diff options
| -rw-r--r-- | include/linux/rhashtable.h | 491 | ||||
| -rw-r--r-- | lib/rhashtable.c | 258 |
2 files changed, 583 insertions, 166 deletions
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index fd82584acd48..5c132d3188be 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -1,7 +1,7 @@ /* * Resizable, Scalable, Concurrent Hash Table * - * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> + * Copyright (c) 2015-2016 Herbert Xu <herbert@gondor.apana.org.au> * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch> * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net> * @@ -53,6 +53,11 @@ struct rhash_head { struct rhash_head __rcu *next; }; +struct rhlist_head { + struct rhash_head rhead; + struct rhlist_head __rcu *next; +}; + /** * struct bucket_table - Table of hash buckets * @size: Number of hash buckets @@ -137,6 +142,7 @@ struct rhashtable_params { * @key_len: Key length for hashfn * @elasticity: Maximum chain length before rehash * @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 @@ -147,12 +153,21 @@ struct rhashtable { unsigned int key_len; unsigned int elasticity; struct rhashtable_params p; + bool rhlist; struct work_struct run_work; struct mutex mutex; spinlock_t lock; }; /** + * 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 @@ -163,9 +178,10 @@ struct rhashtable_walker { }; /** - * struct rhashtable_iter - Hash table iterator, fits into netlink cb + * 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 @@ -173,6 +189,7 @@ struct rhashtable_walker { struct rhashtable_iter { struct rhashtable *ht; struct rhash_head *p; + struct rhlist_head *list; struct rhashtable_walker walker; unsigned int slot; unsigned int skip; @@ -339,13 +356,11 @@ static inline int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, int rhashtable_init(struct rhashtable *ht, const struct rhashtable_params *params); +int rhltable_init(struct rhltable *hlt, + const struct rhashtable_params *params); -struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht, - const void *key, - struct rhash_head *obj, - struct bucket_table *old_tbl, - void **data); -int rhashtable_insert_rehash(struct rhashtable *ht, struct bucket_table *tbl); +void *rhashtable_insert_slow(struct rhashtable *ht, const void *key, + struct rhash_head *obj); void rhashtable_walk_enter(struct rhashtable *ht, struct rhashtable_iter *iter); @@ -507,6 +522,31 @@ void rhashtable_destroy(struct rhashtable *ht); rht_for_each_entry_rcu_continue(tpos, pos, (tbl)->buckets[hash],\ tbl, hash, member) +/** + * rhl_for_each_rcu - iterate over rcu hash table list + * @pos: the &struct rlist_head to use as a loop cursor. + * @list: the head of the list + * + * This hash chain list-traversal primitive should be used on the + * list returned by rhltable_lookup. + */ +#define rhl_for_each_rcu(pos, list) \ + for (pos = list; pos; pos = rcu_dereference_raw(pos->next)) + +/** + * rhl_for_each_entry_rcu - iterate over rcu hash table list of given type + * @tpos: the type * to use as a loop cursor. + * @pos: the &struct rlist_head to use as a loop cursor. + * @list: the head of the list + * @member: name of the &struct rlist_head within the hashable struct. + * + * This hash chain list-traversal primitive should be used on the + * list returned by rhltable_lookup. + */ +#define rhl_for_each_entry_rcu(tpos, pos, list, member) \ + for (pos = list; pos && rht_entry(tpos, pos, member); \ + pos = rcu_dereference_raw(pos->next)) + static inline int rhashtable_compare(struct rhashtable_compare_arg *arg, const void *obj) { @@ -516,18 +556,8 @@ static inline int rhashtable_compare(struct rhashtable_compare_arg *arg, return memcmp(ptr + ht->p.key_offset, arg->key, ht->p.key_len); } -/** - * rhashtable_lookup_fast - search hash table, inlined version - * @ht: hash table - * @key: the pointer to the key - * @params: hash table parameters - * - * Computes the hash value for the key and traverses the bucket chain looking - * for a entry with an identical key. The first matching entry is returned. - * - * Returns the first entry on which the compare function returned true. - */ -static inline void *rhashtable_lookup_fast( +/* Internal function, do not use. */ +static inline struct rhash_head *__rhashtable_lookup( struct rhashtable *ht, const void *key, const struct rhashtable_params params) { @@ -539,8 +569,6 @@ static inline void *rhashtable_lookup_fast( struct rhash_head *he; unsigned int hash; - rcu_read_lock(); - tbl = rht_dereference_rcu(ht->tbl, ht); restart: hash = rht_key_hashfn(ht, tbl, key, params); @@ -549,8 +577,7 @@ restart: params.obj_cmpfn(&arg, rht_obj(ht, he)) : rhashtable_compare(&arg, rht_obj(ht, he))) continue; - rcu_read_unlock(); - return rht_obj(ht, he); + return he; } /* Ensure we see any new tables. */ @@ -559,96 +586,165 @@ restart: tbl = rht_dereference_rcu(tbl->future_tbl, ht); if (unlikely(tbl)) goto restart; - rcu_read_unlock(); return NULL; } +/** + * rhashtable_lookup - search hash table + * @ht: hash table + * @key: the pointer to the key + * @params: hash table parameters + * + * Computes the hash value for the key and traverses the bucket chain looking + * for a entry with an identical key. The first matching entry is returned. + * + * This must only be called under the RCU read lock. + * + * Returns the first entry on which the compare function returned true. + */ +static inline void *rhashtable_lookup( + struct rhashtable *ht, const void *key, + const struct rhashtable_params params) +{ + struct rhash_head *he = __rhashtable_lookup(ht, key, params); + + return he ? rht_obj(ht, he) : NULL; +} + +/** + * rhashtable_lookup_fast - search hash table, without RCU read lock + * @ht: hash table + * @key: the pointer to the key + * @params: hash table parameters + * + * Computes the hash value for the key and traverses the bucket chain looking + * for a entry with an identical key. The first matching entry is returned. + * + * Only use this function when you have other mechanisms guaranteeing + * that the object won't go away after the RCU read lock is released. + * + * Returns the first entry on which the compare function returned true. + */ +static inline void *rhashtable_lookup_fast( + struct rhashtable *ht, const void *key, + const struct rhashtable_params params) +{ + void *obj; + + rcu_read_lock(); + obj = rhashtable_lookup(ht, key, params); + rcu_read_unlock(); + + return obj; +} + +/** + * rhltable_lookup - search hash list table + * @hlt: hash table + * @key: the pointer to the key + * @params: hash table parameters + * + * Computes the hash value for the key and traverses the bucket chain looking + * for a entry with an identical key. All matching entries are returned + * in a list. + * + * This must only be called under the RCU read lock. + * + * Returns the list of entries that match the given key. + */ +static inline struct rhlist_head *rhltable_lookup( + struct rhltable *hlt, const void *key, + const struct rhashtable_params params) +{ + struct rhash_head *he = __rhashtable_lookup(&hlt->ht, key, params); + + return he ? container_of(he, struct rhlist_head, rhead) : NULL; +} + /* Internal function, please use rhashtable_insert_fast() instead. This * function returns the existing element already in hashes in there is a clash, * otherwise it returns an error via ERR_PTR(). */ static inline void *__rhashtable_insert_fast( struct rhashtable *ht, const void *key, struct rhash_head *obj, - const struct rhashtable_params params) + const struct rhashtable_params params, bool rhlist) { struct rhashtable_compare_arg arg = { .ht = ht, .key = key, }; - struct bucket_table *tbl, *new_tbl; + struct rhash_head __rcu **pprev; + struct bucket_table *tbl; struct rhash_head *head; spinlock_t *lock; - unsigned int elasticity; unsigned int hash; - void *data = NULL; - int err; + int elasticity; + void *data; -restart: rcu_read_lock(); tbl = rht_dereference_rcu(ht->tbl, ht); + hash = rht_head_hashfn(ht, tbl, obj, params); + lock = rht_bucket_lock(tbl, hash); + spin_lock_bh(lock); - /* All insertions must grab the oldest table containing - * the hashed bucket that is yet to be rehashed. - */ - for (;;) { - hash = rht_head_hashfn(ht, tbl, obj, params); - lock = rht_bucket_lock(tbl, hash); - spin_lock_bh(lock); - - if (tbl->rehash <= hash) - break; - + if (unlikely(rht_dereference_bucket(tbl->future_tbl, tbl, hash))) { +slow_path: spin_unlock_bh(lock); - tbl = rht_dereference_rcu(tbl->future_tbl, ht); + rcu_read_unlock(); + return rhashtable_insert_slow(ht, key, obj); } - new_tbl = rht_dereference_rcu(tbl->future_tbl, ht); - if (unlikely(new_tbl)) { - tbl = rhashtable_insert_slow(ht, key, obj, new_tbl, &data); - if (!IS_ERR_OR_NULL(tbl)) - goto slow_path; + elasticity = ht->elasticity; + pprev = &tbl->buckets[hash]; + rht_for_each(head, tbl, hash) { + struct rhlist_head *plist; + struct rhlist_head *list; + + elasticity--; + if (!key || + (params.obj_cmpfn ? + params.obj_cmpfn(&arg, rht_obj(ht, head)) : + rhashtable_compare(&arg, rht_obj(ht, head)))) + continue; + + data = rht_obj(ht, head); - err = PTR_ERR(tbl); - if (err == -EEXIST) - err = 0; + if (!rhlist) + goto out; - goto out; - } - err = -E2BIG; - if (unlikely(rht_grow_above_max(ht, tbl))) - goto out; + list = container_of(obj, struct rhlist_head, rhead); + plist = container_of(head, struct rhlist_head, rhead); - if (unlikely(rht_grow_above_100(ht, tbl))) { -slow_path: - spin_unlock_bh(lock); - err = rhashtable_insert_rehash(ht, tbl); - rcu_read_unlock(); - if (err) - return ERR_PTR(err); + RCU_INIT_POINTER(list->next, plist); + head = rht_dereference_bucket(head->next, tbl, hash); + RCU_INIT_POINTER(list->rhead.next, head); + rcu_assign_pointer(*pprev, obj); - goto restart; + goto good; } - err = 0; - elasticity = ht->elasticity; - rht_for_each(head, tbl, hash) { - if (key && - unlikely(!(params.obj_cmpfn ? - params.obj_cmpfn(&arg, rht_obj(ht, head)) : - rhashtable_compare(&arg, rht_obj(ht, head))))) { - data = rht_obj(ht, head); - goto out; - } - if (!--elasticity) - goto slow_path; - } + if (elasticity <= 0) + goto slow_path; + + data = ERR_PTR(-E2BIG); + if (unlikely(rht_grow_above_max(ht, tbl))) + goto out; + + if (unlikely(rht_grow_above_100(ht, tbl))) + goto slow_path; head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash); RCU_INIT_POINTER(obj->next, head); + if (rhlist) { + struct rhlist_head *list; + + list = container_of(obj, struct rhlist_head, rhead); + RCU_INIT_POINTER(list->next, NULL); + } rcu_assign_pointer(tbl->buckets[hash], obj); @@ -656,11 +752,14 @@ slow_path: if (rht_grow_above_75(ht, tbl)) schedule_work(&ht->run_work); +good: + data = NULL; + out: spin_unlock_bh(lock); rcu_read_unlock(); - return err ? ERR_PTR(err) : data; + return data; } /** @@ -685,7 +784,7 @@ static inline int rhashtable_insert_fast( { void *ret; - ret = __rhashtable_insert_fast(ht, NULL, obj, params); + ret = __rhashtable_insert_fast(ht, NULL, obj, params, false); if (IS_ERR(ret)) return PTR_ERR(ret); @@ -693,6 +792,58 @@ static inline int rhashtable_insert_fast( } /** + * rhltable_insert_key - insert object into hash list table + * @hlt: hash list table + * @key: the pointer to the key + * @list: pointer to hash list head inside object + * @params: hash table parameters + * + * Will take a per bucket spinlock to protect against mutual mutations + * on the same bucket. Multiple insertions may occur in parallel unless + * they map to the same bucket lock. + * + * It is safe to call this function from atomic context. + * + * Will trigger an automatic deferred table resizing if the size grows + * beyond the watermark indicated by grow_decision() which can be passed + * to rhashtable_init(). + */ +static inline int rhltable_insert_key( + struct rhltable *hlt, const void *key, struct rhlist_head *list, + const struct rhashtable_params params) +{ + return PTR_ERR(__rhashtable_insert_fast(&hlt->ht, key, &list->rhead, + params, true)); +} + +/** + * rhltable_insert - insert object into hash list table + * @hlt: hash list table + * @list: pointer to hash list head inside object + * @params: hash table parameters + * + * Will take a per bucket spinlock to protect against mutual mutations + * on the same bucket. Multiple insertions may occur in parallel unless + * they map to the same bucket lock. + * + * It is safe to call this function from atomic context. + * + * Will trigger an automatic deferred table resizing if the size grows + * beyond the watermark indicated by grow_decision() which can be passed + * to rhashtable_init(). + */ +static inline int rhltable_insert( + struct rhltable *hlt, struct rhlist_head *list, + const struct rhashtable_params params) +{ + const char *key = rht_obj(&hlt->ht, &list->rhead); + + key += params.key_offset; + + return rhltable_insert_key(hlt, key, list, params); +} + +/** * rhashtable_lookup_insert_fast - lookup and insert object into hash table * @ht: hash table * @obj: pointer to hash head inside object @@ -722,7 +873,8 @@ static inline int rhashtable_lookup_insert_fast( BUG_ON(ht->p.obj_hashfn); - ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params); + ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params, + false); if (IS_ERR(ret)) return PTR_ERR(ret); @@ -759,7 +911,7 @@ static inline int rhashtable_lookup_insert_key( BUG_ON(!ht->p.obj_hashfn || !key); - ret = __rhashtable_insert_fast(ht, key, obj, params); + ret = __rhashtable_insert_fast(ht, key, obj, params, false); if (IS_ERR(ret)) return PTR_ERR(ret); @@ -783,13 +935,14 @@ static inline void *rhashtable_lookup_get_insert_key( { BUG_ON(!ht->p.obj_hashfn || !key); - return __rhashtable_insert_fast(ht, key, obj, params); + return __rhashtable_insert_fast(ht, key, obj, params, false); } /* Internal function, please use rhashtable_remove_fast() instead */ -static inline int __rhashtable_remove_fast( +static inline int __rhashtable_remove_fast_one( struct rhashtable *ht, struct bucket_table *tbl, - struct rhash_head *obj, const struct rhashtable_params params) + struct rhash_head *obj, const struct rhashtable_params params, + bool rhlist) { struct rhash_head __rcu **pprev; struct rhash_head *he; @@ -804,39 +957,66 @@ static inline int __rhashtable_remove_fast( pprev = &tbl->buckets[hash]; rht_for_each(he, tbl, hash) { + struct rhlist_head *list; + + list = container_of(he, struct rhlist_head, rhead); + if (he != obj) { + struct rhlist_head __rcu **lpprev; + pprev = &he->next; - continue; + + if (!rhlist) + continue; + + do { + lpprev = &list->next; + list = rht_dereference_bucket(list->next, + tbl, hash); + } while (list && obj != &list->rhead); + + if (!list) + continue; + + list = rht_dereference_bucket(list->next, tbl, hash); + RCU_INIT_POINTER(*lpprev, list); + err = 0; + break; } - rcu_assign_pointer(*pprev, obj->next); - err = 0; + obj = rht_dereference_bucket(obj->next, tbl, hash); + err = 1; + + if (rhlist) { + list = rht_dereference_bucket(list->next, tbl, hash); + if (list) { + RCU_INIT_POINTER(list->rhead.next, obj); + obj = &list->rhead; + err = 0; + } + } + + rcu_assign_pointer(*pprev, obj); break; } spin_unlock_bh(lock); + if (err > 0) { + atomic_dec(&ht->nelems); + if (unlikely(ht->p.automatic_shrinking && + rht_shrink_below_30(ht, tbl))) + schedule_work(&ht->run_work); + err = 0; + } + return err; } -/** - * rhashtable_remove_fast - remove object from hash table - * @ht: hash table - * @obj: pointer to hash head inside object - * @params: hash table parameters - * - * Since the hash chain is single linked, the removal operation needs to - * walk the bucket chain upon removal. The removal operation is thus - * considerable slow if the hash table is not correctly sized. - * - * Will automatically shrink the table via rhashtable_expand() if the - * shrink_decision function specified at rhashtable_init() returns true. - * - * Returns zero on success, -ENOENT if the entry could not be found. - */ -static inline int rhashtable_remove_fast( +/* Internal function, please use rhashtable_remove_fast() instead */ +static inline int __rhashtable_remove_fast( struct rhashtable *ht, struct rhash_head *obj, - const struct rhashtable_params params) + const struct rhashtable_params params, bool rhlist) { struct bucket_table *tbl; int err; @@ -850,24 +1030,60 @@ static inline int rhashtable_remove_fast( * visible then that guarantees the entry to still be in * the old tbl if it exists. */ - while ((err = __rhashtable_remove_fast(ht, tbl, obj, params)) && + while ((err = __rhashtable_remove_fast_one(ht, tbl, obj, params, + rhlist)) && (tbl = rht_dereference_rcu(tbl->future_tbl, ht))) ; - if (err) - goto out; - - atomic_dec(&ht->nelems); - if (unlikely(ht->p.automatic_shrinking && - rht_shrink_below_30(ht, tbl))) - schedule_work(&ht->run_work); - -out: rcu_read_unlock(); return err; } +/** + * rhashtable_remove_fast - remove object from hash table + * @ht: hash table + * @obj: pointer to hash head inside object + * @params: hash table parameters + * + * Since the hash chain is single linked, the removal operation needs to + * walk the bucket chain upon removal. The removal operation is thus + * considerable slow if the hash table is not correctly sized. + * + * Will automatically shrink the table via rhashtable_expand() if the + * shrink_decision function specified at rhashtable_init() returns true. + * + * Returns zero on success, -ENOENT if the entry could not be found. + */ +static inline int rhashtable_remove_fast( + struct rhashtable *ht, struct rhash_head *obj, + const struct rhashtable_params params) +{ + return __rhashtable_remove_fast(ht, obj, params, false); +} + +/** + * rhltable_remove - remove object from hash list table + * @hlt: hash list table + * @list: pointer to hash list head inside object + * @params: hash table parameters + * + * Since the hash chain is single linked, the removal operation needs to + * walk the bucket chain upon removal. The removal operation is thus + * considerable slow if the hash table is not correctly sized. + * + * Will automatically shrink the table via rhashtable_expand() if the + * shrink_decision function specified at rhashtable_init() returns true. + * + * Returns zero on success, -ENOENT if the entry could not be found. + */ +static inline int rhltable_remove( + struct rhltable *hlt, struct rhlist_head *list, + const struct rhashtable_params params) +{ + return __rhashtable_remove_fast(&hlt->ht, &list->rhead, params, true); +} + /* Internal function, please use rhashtable_replace_fast() instead */ static inline int __rhashtable_replace_fast( struct rhashtable *ht, struct bucket_table *tbl, @@ -958,4 +1174,51 @@ static inline int rhashtable_walk_init(struct rhashtable *ht, return 0; } +/** + * rhltable_walk_enter - Initialise an iterator + * @hlt: Table to walk over + * @iter: Hash table Iterator + * + * This function prepares a hash table walk. + * + * Note that if you restart a walk after rhashtable_walk_stop you + * may see the same object twice. Also, you may miss objects if + * there are removals in between rhashtable_walk_stop and the next + * call to rhashtable_walk_start. + * + * For a completely stable walk you should construct your own data + * structure outside the hash table. + * + * This function may sleep so you must not call it from interrupt + * context or with spin locks held. + * + * You must call rhashtable_walk_exit after this function returns. + */ +static inline void rhltable_walk_enter(struct rhltable *hlt, + struct rhashtable_iter *iter) +{ + return rhashtable_walk_enter(&hlt->ht, iter); +} + +/** + * rhltable_free_and_destroy - free elements and destroy hash list table + * @hlt: the hash list table to destroy + * @free_fn: callback to release resources of element + * @arg: pointer passed to free_fn + * + * See documentation for rhashtable_free_and_destroy. + */ +static inline void rhltable_free_and_destroy(struct rhltable *hlt, + void (*free_fn)(void *ptr, + void *arg), + void *arg) +{ + return rhashtable_free_and_destroy(&hlt->ht, free_fn, arg); +} + +static inline void rhltable_destroy(struct rhltable *hlt) +{ + return rhltable_free_and_destroy(hlt, NULL, NULL); +} + #endif /* _LINUX_RHASHTABLE_H */ diff --git a/lib/rhashtable.c b/lib/rhashtable.c index 06c28728bb53..32d0ad058380 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -378,22 +378,8 @@ static void rht_deferred_worker(struct work_struct *work) schedule_work(&ht->run_work); } -static bool rhashtable_check_elasticity(struct rhashtable *ht, - struct bucket_table *tbl, - unsigned int hash) -{ - unsigned int elasticity = ht->elasticity; - struct rhash_head *head; - - rht_for_each(head, tbl, hash) - if (!--elasticity) - return true; - - return false; -} - -int rhashtable_insert_rehash(struct rhashtable *ht, - struct bucket_table *tbl) +static int rhashtable_insert_rehash(struct rhashtable *ht, + struct bucket_table *tbl) { struct bucket_table *old_tbl; struct bucket_table *new_tbl; @@ -439,57 +425,165 @@ fail: return err; } -EXPORT_SYMBOL_GPL(rhashtable_insert_rehash); -struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht, - const void *key, - struct rhash_head *obj, - struct bucket_table *tbl, - void **data) +static void *rhashtable_lookup_one(struct rhashtable *ht, + struct bucket_table *tbl, unsigned int hash, + const void *key, struct rhash_head *obj) { + struct rhashtable_compare_arg arg = { + .ht = ht, + .key = key, + }; + struct rhash_head __rcu **pprev; struct rhash_head *head; - unsigned int hash; - int err; + int elasticity; - tbl = rhashtable_last_table(ht, tbl); - hash = head_hashfn(ht, tbl, obj); - spin_lock_nested(rht_bucket_lock(tbl, hash), SINGLE_DEPTH_NESTING); - - err = -EEXIST; - if (key) { - *data = rhashtable_lookup_fast(ht, key, ht->p); - if (*data) - goto exit; + elasticity = ht->elasticity; + pprev = &tbl->buckets[hash]; + rht_for_each(head, tbl, hash) { + struct rhlist_head *list; + struct rhlist_head *plist; + + elasticity--; + if (!key || + (ht->p.obj_cmpfn ? + ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) : + rhashtable_compare(&arg, rht_obj(ht, head)))) + continue; + + if (!ht->rhlist) + return rht_obj(ht, head); + + list = container_of(obj, struct rhlist_head, rhead); + plist = container_of(head, struct rhlist_head, rhead); + + RCU_INIT_POINTER(list->next, plist); + head = rht_dereference_bucket(head->next, tbl, hash); + RCU_INIT_POINTER(list->rhead.next, head); + rcu_assign_pointer(*pprev, obj); + + return NULL; } - err = -E2BIG; - if (unlikely(rht_grow_above_max(ht, tbl))) - goto exit; + if (elasticity <= 0) + return ERR_PTR(-EAGAIN); + + return ERR_PTR(-ENOENT); +} + +static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht, + struct bucket_table *tbl, + unsigned int hash, + struct rhash_head *obj, + void *data) +{ + struct bucket_table *new_tbl; + struct rhash_head *head; + + if (!IS_ERR_OR_NULL(data)) + return ERR_PTR(-EEXIST); - err = -EAGAIN; - if (rhashtable_check_elasticity(ht, tbl, hash) || - rht_grow_above_100(ht, tbl)) - goto exit; + if (PTR_ERR(data) != -EAGAIN && PTR_ERR(data) != -ENOENT) + return ERR_CAST(data); - err = 0; + new_tbl = rcu_dereference(tbl->future_tbl); + if (new_tbl) + return new_tbl; + + if (PTR_ERR(data) != -ENOENT) + return ERR_CAST(data); + + if (unlikely(rht_grow_above_max(ht, tbl))) + return ERR_PTR(-E2BIG); + + if (unlikely(rht_grow_above_100(ht, tbl))) + return ERR_PTR(-EAGAIN); head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash); RCU_INIT_POINTER(obj->next, head); + if (ht->rhlist) { + struct rhlist_head *list; + + list = container_of(obj, struct rhlist_head, rhead); + RCU_INIT_POINTER(list->next, NULL); + } rcu_assign_pointer(tbl->buckets[hash], obj); atomic_inc(&ht->nelems); + if (rht_grow_above_75(ht, tbl)) + schedule_work(&ht->run_work); -exit: - spin_unlock(rht_bucket_lock(tbl, hash)); + return NULL; +} - if (err == 0) - return NULL; - else if (err == -EAGAIN) - return tbl; - else - return ERR_PTR(err); +static void *rhashtable_try_insert(struct rhashtable *ht, const void *key, + struct rhash_head *obj) +{ + struct bucket_table *new_tbl; + struct bucket_table *tbl; + unsigned int hash; + spinlock_t *lock; + void *data; + + tbl = rcu_dereference(ht->tbl); + + /* All insertions must grab the oldest table containing + * the hashed bucket that is yet to be rehashed. + */ + for (;;) { + hash = rht_head_hashfn(ht, tbl, obj, ht->p); + lock = rht_bucket_lock(tbl, hash); + spin_lock_bh(lock); + + if (tbl->rehash <= hash) + break; + + spin_unlock_bh(lock); + tbl = rcu_dereference(tbl->future_tbl); + } + + data = rhashtable_lookup_one(ht, tbl, hash, key, obj); + new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data); + if (PTR_ERR(new_tbl) != -EEXIST) + data = ERR_CAST(new_tbl); + + while (!IS_ERR_OR_NULL(new_tbl)) { + tbl = new_tbl; + hash = rht_head_hashfn(ht, tbl, obj, ht->p); + spin_lock_nested(rht_bucket_lock(tbl, hash), + SINGLE_DEPTH_NESTING); + + data = rhashtable_lookup_one(ht, tbl, hash, key, obj); + new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data); + if (PTR_ERR(new_tbl) != -EEXIST) + data = ERR_CAST(new_tbl); + + spin_unlock(rht_bucket_lock(tbl, hash)); + } + + spin_unlock_bh(lock); + + if (PTR_ERR(data) == -EAGAIN) + data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?: + -EAGAIN); + + return data; +} + +void *rhashtable_insert_slow(struct rhashtable *ht, const void *key, + struct rhash_head *obj) +{ + void *data; + + do { + rcu_read_lock(); + data = rhashtable_try_insert(ht, key, obj); + rcu_read_unlock(); + } while (PTR_ERR(data) == -EAGAIN); + + return data; } EXPORT_SYMBOL_GPL(rhashtable_insert_slow); @@ -593,11 +687,16 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_start); void *rhashtable_walk_next(struct rhashtable_iter *iter) { struct bucket_table *tbl = iter->walker.tbl; + struct rhlist_head *list = iter->list; struct rhashtable *ht = iter->ht; struct rhash_head *p = iter->p; + bool rhlist = ht->rhlist; if (p) { - p = rht_dereference_bucket_rcu(p->next, tbl, iter->slot); + if (!rhlist || !(list = rcu_dereference(list->next))) { + p = rcu_dereference(p->next); + list = container_of(p, struct rhlist_head, rhead); + } goto next; } @@ -605,6 +704,18 @@ void *rhashtable_walk_next(struct rhashtable_iter *iter) int skip = iter->skip; rht_for_each_rcu(p, tbl, iter->slot) { + if (rhlist) { + list = container_of(p, struct rhlist_head, + rhead); + do { + if (!skip) + goto next; + skip--; + list = rcu_dereference(list->next); + } while (list); + + continue; + } if (!skip) break; skip--; @@ -614,7 +725,8 @@ next: if (!rht_is_a_nulls(p)) { iter->skip++; iter->p = p; - return rht_obj(ht, p); + iter->list = list; + return rht_obj(ht, rhlist ? &list->rhead : p); } iter->skip = 0; @@ -803,6 +915,48 @@ int rhashtable_init(struct rhashtable *ht, EXPORT_SYMBOL_GPL(rhashtable_init); /** + * rhltable_init - initialize a new hash list table + * @hlt: hash list table to be initialized + * @params: configuration parameters + * + * Initializes a new hash list table. + * + * See documentation for rhashtable_init. + */ +int rhltable_init(struct rhltable *hlt, const struct rhashtable_params *params) +{ + int err; + + /* No rhlist NULLs marking for now. */ + if (params->nulls_base) + return -EINVAL; + + err = rhashtable_init(&hlt->ht, params); + hlt->ht.rhlist = true; + return err; +} +EXPORT_SYMBOL_GPL(rhltable_init); + +static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj, + void (*free_fn)(void *ptr, void *arg), + void *arg) +{ + struct rhlist_head *list; + + if (!ht->rhlist) { + free_fn(rht_obj(ht, obj), arg); + return; + } + + list = container_of(obj, struct rhlist_head, rhead); + do { + obj = &list->rhead; + list = rht_dereference(list->next, ht); + free_fn(rht_obj(ht, obj), arg); + } while (list); +} + +/** * rhashtable_free_and_destroy - free elements and destroy hash table * @ht: the hash table to destroy * @free_fn: callback to release resources of element @@ -839,7 +993,7 @@ void rhashtable_free_and_destroy(struct rhashtable *ht, pos = next, next = !rht_is_a_nulls(pos) ? rht_dereference(pos->next, ht) : NULL) - free_fn(rht_obj(ht, pos), arg); + rhashtable_free_one(ht, pos, free_fn, arg); } } |