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135 lines
3.5 KiB
135 lines
3.5 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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/* |
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* Resizable, Scalable, Concurrent Hash Table |
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* |
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* Simple structures that might be needed in include |
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* files. |
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*/ |
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#ifndef _LINUX_RHASHTABLE_TYPES_H |
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#define _LINUX_RHASHTABLE_TYPES_H |
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#include <linux/atomic.h> |
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#include <linux/compiler.h> |
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#include <linux/mutex.h> |
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#include <linux/workqueue.h> |
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struct rhash_head { |
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struct rhash_head __rcu *next; |
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}; |
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struct rhlist_head { |
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struct rhash_head rhead; |
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struct rhlist_head __rcu *next; |
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}; |
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struct bucket_table; |
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/** |
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* struct rhashtable_compare_arg - Key for the function rhashtable_compare |
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* @ht: Hash table |
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* @key: Key to compare against |
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*/ |
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struct rhashtable_compare_arg { |
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struct rhashtable *ht; |
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const void *key; |
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}; |
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typedef u32 (*rht_hashfn_t)(const void *data, u32 len, u32 seed); |
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typedef u32 (*rht_obj_hashfn_t)(const void *data, u32 len, u32 seed); |
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typedef int (*rht_obj_cmpfn_t)(struct rhashtable_compare_arg *arg, |
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const void *obj); |
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/** |
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* struct rhashtable_params - Hash table construction parameters |
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* @nelem_hint: Hint on number of elements, should be 75% of desired size |
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* @key_len: Length of key |
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* @key_offset: Offset of key in struct to be hashed |
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* @head_offset: Offset of rhash_head in struct to be hashed |
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* @max_size: Maximum size while expanding |
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* @min_size: Minimum size while shrinking |
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* @automatic_shrinking: Enable automatic shrinking of tables |
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* @hashfn: Hash function (default: jhash2 if !(key_len % 4), or jhash) |
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* @obj_hashfn: Function to hash object |
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* @obj_cmpfn: Function to compare key with object |
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*/ |
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struct rhashtable_params { |
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u16 nelem_hint; |
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u16 key_len; |
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u16 key_offset; |
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u16 head_offset; |
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unsigned int max_size; |
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u16 min_size; |
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bool automatic_shrinking; |
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rht_hashfn_t hashfn; |
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rht_obj_hashfn_t obj_hashfn; |
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rht_obj_cmpfn_t obj_cmpfn; |
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}; |
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/** |
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* struct rhashtable - Hash table handle |
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* @tbl: Bucket table |
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* @key_len: Key length for hashfn |
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* @max_elems: Maximum number of elements in table |
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* @p: Configuration parameters |
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* @rhlist: True if this is an rhltable |
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* @run_work: Deferred worker to expand/shrink asynchronously |
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* @mutex: Mutex to protect current/future table swapping |
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* @lock: Spin lock to protect walker list |
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* @nelems: Number of elements in table |
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*/ |
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struct rhashtable { |
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struct bucket_table __rcu *tbl; |
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unsigned int key_len; |
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unsigned int max_elems; |
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struct rhashtable_params p; |
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bool rhlist; |
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struct work_struct run_work; |
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struct mutex mutex; |
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spinlock_t lock; |
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atomic_t nelems; |
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}; |
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/** |
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* struct rhltable - Hash table with duplicate objects in a list |
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* @ht: Underlying rhtable |
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*/ |
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struct rhltable { |
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struct rhashtable ht; |
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}; |
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/** |
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* struct rhashtable_walker - Hash table walker |
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* @list: List entry on list of walkers |
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* @tbl: The table that we were walking over |
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*/ |
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struct rhashtable_walker { |
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struct list_head list; |
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struct bucket_table *tbl; |
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}; |
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/** |
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* struct rhashtable_iter - Hash table iterator |
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* @ht: Table to iterate through |
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* @p: Current pointer |
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* @list: Current hash list pointer |
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* @walker: Associated rhashtable walker |
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* @slot: Current slot |
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* @skip: Number of entries to skip in slot |
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*/ |
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struct rhashtable_iter { |
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struct rhashtable *ht; |
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struct rhash_head *p; |
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struct rhlist_head *list; |
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struct rhashtable_walker walker; |
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unsigned int slot; |
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unsigned int skip; |
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bool end_of_table; |
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}; |
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int rhashtable_init(struct rhashtable *ht, |
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const struct rhashtable_params *params); |
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int rhltable_init(struct rhltable *hlt, |
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const struct rhashtable_params *params); |
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#endif /* _LINUX_RHASHTABLE_TYPES_H */
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