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Rev | Author | Line No. | Line |
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4065 | Serge | 1 | #ifndef _LINUX_RCULIST_H |
2 | #define _LINUX_RCULIST_H |
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3 | |||
4 | #ifdef __KERNEL__ |
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5 | |||
6 | /* |
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7 | * RCU-protected list version |
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8 | */ |
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9 | #include |
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5270 | serge | 10 | #include |
4065 | Serge | 11 | |
12 | /* |
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13 | * Why is there no list_empty_rcu()? Because list_empty() serves this |
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14 | * purpose. The list_empty() function fetches the RCU-protected pointer |
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15 | * and compares it to the address of the list head, but neither dereferences |
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16 | * this pointer itself nor provides this pointer to the caller. Therefore, |
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17 | * it is not necessary to use rcu_dereference(), so that list_empty() can |
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18 | * be used anywhere you would want to use a list_empty_rcu(). |
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19 | */ |
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20 | |||
21 | /* |
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5270 | serge | 22 | * INIT_LIST_HEAD_RCU - Initialize a list_head visible to RCU readers |
23 | * @list: list to be initialized |
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24 | * |
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25 | * You should instead use INIT_LIST_HEAD() for normal initialization and |
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26 | * cleanup tasks, when readers have no access to the list being initialized. |
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27 | * However, if the list being initialized is visible to readers, you |
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28 | * need to keep the compiler from being too mischievous. |
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29 | */ |
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30 | static inline void INIT_LIST_HEAD_RCU(struct list_head *list) |
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31 | { |
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32 | ACCESS_ONCE(list->next) = list; |
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33 | ACCESS_ONCE(list->prev) = list; |
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34 | } |
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35 | |||
36 | /* |
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4065 | Serge | 37 | * return the ->next pointer of a list_head in an rcu safe |
38 | * way, we must not access it directly |
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39 | */ |
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40 | #define list_next_rcu(list) (*((struct list_head __rcu **)(&(list)->next))) |
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41 | |||
42 | /* |
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43 | * Insert a new entry between two known consecutive entries. |
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44 | * |
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45 | * This is only for internal list manipulation where we know |
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46 | * the prev/next entries already! |
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47 | */ |
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48 | #ifndef CONFIG_DEBUG_LIST |
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49 | static inline void __list_add_rcu(struct list_head *new, |
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50 | struct list_head *prev, struct list_head *next) |
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51 | { |
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52 | new->next = next; |
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53 | new->prev = prev; |
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54 | rcu_assign_pointer(list_next_rcu(prev), new); |
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55 | next->prev = new; |
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56 | } |
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57 | #else |
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5056 | serge | 58 | void __list_add_rcu(struct list_head *new, |
4065 | Serge | 59 | struct list_head *prev, struct list_head *next); |
60 | #endif |
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61 | |||
62 | /** |
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63 | * list_add_rcu - add a new entry to rcu-protected list |
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64 | * @new: new entry to be added |
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65 | * @head: list head to add it after |
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66 | * |
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67 | * Insert a new entry after the specified head. |
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68 | * This is good for implementing stacks. |
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69 | * |
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70 | * The caller must take whatever precautions are necessary |
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71 | * (such as holding appropriate locks) to avoid racing |
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72 | * with another list-mutation primitive, such as list_add_rcu() |
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73 | * or list_del_rcu(), running on this same list. |
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74 | * However, it is perfectly legal to run concurrently with |
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75 | * the _rcu list-traversal primitives, such as |
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76 | * list_for_each_entry_rcu(). |
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77 | */ |
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78 | static inline void list_add_rcu(struct list_head *new, struct list_head *head) |
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79 | { |
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80 | __list_add_rcu(new, head, head->next); |
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81 | } |
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82 | |||
83 | /** |
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84 | * list_add_tail_rcu - add a new entry to rcu-protected list |
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85 | * @new: new entry to be added |
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86 | * @head: list head to add it before |
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87 | * |
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88 | * Insert a new entry before the specified head. |
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89 | * This is useful for implementing queues. |
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90 | * |
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91 | * The caller must take whatever precautions are necessary |
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92 | * (such as holding appropriate locks) to avoid racing |
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93 | * with another list-mutation primitive, such as list_add_tail_rcu() |
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94 | * or list_del_rcu(), running on this same list. |
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95 | * However, it is perfectly legal to run concurrently with |
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96 | * the _rcu list-traversal primitives, such as |
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97 | * list_for_each_entry_rcu(). |
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98 | */ |
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99 | static inline void list_add_tail_rcu(struct list_head *new, |
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100 | struct list_head *head) |
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101 | { |
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102 | __list_add_rcu(new, head->prev, head); |
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103 | } |
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104 | |||
105 | /** |
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106 | * list_del_rcu - deletes entry from list without re-initialization |
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107 | * @entry: the element to delete from the list. |
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108 | * |
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109 | * Note: list_empty() on entry does not return true after this, |
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110 | * the entry is in an undefined state. It is useful for RCU based |
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111 | * lockfree traversal. |
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112 | * |
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113 | * In particular, it means that we can not poison the forward |
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114 | * pointers that may still be used for walking the list. |
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115 | * |
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116 | * The caller must take whatever precautions are necessary |
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117 | * (such as holding appropriate locks) to avoid racing |
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118 | * with another list-mutation primitive, such as list_del_rcu() |
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119 | * or list_add_rcu(), running on this same list. |
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120 | * However, it is perfectly legal to run concurrently with |
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121 | * the _rcu list-traversal primitives, such as |
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122 | * list_for_each_entry_rcu(). |
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123 | * |
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124 | * Note that the caller is not permitted to immediately free |
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125 | * the newly deleted entry. Instead, either synchronize_rcu() |
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126 | * or call_rcu() must be used to defer freeing until an RCU |
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127 | * grace period has elapsed. |
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128 | */ |
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129 | static inline void list_del_rcu(struct list_head *entry) |
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130 | { |
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131 | __list_del_entry(entry); |
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132 | entry->prev = LIST_POISON2; |
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133 | } |
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134 | |||
135 | /** |
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136 | * hlist_del_init_rcu - deletes entry from hash list with re-initialization |
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137 | * @n: the element to delete from the hash list. |
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138 | * |
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139 | * Note: list_unhashed() on the node return true after this. It is |
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140 | * useful for RCU based read lockfree traversal if the writer side |
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141 | * must know if the list entry is still hashed or already unhashed. |
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142 | * |
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143 | * In particular, it means that we can not poison the forward pointers |
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144 | * that may still be used for walking the hash list and we can only |
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145 | * zero the pprev pointer so list_unhashed() will return true after |
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146 | * this. |
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147 | * |
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148 | * The caller must take whatever precautions are necessary (such as |
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149 | * holding appropriate locks) to avoid racing with another |
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150 | * list-mutation primitive, such as hlist_add_head_rcu() or |
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151 | * hlist_del_rcu(), running on this same list. However, it is |
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152 | * perfectly legal to run concurrently with the _rcu list-traversal |
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153 | * primitives, such as hlist_for_each_entry_rcu(). |
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154 | */ |
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155 | static inline void hlist_del_init_rcu(struct hlist_node *n) |
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156 | { |
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157 | if (!hlist_unhashed(n)) { |
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158 | __hlist_del(n); |
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159 | n->pprev = NULL; |
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160 | } |
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161 | } |
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162 | |||
163 | /** |
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164 | * list_replace_rcu - replace old entry by new one |
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165 | * @old : the element to be replaced |
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166 | * @new : the new element to insert |
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167 | * |
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168 | * The @old entry will be replaced with the @new entry atomically. |
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169 | * Note: @old should not be empty. |
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170 | */ |
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171 | static inline void list_replace_rcu(struct list_head *old, |
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172 | struct list_head *new) |
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173 | { |
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174 | new->next = old->next; |
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175 | new->prev = old->prev; |
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176 | rcu_assign_pointer(list_next_rcu(new->prev), new); |
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177 | new->next->prev = new; |
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178 | old->prev = LIST_POISON2; |
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179 | } |
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180 | |||
181 | /** |
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182 | * list_splice_init_rcu - splice an RCU-protected list into an existing list. |
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183 | * @list: the RCU-protected list to splice |
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184 | * @head: the place in the list to splice the first list into |
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185 | * @sync: function to sync: synchronize_rcu(), synchronize_sched(), ... |
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186 | * |
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187 | * @head can be RCU-read traversed concurrently with this function. |
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188 | * |
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189 | * Note that this function blocks. |
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190 | * |
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191 | * Important note: the caller must take whatever action is necessary to |
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192 | * prevent any other updates to @head. In principle, it is possible |
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193 | * to modify the list as soon as sync() begins execution. |
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194 | * If this sort of thing becomes necessary, an alternative version |
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195 | * based on call_rcu() could be created. But only if -really- |
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196 | * needed -- there is no shortage of RCU API members. |
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197 | */ |
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198 | static inline void list_splice_init_rcu(struct list_head *list, |
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199 | struct list_head *head, |
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200 | void (*sync)(void)) |
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201 | { |
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202 | struct list_head *first = list->next; |
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203 | struct list_head *last = list->prev; |
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204 | struct list_head *at = head->next; |
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205 | |||
206 | if (list_empty(list)) |
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207 | return; |
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208 | |||
5056 | serge | 209 | /* |
210 | * "first" and "last" tracking list, so initialize it. RCU readers |
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211 | * have access to this list, so we must use INIT_LIST_HEAD_RCU() |
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212 | * instead of INIT_LIST_HEAD(). |
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213 | */ |
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4065 | Serge | 214 | |
5270 | serge | 215 | INIT_LIST_HEAD_RCU(list); |
4065 | Serge | 216 | |
217 | /* |
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218 | * At this point, the list body still points to the source list. |
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219 | * Wait for any readers to finish using the list before splicing |
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220 | * the list body into the new list. Any new readers will see |
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221 | * an empty list. |
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222 | */ |
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223 | |||
224 | sync(); |
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225 | |||
226 | /* |
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227 | * Readers are finished with the source list, so perform splice. |
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228 | * The order is important if the new list is global and accessible |
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229 | * to concurrent RCU readers. Note that RCU readers are not |
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230 | * permitted to traverse the prev pointers without excluding |
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231 | * this function. |
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232 | */ |
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233 | |||
234 | last->next = at; |
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235 | rcu_assign_pointer(list_next_rcu(head), first); |
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236 | first->prev = head; |
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237 | at->prev = last; |
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238 | } |
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239 | |||
240 | /** |
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241 | * list_entry_rcu - get the struct for this entry |
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242 | * @ptr: the &struct list_head pointer. |
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243 | * @type: the type of the struct this is embedded in. |
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5270 | serge | 244 | * @member: the name of the list_head within the struct. |
4065 | Serge | 245 | * |
246 | * This primitive may safely run concurrently with the _rcu list-mutation |
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247 | * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock(). |
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248 | */ |
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249 | #define list_entry_rcu(ptr, type, member) \ |
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5056 | serge | 250 | ({ \ |
251 | typeof(*ptr) __rcu *__ptr = (typeof(*ptr) __rcu __force *)ptr; \ |
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4065 | Serge | 252 | container_of((typeof(ptr))rcu_dereference_raw(__ptr), type, member); \ |
5056 | serge | 253 | }) |
4065 | Serge | 254 | |
255 | /** |
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256 | * Where are list_empty_rcu() and list_first_entry_rcu()? |
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257 | * |
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258 | * Implementing those functions following their counterparts list_empty() and |
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259 | * list_first_entry() is not advisable because they lead to subtle race |
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260 | * conditions as the following snippet shows: |
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261 | * |
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262 | * if (!list_empty_rcu(mylist)) { |
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263 | * struct foo *bar = list_first_entry_rcu(mylist, struct foo, list_member); |
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264 | * do_something(bar); |
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265 | * } |
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266 | * |
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267 | * The list may not be empty when list_empty_rcu checks it, but it may be when |
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268 | * list_first_entry_rcu rereads the ->next pointer. |
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269 | * |
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270 | * Rereading the ->next pointer is not a problem for list_empty() and |
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271 | * list_first_entry() because they would be protected by a lock that blocks |
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272 | * writers. |
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273 | * |
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274 | * See list_first_or_null_rcu for an alternative. |
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275 | */ |
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276 | |||
277 | /** |
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278 | * list_first_or_null_rcu - get the first element from a list |
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279 | * @ptr: the list head to take the element from. |
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280 | * @type: the type of the struct this is embedded in. |
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5270 | serge | 281 | * @member: the name of the list_head within the struct. |
4065 | Serge | 282 | * |
283 | * Note that if the list is empty, it returns NULL. |
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284 | * |
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285 | * This primitive may safely run concurrently with the _rcu list-mutation |
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286 | * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock(). |
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287 | */ |
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288 | #define list_first_or_null_rcu(ptr, type, member) \ |
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5056 | serge | 289 | ({ \ |
290 | struct list_head *__ptr = (ptr); \ |
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4103 | Serge | 291 | struct list_head *__next = ACCESS_ONCE(__ptr->next); \ |
5056 | serge | 292 | likely(__ptr != __next) ? list_entry_rcu(__next, type, member) : NULL; \ |
293 | }) |
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4065 | Serge | 294 | |
295 | /** |
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296 | * list_for_each_entry_rcu - iterate over rcu list of given type |
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297 | * @pos: the type * to use as a loop cursor. |
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298 | * @head: the head for your list. |
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5270 | serge | 299 | * @member: the name of the list_head within the struct. |
4065 | Serge | 300 | * |
301 | * This list-traversal primitive may safely run concurrently with |
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302 | * the _rcu list-mutation primitives such as list_add_rcu() |
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303 | * as long as the traversal is guarded by rcu_read_lock(). |
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304 | */ |
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305 | #define list_for_each_entry_rcu(pos, head, member) \ |
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306 | for (pos = list_entry_rcu((head)->next, typeof(*pos), member); \ |
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307 | &pos->member != (head); \ |
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308 | pos = list_entry_rcu(pos->member.next, typeof(*pos), member)) |
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309 | |||
310 | /** |
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311 | * list_for_each_entry_continue_rcu - continue iteration over list of given type |
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312 | * @pos: the type * to use as a loop cursor. |
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313 | * @head: the head for your list. |
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5270 | serge | 314 | * @member: the name of the list_head within the struct. |
4065 | Serge | 315 | * |
316 | * Continue to iterate over list of given type, continuing after |
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317 | * the current position. |
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318 | */ |
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319 | #define list_for_each_entry_continue_rcu(pos, head, member) \ |
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320 | for (pos = list_entry_rcu(pos->member.next, typeof(*pos), member); \ |
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321 | &pos->member != (head); \ |
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322 | pos = list_entry_rcu(pos->member.next, typeof(*pos), member)) |
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323 | |||
324 | /** |
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325 | * hlist_del_rcu - deletes entry from hash list without re-initialization |
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326 | * @n: the element to delete from the hash list. |
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327 | * |
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328 | * Note: list_unhashed() on entry does not return true after this, |
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329 | * the entry is in an undefined state. It is useful for RCU based |
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330 | * lockfree traversal. |
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331 | * |
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332 | * In particular, it means that we can not poison the forward |
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333 | * pointers that may still be used for walking the hash list. |
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334 | * |
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335 | * The caller must take whatever precautions are necessary |
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336 | * (such as holding appropriate locks) to avoid racing |
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337 | * with another list-mutation primitive, such as hlist_add_head_rcu() |
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338 | * or hlist_del_rcu(), running on this same list. |
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339 | * However, it is perfectly legal to run concurrently with |
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340 | * the _rcu list-traversal primitives, such as |
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341 | * hlist_for_each_entry(). |
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342 | */ |
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343 | static inline void hlist_del_rcu(struct hlist_node *n) |
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344 | { |
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345 | __hlist_del(n); |
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346 | n->pprev = LIST_POISON2; |
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347 | } |
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348 | |||
349 | /** |
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350 | * hlist_replace_rcu - replace old entry by new one |
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351 | * @old : the element to be replaced |
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352 | * @new : the new element to insert |
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353 | * |
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354 | * The @old entry will be replaced with the @new entry atomically. |
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355 | */ |
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356 | static inline void hlist_replace_rcu(struct hlist_node *old, |
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357 | struct hlist_node *new) |
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358 | { |
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359 | struct hlist_node *next = old->next; |
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360 | |||
361 | new->next = next; |
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362 | new->pprev = old->pprev; |
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363 | rcu_assign_pointer(*(struct hlist_node __rcu **)new->pprev, new); |
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364 | if (next) |
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365 | new->next->pprev = &new->next; |
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366 | old->pprev = LIST_POISON2; |
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367 | } |
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368 | |||
369 | /* |
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370 | * return the first or the next element in an RCU protected hlist |
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371 | */ |
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372 | #define hlist_first_rcu(head) (*((struct hlist_node __rcu **)(&(head)->first))) |
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373 | #define hlist_next_rcu(node) (*((struct hlist_node __rcu **)(&(node)->next))) |
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374 | #define hlist_pprev_rcu(node) (*((struct hlist_node __rcu **)((node)->pprev))) |
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375 | |||
376 | /** |
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377 | * hlist_add_head_rcu |
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378 | * @n: the element to add to the hash list. |
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379 | * @h: the list to add to. |
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380 | * |
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381 | * Description: |
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382 | * Adds the specified element to the specified hlist, |
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383 | * while permitting racing traversals. |
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384 | * |
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385 | * The caller must take whatever precautions are necessary |
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386 | * (such as holding appropriate locks) to avoid racing |
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387 | * with another list-mutation primitive, such as hlist_add_head_rcu() |
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388 | * or hlist_del_rcu(), running on this same list. |
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389 | * However, it is perfectly legal to run concurrently with |
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390 | * the _rcu list-traversal primitives, such as |
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391 | * hlist_for_each_entry_rcu(), used to prevent memory-consistency |
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392 | * problems on Alpha CPUs. Regardless of the type of CPU, the |
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393 | * list-traversal primitive must be guarded by rcu_read_lock(). |
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394 | */ |
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395 | static inline void hlist_add_head_rcu(struct hlist_node *n, |
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396 | struct hlist_head *h) |
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397 | { |
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398 | struct hlist_node *first = h->first; |
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399 | |||
400 | n->next = first; |
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401 | n->pprev = &h->first; |
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402 | rcu_assign_pointer(hlist_first_rcu(h), n); |
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403 | if (first) |
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404 | first->pprev = &n->next; |
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405 | } |
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406 | |||
407 | /** |
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408 | * hlist_add_before_rcu |
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409 | * @n: the new element to add to the hash list. |
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410 | * @next: the existing element to add the new element before. |
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411 | * |
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412 | * Description: |
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413 | * Adds the specified element to the specified hlist |
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414 | * before the specified node while permitting racing traversals. |
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415 | * |
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416 | * The caller must take whatever precautions are necessary |
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417 | * (such as holding appropriate locks) to avoid racing |
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418 | * with another list-mutation primitive, such as hlist_add_head_rcu() |
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419 | * or hlist_del_rcu(), running on this same list. |
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420 | * However, it is perfectly legal to run concurrently with |
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421 | * the _rcu list-traversal primitives, such as |
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422 | * hlist_for_each_entry_rcu(), used to prevent memory-consistency |
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423 | * problems on Alpha CPUs. |
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424 | */ |
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425 | static inline void hlist_add_before_rcu(struct hlist_node *n, |
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426 | struct hlist_node *next) |
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427 | { |
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428 | n->pprev = next->pprev; |
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429 | n->next = next; |
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430 | rcu_assign_pointer(hlist_pprev_rcu(n), n); |
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431 | next->pprev = &n->next; |
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432 | } |
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433 | |||
434 | /** |
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5056 | serge | 435 | * hlist_add_behind_rcu |
436 | * @n: the new element to add to the hash list. |
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4065 | Serge | 437 | * @prev: the existing element to add the new element after. |
438 | * |
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439 | * Description: |
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440 | * Adds the specified element to the specified hlist |
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441 | * after the specified node while permitting racing traversals. |
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442 | * |
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443 | * The caller must take whatever precautions are necessary |
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444 | * (such as holding appropriate locks) to avoid racing |
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445 | * with another list-mutation primitive, such as hlist_add_head_rcu() |
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446 | * or hlist_del_rcu(), running on this same list. |
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447 | * However, it is perfectly legal to run concurrently with |
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448 | * the _rcu list-traversal primitives, such as |
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449 | * hlist_for_each_entry_rcu(), used to prevent memory-consistency |
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450 | * problems on Alpha CPUs. |
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451 | */ |
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5056 | serge | 452 | static inline void hlist_add_behind_rcu(struct hlist_node *n, |
453 | struct hlist_node *prev) |
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4065 | Serge | 454 | { |
455 | n->next = prev->next; |
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456 | n->pprev = &prev->next; |
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457 | rcu_assign_pointer(hlist_next_rcu(prev), n); |
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458 | if (n->next) |
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459 | n->next->pprev = &n->next; |
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460 | } |
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461 | |||
462 | #define __hlist_for_each_rcu(pos, head) \ |
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463 | for (pos = rcu_dereference(hlist_first_rcu(head)); \ |
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464 | pos; \ |
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465 | pos = rcu_dereference(hlist_next_rcu(pos))) |
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466 | |||
467 | /** |
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468 | * hlist_for_each_entry_rcu - iterate over rcu list of given type |
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469 | * @pos: the type * to use as a loop cursor. |
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470 | * @head: the head for your list. |
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471 | * @member: the name of the hlist_node within the struct. |
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472 | * |
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473 | * This list-traversal primitive may safely run concurrently with |
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474 | * the _rcu list-mutation primitives such as hlist_add_head_rcu() |
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475 | * as long as the traversal is guarded by rcu_read_lock(). |
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476 | */ |
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477 | #define hlist_for_each_entry_rcu(pos, head, member) \ |
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478 | for (pos = hlist_entry_safe (rcu_dereference_raw(hlist_first_rcu(head)),\ |
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479 | typeof(*(pos)), member); \ |
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480 | pos; \ |
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481 | pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\ |
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482 | &(pos)->member)), typeof(*(pos)), member)) |
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483 | |||
484 | /** |
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485 | * hlist_for_each_entry_rcu_notrace - iterate over rcu list of given type (for tracing) |
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486 | * @pos: the type * to use as a loop cursor. |
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487 | * @head: the head for your list. |
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488 | * @member: the name of the hlist_node within the struct. |
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489 | * |
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490 | * This list-traversal primitive may safely run concurrently with |
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491 | * the _rcu list-mutation primitives such as hlist_add_head_rcu() |
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492 | * as long as the traversal is guarded by rcu_read_lock(). |
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493 | * |
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494 | * This is the same as hlist_for_each_entry_rcu() except that it does |
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495 | * not do any RCU debugging or tracing. |
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496 | */ |
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497 | #define hlist_for_each_entry_rcu_notrace(pos, head, member) \ |
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498 | for (pos = hlist_entry_safe (rcu_dereference_raw_notrace(hlist_first_rcu(head)),\ |
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499 | typeof(*(pos)), member); \ |
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500 | pos; \ |
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501 | pos = hlist_entry_safe(rcu_dereference_raw_notrace(hlist_next_rcu(\ |
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502 | &(pos)->member)), typeof(*(pos)), member)) |
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503 | |||
504 | /** |
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505 | * hlist_for_each_entry_rcu_bh - iterate over rcu list of given type |
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506 | * @pos: the type * to use as a loop cursor. |
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507 | * @head: the head for your list. |
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508 | * @member: the name of the hlist_node within the struct. |
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509 | * |
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510 | * This list-traversal primitive may safely run concurrently with |
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511 | * the _rcu list-mutation primitives such as hlist_add_head_rcu() |
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512 | * as long as the traversal is guarded by rcu_read_lock(). |
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513 | */ |
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514 | #define hlist_for_each_entry_rcu_bh(pos, head, member) \ |
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515 | for (pos = hlist_entry_safe(rcu_dereference_bh(hlist_first_rcu(head)),\ |
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516 | typeof(*(pos)), member); \ |
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517 | pos; \ |
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518 | pos = hlist_entry_safe(rcu_dereference_bh(hlist_next_rcu(\ |
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519 | &(pos)->member)), typeof(*(pos)), member)) |
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520 | |||
521 | /** |
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522 | * hlist_for_each_entry_continue_rcu - iterate over a hlist continuing after current point |
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523 | * @pos: the type * to use as a loop cursor. |
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524 | * @member: the name of the hlist_node within the struct. |
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525 | */ |
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526 | #define hlist_for_each_entry_continue_rcu(pos, member) \ |
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527 | for (pos = hlist_entry_safe(rcu_dereference((pos)->member.next),\ |
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528 | typeof(*(pos)), member); \ |
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529 | pos; \ |
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530 | pos = hlist_entry_safe(rcu_dereference((pos)->member.next),\ |
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531 | typeof(*(pos)), member)) |
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532 | |||
533 | /** |
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534 | * hlist_for_each_entry_continue_rcu_bh - iterate over a hlist continuing after current point |
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535 | * @pos: the type * to use as a loop cursor. |
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536 | * @member: the name of the hlist_node within the struct. |
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537 | */ |
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538 | #define hlist_for_each_entry_continue_rcu_bh(pos, member) \ |
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539 | for (pos = hlist_entry_safe(rcu_dereference_bh((pos)->member.next),\ |
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540 | typeof(*(pos)), member); \ |
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541 | pos; \ |
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542 | pos = hlist_entry_safe(rcu_dereference_bh((pos)->member.next),\ |
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543 | typeof(*(pos)), member)) |
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544 | |||
5270 | serge | 545 | /** |
546 | * hlist_for_each_entry_from_rcu - iterate over a hlist continuing from current point |
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547 | * @pos: the type * to use as a loop cursor. |
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548 | * @member: the name of the hlist_node within the struct. |
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549 | */ |
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550 | #define hlist_for_each_entry_from_rcu(pos, member) \ |
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551 | for (; pos; \ |
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552 | pos = hlist_entry_safe(rcu_dereference((pos)->member.next),\ |
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553 | typeof(*(pos)), member)) |
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4065 | Serge | 554 | |
555 | #endif /* __KERNEL__ */ |
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556 | #endif |