[linux-block.git] / include / linux / rhashtable-types.h

/* 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 */
Commit	Line	Data
0eb71a9d N	1	/* SPDX-License-Identifier: GPL-2.0 */
	2	/*
	3	* Resizable, Scalable, Concurrent Hash Table
	4	*
	5	* Simple structures that might be needed in include
	6	* files.
	7	*/
	8
	9	#ifndef _LINUX_RHASHTABLE_TYPES_H
	10	#define _LINUX_RHASHTABLE_TYPES_H
	11
	12	#include <linux/atomic.h>
	13	#include <linux/compiler.h>
	14	#include <linux/mutex.h>
	15	#include <linux/workqueue.h>
	16
	17	struct rhash_head {
	18	struct rhash_head __rcu *next;
	19	};
	20
	21	struct rhlist_head {
	22	struct rhash_head rhead;
	23	struct rhlist_head __rcu *next;
	24	};
	25
	26	struct bucket_table;
	27
	28	/**
	29	* struct rhashtable_compare_arg - Key for the function rhashtable_compare
	30	* @ht: Hash table
	31	* @key: Key to compare against
	32	*/
	33	struct rhashtable_compare_arg {
	34	struct rhashtable *ht;
	35	const void *key;
	36	};
	37
	38	typedef u32 (rht_hashfn_t)(const void data, u32 len, u32 seed);
	39	typedef u32 (rht_obj_hashfn_t)(const void data, u32 len, u32 seed);
	40	typedef int (rht_obj_cmpfn_t)(struct rhashtable_compare_arg arg,
	41	const void *obj);
	42
	43	/**
	44	* struct rhashtable_params - Hash table construction parameters
	45	* @nelem_hint: Hint on number of elements, should be 75% of desired size
	46	* @key_len: Length of key
	47	* @key_offset: Offset of key in struct to be hashed
	48	* @head_offset: Offset of rhash_head in struct to be hashed
	49	* @max_size: Maximum size while expanding
	50	* @min_size: Minimum size while shrinking
	51	* @locks_mul: Number of bucket locks to allocate per cpu (default: 32)
	52	* @automatic_shrinking: Enable automatic shrinking of tables
0eb71a9d N	53	* @hashfn: Hash function (default: jhash2 if !(key_len % 4), or jhash)
	54	* @obj_hashfn: Function to hash object
	55	* @obj_cmpfn: Function to compare key with object
	56	*/
	57	struct rhashtable_params {
	58	u16 nelem_hint;
	59	u16 key_len;
	60	u16 key_offset;
	61	u16 head_offset;
	62	unsigned int max_size;
	63	u16 min_size;
	64	bool automatic_shrinking;
	65	u8 locks_mul;
0eb71a9d N	66	rht_hashfn_t hashfn;
	67	rht_obj_hashfn_t obj_hashfn;
	68	rht_obj_cmpfn_t obj_cmpfn;
	69	};
	70
	71	/**
	72	* struct rhashtable - Hash table handle
	73	* @tbl: Bucket table
	74	* @key_len: Key length for hashfn
	75	* @max_elems: Maximum number of elements in table
	76	* @p: Configuration parameters
	77	* @rhlist: True if this is an rhltable
	78	* @run_work: Deferred worker to expand/shrink asynchronously
	79	* @mutex: Mutex to protect current/future table swapping
	80	* @lock: Spin lock to protect walker list
	81	* @nelems: Number of elements in table
	82	*/
	83	struct rhashtable {
	84	struct bucket_table __rcu *tbl;
	85	unsigned int key_len;
	86	unsigned int max_elems;
	87	struct rhashtable_params p;
	88	bool rhlist;
	89	struct work_struct run_work;
	90	struct mutex mutex;
	91	spinlock_t lock;
	92	atomic_t nelems;
	93	};
	94
	95	/**
	96	* struct rhltable - Hash table with duplicate objects in a list
	97	* @ht: Underlying rhtable
	98	*/
	99	struct rhltable {
	100	struct rhashtable ht;
	101	};
	102
	103	/**
	104	* struct rhashtable_walker - Hash table walker
	105	* @list: List entry on list of walkers
	106	* @tbl: The table that we were walking over
	107	*/
	108	struct rhashtable_walker {
	109	struct list_head list;
	110	struct bucket_table *tbl;
	111	};
	112
	113	/**
	114	* struct rhashtable_iter - Hash table iterator
	115	* @ht: Table to iterate through
	116	* @p: Current pointer
	117	* @list: Current hash list pointer
	118	* @walker: Associated rhashtable walker
	119	* @slot: Current slot
	120	* @skip: Number of entries to skip in slot
	121	*/
	122	struct rhashtable_iter {
	123	struct rhashtable *ht;
	124	struct rhash_head *p;
	125	struct rhlist_head *list;
	126	struct rhashtable_walker walker;
	127	unsigned int slot;
	128	unsigned int skip;
	129	bool end_of_table;
130	};
131
132	int rhashtable_init(struct rhashtable *ht,
133	const struct rhashtable_params *params);
134	int rhltable_init(struct rhltable *hlt,
135	const struct rhashtable_params *params);
136
137	#endif /* _LINUX_RHASHTABLE_TYPES_H */