1 | #ifndef _LINUX_LIST_H |
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2 | #define _LINUX_LIST_H |
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3 | |
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4 | /* |
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5 | * Simple doubly linked list implementation. |
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6 | * |
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7 | * Some of the internal functions ("__xxx") are useful when |
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8 | * manipulating whole lists rather than single entries, as |
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9 | * sometimes we already know the next/prev entries and we can |
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10 | * generate better code by using them directly rather than |
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11 | * using the generic single-entry routines. |
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12 | */ |
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13 | |
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14 | struct list_head { |
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15 | struct list_head *next, *prev; |
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16 | }; |
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17 | |
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18 | #define LIST_HEAD_INIT(name) { &(name), &(name) } |
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19 | |
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20 | #define LIST_HEAD(name) \ |
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21 | struct list_head name = LIST_HEAD_INIT(name) |
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22 | |
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23 | #define INIT_LIST_HEAD(ptr) do { \ |
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24 | (ptr)->next = (ptr); (ptr)->prev = (ptr); \ |
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25 | } while (0) |
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26 | |
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27 | /* |
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28 | * Insert a new entry between two known consecutive entries. |
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29 | * |
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30 | * This is only for internal list manipulation where we know |
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31 | * the prev/next entries already! |
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32 | */ |
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33 | static __inline__ void __list_add(struct list_head * new, |
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34 | struct list_head * prev, |
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35 | struct list_head * next) |
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36 | { |
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37 | next->prev = new; |
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38 | new->next = next; |
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39 | new->prev = prev; |
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40 | prev->next = new; |
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41 | } |
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42 | |
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43 | /** |
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44 | * list_add - add a new entry |
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45 | * @new: new entry to be added |
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46 | * @head: list head to add it after |
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47 | * |
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48 | * Insert a new entry after the specified head. |
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49 | * This is good for implementing stacks. |
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50 | */ |
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51 | static __inline__ void list_add(struct list_head *new, struct list_head *head) |
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52 | { |
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53 | __list_add(new, head, head->next); |
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54 | } |
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55 | |
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56 | /** |
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57 | * list_add_tail - add a new entry |
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58 | * @new: new entry to be added |
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59 | * @head: list head to add it before |
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60 | * |
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61 | * Insert a new entry before the specified head. |
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62 | * This is useful for implementing queues. |
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63 | */ |
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64 | static __inline__ void list_add_tail(struct list_head *new, struct list_head *head) |
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65 | { |
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66 | __list_add(new, head->prev, head); |
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67 | } |
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68 | |
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69 | /* |
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70 | * Delete a list entry by making the prev/next entries |
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71 | * point to each other. |
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72 | * |
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73 | * This is only for internal list manipulation where we know |
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74 | * the prev/next entries already! |
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75 | */ |
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76 | static __inline__ void __list_del(struct list_head * prev, |
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77 | struct list_head * next) |
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78 | { |
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79 | next->prev = prev; |
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80 | prev->next = next; |
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81 | } |
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82 | |
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83 | /** |
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84 | * list_del - deletes entry from list. |
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85 | * @entry: the element to delete from the list. |
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86 | * Note: list_empty on entry does not return true after this, the entry is in an undefined state. |
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87 | */ |
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88 | static __inline__ void list_del(struct list_head *entry) |
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89 | { |
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90 | __list_del(entry->prev, entry->next); |
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91 | } |
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92 | |
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93 | /** |
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94 | * list_del_init - deletes entry from list and reinitialize it. |
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95 | * @entry: the element to delete from the list. |
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96 | */ |
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97 | static __inline__ void list_del_init(struct list_head *entry) |
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98 | { |
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99 | __list_del(entry->prev, entry->next); |
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100 | INIT_LIST_HEAD(entry); |
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101 | } |
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102 | |
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103 | /** |
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104 | * list_empty - tests whether a list is empty |
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105 | * @head: the list to test. |
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106 | */ |
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107 | static __inline__ int list_empty(struct list_head *head) |
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108 | { |
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109 | return head->next == head; |
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110 | } |
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111 | |
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112 | /** |
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113 | * list_splice - join two lists |
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114 | * @list: the new list to add. |
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115 | * @head: the place to add it in the first list. |
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116 | */ |
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117 | static __inline__ void list_splice(struct list_head *list, struct list_head *head) |
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118 | { |
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119 | struct list_head *first = list->next; |
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120 | |
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121 | if (first != list) { |
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122 | struct list_head *last = list->prev; |
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123 | struct list_head *at = head->next; |
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124 | |
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125 | first->prev = head; |
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126 | head->next = first; |
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127 | |
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128 | last->next = at; |
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129 | at->prev = last; |
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130 | } |
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131 | } |
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132 | |
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133 | /** |
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134 | * list_entry - get the struct for this entry |
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135 | * @ptr: the &struct list_head pointer. |
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136 | * @type: the type of the struct this is embedded in. |
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137 | * @member: the name of the list_struct within the struct. |
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138 | */ |
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139 | #define list_entry(ptr, type, member) \ |
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140 | ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member))) |
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141 | |
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142 | /** |
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143 | * list_for_each - iterate over a list |
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144 | * @pos: the &struct list_head to use as a loop counter. |
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145 | * @head: the head for your list. |
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146 | */ |
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147 | #define list_for_each(pos, head) \ |
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148 | for (pos = (head)->next; pos != (head); pos = pos->next) |
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149 | |
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150 | /** |
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151 | * list_for_each_safe - iterate over a list safe against removal of list entry |
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152 | * @pos: the &struct list_head to use as a loop counter. |
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153 | * @n: another &struct list_head to use as temporary storage |
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154 | * @head: the head for your list. |
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155 | */ |
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156 | #define list_for_each_safe(pos, n, head) \ |
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157 | for (pos = (head)->next, n = pos->next; pos != (head); \ |
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158 | pos = n, n = pos->next) |
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159 | |
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160 | /** |
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161 | * list_for_each_entry - iterate over list of given type |
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162 | * @pos: the type * to use as a loop counter. |
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163 | * @head: the head for your list. |
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164 | * @member: the name of the list_struct within the struct. |
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165 | */ |
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166 | #define list_for_each_entry(pos, head, member) \ |
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167 | for (pos = list_entry((head)->next, typeof(*pos), member); \ |
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168 | &pos->member != (head); \ |
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169 | pos = list_entry(pos->member.next, typeof(*pos), member)) |
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170 | |
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171 | /** |
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172 | * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry |
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173 | * @pos: the type * to use as a loop counter. |
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174 | * @n: another type * to use as temporary storage |
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175 | * @head: the head for your list. |
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176 | * @member: the name of the list_struct within the struct. |
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177 | */ |
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178 | #define list_for_each_entry_safe(pos, n, head, member) \ |
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179 | for (pos = list_entry((head)->next, typeof(*pos), member), \ |
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180 | n = list_entry(pos->member.next, typeof(*pos), member); \ |
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181 | &pos->member != (head); \ |
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182 | pos = n, n = list_entry(n->member.next, typeof(*n), member)) |
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183 | #endif /* _LINUX_LIST_H */ |
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184 | |
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