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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Resizable, Scalable, Concurrent Hash Table
*
* Simple structures that might be needed in include
* files.
*/
#ifndef _LINUX_RHASHTABLE_TYPES_H
#define _LINUX_RHASHTABLE_TYPES_H
#include <linux/atomic.h>
#include <linux/compiler.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>
struct rhash_head {
struct rhash_head __rcu *next;
};
struct rhlist_head {
struct rhash_head rhead;
struct rhlist_head __rcu *next;
};
struct bucket_table;
/**
* struct rhashtable_compare_arg - Key for the function rhashtable_compare
* @ht: Hash table
* @key: Key to compare against
*/
struct rhashtable_compare_arg {
struct rhashtable *ht;
const void *key;
};
typedef u32 (*rht_hashfn_t)(const void *data, u32 len, u32 seed);
typedef u32 (*rht_obj_hashfn_t)(const void *data, u32 len, u32 seed);
typedef int (*rht_obj_cmpfn_t)(struct rhashtable_compare_arg *arg,
const void *obj);
/**
* struct rhashtable_params - Hash table construction parameters
* @nelem_hint: Hint on number of elements, should be 75% of desired size
* @key_len: Length of key
* @key_offset: Offset of key in struct to be hashed
* @head_offset: Offset of rhash_head in struct to be hashed
* @max_size: Maximum size while expanding
* @min_size: Minimum size while shrinking
* @locks_mul: Number of bucket locks to allocate per cpu (default: 32)
* @automatic_shrinking: Enable automatic shrinking of tables
* @hashfn: Hash function (default: jhash2 if !(key_len % 4), or jhash)
* @obj_hashfn: Function to hash object
* @obj_cmpfn: Function to compare key with object
*/
struct rhashtable_params {
u16 nelem_hint;
u16 key_len;
u16 key_offset;
u16 head_offset;
unsigned int max_size;
u16 min_size;
bool automatic_shrinking;
u8 locks_mul;
rht_hashfn_t hashfn;
rht_obj_hashfn_t obj_hashfn;
rht_obj_cmpfn_t obj_cmpfn;
};
/**
* struct rhashtable - Hash table handle
* @tbl: Bucket table
* @key_len: Key length for hashfn
* @max_elems: Maximum number of elements in table
* @p: Configuration parameters
* @rhlist: True if this is an rhltable
* @run_work: Deferred worker to expand/shrink asynchronously
* @mutex: Mutex to protect current/future table swapping
* @lock: Spin lock to protect walker list
* @nelems: Number of elements in table
*/
struct rhashtable {
struct bucket_table __rcu *tbl;
unsigned int key_len;
unsigned int max_elems;
struct rhashtable_params p;
bool rhlist;
struct work_struct run_work;
struct mutex mutex;
spinlock_t lock;
atomic_t nelems;
};
/**
* struct rhltable - Hash table with duplicate objects in a list
* @ht: Underlying rhtable
*/
struct rhltable {
struct rhashtable ht;
};
/**
* struct rhashtable_walker - Hash table walker
* @list: List entry on list of walkers
* @tbl: The table that we were walking over
*/
struct rhashtable_walker {
struct list_head list;
struct bucket_table *tbl;
};
/**
* struct rhashtable_iter - Hash table iterator
* @ht: Table to iterate through
* @p: Current pointer
* @list: Current hash list pointer
* @walker: Associated rhashtable walker
* @slot: Current slot
* @skip: Number of entries to skip in slot
*/
struct rhashtable_iter {
struct rhashtable *ht;
struct rhash_head *p;
struct rhlist_head *list;
struct rhashtable_walker walker;
unsigned int slot;
unsigned int skip;
bool end_of_table;
};
int rhashtable_init(struct rhashtable *ht,
const struct rhashtable_params *params);
int rhltable_init(struct rhltable *hlt,
const struct rhashtable_params *params);
#endif /* _LINUX_RHASHTABLE_TYPES_H */
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