Viewing: cfs_hash.h
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*
* Copyright (c) 2012, 2015, Intel Corporation.
*/
/*
* This file is part of Lustre, http://www.lustre.org/
*
* Hashing routines
*/
#ifndef __LIBCFS_HASH_H__
#define __LIBCFS_HASH_H__
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/refcount.h>
#include <linux/libcfs/libcfs_debug.h>
#include <linux/libcfs/libcfs_private.h>
/* disable debug */
#define CFS_HASH_DEBUG_NONE 0
/* record hash depth and output to console when it's too deep,
* computing overhead is low but consume more memory
*/
#define CFS_HASH_DEBUG_1 1
/* expensive, check key validation */
#define CFS_HASH_DEBUG_2 2
#define CFS_HASH_DEBUG_LEVEL CFS_HASH_DEBUG_NONE
struct cfs_hash_ops;
struct cfs_hash_lock_ops;
struct cfs_hash_hlist_ops;
union cfs_hash_lock {
rwlock_t rw; /*< rwlock */
spinlock_t spin; /*< spinlock */
struct rw_semaphore rw_sem; /*< rwsem */
};
/*
* cfs_hash_bucket is a container of:
* - lock, counter ...
* - array of hash-head starting from hsb_head[0], hash-head can be one of
* . struct cfs_hash_head
* . struct cfs_hash_head_dep
* . struct cfs_hash_dhead
* . struct cfs_hash_dhead_dep
* which depends on requirement of user
* - some extra bytes (caller can require it while creating hash)
*/
struct cfs_hash_bucket {
union cfs_hash_lock hsb_lock; /*< bucket lock */
__u32 hsb_count; /*< current entries */
__u32 hsb_version; /*< change version */
unsigned int hsb_index; /*< index of bucket */
int hsb_depmax; /*< max depth on bucket */
long hsb_head[]; /*< hash-head array */
};
/*
* cfs_hash bucket descriptor, it's normally in stack of caller
*/
struct cfs_hash_bd {
/*< address of bucket */
struct cfs_hash_bucket *bd_bucket;
/*< offset in bucket */
unsigned int bd_offset;
};
#define CFS_HASH_NAME_LEN 16 /*< default name length */
#define CFS_HASH_BIGNAME_LEN 64 /*< bigname for param tree */
#define CFS_HASH_BKT_BITS 3 /*< default bits of bucket */
#define CFS_HASH_BITS_MAX 30 /*< max bits of bucket */
#define CFS_HASH_BITS_MIN CFS_HASH_BKT_BITS
/*
* common hash attributes.
*/
enum cfs_hash_tag {
/*
* don't need any lock, caller will protect operations with it's
* own lock. With this flag:
* . CFS_HASH_NO_BKTLOCK, CFS_HASH_RW_BKTLOCK, CFS_HASH_SPIN_BKTLOCK
* will be ignored.
* . Some functions will be disabled with this flag, i.e:
* cfs_hash_for_each_empty, cfs_hash_rehash
*/
CFS_HASH_NO_LOCK = BIT(0),
/* no bucket lock, use one spinlock to protect the whole hash */
CFS_HASH_NO_BKTLOCK = BIT(1),
/* rwlock to protect bucket */
CFS_HASH_RW_BKTLOCK = BIT(2),
/* spinlock to protect bucket */
CFS_HASH_SPIN_BKTLOCK = BIT(3),
/* always add new item to tail */
CFS_HASH_ADD_TAIL = BIT(4),
/* hash-table doesn't have refcount on item */
CFS_HASH_NO_ITEMREF = BIT(5),
/* big name for param-tree */
CFS_HASH_BIGNAME = BIT(6),
/* track global count */
CFS_HASH_COUNTER = BIT(7),
/* rehash item by new key */
CFS_HASH_REHASH_KEY = BIT(8),
/* Enable dynamic hash resizing */
CFS_HASH_REHASH = BIT(9),
/* can shrink hash-size */
CFS_HASH_SHRINK = BIT(10),
/* assert hash is empty on exit */
CFS_HASH_ASSERT_EMPTY = BIT(11),
/* record hlist depth */
CFS_HASH_DEPTH = BIT(12),
/*
* rehash is always scheduled in a different thread, so current
* change on hash table is non-blocking
*/
CFS_HASH_NBLK_CHANGE = BIT(13),
/* rw semaphore lock to protect bucket */
CFS_HASH_RW_SEM_BKTLOCK = BIT(14),
/* NB, we typed hs_flags as __u16, please change it
* if you need to extend >=16 flags
*/
};
/* most used attributes */
#define CFS_HASH_DEFAULT (CFS_HASH_RW_BKTLOCK | \
CFS_HASH_COUNTER | CFS_HASH_REHASH)
/*
* cfs_hash is a hash-table implementation for general purpose, it can support:
* . two refcount modes
* hash-table with & without refcount
* . four lock modes
* nolock, one-spinlock, rw-bucket-lock, spin-bucket-lock
* . general operations
* lookup, add(add_tail or add_head), delete
* . rehash
* grows or shrink
* . iteration
* locked iteration and unlocked iteration
* . bigname
* support long name hash
* . debug
* trace max searching depth
*
* Rehash:
* When the htable grows or shrinks, a separate task (cfs_hash_rehash_worker)
* is spawned to handle the rehash in the background, it's possible that other
* processes can concurrently perform additions, deletions, and lookups
* without being blocked on rehash completion, because rehash will release
* the global wrlock for each bucket.
*
* rehash and iteration can't run at the same time because it's too tricky
* to keep both of them safe and correct.
* As they are relatively rare operations, so:
* . if iteration is in progress while we try to launch rehash, then
* it just giveup, iterator will launch rehash at the end.
* . if rehash is in progress while we try to iterate the hash table,
* then we just wait (shouldn't be very long time), anyway, nobody
* should expect iteration of whole hash-table to be non-blocking.
*
* During rehashing, a (key,object) pair may be in one of two buckets,
* depending on whether the worker task has yet to transfer the object
* to its new location in the table. Lookups and deletions need to search both
* locations; additions must take care to only insert into the new bucket.
*/
struct cfs_hash {
/* serialize with rehash, or serialize all operations if
* the hash-table has CFS_HASH_NO_BKTLOCK
*/
union cfs_hash_lock hs_lock;
/* hash operations */
struct cfs_hash_ops *hs_ops;
/* hash lock operations */
struct cfs_hash_lock_ops *hs_lops;
/* hash list operations */
struct cfs_hash_hlist_ops *hs_hops;
/* hash buckets-table */
struct cfs_hash_bucket **hs_buckets;
/* total number of items on this hash-table */
atomic_t hs_count;
/* hash flags, see cfs_hash_tag for detail */
__u16 hs_flags;
/* # of extra-bytes for bucket, for user saving extended attributes */
__u16 hs_extra_bytes;
/* wants to iterate */
__u8 hs_iterating;
/* hash-table is dying */
__u8 hs_exiting;
/* current hash bits */
__u8 hs_cur_bits;
/* min hash bits */
__u8 hs_min_bits;
/* max hash bits */
__u8 hs_max_bits;
/* bits for rehash */
__u8 hs_rehash_bits;
/* bits for each bucket */
__u8 hs_bkt_bits;
/* resize min threshold */
__u16 hs_min_theta;
/* resize max threshold */
__u16 hs_max_theta;
/* resize count */
__u32 hs_rehash_count;
/* # of iterators (caller of cfs_hash_for_each_*) */
__u32 hs_iterators;
/* rehash workitem */
struct work_struct hs_rehash_work;
/* refcount on this hash table */
struct kref hs_refcount;
/* rehash buckets-table */
struct cfs_hash_bucket **hs_rehash_buckets;
#if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1
/* serialize debug members */
spinlock_t hs_dep_lock;
/* max depth */
unsigned int hs_dep_max;
/* id of the deepest bucket */
unsigned int hs_dep_bkt;
/* offset in the deepest bucket */
unsigned int hs_dep_off;
/* bits when we found the max depth */
unsigned int hs_dep_bits;
/* workitem to output max depth */
struct work_struct hs_dep_work;
#endif
/* name of htable */
char hs_name[];
};
struct cfs_hash_lock_ops {
/* lock the hash table */
void (*hs_lock)(union cfs_hash_lock *lock, int exclusive);
/* unlock the hash table */
void (*hs_unlock)(union cfs_hash_lock *lock, int exclusive);
/* lock the hash bucket */
void (*hs_bkt_lock)(union cfs_hash_lock *lock, int exclusive);
/* unlock the hash bucket */
void (*hs_bkt_unlock)(union cfs_hash_lock *lock, int exclusive);
};
struct cfs_hash_hlist_ops {
/* return hlist_head of hash-head of @bd */
struct hlist_head *(*hop_hhead)(struct cfs_hash *hs,
struct cfs_hash_bd *bd);
/* return hash-head size */
int (*hop_hhead_size)(struct cfs_hash *hs);
/* add @hnode to hash-head of @bd */
int (*hop_hnode_add)(struct cfs_hash *hs, struct cfs_hash_bd *bd,
struct hlist_node *hnode);
/* remove @hnode from hash-head of @bd */
int (*hop_hnode_del)(struct cfs_hash *hs, struct cfs_hash_bd *bd,
struct hlist_node *hnode);
};
struct cfs_hash_ops {
/* return hashed value from @key */
unsigned int (*hs_hash)(struct cfs_hash *hs, const void *key,
const unsigned int bits);
/* return key address of @hnode */
void * (*hs_key)(struct hlist_node *hnode);
/* copy key from @hnode to @key */
void (*hs_keycpy)(struct hlist_node *hnode, void *key);
/*
* compare @key with key of @hnode
* returns 1 on a match
*/
int (*hs_keycmp)(const void *key, struct hlist_node *hnode);
/* return object address of @hnode, i.e: container_of(...hnode) */
void * (*hs_object)(struct hlist_node *hnode);
/* get refcount of item, always called with holding bucket-lock */
void (*hs_get)(struct cfs_hash *hs, struct hlist_node *hnode);
/* release refcount of item */
void (*hs_put)(struct cfs_hash *hs, struct hlist_node *hnode);
/* release refcount of item, always called with holding bucket-lock */
void (*hs_put_locked)(struct cfs_hash *hs, struct hlist_node *node);
/* it's called before removing of @hnode */
void (*hs_exit)(struct cfs_hash *hs, struct hlist_node *hnode);
};
/* total number of buckets in @hs */
#define CFS_HASH_NBKT(hs) \
(1U << ((hs)->hs_cur_bits - (hs)->hs_bkt_bits))
/* total number of buckets in @hs while rehashing */
#define CFS_HASH_RH_NBKT(hs) \
(1U << ((hs)->hs_rehash_bits - (hs)->hs_bkt_bits))
/* number of hlist for in bucket */
#define CFS_HASH_BKT_NHLIST(hs) (1U << (hs)->hs_bkt_bits)
/* total number of hlist in @hs */
#define CFS_HASH_NHLIST(hs) (1U << (hs)->hs_cur_bits)
/* total number of hlist in @hs while rehashing */
#define CFS_HASH_RH_NHLIST(hs) (1U << (hs)->hs_rehash_bits)
static inline int
cfs_hash_with_no_lock(struct cfs_hash *hs)
{
/* caller will serialize all operations for this hash-table */
return (hs->hs_flags & CFS_HASH_NO_LOCK) != 0;
}
static inline int
cfs_hash_with_no_bktlock(struct cfs_hash *hs)
{
/* no bucket lock, one single lock to protect the hash-table */
return (hs->hs_flags & CFS_HASH_NO_BKTLOCK) != 0;
}
static inline int
cfs_hash_with_rw_bktlock(struct cfs_hash *hs)
{
/* rwlock to protect hash bucket */
return (hs->hs_flags & CFS_HASH_RW_BKTLOCK) != 0;
}
static inline int
cfs_hash_with_spin_bktlock(struct cfs_hash *hs)
{
/* spinlock to protect hash bucket */
return (hs->hs_flags & CFS_HASH_SPIN_BKTLOCK) != 0;
}
static inline int
cfs_hash_with_rw_sem_bktlock(struct cfs_hash *hs)
{
/* rw sem lock to protect hash bucket */
return (hs->hs_flags & CFS_HASH_RW_SEM_BKTLOCK) != 0;
}
static inline int
cfs_hash_with_add_tail(struct cfs_hash *hs)
{
return (hs->hs_flags & CFS_HASH_ADD_TAIL) != 0;
}
static inline int
cfs_hash_with_no_itemref(struct cfs_hash *hs)
{
/* hash-table doesn't keep refcount on item, item can't be removed from
* hash unless it's ZERO refcount
*/
return (hs->hs_flags & CFS_HASH_NO_ITEMREF) != 0;
}
static inline int
cfs_hash_with_bigname(struct cfs_hash *hs)
{
return (hs->hs_flags & CFS_HASH_BIGNAME) != 0;
}
static inline int
cfs_hash_with_counter(struct cfs_hash *hs)
{
return (hs->hs_flags & CFS_HASH_COUNTER) != 0;
}
static inline int
cfs_hash_with_rehash(struct cfs_hash *hs)
{
return (hs->hs_flags & CFS_HASH_REHASH) != 0;
}
static inline int
cfs_hash_with_rehash_key(struct cfs_hash *hs)
{
return (hs->hs_flags & CFS_HASH_REHASH_KEY) != 0;
}
static inline int
cfs_hash_with_shrink(struct cfs_hash *hs)
{
return (hs->hs_flags & CFS_HASH_SHRINK) != 0;
}
static inline int
cfs_hash_with_assert_empty(struct cfs_hash *hs)
{
return (hs->hs_flags & CFS_HASH_ASSERT_EMPTY) != 0;
}
static inline int
cfs_hash_with_depth(struct cfs_hash *hs)
{
return (hs->hs_flags & CFS_HASH_DEPTH) != 0;
}
static inline int
cfs_hash_with_nblk_change(struct cfs_hash *hs)
{
return (hs->hs_flags & CFS_HASH_NBLK_CHANGE) != 0;
}
static inline int
cfs_hash_is_exiting(struct cfs_hash *hs)
{
/* cfs_hash_destroy is called */
return hs->hs_exiting;
}
static inline int
cfs_hash_is_rehashing(struct cfs_hash *hs)
{
/* rehash is launched */
return hs->hs_rehash_bits != 0;
}
static inline int
cfs_hash_is_iterating(struct cfs_hash *hs)
{
/* someone is calling cfs_hash_for_each_* */
return hs->hs_iterating || hs->hs_iterators != 0;
}
static inline int
cfs_hash_bkt_size(struct cfs_hash *hs)
{
return offsetof(struct cfs_hash_bucket, hsb_head[0]) +
hs->hs_hops->hop_hhead_size(hs) * CFS_HASH_BKT_NHLIST(hs) +
hs->hs_extra_bytes;
}
static inline unsigned int
cfs_hash_id(struct cfs_hash *hs, const void *key, const unsigned int bits)
{
return hs->hs_ops->hs_hash(hs, key, bits);
}
static inline void *
cfs_hash_key(struct cfs_hash *hs, struct hlist_node *hnode)
{
return hs->hs_ops->hs_key(hnode);
}
static inline void
cfs_hash_keycpy(struct cfs_hash *hs, struct hlist_node *hnode, void *key)
{
if (hs->hs_ops->hs_keycpy != NULL)
hs->hs_ops->hs_keycpy(hnode, key);
}
/*
* Returns 1 on a match,
*/
static inline int
cfs_hash_keycmp(struct cfs_hash *hs, const void *key, struct hlist_node *hnode)
{
return hs->hs_ops->hs_keycmp(key, hnode);
}
static inline void *
cfs_hash_object(struct cfs_hash *hs, struct hlist_node *hnode)
{
return hs->hs_ops->hs_object(hnode);
}
static inline void
cfs_hash_get(struct cfs_hash *hs, struct hlist_node *hnode)
{
return hs->hs_ops->hs_get(hs, hnode);
}
static inline void
cfs_hash_put_locked(struct cfs_hash *hs, struct hlist_node *hnode)
{
return hs->hs_ops->hs_put_locked(hs, hnode);
}
static inline void
cfs_hash_put(struct cfs_hash *hs, struct hlist_node *hnode)
{
return hs->hs_ops->hs_put(hs, hnode);
}
static inline void
cfs_hash_exit(struct cfs_hash *hs, struct hlist_node *hnode)
{
if (hs->hs_ops->hs_exit)
hs->hs_ops->hs_exit(hs, hnode);
}
static inline void cfs_hash_lock(struct cfs_hash *hs, int excl)
{
hs->hs_lops->hs_lock(&hs->hs_lock, excl);
}
static inline void cfs_hash_unlock(struct cfs_hash *hs, int excl)
{
hs->hs_lops->hs_unlock(&hs->hs_lock, excl);
}
static inline void cfs_hash_bd_lock(struct cfs_hash *hs,
struct cfs_hash_bd *bd, int excl)
{
hs->hs_lops->hs_bkt_lock(&bd->bd_bucket->hsb_lock, excl);
}
static inline void cfs_hash_bd_unlock(struct cfs_hash *hs,
struct cfs_hash_bd *bd, int excl)
{
hs->hs_lops->hs_bkt_unlock(&bd->bd_bucket->hsb_lock, excl);
}
/*
* operations on cfs_hash bucket (bd: bucket descriptor),
* they are normally for hash-table without rehash
*/
void cfs_hash_bd_get(struct cfs_hash *hs, const void *key,
struct cfs_hash_bd *bd);
static inline void
cfs_hash_bd_get_and_lock(struct cfs_hash *hs, const void *key,
struct cfs_hash_bd *bd, int excl)
{
cfs_hash_bd_get(hs, key, bd);
cfs_hash_bd_lock(hs, bd, excl);
}
static inline void
cfs_hash_bd_index_set(struct cfs_hash *hs, unsigned int index,
struct cfs_hash_bd *bd)
{
bd->bd_bucket = hs->hs_buckets[index >> hs->hs_bkt_bits];
bd->bd_offset = index & (CFS_HASH_BKT_NHLIST(hs) - 1U);
}
static inline void *
cfs_hash_bd_extra_get(struct cfs_hash *hs, struct cfs_hash_bd *bd)
{
LASSERT(hs->hs_extra_bytes);
return (void *)bd->bd_bucket +
cfs_hash_bkt_size(hs) - hs->hs_extra_bytes;
}
static inline __u32
cfs_hash_bd_version_get(struct cfs_hash_bd *bd)
{
/* need hold cfs_hash_bd_lock */
return bd->bd_bucket->hsb_version;
}
static inline __u32
cfs_hash_bd_count_get(struct cfs_hash_bd *bd)
{
/* need hold cfs_hash_bd_lock */
return bd->bd_bucket->hsb_count;
}
static inline int
cfs_hash_bd_compare(struct cfs_hash_bd *bd1, struct cfs_hash_bd *bd2)
{
if (bd1->bd_bucket->hsb_index != bd2->bd_bucket->hsb_index)
return bd1->bd_bucket->hsb_index - bd2->bd_bucket->hsb_index;
if (bd1->bd_offset != bd2->bd_offset)
return bd1->bd_offset - bd2->bd_offset;
return 0;
}
void cfs_hash_bd_add_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd,
struct hlist_node *hnode);
void cfs_hash_bd_del_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd,
struct hlist_node *hnode);
void cfs_hash_bd_move_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd_old,
struct cfs_hash_bd *bd_new,
struct hlist_node *hnode);
static inline int
cfs_hash_bd_dec_and_lock(struct cfs_hash *hs, struct cfs_hash_bd *bd,
refcount_t *condition)
{
LASSERT(cfs_hash_with_spin_bktlock(hs));
return refcount_dec_and_lock(condition, &bd->bd_bucket->hsb_lock.spin);
}
static inline struct hlist_head *
cfs_hash_bd_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd)
{
return hs->hs_hops->hop_hhead(hs, bd);
}
struct hlist_node *
cfs_hash_bd_lookup_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd,
const void *key);
struct hlist_node *
cfs_hash_bd_peek_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd,
const void *key);
struct hlist_node *
cfs_hash_bd_findadd_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd,
const void *key, struct hlist_node *hnode,
int insist_add);
struct hlist_node *
cfs_hash_bd_finddel_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd,
const void *key, struct hlist_node *hnode);
/*
* operations on cfs_hash bucket (bd: bucket descriptor),
* they are safe for hash-table with rehash
*/
void cfs_hash_dual_bd_get(struct cfs_hash *hs, const void *key,
struct cfs_hash_bd *bds);
void cfs_hash_dual_bd_lock(struct cfs_hash *hs, struct cfs_hash_bd *bds,
int excl);
void cfs_hash_dual_bd_unlock(struct cfs_hash *hs, struct cfs_hash_bd *bds,
int excl);
static inline void
cfs_hash_dual_bd_get_and_lock(struct cfs_hash *hs, const void *key,
struct cfs_hash_bd *bds, int excl)
{
cfs_hash_dual_bd_get(hs, key, bds);
cfs_hash_dual_bd_lock(hs, bds, excl);
}
struct hlist_node *
cfs_hash_dual_bd_lookup_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds,
const void *key);
struct hlist_node *
cfs_hash_dual_bd_findadd_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds,
const void *key, struct hlist_node *hnode,
int insist_add);
struct hlist_node *
cfs_hash_dual_bd_finddel_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds,
const void *key, struct hlist_node *hnode);
/* Hash init/cleanup functions */
struct cfs_hash *
cfs_hash_create(const char *name, unsigned int cur_bits, unsigned int max_bits,
unsigned int bkt_bits, unsigned int extra_bytes,
unsigned int min_theta, unsigned int max_theta,
struct cfs_hash_ops *ops, unsigned int flags);
struct cfs_hash *cfs_hash_getref(struct cfs_hash *hs);
void cfs_hash_putref(struct cfs_hash *hs);
/* Hash addition functions */
void cfs_hash_add(struct cfs_hash *hs, const void *key,
struct hlist_node *hnode);
int cfs_hash_add_unique(struct cfs_hash *hs, const void *key,
struct hlist_node *hnode);
void *cfs_hash_findadd_unique(struct cfs_hash *hs, const void *key,
struct hlist_node *hnode);
/* Hash deletion functions */
void *cfs_hash_del(struct cfs_hash *hs, const void *key,
struct hlist_node *hnode);
void *cfs_hash_del_key(struct cfs_hash *hs, const void *key);
/* Hash lookup/for_each functions */
#define CFS_HASH_LOOP_HOG 1024
typedef int (*cfs_hash_for_each_cb_t)(struct cfs_hash *hs,
struct cfs_hash_bd *bd,
struct hlist_node *node,
void *data);
void *cfs_hash_lookup(struct cfs_hash *hs, const void *key);
void cfs_hash_for_each(struct cfs_hash *hs, cfs_hash_for_each_cb_t func,
void *data);
void cfs_hash_for_each_safe(struct cfs_hash *hs, cfs_hash_for_each_cb_t func,
void *data);
int cfs_hash_for_each_nolock(struct cfs_hash *hs, cfs_hash_for_each_cb_t func,
void *data, int start);
int cfs_hash_for_each_empty(struct cfs_hash *hs, cfs_hash_for_each_cb_t func,
void *data);
void cfs_hash_for_each_key(struct cfs_hash *hs, const void *key,
cfs_hash_for_each_cb_t func, void *data);
typedef int (*cfs_hash_cond_opt_cb_t)(void *obj, void *data);
void cfs_hash_cond_del(struct cfs_hash *hs, cfs_hash_cond_opt_cb_t func,
void *data);
void cfs_hash_hlist_for_each(struct cfs_hash *hs, unsigned int hindex,
cfs_hash_for_each_cb_t func, void *data);
int cfs_hash_is_empty(struct cfs_hash *hs);
__u64 cfs_hash_size_get(struct cfs_hash *hs);
/*
* Rehash - Theta is calculated to be the average chained
* hash depth assuming a perfectly uniform hash function.
*/
void cfs_hash_rehash_cancel_locked(struct cfs_hash *hs);
void cfs_hash_rehash_cancel(struct cfs_hash *hs);
void cfs_hash_rehash(struct cfs_hash *hs, int do_rehash);
void cfs_hash_rehash_key(struct cfs_hash *hs, const void *old_key,
void *new_key, struct hlist_node *hnode);
#if CFS_HASH_DEBUG_LEVEL > CFS_HASH_DEBUG_1
/* Validate hnode references the correct key */
static inline void
cfs_hash_key_validate(struct cfs_hash *hs, const void *key,
struct hlist_node *hnode)
{
LASSERT(cfs_hash_keycmp(hs, key, hnode));
}
/* Validate hnode is in the correct bucket */
static inline void
cfs_hash_bucket_validate(struct cfs_hash *hs, struct cfs_hash_bd *bd,
struct hlist_node *hnode)
{
struct cfs_hash_bd bds[2];
cfs_hash_dual_bd_get(hs, cfs_hash_key(hs, hnode), bds);
LASSERT(bds[0].bd_bucket == bd->bd_bucket ||
bds[1].bd_bucket == bd->bd_bucket);
}
#else /* CFS_HASH_DEBUG_LEVEL > CFS_HASH_DEBUG_1 */
static inline void
cfs_hash_key_validate(struct cfs_hash *hs, const void *key,
struct hlist_node *hnode) {}
static inline void
cfs_hash_bucket_validate(struct cfs_hash *hs, struct cfs_hash_bd *bd,
struct hlist_node *hnode) {}
#endif /* CFS_HASH_DEBUG_LEVEL */
#define CFS_HASH_THETA_BITS 10
#define CFS_HASH_MIN_THETA (1U << (CFS_HASH_THETA_BITS - 1))
#define CFS_HASH_MAX_THETA (1U << (CFS_HASH_THETA_BITS + 1))
/* Return integer component of theta */
static inline int __cfs_hash_theta_int(int theta)
{
return (theta >> CFS_HASH_THETA_BITS);
}
/* Return a fractional value between 0 and 999 */
static inline int __cfs_hash_theta_frac(int theta)
{
return ((theta * 1000) >> CFS_HASH_THETA_BITS) -
(__cfs_hash_theta_int(theta) * 1000);
}
static inline int __cfs_hash_theta(struct cfs_hash *hs)
{
return (atomic_read(&hs->hs_count) <<
CFS_HASH_THETA_BITS) >> hs->hs_cur_bits;
}
static inline void
__cfs_hash_set_theta(struct cfs_hash *hs, int min, int max)
{
LASSERT(min < max);
hs->hs_min_theta = (__u16)min;
hs->hs_max_theta = (__u16)max;
}
/* Generic djb2 hash algorithm for character arrays. */
static inline unsigned
cfs_hash_djb2_hash(const void *key, size_t size, const unsigned int bits)
{
unsigned int i, hash = 5381;
LASSERT(key != NULL);
for (i = 0; i < size; i++)
hash = hash * 33 + ((char *)key)[i];
return (hash & ((1U << bits) - 1));
}
/* iterate over all buckets in @bds (array of struct cfs_hash_bd) */
#define cfs_hash_for_each_bd(bds, n, i) \
for (i = 0; i < n && (bds)[i].bd_bucket != NULL; i++)
/* iterate over all buckets of @hs */
#define cfs_hash_for_each_bucket(hs, bd, pos) \
for (pos = 0; \
pos < CFS_HASH_NBKT(hs) && \
((bd)->bd_bucket = (hs)->hs_buckets[pos]) != NULL; pos++)
/* iterate over all hlist of bucket @bd */
#define cfs_hash_bd_for_each_hlist(hs, bd, hlist) \
for ((bd)->bd_offset = 0; \
(bd)->bd_offset < CFS_HASH_BKT_NHLIST(hs) && \
(hlist = cfs_hash_bd_hhead(hs, bd)) != NULL; \
(bd)->bd_offset++)
/* !__LIBCFS__HASH_H__ */
#endif
