/* 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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