights Reserved. |
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5 | * |
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6 | * Permission is hereby granted, free of charge, to any person obtaining a |
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7 | * copy of this software and associated documentation files (the |
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8 | * "Software"), to deal in the Software without restriction, including |
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9 | * without limitation the rights to use, copy, modify, merge, publish, |
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10 | * distribute, sub license, and/or sell copies of the Software, and to |
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11 | * permit persons to whom the Software is furnished to do so, subject to |
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12 | * the following conditions: |
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13 | * |
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14 | * The above copyright notice and this permission notice (including the |
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15 | * next paragraph) shall be included in all copies or substantial portions |
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16 | * of the Software. |
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17 | * |
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18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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19 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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20 | * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL |
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21 | * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, |
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22 | * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR |
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23 | * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE |
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24 | * USE OR OTHER DEALINGS IN THE SOFTWARE. |
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25 | * |
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26 | **************************************************************************/ |
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27 | /* |
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28 | * Authors: Thomas Hellstrom |
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29 | */ |
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30 | |||
31 | #include |
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32 | #include |
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6296 | serge | 33 | #include |
5078 | serge | 34 | #include |
35 | #include |
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36 | #include |
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37 | #include |
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38 | |||
39 | #define TTM_WRITE_LOCK_PENDING (1 << 0) |
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40 | #define TTM_VT_LOCK_PENDING (1 << 1) |
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41 | #define TTM_SUSPEND_LOCK_PENDING (1 << 2) |
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42 | #define TTM_VT_LOCK (1 << 3) |
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43 | #define TTM_SUSPEND_LOCK (1 << 4) |
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44 | |||
45 | void ttm_lock_init(struct ttm_lock *lock) |
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46 | { |
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47 | spin_lock_init(&lock->lock); |
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48 | init_waitqueue_head(&lock->queue); |
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49 | lock->rw = 0; |
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50 | lock->flags = 0; |
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51 | } |
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52 | EXPORT_SYMBOL(ttm_lock_init); |
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53 | |||
54 | void ttm_read_unlock(struct ttm_lock *lock) |
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55 | { |
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56 | spin_lock(&lock->lock); |
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57 | if (--lock->rw == 0) |
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58 | wake_up_all(&lock->queue); |
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59 | spin_unlock(&lock->lock); |
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60 | } |
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61 | EXPORT_SYMBOL(ttm_read_unlock); |
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62 | |||
63 | static bool __ttm_read_lock(struct ttm_lock *lock) |
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64 | { |
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65 | bool locked = false; |
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66 | |||
67 | spin_lock(&lock->lock); |
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68 | if (lock->rw >= 0 && lock->flags == 0) { |
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69 | ++lock->rw; |
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70 | locked = true; |
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71 | } |
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72 | spin_unlock(&lock->lock); |
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73 | return locked; |
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74 | } |
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75 | |||
76 | int ttm_read_lock(struct ttm_lock *lock, bool interruptible) |
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77 | { |
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78 | int ret = 0; |
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79 | |||
80 | if (interruptible) |
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81 | ret = wait_event_interruptible(lock->queue, |
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82 | __ttm_read_lock(lock)); |
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83 | else |
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84 | wait_event(lock->queue, __ttm_read_lock(lock)); |
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85 | return ret; |
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86 | } |
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87 | EXPORT_SYMBOL(ttm_read_lock); |
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88 | |||
89 | static bool __ttm_read_trylock(struct ttm_lock *lock, bool *locked) |
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90 | { |
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91 | bool block = true; |
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92 | |||
93 | *locked = false; |
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94 | |||
95 | spin_lock(&lock->lock); |
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96 | if (lock->rw >= 0 && lock->flags == 0) { |
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97 | ++lock->rw; |
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98 | block = false; |
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99 | *locked = true; |
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100 | } else if (lock->flags == 0) { |
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101 | block = false; |
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102 | } |
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103 | spin_unlock(&lock->lock); |
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104 | |||
105 | return !block; |
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106 | } |
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107 | |||
108 | int ttm_read_trylock(struct ttm_lock *lock, bool interruptible) |
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109 | { |
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110 | int ret = 0; |
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111 | bool locked; |
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112 | |||
113 | if (interruptible) |
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114 | ret = wait_event_interruptible |
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115 | (lock->queue, __ttm_read_trylock(lock, &locked)); |
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116 | else |
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117 | wait_event(lock->queue, __ttm_read_trylock(lock, &locked)); |
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118 | |||
119 | if (unlikely(ret != 0)) { |
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120 | BUG_ON(locked); |
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121 | return ret; |
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122 | } |
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123 | |||
124 | return (locked) ? 0 : -EBUSY; |
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125 | } |
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126 | |||
127 | void ttm_write_unlock(struct ttm_lock *lock) |
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128 | { |
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129 | spin_lock(&lock->lock); |
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130 | lock->rw = 0; |
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131 | wake_up_all(&lock->queue); |
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132 | spin_unlock(&lock->lock); |
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133 | } |
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134 | EXPORT_SYMBOL(ttm_write_unlock); |
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135 | |||
136 | static bool __ttm_write_lock(struct ttm_lock *lock) |
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137 | { |
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138 | bool locked = false; |
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139 | |||
140 | spin_lock(&lock->lock); |
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141 | if (lock->rw == 0 && ((lock->flags & ~TTM_WRITE_LOCK_PENDING) == 0)) { |
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142 | lock->rw = -1; |
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143 | lock->flags &= ~TTM_WRITE_LOCK_PENDING; |
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144 | locked = true; |
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145 | } else { |
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146 | lock->flags |= TTM_WRITE_LOCK_PENDING; |
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147 | } |
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148 | spin_unlock(&lock->lock); |
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149 | return locked; |
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150 | } |
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151 | |||
152 | int ttm_write_lock(struct ttm_lock *lock, bool interruptible) |
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153 | { |
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154 | int ret = 0; |
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155 | |||
156 | if (interruptible) { |
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157 | ret = wait_event_interruptible(lock->queue, |
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158 | __ttm_write_lock(lock)); |
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159 | if (unlikely(ret != 0)) { |
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160 | spin_lock(&lock->lock); |
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161 | lock->flags &= ~TTM_WRITE_LOCK_PENDING; |
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162 | wake_up_all(&lock->queue); |
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163 | spin_unlock(&lock->lock); |
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164 | } |
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165 | } else |
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6296 | serge | 166 | wait_event(lock->queue, __ttm_write_lock(lock)); |
5078 | serge | 167 | |
168 | return ret; |
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169 | } |
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170 | EXPORT_SYMBOL(ttm_write_lock); |
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171 | |||
172 | static int __ttm_vt_unlock(struct ttm_lock *lock) |
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173 | { |
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174 | int ret = 0; |
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175 | |||
176 | spin_lock(&lock->lock); |
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177 | if (unlikely(!(lock->flags & TTM_VT_LOCK))) |
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178 | ret = -EINVAL; |
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179 | lock->flags &= ~TTM_VT_LOCK; |
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180 | wake_up_all(&lock->queue); |
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181 | spin_unlock(&lock->lock); |
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182 | |||
183 | return ret; |
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184 | } |
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185 | |||
186 | static void ttm_vt_lock_remove(struct ttm_base_object **p_base) |
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187 | { |
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188 | struct ttm_base_object *base = *p_base; |
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189 | struct ttm_lock *lock = container_of(base, struct ttm_lock, base); |
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190 | int ret; |
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191 | |||
192 | *p_base = NULL; |
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193 | ret = __ttm_vt_unlock(lock); |
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194 | BUG_ON(ret != 0); |
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195 | } |
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196 | |||
197 | static bool __ttm_vt_lock(struct ttm_lock *lock) |
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198 | { |
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199 | bool locked = false; |
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200 | |||
201 | spin_lock(&lock->lock); |
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202 | if (lock->rw == 0) { |
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203 | lock->flags &= ~TTM_VT_LOCK_PENDING; |
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204 | lock->flags |= TTM_VT_LOCK; |
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205 | locked = true; |
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206 | } else { |
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207 | lock->flags |= TTM_VT_LOCK_PENDING; |
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208 | } |
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209 | spin_unlock(&lock->lock); |
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210 | return locked; |
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211 | } |
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212 | |||
213 | int ttm_vt_lock(struct ttm_lock *lock, |
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214 | bool interruptible, |
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215 | struct ttm_object_file *tfile) |
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216 | { |
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217 | int ret = 0; |
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218 | |||
219 | if (interruptible) { |
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220 | ret = wait_event_interruptible(lock->queue, |
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221 | __ttm_vt_lock(lock)); |
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222 | if (unlikely(ret != 0)) { |
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223 | spin_lock(&lock->lock); |
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224 | lock->flags &= ~TTM_VT_LOCK_PENDING; |
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225 | wake_up_all(&lock->queue); |
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226 | spin_unlock(&lock->lock); |
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227 | return ret; |
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228 | } |
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229 | } else |
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230 | wait_event(lock->queue, __ttm_vt_lock(lock)); |
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231 | |||
232 | /* |
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233 | * Add a base-object, the destructor of which will |
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234 | * make sure the lock is released if the client dies |
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235 | * while holding it. |
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236 | */ |
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237 | |||
238 | ret = ttm_base_object_init(tfile, &lock->base, false, |
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239 | ttm_lock_type, &ttm_vt_lock_remove, NULL); |
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240 | if (ret) |
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241 | (void)__ttm_vt_unlock(lock); |
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242 | else |
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243 | lock->vt_holder = tfile; |
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244 | |||
245 | return ret; |
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246 | } |
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247 | EXPORT_SYMBOL(ttm_vt_lock); |
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248 | |||
249 | int ttm_vt_unlock(struct ttm_lock *lock) |
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250 | { |
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251 | return ttm_ref_object_base_unref(lock->vt_holder, |
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252 | lock->base.hash.key, TTM_REF_USAGE); |
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253 | } |
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254 | EXPORT_SYMBOL(ttm_vt_unlock); |
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255 | |||
256 | void ttm_suspend_unlock(struct ttm_lock *lock) |
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257 | { |
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258 | spin_lock(&lock->lock); |
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259 | lock->flags &= ~TTM_SUSPEND_LOCK; |
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260 | wake_up_all(&lock->queue); |
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261 | spin_unlock(&lock->lock); |
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262 | } |
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263 | EXPORT_SYMBOL(ttm_suspend_unlock); |
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264 | |||
265 | static bool __ttm_suspend_lock(struct ttm_lock *lock) |
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266 | { |
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267 | bool locked = false; |
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268 | |||
269 | spin_lock(&lock->lock); |
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270 | if (lock->rw == 0) { |
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271 | lock->flags &= ~TTM_SUSPEND_LOCK_PENDING; |
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272 | lock->flags |= TTM_SUSPEND_LOCK; |
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273 | locked = true; |
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274 | } else { |
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275 | lock->flags |= TTM_SUSPEND_LOCK_PENDING; |
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276 | } |
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277 | spin_unlock(&lock->lock); |
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278 | return locked; |
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279 | } |
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280 | |||
281 | void ttm_suspend_lock(struct ttm_lock *lock) |
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282 | { |
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283 | wait_event(lock->queue, __ttm_suspend_lock(lock)); |
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284 | } |
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285 | EXPORT_SYMBOL(ttm_suspend_lock);><>><>><>><>><> |