diff options
Diffstat (limited to 'drivers/staging/lustre/lnet/libcfs/hash.c')
| -rw-r--r-- | drivers/staging/lustre/lnet/libcfs/hash.c | 2064 |
1 files changed, 0 insertions, 2064 deletions
diff --git a/drivers/staging/lustre/lnet/libcfs/hash.c b/drivers/staging/lustre/lnet/libcfs/hash.c deleted file mode 100644 index f7b3c9306456..000000000000 --- a/drivers/staging/lustre/lnet/libcfs/hash.c +++ /dev/null @@ -1,2064 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * GPL HEADER START - * - * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 only, - * as published by the Free Software Foundation. - * - * This program is distributed in the hope that it will be useful, but - * WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License version 2 for more details (a copy is included - * in the LICENSE file that accompanied this code). - * - * You should have received a copy of the GNU General Public License - * version 2 along with this program; If not, see - * http://www.gnu.org/licenses/gpl-2.0.html - * - * GPL HEADER END - */ -/* - * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved. - * Use is subject to license terms. - * - * Copyright (c) 2011, 2012, Intel Corporation. - */ -/* - * This file is part of Lustre, http://www.lustre.org/ - * Lustre is a trademark of Sun Microsystems, Inc. - * - * libcfs/libcfs/hash.c - * - * Implement a hash class for hash process in lustre system. - * - * Author: YuZhangyong <yzy@clusterfs.com> - * - * 2008-08-15: Brian Behlendorf <behlendorf1@llnl.gov> - * - Simplified API and improved documentation - * - Added per-hash feature flags: - * * CFS_HASH_DEBUG additional validation - * * CFS_HASH_REHASH dynamic rehashing - * - Added per-hash statistics - * - General performance enhancements - * - * 2009-07-31: Liang Zhen <zhen.liang@sun.com> - * - move all stuff to libcfs - * - don't allow cur_bits != max_bits without setting of CFS_HASH_REHASH - * - ignore hs_rwlock if without CFS_HASH_REHASH setting - * - buckets are allocated one by one(instead of contiguous memory), - * to avoid unnecessary cacheline conflict - * - * 2010-03-01: Liang Zhen <zhen.liang@sun.com> - * - "bucket" is a group of hlist_head now, user can specify bucket size - * by bkt_bits of cfs_hash_create(), all hlist_heads in a bucket share - * one lock for reducing memory overhead. - * - * - support lockless hash, caller will take care of locks: - * avoid lock overhead for hash tables that are already protected - * by locking in the caller for another reason - * - * - support both spin_lock/rwlock for bucket: - * overhead of spinlock contention is lower than read/write - * contention of rwlock, so using spinlock to serialize operations on - * bucket is more reasonable for those frequently changed hash tables - * - * - support one-single lock mode: - * one lock to protect all hash operations to avoid overhead of - * multiple locks if hash table is always small - * - * - removed a lot of unnecessary addref & decref on hash element: - * addref & decref are atomic operations in many use-cases which - * are expensive. - * - * - support non-blocking cfs_hash_add() and cfs_hash_findadd(): - * some lustre use-cases require these functions to be strictly - * non-blocking, we need to schedule required rehash on a different - * thread on those cases. - * - * - safer rehash on large hash table - * In old implementation, rehash function will exclusively lock the - * hash table and finish rehash in one batch, it's dangerous on SMP - * system because rehash millions of elements could take long time. - * New implemented rehash can release lock and relax CPU in middle - * of rehash, it's safe for another thread to search/change on the - * hash table even it's in rehasing. - * - * - support two different refcount modes - * . hash table has refcount on element - * . hash table doesn't change refcount on adding/removing element - * - * - support long name hash table (for param-tree) - * - * - fix a bug for cfs_hash_rehash_key: - * in old implementation, cfs_hash_rehash_key could screw up the - * hash-table because @key is overwritten without any protection. - * Now we need user to define hs_keycpy for those rehash enabled - * hash tables, cfs_hash_rehash_key will overwrite hash-key - * inside lock by calling hs_keycpy. - * - * - better hash iteration: - * Now we support both locked iteration & lockless iteration of hash - * table. Also, user can break the iteration by return 1 in callback. - */ -#include <linux/seq_file.h> -#include <linux/log2.h> - -#include <linux/libcfs/libcfs.h> - -#if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1 -static unsigned int warn_on_depth = 8; -module_param(warn_on_depth, uint, 0644); -MODULE_PARM_DESC(warn_on_depth, "warning when hash depth is high."); -#endif - -struct workqueue_struct *cfs_rehash_wq; - -static inline void -cfs_hash_nl_lock(union cfs_hash_lock *lock, int exclusive) {} - -static inline void -cfs_hash_nl_unlock(union cfs_hash_lock *lock, int exclusive) {} - -static inline void -cfs_hash_spin_lock(union cfs_hash_lock *lock, int exclusive) - __acquires(&lock->spin) -{ - spin_lock(&lock->spin); -} - -static inline void -cfs_hash_spin_unlock(union cfs_hash_lock *lock, int exclusive) - __releases(&lock->spin) -{ - spin_unlock(&lock->spin); -} - -static inline void -cfs_hash_rw_lock(union cfs_hash_lock *lock, int exclusive) - __acquires(&lock->rw) -{ - if (!exclusive) - read_lock(&lock->rw); - else - write_lock(&lock->rw); -} - -static inline void -cfs_hash_rw_unlock(union cfs_hash_lock *lock, int exclusive) - __releases(&lock->rw) -{ - if (!exclusive) - read_unlock(&lock->rw); - else - write_unlock(&lock->rw); -} - -/** No lock hash */ -static struct cfs_hash_lock_ops cfs_hash_nl_lops = { - .hs_lock = cfs_hash_nl_lock, - .hs_unlock = cfs_hash_nl_unlock, - .hs_bkt_lock = cfs_hash_nl_lock, - .hs_bkt_unlock = cfs_hash_nl_unlock, -}; - -/** no bucket lock, one spinlock to protect everything */ -static struct cfs_hash_lock_ops cfs_hash_nbl_lops = { - .hs_lock = cfs_hash_spin_lock, - .hs_unlock = cfs_hash_spin_unlock, - .hs_bkt_lock = cfs_hash_nl_lock, - .hs_bkt_unlock = cfs_hash_nl_unlock, -}; - -/** spin bucket lock, rehash is enabled */ -static struct cfs_hash_lock_ops cfs_hash_bkt_spin_lops = { - .hs_lock = cfs_hash_rw_lock, - .hs_unlock = cfs_hash_rw_unlock, - .hs_bkt_lock = cfs_hash_spin_lock, - .hs_bkt_unlock = cfs_hash_spin_unlock, -}; - -/** rw bucket lock, rehash is enabled */ -static struct cfs_hash_lock_ops cfs_hash_bkt_rw_lops = { - .hs_lock = cfs_hash_rw_lock, - .hs_unlock = cfs_hash_rw_unlock, - .hs_bkt_lock = cfs_hash_rw_lock, - .hs_bkt_unlock = cfs_hash_rw_unlock, -}; - -/** spin bucket lock, rehash is disabled */ -static struct cfs_hash_lock_ops cfs_hash_nr_bkt_spin_lops = { - .hs_lock = cfs_hash_nl_lock, - .hs_unlock = cfs_hash_nl_unlock, - .hs_bkt_lock = cfs_hash_spin_lock, - .hs_bkt_unlock = cfs_hash_spin_unlock, -}; - -/** rw bucket lock, rehash is disabled */ -static struct cfs_hash_lock_ops cfs_hash_nr_bkt_rw_lops = { - .hs_lock = cfs_hash_nl_lock, - .hs_unlock = cfs_hash_nl_unlock, - .hs_bkt_lock = cfs_hash_rw_lock, - .hs_bkt_unlock = cfs_hash_rw_unlock, -}; - -static void -cfs_hash_lock_setup(struct cfs_hash *hs) -{ - if (cfs_hash_with_no_lock(hs)) { - hs->hs_lops = &cfs_hash_nl_lops; - - } else if (cfs_hash_with_no_bktlock(hs)) { - hs->hs_lops = &cfs_hash_nbl_lops; - spin_lock_init(&hs->hs_lock.spin); - - } else if (cfs_hash_with_rehash(hs)) { - rwlock_init(&hs->hs_lock.rw); - - if (cfs_hash_with_rw_bktlock(hs)) - hs->hs_lops = &cfs_hash_bkt_rw_lops; - else if (cfs_hash_with_spin_bktlock(hs)) - hs->hs_lops = &cfs_hash_bkt_spin_lops; - else - LBUG(); - } else { - if (cfs_hash_with_rw_bktlock(hs)) - hs->hs_lops = &cfs_hash_nr_bkt_rw_lops; - else if (cfs_hash_with_spin_bktlock(hs)) - hs->hs_lops = &cfs_hash_nr_bkt_spin_lops; - else - LBUG(); - } -} - -/** - * Simple hash head without depth tracking - * new element is always added to head of hlist - */ -struct cfs_hash_head { - struct hlist_head hh_head; /**< entries list */ -}; - -static int -cfs_hash_hh_hhead_size(struct cfs_hash *hs) -{ - return sizeof(struct cfs_hash_head); -} - -static struct hlist_head * -cfs_hash_hh_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd) -{ - struct cfs_hash_head *head; - - head = (struct cfs_hash_head *)&bd->bd_bucket->hsb_head[0]; - return &head[bd->bd_offset].hh_head; -} - -static int -cfs_hash_hh_hnode_add(struct cfs_hash *hs, struct cfs_hash_bd *bd, - struct hlist_node *hnode) -{ - hlist_add_head(hnode, cfs_hash_hh_hhead(hs, bd)); - return -1; /* unknown depth */ -} - -static int -cfs_hash_hh_hnode_del(struct cfs_hash *hs, struct cfs_hash_bd *bd, - struct hlist_node *hnode) -{ - hlist_del_init(hnode); - return -1; /* unknown depth */ -} - -/** - * Simple hash head with depth tracking - * new element is always added to head of hlist - */ -struct cfs_hash_head_dep { - struct hlist_head hd_head; /**< entries list */ - unsigned int hd_depth; /**< list length */ -}; - -static int -cfs_hash_hd_hhead_size(struct cfs_hash *hs) -{ - return sizeof(struct cfs_hash_head_dep); -} - -static struct hlist_head * -cfs_hash_hd_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd) -{ - struct cfs_hash_head_dep *head; - - head = (struct cfs_hash_head_dep *)&bd->bd_bucket->hsb_head[0]; - return &head[bd->bd_offset].hd_head; -} - -static int -cfs_hash_hd_hnode_add(struct cfs_hash *hs, struct cfs_hash_bd *bd, - struct hlist_node *hnode) -{ - struct cfs_hash_head_dep *hh; - - hh = container_of(cfs_hash_hd_hhead(hs, bd), - struct cfs_hash_head_dep, hd_head); - hlist_add_head(hnode, &hh->hd_head); - return ++hh->hd_depth; -} - -static int -cfs_hash_hd_hnode_del(struct cfs_hash *hs, struct cfs_hash_bd *bd, - struct hlist_node *hnode) -{ - struct cfs_hash_head_dep *hh; - - hh = container_of(cfs_hash_hd_hhead(hs, bd), - struct cfs_hash_head_dep, hd_head); - hlist_del_init(hnode); - return --hh->hd_depth; -} - -/** - * double links hash head without depth tracking - * new element is always added to tail of hlist - */ -struct cfs_hash_dhead { - struct hlist_head dh_head; /**< entries list */ - struct hlist_node *dh_tail; /**< the last entry */ -}; - -static int -cfs_hash_dh_hhead_size(struct cfs_hash *hs) -{ - return sizeof(struct cfs_hash_dhead); -} - -static struct hlist_head * -cfs_hash_dh_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd) -{ - struct cfs_hash_dhead *head; - - head = (struct cfs_hash_dhead *)&bd->bd_bucket->hsb_head[0]; - return &head[bd->bd_offset].dh_head; -} - -static int -cfs_hash_dh_hnode_add(struct cfs_hash *hs, struct cfs_hash_bd *bd, - struct hlist_node *hnode) -{ - struct cfs_hash_dhead *dh; - - dh = container_of(cfs_hash_dh_hhead(hs, bd), - struct cfs_hash_dhead, dh_head); - if (dh->dh_tail) /* not empty */ - hlist_add_behind(hnode, dh->dh_tail); - else /* empty list */ - hlist_add_head(hnode, &dh->dh_head); - dh->dh_tail = hnode; - return -1; /* unknown depth */ -} - -static int -cfs_hash_dh_hnode_del(struct cfs_hash *hs, struct cfs_hash_bd *bd, - struct hlist_node *hnd) -{ - struct cfs_hash_dhead *dh; - - dh = container_of(cfs_hash_dh_hhead(hs, bd), - struct cfs_hash_dhead, dh_head); - if (!hnd->next) { /* it's the tail */ - dh->dh_tail = (hnd->pprev == &dh->dh_head.first) ? NULL : - container_of(hnd->pprev, struct hlist_node, next); - } - hlist_del_init(hnd); - return -1; /* unknown depth */ -} - -/** - * double links hash head with depth tracking - * new element is always added to tail of hlist - */ -struct cfs_hash_dhead_dep { - struct hlist_head dd_head; /**< entries list */ - struct hlist_node *dd_tail; /**< the last entry */ - unsigned int dd_depth; /**< list length */ -}; - -static int -cfs_hash_dd_hhead_size(struct cfs_hash *hs) -{ - return sizeof(struct cfs_hash_dhead_dep); -} - -static struct hlist_head * -cfs_hash_dd_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd) -{ - struct cfs_hash_dhead_dep *head; - - head = (struct cfs_hash_dhead_dep *)&bd->bd_bucket->hsb_head[0]; - return &head[bd->bd_offset].dd_head; -} - -static int -cfs_hash_dd_hnode_add(struct cfs_hash *hs, struct cfs_hash_bd *bd, - struct hlist_node *hnode) -{ - struct cfs_hash_dhead_dep *dh; - - dh = container_of(cfs_hash_dd_hhead(hs, bd), - struct cfs_hash_dhead_dep, dd_head); - if (dh->dd_tail) /* not empty */ - hlist_add_behind(hnode, dh->dd_tail); - else /* empty list */ - hlist_add_head(hnode, &dh->dd_head); - dh->dd_tail = hnode; - return ++dh->dd_depth; -} - -static int -cfs_hash_dd_hnode_del(struct cfs_hash *hs, struct cfs_hash_bd *bd, - struct hlist_node *hnd) -{ - struct cfs_hash_dhead_dep *dh; - - dh = container_of(cfs_hash_dd_hhead(hs, bd), - struct cfs_hash_dhead_dep, dd_head); - if (!hnd->next) { /* it's the tail */ - dh->dd_tail = (hnd->pprev == &dh->dd_head.first) ? NULL : - container_of(hnd->pprev, struct hlist_node, next); - } - hlist_del_init(hnd); - return --dh->dd_depth; -} - -static struct cfs_hash_hlist_ops cfs_hash_hh_hops = { - .hop_hhead = cfs_hash_hh_hhead, - .hop_hhead_size = cfs_hash_hh_hhead_size, - .hop_hnode_add = cfs_hash_hh_hnode_add, - .hop_hnode_del = cfs_hash_hh_hnode_del, -}; - -static struct cfs_hash_hlist_ops cfs_hash_hd_hops = { - .hop_hhead = cfs_hash_hd_hhead, - .hop_hhead_size = cfs_hash_hd_hhead_size, - .hop_hnode_add = cfs_hash_hd_hnode_add, - .hop_hnode_del = cfs_hash_hd_hnode_del, -}; - -static struct cfs_hash_hlist_ops cfs_hash_dh_hops = { - .hop_hhead = cfs_hash_dh_hhead, - .hop_hhead_size = cfs_hash_dh_hhead_size, - .hop_hnode_add = cfs_hash_dh_hnode_add, - .hop_hnode_del = cfs_hash_dh_hnode_del, -}; - -static struct cfs_hash_hlist_ops cfs_hash_dd_hops = { - .hop_hhead = cfs_hash_dd_hhead, - .hop_hhead_size = cfs_hash_dd_hhead_size, - .hop_hnode_add = cfs_hash_dd_hnode_add, - .hop_hnode_del = cfs_hash_dd_hnode_del, -}; - -static void -cfs_hash_hlist_setup(struct cfs_hash *hs) -{ - if (cfs_hash_with_add_tail(hs)) { - hs->hs_hops = cfs_hash_with_depth(hs) ? - &cfs_hash_dd_hops : &cfs_hash_dh_hops; - } else { - hs->hs_hops = cfs_hash_with_depth(hs) ? - &cfs_hash_hd_hops : &cfs_hash_hh_hops; - } -} - -static void -cfs_hash_bd_from_key(struct cfs_hash *hs, struct cfs_hash_bucket **bkts, - unsigned int bits, const void *key, struct cfs_hash_bd *bd) -{ - unsigned int index = cfs_hash_id(hs, key, (1U << bits) - 1); - - LASSERT(bits == hs->hs_cur_bits || bits == hs->hs_rehash_bits); - - bd->bd_bucket = bkts[index & ((1U << (bits - hs->hs_bkt_bits)) - 1)]; - bd->bd_offset = index >> (bits - hs->hs_bkt_bits); -} - -void -cfs_hash_bd_get(struct cfs_hash *hs, const void *key, struct cfs_hash_bd *bd) -{ - /* NB: caller should hold hs->hs_rwlock if REHASH is set */ - if (likely(!hs->hs_rehash_buckets)) { - cfs_hash_bd_from_key(hs, hs->hs_buckets, - hs->hs_cur_bits, key, bd); - } else { - LASSERT(hs->hs_rehash_bits); - cfs_hash_bd_from_key(hs, hs->hs_rehash_buckets, - hs->hs_rehash_bits, key, bd); - } -} -EXPORT_SYMBOL(cfs_hash_bd_get); - -static inline void -cfs_hash_bd_dep_record(struct cfs_hash *hs, struct cfs_hash_bd *bd, int dep_cur) -{ - if (likely(dep_cur <= bd->bd_bucket->hsb_depmax)) - return; - - bd->bd_bucket->hsb_depmax = dep_cur; -# if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1 - if (likely(!warn_on_depth || - max(warn_on_depth, hs->hs_dep_max) >= dep_cur)) - return; - - spin_lock(&hs->hs_dep_lock); - hs->hs_dep_max = dep_cur; - hs->hs_dep_bkt = bd->bd_bucket->hsb_index; - hs->hs_dep_off = bd->bd_offset; - hs->hs_dep_bits = hs->hs_cur_bits; - spin_unlock(&hs->hs_dep_lock); - - queue_work(cfs_rehash_wq, &hs->hs_dep_work); -# endif -} - -void -cfs_hash_bd_add_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd, - struct hlist_node *hnode) -{ - int rc; - - rc = hs->hs_hops->hop_hnode_add(hs, bd, hnode); - cfs_hash_bd_dep_record(hs, bd, rc); - bd->bd_bucket->hsb_version++; - if (unlikely(!bd->bd_bucket->hsb_version)) - bd->bd_bucket->hsb_version++; - bd->bd_bucket->hsb_count++; - - if (cfs_hash_with_counter(hs)) - atomic_inc(&hs->hs_count); - if (!cfs_hash_with_no_itemref(hs)) - cfs_hash_get(hs, hnode); -} -EXPORT_SYMBOL(cfs_hash_bd_add_locked); - -void -cfs_hash_bd_del_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd, - struct hlist_node *hnode) -{ - hs->hs_hops->hop_hnode_del(hs, bd, hnode); - - LASSERT(bd->bd_bucket->hsb_count > 0); - bd->bd_bucket->hsb_count--; - bd->bd_bucket->hsb_version++; - if (unlikely(!bd->bd_bucket->hsb_version)) - bd->bd_bucket->hsb_version++; - - if (cfs_hash_with_counter(hs)) { - LASSERT(atomic_read(&hs->hs_count) > 0); - atomic_dec(&hs->hs_count); - } - if (!cfs_hash_with_no_itemref(hs)) - cfs_hash_put_locked(hs, hnode); -} -EXPORT_SYMBOL(cfs_hash_bd_del_locked); - -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) -{ - struct cfs_hash_bucket *obkt = bd_old->bd_bucket; - struct cfs_hash_bucket *nbkt = bd_new->bd_bucket; - int rc; - - if (!cfs_hash_bd_compare(bd_old, bd_new)) - return; - - /* use cfs_hash_bd_hnode_add/del, to avoid atomic & refcount ops - * in cfs_hash_bd_del/add_locked - */ - hs->hs_hops->hop_hnode_del(hs, bd_old, hnode); - rc = hs->hs_hops->hop_hnode_add(hs, bd_new, hnode); - cfs_hash_bd_dep_record(hs, bd_new, rc); - - LASSERT(obkt->hsb_count > 0); - obkt->hsb_count--; - obkt->hsb_version++; - if (unlikely(!obkt->hsb_version)) - obkt->hsb_version++; - nbkt->hsb_count++; - nbkt->hsb_version++; - if (unlikely(!nbkt->hsb_version)) - nbkt->hsb_version++; -} - -enum { - /** always set, for sanity (avoid ZERO intent) */ - CFS_HS_LOOKUP_MASK_FIND = BIT(0), - /** return entry with a ref */ - CFS_HS_LOOKUP_MASK_REF = BIT(1), - /** add entry if not existing */ - CFS_HS_LOOKUP_MASK_ADD = BIT(2), - /** delete entry, ignore other masks */ - CFS_HS_LOOKUP_MASK_DEL = BIT(3), -}; - -enum cfs_hash_lookup_intent { - /** return item w/o refcount */ - CFS_HS_LOOKUP_IT_PEEK = CFS_HS_LOOKUP_MASK_FIND, - /** return item with refcount */ - CFS_HS_LOOKUP_IT_FIND = (CFS_HS_LOOKUP_MASK_FIND | - CFS_HS_LOOKUP_MASK_REF), - /** return item w/o refcount if existed, otherwise add */ - CFS_HS_LOOKUP_IT_ADD = (CFS_HS_LOOKUP_MASK_FIND | - CFS_HS_LOOKUP_MASK_ADD), - /** return item with refcount if existed, otherwise add */ - CFS_HS_LOOKUP_IT_FINDADD = (CFS_HS_LOOKUP_IT_FIND | - CFS_HS_LOOKUP_MASK_ADD), - /** delete if existed */ - CFS_HS_LOOKUP_IT_FINDDEL = (CFS_HS_LOOKUP_MASK_FIND | - CFS_HS_LOOKUP_MASK_DEL) -}; - -static struct hlist_node * -cfs_hash_bd_lookup_intent(struct cfs_hash *hs, struct cfs_hash_bd *bd, - const void *key, struct hlist_node *hnode, - enum cfs_hash_lookup_intent intent) - -{ - struct hlist_head *hhead = cfs_hash_bd_hhead(hs, bd); - struct hlist_node *ehnode; - struct hlist_node *match; - int intent_add = intent & CFS_HS_LOOKUP_MASK_ADD; - - /* with this function, we can avoid a lot of useless refcount ops, - * which are expensive atomic operations most time. - */ - match = intent_add ? NULL : hnode; - hlist_for_each(ehnode, hhead) { - if (!cfs_hash_keycmp(hs, key, ehnode)) - continue; - - if (match && match != ehnode) /* can't match */ - continue; - - /* match and ... */ - if (intent & CFS_HS_LOOKUP_MASK_DEL) { - cfs_hash_bd_del_locked(hs, bd, ehnode); - return ehnode; - } - - /* caller wants refcount? */ - if (intent & CFS_HS_LOOKUP_MASK_REF) - cfs_hash_get(hs, ehnode); - return ehnode; - } - /* no match item */ - if (!intent_add) - return NULL; - - LASSERT(hnode); - cfs_hash_bd_add_locked(hs, bd, hnode); - return hnode; -} - -struct hlist_node * -cfs_hash_bd_lookup_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd, - const void *key) -{ - return cfs_hash_bd_lookup_intent(hs, bd, key, NULL, - CFS_HS_LOOKUP_IT_FIND); -} -EXPORT_SYMBOL(cfs_hash_bd_lookup_locked); - -struct hlist_node * -cfs_hash_bd_peek_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd, - const void *key) -{ - return cfs_hash_bd_lookup_intent(hs, bd, key, NULL, - CFS_HS_LOOKUP_IT_PEEK); -} -EXPORT_SYMBOL(cfs_hash_bd_peek_locked); - -static void -cfs_hash_multi_bd_lock(struct cfs_hash *hs, struct cfs_hash_bd *bds, - unsigned int n, int excl) -{ - struct cfs_hash_bucket *prev = NULL; - int i; - - /** - * bds must be ascendantly ordered by bd->bd_bucket->hsb_index. - * NB: it's possible that several bds point to the same bucket but - * have different bd::bd_offset, so need take care of deadlock. - */ - cfs_hash_for_each_bd(bds, n, i) { - if (prev == bds[i].bd_bucket) - continue; - - LASSERT(!prev || prev->hsb_index < bds[i].bd_bucket->hsb_index); - cfs_hash_bd_lock(hs, &bds[i], excl); - prev = bds[i].bd_bucket; - } -} - -static void -cfs_hash_multi_bd_unlock(struct cfs_hash *hs, struct cfs_hash_bd *bds, - unsigned int n, int excl) -{ - struct cfs_hash_bucket *prev = NULL; - int i; - - cfs_hash_for_each_bd(bds, n, i) { - if (prev != bds[i].bd_bucket) { - cfs_hash_bd_unlock(hs, &bds[i], excl); - prev = bds[i].bd_bucket; - } - } -} - -static struct hlist_node * -cfs_hash_multi_bd_lookup_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds, - unsigned int n, const void *key) -{ - struct hlist_node *ehnode; - unsigned int i; - - cfs_hash_for_each_bd(bds, n, i) { - ehnode = cfs_hash_bd_lookup_intent(hs, &bds[i], key, NULL, - CFS_HS_LOOKUP_IT_FIND); - if (ehnode) - return ehnode; - } - return NULL; -} - -static struct hlist_node * -cfs_hash_multi_bd_findadd_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds, - unsigned int n, const void *key, - struct hlist_node *hnode, int noref) -{ - struct hlist_node *ehnode; - int intent; - unsigned int i; - - LASSERT(hnode); - intent = (!noref * CFS_HS_LOOKUP_MASK_REF) | CFS_HS_LOOKUP_IT_PEEK; - - cfs_hash_for_each_bd(bds, n, i) { - ehnode = cfs_hash_bd_lookup_intent(hs, &bds[i], key, - NULL, intent); - if (ehnode) - return ehnode; - } - - if (i == 1) { /* only one bucket */ - cfs_hash_bd_add_locked(hs, &bds[0], hnode); - } else { - struct cfs_hash_bd mybd; - - cfs_hash_bd_get(hs, key, &mybd); - cfs_hash_bd_add_locked(hs, &mybd, hnode); - } - - return hnode; -} - -static struct hlist_node * -cfs_hash_multi_bd_finddel_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds, - unsigned int n, const void *key, - struct hlist_node *hnode) -{ - struct hlist_node *ehnode; - unsigned int i; - - cfs_hash_for_each_bd(bds, n, i) { - ehnode = cfs_hash_bd_lookup_intent(hs, &bds[i], key, hnode, - CFS_HS_LOOKUP_IT_FINDDEL); - if (ehnode) - return ehnode; - } - return NULL; -} - -static void -cfs_hash_bd_order(struct cfs_hash_bd *bd1, struct cfs_hash_bd *bd2) -{ - int rc; - - if (!bd2->bd_bucket) - return; - - if (!bd1->bd_bucket) { - *bd1 = *bd2; - bd2->bd_bucket = NULL; - return; - } - - rc = cfs_hash_bd_compare(bd1, bd2); - if (!rc) - bd2->bd_bucket = NULL; - else if (rc > 0) - swap(*bd1, *bd2); /* swap bd1 and bd2 */ -} - -void -cfs_hash_dual_bd_get(struct cfs_hash *hs, const void *key, - struct cfs_hash_bd *bds) -{ - /* NB: caller should hold hs_lock.rw if REHASH is set */ - cfs_hash_bd_from_key(hs, hs->hs_buckets, - hs->hs_cur_bits, key, &bds[0]); - if (likely(!hs->hs_rehash_buckets)) { - /* no rehash or not rehashing */ - bds[1].bd_bucket = NULL; - return; - } - - LASSERT(hs->hs_rehash_bits); - cfs_hash_bd_from_key(hs, hs->hs_rehash_buckets, - hs->hs_rehash_bits, key, &bds[1]); - - cfs_hash_bd_order(&bds[0], &bds[1]); -} - -void -cfs_hash_dual_bd_lock(struct cfs_hash *hs, struct cfs_hash_bd *bds, int excl) -{ - cfs_hash_multi_bd_lock(hs, bds, 2, excl); -} - -void -cfs_hash_dual_bd_unlock(struct cfs_hash *hs, struct cfs_hash_bd *bds, int excl) -{ - cfs_hash_multi_bd_unlock(hs, bds, 2, excl); -} - -struct hlist_node * -cfs_hash_dual_bd_lookup_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds, - const void *key) -{ - return cfs_hash_multi_bd_lookup_locked(hs, bds, 2, 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 noref) -{ - return cfs_hash_multi_bd_findadd_locked(hs, bds, 2, key, - hnode, noref); -} - -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) -{ - return cfs_hash_multi_bd_finddel_locked(hs, bds, 2, key, hnode); -} - -static void -cfs_hash_buckets_free(struct cfs_hash_bucket **buckets, - int bkt_size, int prev_size, int size) -{ - int i; - - for (i = prev_size; i < size; i++) - kfree(buckets[i]); - - kvfree(buckets); -} - -/* - * Create or grow bucket memory. Return old_buckets if no allocation was - * needed, the newly allocated buckets if allocation was needed and - * successful, and NULL on error. - */ -static struct cfs_hash_bucket ** -cfs_hash_buckets_realloc(struct cfs_hash *hs, struct cfs_hash_bucket **old_bkts, - unsigned int old_size, unsigned int new_size) -{ - struct cfs_hash_bucket **new_bkts; - int i; - - LASSERT(!old_size || old_bkts); - - if (old_bkts && old_size == new_size) - return old_bkts; - - new_bkts = kvmalloc_array(new_size, sizeof(new_bkts[0]), GFP_KERNEL); - if (!new_bkts) - return NULL; - - if (old_bkts) { - memcpy(new_bkts, old_bkts, - min(old_size, new_size) * sizeof(*old_bkts)); - } - - for (i = old_size; i < new_size; i++) { - struct hlist_head *hhead; - struct cfs_hash_bd bd; - - new_bkts[i] = kzalloc(cfs_hash_bkt_size(hs), GFP_KERNEL); - if (!new_bkts[i]) { - cfs_hash_buckets_free(new_bkts, cfs_hash_bkt_size(hs), - old_size, new_size); - return NULL; - } - - new_bkts[i]->hsb_index = i; - new_bkts[i]->hsb_version = 1; /* shouldn't be zero */ - new_bkts[i]->hsb_depmax = -1; /* unknown */ - bd.bd_bucket = new_bkts[i]; - cfs_hash_bd_for_each_hlist(hs, &bd, hhead) - INIT_HLIST_HEAD(hhead); - - if (cfs_hash_with_no_lock(hs) || - cfs_hash_with_no_bktlock(hs)) - continue; - - if (cfs_hash_with_rw_bktlock(hs)) - rwlock_init(&new_bkts[i]->hsb_lock.rw); - else if (cfs_hash_with_spin_bktlock(hs)) - spin_lock_init(&new_bkts[i]->hsb_lock.spin); - else - LBUG(); /* invalid use-case */ - } - return new_bkts; -} - -/** - * Initialize new libcfs hash, where: - * @name - Descriptive hash name - * @cur_bits - Initial hash table size, in bits - * @max_bits - Maximum allowed hash table resize, in bits - * @ops - Registered hash table operations - * @flags - CFS_HASH_REHASH enable synamic hash resizing - * - CFS_HASH_SORT enable chained hash sort - */ -static void cfs_hash_rehash_worker(struct work_struct *work); - -#if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1 -static void cfs_hash_dep_print(struct work_struct *work) -{ - struct cfs_hash *hs = container_of(work, struct cfs_hash, hs_dep_work); - int dep; - int bkt; - int off; - int bits; - - spin_lock(&hs->hs_dep_lock); - dep = hs->hs_dep_max; - bkt = hs->hs_dep_bkt; - off = hs->hs_dep_off; - bits = hs->hs_dep_bits; - spin_unlock(&hs->hs_dep_lock); - - LCONSOLE_WARN("#### HASH %s (bits: %d): max depth %d at bucket %d/%d\n", - hs->hs_name, bits, dep, bkt, off); - spin_lock(&hs->hs_dep_lock); - hs->hs_dep_bits = 0; /* mark as workitem done */ - spin_unlock(&hs->hs_dep_lock); - return 0; -} - -static void cfs_hash_depth_wi_init(struct cfs_hash *hs) -{ - spin_lock_init(&hs->hs_dep_lock); - INIT_WORK(&hs->hs_dep_work, cfs_hash_dep_print); -} - -static void cfs_hash_depth_wi_cancel(struct cfs_hash *hs) -{ - cancel_work_sync(&hs->hs_dep_work); -} - -#else /* CFS_HASH_DEBUG_LEVEL < CFS_HASH_DEBUG_1 */ - -static inline void cfs_hash_depth_wi_init(struct cfs_hash *hs) {} -static inline void cfs_hash_depth_wi_cancel(struct cfs_hash *hs) {} - -#endif /* CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1 */ - -struct cfs_hash * -cfs_hash_create(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 *hs; - int len; - - BUILD_BUG_ON(CFS_HASH_THETA_BITS >= 15); - - LASSERT(name); - LASSERT(ops->hs_key); - LASSERT(ops->hs_hash); - LASSERT(ops->hs_object); - LASSERT(ops->hs_keycmp); - LASSERT(ops->hs_get); - LASSERT(ops->hs_put || ops->hs_put_locked); - - if (flags & CFS_HASH_REHASH) - flags |= CFS_HASH_COUNTER; /* must have counter */ - - LASSERT(cur_bits > 0); - LASSERT(cur_bits >= bkt_bits); - LASSERT(max_bits >= cur_bits && max_bits < 31); - LASSERT(ergo(!(flags & CFS_HASH_REHASH), cur_bits == max_bits)); - LASSERT(ergo(flags & CFS_HASH_REHASH, !(flags & CFS_HASH_NO_LOCK))); - LASSERT(ergo(flags & CFS_HASH_REHASH_KEY, ops->hs_keycpy)); - - len = !(flags & CFS_HASH_BIGNAME) ? - CFS_HASH_NAME_LEN : CFS_HASH_BIGNAME_LEN; - hs = kzalloc(offsetof(struct cfs_hash, hs_name[len]), GFP_KERNEL); - if (!hs) - return NULL; - - strlcpy(hs->hs_name, name, len); - hs->hs_flags = flags; - - atomic_set(&hs->hs_refcount, 1); - atomic_set(&hs->hs_count, 0); - - cfs_hash_lock_setup(hs); - cfs_hash_hlist_setup(hs); - - hs->hs_cur_bits = (u8)cur_bits; - hs->hs_min_bits = (u8)cur_bits; - hs->hs_max_bits = (u8)max_bits; - hs->hs_bkt_bits = (u8)bkt_bits; - - hs->hs_ops = ops; - hs->hs_extra_bytes = extra_bytes; - hs->hs_rehash_bits = 0; - INIT_WORK(&hs->hs_rehash_work, cfs_hash_rehash_worker); - cfs_hash_depth_wi_init(hs); - - if (cfs_hash_with_rehash(hs)) - __cfs_hash_set_theta(hs, min_theta, max_theta); - - hs->hs_buckets = cfs_hash_buckets_realloc(hs, NULL, 0, - CFS_HASH_NBKT(hs)); - if (hs->hs_buckets) - return hs; - - kfree(hs); - return NULL; -} -EXPORT_SYMBOL(cfs_hash_create); - -/** - * Cleanup libcfs hash @hs. - */ -static void -cfs_hash_destroy(struct cfs_hash *hs) -{ - struct hlist_node *hnode; - struct hlist_node *pos; - struct cfs_hash_bd bd; - int i; - - LASSERT(hs); - LASSERT(!cfs_hash_is_exiting(hs) && - !cfs_hash_is_iterating(hs)); - - /** - * prohibit further rehashes, don't need any lock because - * I'm the only (last) one can change it. - */ - hs->hs_exiting = 1; - if (cfs_hash_with_rehash(hs)) - cfs_hash_rehash_cancel(hs); - - cfs_hash_depth_wi_cancel(hs); - /* rehash should be done/canceled */ - LASSERT(hs->hs_buckets && !hs->hs_rehash_buckets); - - cfs_hash_for_each_bucket(hs, &bd, i) { - struct hlist_head *hhead; - - LASSERT(bd.bd_bucket); - /* no need to take this lock, just for consistent code */ - cfs_hash_bd_lock(hs, &bd, 1); - - cfs_hash_bd_for_each_hlist(hs, &bd, hhead) { - hlist_for_each_safe(hnode, pos, hhead) { - LASSERTF(!cfs_hash_with_assert_empty(hs), - "hash %s bucket %u(%u) is not empty: %u items left\n", - hs->hs_name, bd.bd_bucket->hsb_index, - bd.bd_offset, bd.bd_bucket->hsb_count); - /* can't assert key valicate, because we - * can interrupt rehash - */ - cfs_hash_bd_del_locked(hs, &bd, hnode); - cfs_hash_exit(hs, hnode); - } - } - LASSERT(!bd.bd_bucket->hsb_count); - cfs_hash_bd_unlock(hs, &bd, 1); - cond_resched(); - } - - LASSERT(!atomic_read(&hs->hs_count)); - - cfs_hash_buckets_free(hs->hs_buckets, cfs_hash_bkt_size(hs), - 0, CFS_HASH_NBKT(hs)); - i = cfs_hash_with_bigname(hs) ? - CFS_HASH_BIGNAME_LEN : CFS_HASH_NAME_LEN; - kfree(hs); -} - -struct cfs_hash *cfs_hash_getref(struct cfs_hash *hs) -{ - if (atomic_inc_not_zero(&hs->hs_refcount)) - return hs; - return NULL; -} -EXPORT_SYMBOL(cfs_hash_getref); - -void cfs_hash_putref(struct cfs_hash *hs) -{ - if (atomic_dec_and_test(&hs->hs_refcount)) - cfs_hash_destroy(hs); -} -EXPORT_SYMBOL(cfs_hash_putref); - -static inline int -cfs_hash_rehash_bits(struct cfs_hash *hs) -{ - if (cfs_hash_with_no_lock(hs) || - !cfs_hash_with_rehash(hs)) - return -EOPNOTSUPP; - - if (unlikely(cfs_hash_is_exiting(hs))) - return -ESRCH; - - if (unlikely(cfs_hash_is_rehashing(hs))) - return -EALREADY; - - if (unlikely(cfs_hash_is_iterating(hs))) - return -EAGAIN; - - /* XXX: need to handle case with max_theta != 2.0 - * and the case with min_theta != 0.5 - */ - if ((hs->hs_cur_bits < hs->hs_max_bits) && - (__cfs_hash_theta(hs) > hs->hs_max_theta)) - return hs->hs_cur_bits + 1; - - if (!cfs_hash_with_shrink(hs)) - return 0; - - if ((hs->hs_cur_bits > hs->hs_min_bits) && - (__cfs_hash_theta(hs) < hs->hs_min_theta)) - return hs->hs_cur_bits - 1; - - return 0; -} - -/** - * don't allow inline rehash if: - * - user wants non-blocking change (add/del) on hash table - * - too many elements - */ -static inline int -cfs_hash_rehash_inline(struct cfs_hash *hs) -{ - return !cfs_hash_with_nblk_change(hs) && - atomic_read(&hs->hs_count) < CFS_HASH_LOOP_HOG; -} - -/** - * Add item @hnode to libcfs hash @hs using @key. The registered - * ops->hs_get function will be called when the item is added. - */ -void -cfs_hash_add(struct cfs_hash *hs, const void *key, struct hlist_node *hnode) -{ - struct cfs_hash_bd bd; - int bits; - - LASSERT(hlist_unhashed(hnode)); - - cfs_hash_lock(hs, 0); - cfs_hash_bd_get_and_lock(hs, key, &bd, 1); - - cfs_hash_key_validate(hs, key, hnode); - cfs_hash_bd_add_locked(hs, &bd, hnode); - - cfs_hash_bd_unlock(hs, &bd, 1); - - bits = cfs_hash_rehash_bits(hs); - cfs_hash_unlock(hs, 0); - if (bits > 0) - cfs_hash_rehash(hs, cfs_hash_rehash_inline(hs)); -} -EXPORT_SYMBOL(cfs_hash_add); - -static struct hlist_node * -cfs_hash_find_or_add(struct cfs_hash *hs, const void *key, - struct hlist_node *hnode, int noref) -{ - struct hlist_node *ehnode; - struct cfs_hash_bd bds[2]; - int bits = 0; - - LASSERTF(hlist_unhashed(hnode), "hnode = %p\n", hnode); - - cfs_hash_lock(hs, 0); - cfs_hash_dual_bd_get_and_lock(hs, key, bds, 1); - - cfs_hash_key_validate(hs, key, hnode); - ehnode = cfs_hash_dual_bd_findadd_locked(hs, bds, key, - hnode, noref); - cfs_hash_dual_bd_unlock(hs, bds, 1); - - if (ehnode == hnode) /* new item added */ - bits = cfs_hash_rehash_bits(hs); - cfs_hash_unlock(hs, 0); - if (bits > 0) - cfs_hash_rehash(hs, cfs_hash_rehash_inline(hs)); - - return ehnode; -} - -/** - * Add item @hnode to libcfs hash @hs using @key. The registered - * ops->hs_get function will be called if the item was added. - * Returns 0 on success or -EALREADY on key collisions. - */ -int -cfs_hash_add_unique(struct cfs_hash *hs, const void *key, - struct hlist_node *hnode) -{ - return cfs_hash_find_or_add(hs, key, hnode, 1) != hnode ? - -EALREADY : 0; -} -EXPORT_SYMBOL(cfs_hash_add_unique); - -/** - * Add item @hnode to libcfs hash @hs using @key. If this @key - * already exists in the hash then ops->hs_get will be called on the - * conflicting entry and that entry will be returned to the caller. - * Otherwise ops->hs_get is called on the item which was added. - */ -void * -cfs_hash_findadd_unique(struct cfs_hash *hs, const void *key, - struct hlist_node *hnode) -{ - hnode = cfs_hash_find_or_add(hs, key, hnode, 0); - - return cfs_hash_object(hs, hnode); -} -EXPORT_SYMBOL(cfs_hash_findadd_unique); - -/** - * Delete item @hnode from the libcfs hash @hs using @key. The @key - * is required to ensure the correct hash bucket is locked since there - * is no direct linkage from the item to the bucket. The object - * removed from the hash will be returned and obs->hs_put is called - * on the removed object. - */ -void * -cfs_hash_del(struct cfs_hash *hs, const void *key, struct hlist_node *hnode) -{ - void *obj = NULL; - int bits = 0; - struct cfs_hash_bd bds[2]; - - cfs_hash_lock(hs, 0); - cfs_hash_dual_bd_get_and_lock(hs, key, bds, 1); - - /* NB: do nothing if @hnode is not in hash table */ - if (!hnode || !hlist_unhashed(hnode)) { - if (!bds[1].bd_bucket && hnode) { - cfs_hash_bd_del_locked(hs, &bds[0], hnode); - } else { - hnode = cfs_hash_dual_bd_finddel_locked(hs, bds, - key, hnode); - } - } - - if (hnode) { - obj = cfs_hash_object(hs, hnode); - bits = cfs_hash_rehash_bits(hs); - } - - cfs_hash_dual_bd_unlock(hs, bds, 1); - cfs_hash_unlock(hs, 0); - if (bits > 0) - cfs_hash_rehash(hs, cfs_hash_rehash_inline(hs)); - - return obj; -} -EXPORT_SYMBOL(cfs_hash_del); - -/** - * Delete item given @key in libcfs hash @hs. The first @key found in - * the hash will be removed, if the key exists multiple times in the hash - * @hs this function must be called once per key. The removed object - * will be returned and ops->hs_put is called on the removed object. - */ -void * -cfs_hash_del_key(struct cfs_hash *hs, const void *key) -{ - return cfs_hash_del(hs, key, NULL); -} -EXPORT_SYMBOL(cfs_hash_del_key); - -/** - * Lookup an item using @key in the libcfs hash @hs and return it. - * If the @key is found in the hash hs->hs_get() is called and the - * matching objects is returned. It is the callers responsibility - * to call the counterpart ops->hs_put using the cfs_hash_put() macro - * when when finished with the object. If the @key was not found - * in the hash @hs NULL is returned. - */ -void * -cfs_hash_lookup(struct cfs_hash *hs, const void *key) -{ - void *obj = NULL; - struct hlist_node *hnode; - struct cfs_hash_bd bds[2]; - - cfs_hash_lock(hs, 0); - cfs_hash_dual_bd_get_and_lock(hs, key, bds, 0); - - hnode = cfs_hash_dual_bd_lookup_locked(hs, bds, key); - if (hnode) - obj = cfs_hash_object(hs, hnode); - - cfs_hash_dual_bd_unlock(hs, bds, 0); - cfs_hash_unlock(hs, 0); - - return obj; -} -EXPORT_SYMBOL(cfs_hash_lookup); - -static void -cfs_hash_for_each_enter(struct cfs_hash *hs) -{ - LASSERT(!cfs_hash_is_exiting(hs)); - - if (!cfs_hash_with_rehash(hs)) - return; - /* - * NB: it's race on cfs_has_t::hs_iterating, but doesn't matter - * because it's just an unreliable signal to rehash-thread, - * rehash-thread will try to finish rehash ASAP when seeing this. - */ - hs->hs_iterating = 1; - - cfs_hash_lock(hs, 1); - hs->hs_iterators++; - cfs_hash_unlock(hs, 1); - - /* NB: iteration is mostly called by service thread, - * we tend to cancel pending rehash-request, instead of - * blocking service thread, we will relaunch rehash request - * after iteration - */ - if (cfs_hash_is_rehashing(hs)) - cfs_hash_rehash_cancel(hs); -} - -static void -cfs_hash_for_each_exit(struct cfs_hash *hs) -{ - int remained; - int bits; - - if (!cfs_hash_with_rehash(hs)) - return; - cfs_hash_lock(hs, 1); - remained = --hs->hs_iterators; - bits = cfs_hash_rehash_bits(hs); - cfs_hash_unlock(hs, 1); - /* NB: it's race on cfs_has_t::hs_iterating, see above */ - if (!remained) - hs->hs_iterating = 0; - if (bits > 0) { - cfs_hash_rehash(hs, atomic_read(&hs->hs_count) < - CFS_HASH_LOOP_HOG); - } -} - -/** - * For each item in the libcfs hash @hs call the passed callback @func - * and pass to it as an argument each hash item and the private @data. - * - * a) the function may sleep! - * b) during the callback: - * . the bucket lock is held so the callback must never sleep. - * . if @removal_safe is true, use can remove current item by - * cfs_hash_bd_del_locked - */ -static u64 -cfs_hash_for_each_tight(struct cfs_hash *hs, cfs_hash_for_each_cb_t func, - void *data, int remove_safe) -{ - struct hlist_node *hnode; - struct hlist_node *pos; - struct cfs_hash_bd bd; - u64 count = 0; - int excl = !!remove_safe; - int loop = 0; - int i; - - cfs_hash_for_each_enter(hs); - - cfs_hash_lock(hs, 0); - LASSERT(!cfs_hash_is_rehashing(hs)); - - cfs_hash_for_each_bucket(hs, &bd, i) { - struct hlist_head *hhead; - - cfs_hash_bd_lock(hs, &bd, excl); - if (!func) { /* only glimpse size */ - count += bd.bd_bucket->hsb_count; - cfs_hash_bd_unlock(hs, &bd, excl); - continue; - } - - cfs_hash_bd_for_each_hlist(hs, &bd, hhead) { - hlist_for_each_safe(hnode, pos, hhead) { - cfs_hash_bucket_validate(hs, &bd, hnode); - count++; - loop++; - if (func(hs, &bd, hnode, data)) { - cfs_hash_bd_unlock(hs, &bd, excl); - goto out; - } - } - } - cfs_hash_bd_unlock(hs, &bd, excl); - if (loop < CFS_HASH_LOOP_HOG) - continue; - loop = 0; - cfs_hash_unlock(hs, 0); - cond_resched(); - cfs_hash_lock(hs, 0); - } - out: - cfs_hash_unlock(hs, 0); - - cfs_hash_for_each_exit(hs); - return count; -} - -struct cfs_hash_cond_arg { - cfs_hash_cond_opt_cb_t func; - void *arg; -}; - -static int -cfs_hash_cond_del_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd, - struct hlist_node *hnode, void *data) -{ - struct cfs_hash_cond_arg *cond = data; - - if (cond->func(cfs_hash_object(hs, hnode), cond->arg)) - cfs_hash_bd_del_locked(hs, bd, hnode); - return 0; -} - -/** - * Delete item from the libcfs hash @hs when @func return true. - * The write lock being hold during loop for each bucket to avoid - * any object be reference. - */ -void -cfs_hash_cond_del(struct cfs_hash *hs, cfs_hash_cond_opt_cb_t func, void *data) -{ - struct cfs_hash_cond_arg arg = { - .func = func, - .arg = data, - }; - - cfs_hash_for_each_tight(hs, cfs_hash_cond_del_locked, &arg, 1); -} -EXPORT_SYMBOL(cfs_hash_cond_del); - -void -cfs_hash_for_each(struct cfs_hash *hs, cfs_hash_for_each_cb_t func, - void *data) -{ - cfs_hash_for_each_tight(hs, func, data, 0); -} -EXPORT_SYMBOL(cfs_hash_for_each); - -void -cfs_hash_for_each_safe(struct cfs_hash *hs, cfs_hash_for_each_cb_t func, - void *data) -{ - cfs_hash_for_each_tight(hs, func, data, 1); -} -EXPORT_SYMBOL(cfs_hash_for_each_safe); - -static int -cfs_hash_peek(struct cfs_hash *hs, struct cfs_hash_bd *bd, - struct hlist_node *hnode, void *data) -{ - *(int *)data = 0; - return 1; /* return 1 to break the loop */ -} - -int -cfs_hash_is_empty(struct cfs_hash *hs) -{ - int empty = 1; - - cfs_hash_for_each_tight(hs, cfs_hash_peek, &empty, 0); - return empty; -} -EXPORT_SYMBOL(cfs_hash_is_empty); - -u64 -cfs_hash_size_get(struct cfs_hash *hs) -{ - return cfs_hash_with_counter(hs) ? - atomic_read(&hs->hs_count) : - cfs_hash_for_each_tight(hs, NULL, NULL, 0); -} -EXPORT_SYMBOL(cfs_hash_size_get); - -/* - * cfs_hash_for_each_relax: - * Iterate the hash table and call @func on each item without - * any lock. This function can't guarantee to finish iteration - * if these features are enabled: - * - * a. if rehash_key is enabled, an item can be moved from - * one bucket to another bucket - * b. user can remove non-zero-ref item from hash-table, - * so the item can be removed from hash-table, even worse, - * it's possible that user changed key and insert to another - * hash bucket. - * there's no way for us to finish iteration correctly on previous - * two cases, so iteration has to be stopped on change. - */ -static int -cfs_hash_for_each_relax(struct cfs_hash *hs, cfs_hash_for_each_cb_t func, - void *data, int start) -{ - struct hlist_node *next = NULL; - struct hlist_node *hnode; - struct cfs_hash_bd bd; - u32 version; - int count = 0; - int stop_on_change; - int has_put_locked; - int end = -1; - int rc = 0; - int i; - - stop_on_change = cfs_hash_with_rehash_key(hs) || - !cfs_hash_with_no_itemref(hs); - has_put_locked = hs->hs_ops->hs_put_locked != NULL; - cfs_hash_lock(hs, 0); -again: - LASSERT(!cfs_hash_is_rehashing(hs)); - - cfs_hash_for_each_bucket(hs, &bd, i) { - struct hlist_head *hhead; - - if (i < start) - continue; - else if (end > 0 && i >= end) - break; - - cfs_hash_bd_lock(hs, &bd, 0); - version = cfs_hash_bd_version_get(&bd); - - cfs_hash_bd_for_each_hlist(hs, &bd, hhead) { - hnode = hhead->first; - if (!hnode) - continue; - cfs_hash_get(hs, hnode); - - for (; hnode; hnode = next) { - cfs_hash_bucket_validate(hs, &bd, hnode); - next = hnode->next; - if (next) - cfs_hash_get(hs, next); - cfs_hash_bd_unlock(hs, &bd, 0); - cfs_hash_unlock(hs, 0); - - rc = func(hs, &bd, hnode, data); - if (stop_on_change || !has_put_locked) - cfs_hash_put(hs, hnode); - cond_resched(); - count++; - - cfs_hash_lock(hs, 0); - cfs_hash_bd_lock(hs, &bd, 0); - if (stop_on_change) { - if (version != - cfs_hash_bd_version_get(&bd)) - rc = -EINTR; - } else if (has_put_locked) { - cfs_hash_put_locked(hs, hnode); - } - if (rc) /* callback wants to break iteration */ - break; - } - if (next) { - if (has_put_locked) { - cfs_hash_put_locked(hs, next); - next = NULL; - } - break; - } else if (rc) { - break; - } - } - cfs_hash_bd_unlock(hs, &bd, 0); - if (next && !has_put_locked) { - cfs_hash_put(hs, next); - next = NULL; - } - if (rc) /* callback wants to break iteration */ - break; - } - if (start > 0 && !rc) { - end = start; - start = 0; - goto again; - } - - cfs_hash_unlock(hs, 0); - return count; -} - -int -cfs_hash_for_each_nolock(struct cfs_hash *hs, cfs_hash_for_each_cb_t func, - void *data, int start) -{ - if (cfs_hash_with_no_lock(hs) || - cfs_hash_with_rehash_key(hs) || - !cfs_hash_with_no_itemref(hs)) - return -EOPNOTSUPP; - - if (!hs->hs_ops->hs_get || - (!hs->hs_ops->hs_put && !hs->hs_ops->hs_put_locked)) - return -EOPNOTSUPP; - - cfs_hash_for_each_enter(hs); - cfs_hash_for_each_relax(hs, func, data, start); - cfs_hash_for_each_exit(hs); - - return 0; -} -EXPORT_SYMBOL(cfs_hash_for_each_nolock); - -/** - * For each hash bucket in the libcfs hash @hs call the passed callback - * @func until all the hash buckets are empty. The passed callback @func - * or the previously registered callback hs->hs_put must remove the item - * from the hash. You may either use the cfs_hash_del() or hlist_del() - * functions. No rwlocks will be held during the callback @func it is - * safe to sleep if needed. This function will not terminate until the - * hash is empty. Note it is still possible to concurrently add new - * items in to the hash. It is the callers responsibility to ensure - * the required locking is in place to prevent concurrent insertions. - */ -int -cfs_hash_for_each_empty(struct cfs_hash *hs, cfs_hash_for_each_cb_t func, - void *data) -{ - unsigned int i = 0; - - if (cfs_hash_with_no_lock(hs)) - return -EOPNOTSUPP; - - if (!hs->hs_ops->hs_get || - (!hs->hs_ops->hs_put && !hs->hs_ops->hs_put_locked)) - return -EOPNOTSUPP; - - cfs_hash_for_each_enter(hs); - while (cfs_hash_for_each_relax(hs, func, data, 0)) { - CDEBUG(D_INFO, "Try to empty hash: %s, loop: %u\n", - hs->hs_name, i++); - } - cfs_hash_for_each_exit(hs); - return 0; -} -EXPORT_SYMBOL(cfs_hash_for_each_empty); - -void -cfs_hash_hlist_for_each(struct cfs_hash *hs, unsigned int hindex, - cfs_hash_for_each_cb_t func, void *data) -{ - struct hlist_head *hhead; - struct hlist_node *hnode; - struct cfs_hash_bd bd; - - cfs_hash_for_each_enter(hs); - cfs_hash_lock(hs, 0); - if (hindex >= CFS_HASH_NHLIST(hs)) - goto out; - - cfs_hash_bd_index_set(hs, hindex, &bd); - - cfs_hash_bd_lock(hs, &bd, 0); - hhead = cfs_hash_bd_hhead(hs, &bd); - hlist_for_each(hnode, hhead) { - if (func(hs, &bd, hnode, data)) - break; - } - cfs_hash_bd_unlock(hs, &bd, 0); -out: - cfs_hash_unlock(hs, 0); - cfs_hash_for_each_exit(hs); -} -EXPORT_SYMBOL(cfs_hash_hlist_for_each); - -/* - * For each item in the libcfs hash @hs which matches the @key call - * the passed callback @func and pass to it as an argument each hash - * item and the private @data. During the callback the bucket lock - * is held so the callback must never sleep. - */ -void -cfs_hash_for_each_key(struct cfs_hash *hs, const void *key, - cfs_hash_for_each_cb_t func, void *data) -{ - struct hlist_node *hnode; - struct cfs_hash_bd bds[2]; - unsigned int i; - - cfs_hash_lock(hs, 0); - - cfs_hash_dual_bd_get_and_lock(hs, key, bds, 0); - - cfs_hash_for_each_bd(bds, 2, i) { - struct hlist_head *hlist = cfs_hash_bd_hhead(hs, &bds[i]); - - hlist_for_each(hnode, hlist) { - cfs_hash_bucket_validate(hs, &bds[i], hnode); - - if (cfs_hash_keycmp(hs, key, hnode)) { - if (func(hs, &bds[i], hnode, data)) - break; - } - } - } - - cfs_hash_dual_bd_unlock(hs, bds, 0); - cfs_hash_unlock(hs, 0); -} -EXPORT_SYMBOL(cfs_hash_for_each_key); - -/** - * Rehash the libcfs hash @hs to the given @bits. This can be used - * to grow the hash size when excessive chaining is detected, or to - * shrink the hash when it is larger than needed. When the CFS_HASH_REHASH - * flag is set in @hs the libcfs hash may be dynamically rehashed - * during addition or removal if the hash's theta value exceeds - * either the hs->hs_min_theta or hs->max_theta values. By default - * these values are tuned to keep the chained hash depth small, and - * this approach assumes a reasonably uniform hashing function. The - * theta thresholds for @hs are tunable via cfs_hash_set_theta(). - */ -void -cfs_hash_rehash_cancel(struct cfs_hash *hs) -{ - LASSERT(cfs_hash_with_rehash(hs)); - cancel_work_sync(&hs->hs_rehash_work); -} - -void -cfs_hash_rehash(struct cfs_hash *hs, int do_rehash) -{ - int rc; - - LASSERT(cfs_hash_with_rehash(hs) && !cfs_hash_with_no_lock(hs)); - - cfs_hash_lock(hs, 1); - - rc = cfs_hash_rehash_bits(hs); - if (rc <= 0) { - cfs_hash_unlock(hs, 1); - return; - } - - hs->hs_rehash_bits = rc; - if (!do_rehash) { - /* launch and return */ - queue_work(cfs_rehash_wq, &hs->hs_rehash_work); - cfs_hash_unlock(hs, 1); - return; - } - - /* rehash right now */ - cfs_hash_unlock(hs, 1); - - cfs_hash_rehash_worker(&hs->hs_rehash_work); -} - -static int -cfs_hash_rehash_bd(struct cfs_hash *hs, struct cfs_hash_bd *old) -{ - struct cfs_hash_bd new; - struct hlist_head *hhead; - struct hlist_node *hnode; - struct hlist_node *pos; - void *key; - int c = 0; - - /* hold cfs_hash_lock(hs, 1), so don't need any bucket lock */ - cfs_hash_bd_for_each_hlist(hs, old, hhead) { - hlist_for_each_safe(hnode, pos, hhead) { - key = cfs_hash_key(hs, hnode); - LASSERT(key); - /* Validate hnode is in the correct bucket. */ - cfs_hash_bucket_validate(hs, old, hnode); - /* - * Delete from old hash bucket; move to new bucket. - * ops->hs_key must be defined. - */ - cfs_hash_bd_from_key(hs, hs->hs_rehash_buckets, - hs->hs_rehash_bits, key, &new); - cfs_hash_bd_move_locked(hs, old, &new, hnode); - c++; - } - } - - return c; -} - -static void -cfs_hash_rehash_worker(struct work_struct *work) -{ - struct cfs_hash *hs = container_of(work, struct cfs_hash, hs_rehash_work); - struct cfs_hash_bucket **bkts; - struct cfs_hash_bd bd; - unsigned int old_size; - unsigned int new_size; - int bsize; - int count = 0; - int rc = 0; - int i; - - LASSERT(hs && cfs_hash_with_rehash(hs)); - - cfs_hash_lock(hs, 0); - LASSERT(cfs_hash_is_rehashing(hs)); - - old_size = CFS_HASH_NBKT(hs); - new_size = CFS_HASH_RH_NBKT(hs); - - cfs_hash_unlock(hs, 0); - - /* - * don't need hs::hs_rwlock for hs::hs_buckets, - * because nobody can change bkt-table except me. - */ - bkts = cfs_hash_buckets_realloc(hs, hs->hs_buckets, - old_size, new_size); - cfs_hash_lock(hs, 1); - if (!bkts) { - rc = -ENOMEM; - goto out; - } - - if (bkts == hs->hs_buckets) { - bkts = NULL; /* do nothing */ - goto out; - } - - rc = __cfs_hash_theta(hs); - if ((rc >= hs->hs_min_theta) && (rc <= hs->hs_max_theta)) { - /* free the new allocated bkt-table */ - old_size = new_size; - new_size = CFS_HASH_NBKT(hs); - rc = -EALREADY; - goto out; - } - - LASSERT(!hs->hs_rehash_buckets); - hs->hs_rehash_buckets = bkts; - - rc = 0; - cfs_hash_for_each_bucket(hs, &bd, i) { - if (cfs_hash_is_exiting(hs)) { - rc = -ESRCH; - /* someone wants to destroy the hash, abort now */ - if (old_size < new_size) /* OK to free old bkt-table */ - break; - /* it's shrinking, need free new bkt-table */ - hs->hs_rehash_buckets = NULL; - old_size = new_size; - new_size = CFS_HASH_NBKT(hs); - goto out; - } - - count += cfs_hash_rehash_bd(hs, &bd); - if (count < CFS_HASH_LOOP_HOG || - cfs_hash_is_iterating(hs)) { /* need to finish ASAP */ - continue; - } - - count = 0; - cfs_hash_unlock(hs, 1); - cond_resched(); - cfs_hash_lock(hs, 1); - } - - hs->hs_rehash_count++; - - bkts = hs->hs_buckets; - hs->hs_buckets = hs->hs_rehash_buckets; - hs->hs_rehash_buckets = NULL; - - hs->hs_cur_bits = hs->hs_rehash_bits; -out: - hs->hs_rehash_bits = 0; - bsize = cfs_hash_bkt_size(hs); - cfs_hash_unlock(hs, 1); - /* can't refer to @hs anymore because it could be destroyed */ - if (bkts) - cfs_hash_buckets_free(bkts, bsize, new_size, old_size); - if (rc) - CDEBUG(D_INFO, "early quit of rehashing: %d\n", rc); -} - -/** - * Rehash the object referenced by @hnode in the libcfs hash @hs. The - * @old_key must be provided to locate the objects previous location - * in the hash, and the @new_key will be used to reinsert the object. - * Use this function instead of a cfs_hash_add() + cfs_hash_del() - * combo when it is critical that there is no window in time where the - * object is missing from the hash. When an object is being rehashed - * the registered cfs_hash_get() and cfs_hash_put() functions will - * not be called. - */ -void cfs_hash_rehash_key(struct cfs_hash *hs, const void *old_key, - void *new_key, struct hlist_node *hnode) -{ - struct cfs_hash_bd bds[3]; - struct cfs_hash_bd old_bds[2]; - struct cfs_hash_bd new_bd; - - LASSERT(!hlist_unhashed(hnode)); - - cfs_hash_lock(hs, 0); - - cfs_hash_dual_bd_get(hs, old_key, old_bds); - cfs_hash_bd_get(hs, new_key, &new_bd); - - bds[0] = old_bds[0]; - bds[1] = old_bds[1]; - bds[2] = new_bd; - - /* NB: bds[0] and bds[1] are ordered already */ - cfs_hash_bd_order(&bds[1], &bds[2]); - cfs_hash_bd_order(&bds[0], &bds[1]); - - cfs_hash_multi_bd_lock(hs, bds, 3, 1); - if (likely(!old_bds[1].bd_bucket)) { - cfs_hash_bd_move_locked(hs, &old_bds[0], &new_bd, hnode); - } else { - cfs_hash_dual_bd_finddel_locked(hs, old_bds, old_key, hnode); - cfs_hash_bd_add_locked(hs, &new_bd, hnode); - } - /* overwrite key inside locks, otherwise may screw up with - * other operations, i.e: rehash - */ - cfs_hash_keycpy(hs, hnode, new_key); - - cfs_hash_multi_bd_unlock(hs, bds, 3, 1); - cfs_hash_unlock(hs, 0); -} -EXPORT_SYMBOL(cfs_hash_rehash_key); - -void cfs_hash_debug_header(struct seq_file *m) -{ - seq_printf(m, "%-*s cur min max theta t-min t-max flags rehash count maxdep maxdepb distribution\n", - CFS_HASH_BIGNAME_LEN, "name"); -} -EXPORT_SYMBOL(cfs_hash_debug_header); - -static struct cfs_hash_bucket ** -cfs_hash_full_bkts(struct cfs_hash *hs) -{ - /* NB: caller should hold hs->hs_rwlock if REHASH is set */ - if (!hs->hs_rehash_buckets) - return hs->hs_buckets; - - LASSERT(hs->hs_rehash_bits); - return hs->hs_rehash_bits > hs->hs_cur_bits ? - hs->hs_rehash_buckets : hs->hs_buckets; -} - -static unsigned int -cfs_hash_full_nbkt(struct cfs_hash *hs) -{ - /* NB: caller should hold hs->hs_rwlock if REHASH is set */ - if (!hs->hs_rehash_buckets) - return CFS_HASH_NBKT(hs); - - LASSERT(hs->hs_rehash_bits); - return hs->hs_rehash_bits > hs->hs_cur_bits ? - CFS_HASH_RH_NBKT(hs) : CFS_HASH_NBKT(hs); -} - -void cfs_hash_debug_str(struct cfs_hash *hs, struct seq_file *m) -{ - int dist[8] = { 0, }; - int maxdep = -1; - int maxdepb = -1; - int total = 0; - int theta; - int i; - - cfs_hash_lock(hs, 0); - theta = __cfs_hash_theta(hs); - - seq_printf(m, "%-*s %5d %5d %5d %d.%03d %d.%03d %d.%03d 0x%02x %6d ", - CFS_HASH_BIGNAME_LEN, hs->hs_name, - 1 << hs->hs_cur_bits, 1 << hs->hs_min_bits, - 1 << hs->hs_max_bits, - __cfs_hash_theta_int(theta), __cfs_hash_theta_frac(theta), - __cfs_hash_theta_int(hs->hs_min_theta), - __cfs_hash_theta_frac(hs->hs_min_theta), - __cfs_hash_theta_int(hs->hs_max_theta), - __cfs_hash_theta_frac(hs->hs_max_theta), - hs->hs_flags, hs->hs_rehash_count); - - /* - * The distribution is a summary of the chained hash depth in - * each of the libcfs hash buckets. Each buckets hsb_count is - * divided by the hash theta value and used to generate a - * histogram of the hash distribution. A uniform hash will - * result in all hash buckets being close to the average thus - * only the first few entries in the histogram will be non-zero. - * If you hash function results in a non-uniform hash the will - * be observable by outlier bucks in the distribution histogram. - * - * Uniform hash distribution: 128/128/0/0/0/0/0/0 - * Non-Uniform hash distribution: 128/125/0/0/0/0/2/1 - */ - for (i = 0; i < cfs_hash_full_nbkt(hs); i++) { - struct cfs_hash_bd bd; - - bd.bd_bucket = cfs_hash_full_bkts(hs)[i]; - cfs_hash_bd_lock(hs, &bd, 0); - if (maxdep < bd.bd_bucket->hsb_depmax) { - maxdep = bd.bd_bucket->hsb_depmax; - maxdepb = ffz(~maxdep); - } - total += bd.bd_bucket->hsb_count; - dist[min(fls(bd.bd_bucket->hsb_count / max(theta, 1)), 7)]++; - cfs_hash_bd_unlock(hs, &bd, 0); - } - - seq_printf(m, "%7d %7d %7d ", total, maxdep, maxdepb); - for (i = 0; i < 8; i++) - seq_printf(m, "%d%c", dist[i], (i == 7) ? '\n' : '/'); - - cfs_hash_unlock(hs, 0); -} -EXPORT_SYMBOL(cfs_hash_debug_str); |