| 1 | |
| 2 | * Statically sized hash table implementation
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| 3 | * (C) 2012 Sasha Levin <[email protected]>
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| 4 |
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| 5 |
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| 6 | #ifndef _LINUX_HASHTABLE_H
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| 7 | #define _LINUX_HASHTABLE_H
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| 8 |
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| 9 | #include <linux/list.h>
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| 10 | #include <linux/types.h>
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| 11 | #include <linux/kernel.h>
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| 12 | #include <linux/hash.h>
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| 13 | #include <linux/rculist.h>
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| 14 |
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| 15 | #define DEFINE_HASHTABLE(name, bits) \
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| 16 | struct hlist_head name[1 << (bits)] = \
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| 17 | { [0 ... ((1 << (bits)) - 1)] = HLIST_HEAD_INIT }
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| 18 |
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| 19 | #define DECLARE_HASHTABLE(name, bits) \
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| 20 | struct hlist_head name[1 << (bits)]
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| 21 |
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| 22 | #define HASH_SIZE(name) (ARRAY_SIZE(name))
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| 23 | #define HASH_BITS(name) ilog2(HASH_SIZE(name))
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| 24 |
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| 25 |
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| 26 | #define hash_min(val, bits) \
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| 27 | (sizeof(val) <= 4 ? hash_32(val, bits) : hash_long(val, bits))
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| 28 |
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| 29 | static inline void __hash_init(struct hlist_head *ht, unsigned int sz)
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| 30 | {
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| 31 | unsigned int i;
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| 32 |
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| 33 | for (i = 0; i < sz; i++)
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| 34 | INIT_HLIST_HEAD(&ht[i]);
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| 35 | }
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| 36 |
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| 37 | |
| 38 | * hash_init - initialize a hash table
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| 39 | * @hashtable: hashtable to be initialized
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| 40 | *
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| 41 | * Calculates the size of the hashtable from the given parameter, otherwise
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| 42 | * same as hash_init_size.
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| 43 | *
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| 44 | * This has to be a macro since HASH_BITS() will not work on pointers since
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| 45 | * it calculates the size during preprocessing.
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| 46 |
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| 47 | #define hash_init(hashtable) __hash_init(hashtable, HASH_SIZE(hashtable))
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| 48 |
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| 49 | |
| 50 | * hash_add - add an object to a hashtable
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| 51 | * @hashtable: hashtable to add to
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| 52 | * @node: the &struct hlist_node of the object to be added
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| 53 | * @key: the key of the object to be added
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| 54 |
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| 55 | #define hash_add(hashtable, node, key) \
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| 56 | hlist_add_head(node, &hashtable[hash_min(key, HASH_BITS(hashtable))])
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| 57 |
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| 58 | |
| 59 | * hash_add_rcu - add an object to a rcu enabled hashtable
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| 60 | * @hashtable: hashtable to add to
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| 61 | * @node: the &struct hlist_node of the object to be added
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| 62 | * @key: the key of the object to be added
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| 63 |
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| 64 | #define hash_add_rcu(hashtable, node, key) \
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| 65 | hlist_add_head_rcu(node, &hashtable[hash_min(key, HASH_BITS(hashtable))])
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| 66 |
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| 67 | |
| 68 | * hash_hashed - check whether an object is in any hashtable
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| 69 | * @node: the &struct hlist_node of the object to be checked
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| 70 |
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| 71 | static inline bool hash_hashed(struct hlist_node *node)
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| 72 | {
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| 73 | return !hlist_unhashed(node);
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| 74 | }
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| 75 |
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| 76 | static inline bool __hash_empty(struct hlist_head *ht, unsigned int sz)
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| 77 | {
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| 78 | unsigned int i;
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| 79 |
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| 80 | for (i = 0; i < sz; i++)
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| 81 | if (!hlist_empty(&ht[i]))
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| 82 | return false;
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| 83 |
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| 84 | return true;
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| 85 | }
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| 86 |
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| 87 | |
| 88 | * hash_empty - check whether a hashtable is empty
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| 89 | * @hashtable: hashtable to check
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| 90 | *
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| 91 | * This has to be a macro since HASH_BITS() will not work on pointers since
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| 92 | * it calculates the size during preprocessing.
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| 93 |
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| 94 | #define hash_empty(hashtable) __hash_empty(hashtable, HASH_SIZE(hashtable))
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| 95 |
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| 96 | |
| 97 | * hash_del - remove an object from a hashtable
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| 98 | * @node: &struct hlist_node of the object to remove
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| 99 |
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| 100 | static inline void hash_del(struct hlist_node *node)
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| 101 | {
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| 102 | hlist_del_init(node);
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| 103 | }
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| 104 |
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| 105 | |
| 106 | * hash_del_rcu - remove an object from a rcu enabled hashtable
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| 107 | * @node: &struct hlist_node of the object to remove
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| 108 |
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| 109 | static inline void hash_del_rcu(struct hlist_node *node)
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| 110 | {
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| 111 | hlist_del_init_rcu(node);
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| 112 | }
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| 113 |
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| 114 | |
| 115 | * hash_for_each - iterate over a hashtable
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| 116 | * @name: hashtable to iterate
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| 117 | * @bkt: integer to use as bucket loop cursor
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| 118 | * @obj: the type * to use as a loop cursor for each entry
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| 119 | * @member: the name of the hlist_node within the struct
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| 120 |
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| 121 | #define hash_for_each(name, bkt, obj, member) \
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| 122 | for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
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| 123 | (bkt)++)\
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| 124 | hlist_for_each_entry(obj, &name[bkt], member)
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| 125 |
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| 126 | |
| 127 | * hash_for_each_rcu - iterate over a rcu enabled hashtable
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| 128 | * @name: hashtable to iterate
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| 129 | * @bkt: integer to use as bucket loop cursor
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| 130 | * @obj: the type * to use as a loop cursor for each entry
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| 131 | * @member: the name of the hlist_node within the struct
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| 132 |
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| 133 | #define hash_for_each_rcu(name, bkt, obj, member) \
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| 134 | for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
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| 135 | (bkt)++)\
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| 136 | hlist_for_each_entry_rcu(obj, &name[bkt], member)
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| 137 |
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| 138 | |
| 139 | * hash_for_each_safe - iterate over a hashtable safe against removal of
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| 140 | * hash entry
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| 141 | * @name: hashtable to iterate
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| 142 | * @bkt: integer to use as bucket loop cursor
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| 143 | * @tmp: a &struct used for temporary storage
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| 144 | * @obj: the type * to use as a loop cursor for each entry
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| 145 | * @member: the name of the hlist_node within the struct
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| 146 |
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| 147 | #define hash_for_each_safe(name, bkt, tmp, obj, member) \
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| 148 | for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
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| 149 | (bkt)++)\
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| 150 | hlist_for_each_entry_safe(obj, tmp, &name[bkt], member)
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| 151 |
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| 152 | |
| 153 | * hash_for_each_possible - iterate over all possible objects hashing to the
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| 154 | * same bucket
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| 155 | * @name: hashtable to iterate
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| 156 | * @obj: the type * to use as a loop cursor for each entry
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| 157 | * @member: the name of the hlist_node within the struct
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| 158 | * @key: the key of the objects to iterate over
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| 159 |
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| 160 | #define hash_for_each_possible(name, obj, member, key) \
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| 161 | hlist_for_each_entry(obj, &name[hash_min(key, HASH_BITS(name))], member)
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| 162 |
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| 163 | |
| 164 | * hash_for_each_possible_rcu - iterate over all possible objects hashing to the
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| 165 | * same bucket in an rcu enabled hashtable
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| 166 | * in a rcu enabled hashtable
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| 167 | * @name: hashtable to iterate
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| 168 | * @obj: the type * to use as a loop cursor for each entry
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| 169 | * @member: the name of the hlist_node within the struct
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| 170 | * @key: the key of the objects to iterate over
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| 171 |
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| 172 | #define hash_for_each_possible_rcu(name, obj, member, key) \
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| 173 | hlist_for_each_entry_rcu(obj, &name[hash_min(key, HASH_BITS(name))],\
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| 174 | member)
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| 175 |
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| 176 | |
| 177 | * hash_for_each_possible_rcu_notrace - iterate over all possible objects hashing
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| 178 | * to the same bucket in an rcu enabled hashtable in a rcu enabled hashtable
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| 179 | * @name: hashtable to iterate
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| 180 | * @obj: the type * to use as a loop cursor for each entry
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| 181 | * @member: the name of the hlist_node within the struct
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| 182 | * @key: the key of the objects to iterate over
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| 183 | *
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| 184 | * This is the same as hash_for_each_possible_rcu() except that it does
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| 185 | * not do any RCU debugging or tracing.
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| 186 |
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| 187 | #define hash_for_each_possible_rcu_notrace(name, obj, member, key) \
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| 188 | hlist_for_each_entry_rcu_notrace(obj, \
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| 189 | &name[hash_min(key, HASH_BITS(name))], member)
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| 190 |
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| 191 | |
| 192 | * hash_for_each_possible_safe - iterate over all possible objects hashing to the
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| 193 | * same bucket safe against removals
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| 194 | * @name: hashtable to iterate
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| 195 | * @obj: the type * to use as a loop cursor for each entry
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| 196 | * @tmp: a &struct used for temporary storage
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| 197 | * @member: the name of the hlist_node within the struct
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| 198 | * @key: the key of the objects to iterate over
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| 199 |
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| 200 | #define hash_for_each_possible_safe(name, obj, tmp, member, key) \
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| 201 | hlist_for_each_entry_safe(obj, tmp,\
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| 202 | &name[hash_min(key, HASH_BITS(name))], member)
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| 203 |
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| 204 |
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| 205 | #endif
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