diff options
Diffstat (limited to 'linux/rhashtable.c')
-rw-r--r-- | linux/rhashtable.c | 338 |
1 files changed, 1 insertions, 337 deletions
diff --git a/linux/rhashtable.c b/linux/rhashtable.c index 035d82aa..03369ead 100644 --- a/linux/rhashtable.c +++ b/linux/rhashtable.c @@ -25,7 +25,6 @@ #include <linux/random.h> #include <linux/rhashtable.h> #include <linux/err.h> -#include <linux/export.h> #define HASH_DEFAULT_SIZE 64UL #define HASH_MIN_SIZE 4U @@ -38,36 +37,11 @@ static u32 head_hashfn(struct rhashtable *ht, return rht_head_hashfn(ht, tbl, he, ht->p); } -#ifdef CONFIG_PROVE_LOCKING -#define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT)) - -int lockdep_rht_mutex_is_held(struct rhashtable *ht) -{ - return (debug_locks) ? lockdep_is_held(&ht->mutex) : 1; -} -EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held); - -int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash) -{ - spinlock_t *lock = rht_bucket_lock(tbl, hash); - - return (debug_locks) ? lockdep_is_held(lock) : 1; -} -EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held); -#else -#define ASSERT_RHT_MUTEX(HT) -#endif - - static int alloc_bucket_locks(struct rhashtable *ht, struct bucket_table *tbl, gfp_t gfp) { unsigned int i, size; -#if defined(CONFIG_PROVE_LOCKING) - unsigned int nr_pcpus = 2; -#else unsigned int nr_pcpus = num_possible_cpus(); -#endif nr_pcpus = min_t(unsigned int, nr_pcpus, 64UL); size = roundup_pow_of_two(nr_pcpus * ht->p.locks_mul); @@ -77,11 +51,6 @@ static int alloc_bucket_locks(struct rhashtable *ht, struct bucket_table *tbl, if (sizeof(spinlock_t) != 0) { tbl->locks = NULL; -#ifdef CONFIG_NUMA - if (size * sizeof(spinlock_t) > PAGE_SIZE && - gfp == GFP_KERNEL) - tbl->locks = vmalloc(size * sizeof(spinlock_t)); -#endif if (gfp != GFP_KERNEL) gfp |= __GFP_NOWARN | __GFP_NORETRY; @@ -270,28 +239,11 @@ static int rhashtable_rehash_table(struct rhashtable *ht) return rht_dereference(new_tbl->future_tbl, ht) ? -EAGAIN : 0; } -/** - * rhashtable_expand - Expand hash table while allowing concurrent lookups - * @ht: the hash table to expand - * - * A secondary bucket array is allocated and the hash entries are migrated. - * - * This function may only be called in a context where it is safe to call - * synchronize_rcu(), e.g. not within a rcu_read_lock() section. - * - * The caller must ensure that no concurrent resizing occurs by holding - * ht->mutex. - * - * It is valid to have concurrent insertions and deletions protected by per - * bucket locks or concurrent RCU protected lookups and traversals. - */ static int rhashtable_expand(struct rhashtable *ht) { struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht); int err; - ASSERT_RHT_MUTEX(ht); - old_tbl = rhashtable_last_table(ht, old_tbl); new_tbl = bucket_table_alloc(ht, old_tbl->size * 2, GFP_KERNEL); @@ -305,22 +257,6 @@ static int rhashtable_expand(struct rhashtable *ht) return err; } -/** - * rhashtable_shrink - Shrink hash table while allowing concurrent lookups - * @ht: the hash table to shrink - * - * This function shrinks the hash table to fit, i.e., the smallest - * size would not cause it to expand right away automatically. - * - * The caller must ensure that no concurrent resizing occurs by holding - * ht->mutex. - * - * The caller must ensure that no concurrent table mutations take place. - * It is however valid to have concurrent lookups if they are RCU protected. - * - * It is valid to have concurrent insertions and deletions protected by per - * bucket locks or concurrent RCU protected lookups and traversals. - */ static int rhashtable_shrink(struct rhashtable *ht) { struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht); @@ -328,8 +264,6 @@ static int rhashtable_shrink(struct rhashtable *ht) unsigned int size = 0; int err; - ASSERT_RHT_MUTEX(ht); - if (nelems) size = roundup_pow_of_two(nelems * 3 / 2); if (size < ht->p.min_size) @@ -438,7 +372,6 @@ fail: return err; } -EXPORT_SYMBOL_GPL(rhashtable_insert_rehash); struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht, const void *key, @@ -486,191 +419,6 @@ exit: else return ERR_PTR(err); } -EXPORT_SYMBOL_GPL(rhashtable_insert_slow); - -/** - * rhashtable_walk_init - Initialise an iterator - * @ht: Table to walk over - * @iter: Hash table Iterator - * @gfp: GFP flags for allocations - * - * 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 if this function returns - * successfully. - */ -int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter, - gfp_t gfp) -{ - iter->ht = ht; - iter->p = NULL; - iter->slot = 0; - iter->skip = 0; - - iter->walker = kmalloc(sizeof(*iter->walker), gfp); - if (!iter->walker) - return -ENOMEM; - - spin_lock(&ht->lock); - iter->walker->tbl = - rcu_dereference_protected(ht->tbl, lockdep_is_held(&ht->lock)); - list_add(&iter->walker->list, &iter->walker->tbl->walkers); - spin_unlock(&ht->lock); - - return 0; -} -EXPORT_SYMBOL_GPL(rhashtable_walk_init); - -/** - * rhashtable_walk_exit - Free an iterator - * @iter: Hash table Iterator - * - * This function frees resources allocated by rhashtable_walk_init. - */ -void rhashtable_walk_exit(struct rhashtable_iter *iter) -{ - spin_lock(&iter->ht->lock); - if (iter->walker->tbl) - list_del(&iter->walker->list); - spin_unlock(&iter->ht->lock); - kfree(iter->walker); -} -EXPORT_SYMBOL_GPL(rhashtable_walk_exit); - -/** - * rhashtable_walk_start - Start a hash table walk - * @iter: Hash table iterator - * - * Start a hash table walk. Note that we take the RCU lock in all - * cases including when we return an error. So you must always call - * rhashtable_walk_stop to clean up. - * - * Returns zero if successful. - * - * Returns -EAGAIN if resize event occured. Note that the iterator - * will rewind back to the beginning and you may use it immediately - * by calling rhashtable_walk_next. - */ -int rhashtable_walk_start(struct rhashtable_iter *iter) - __acquires(RCU) -{ - struct rhashtable *ht = iter->ht; - - rcu_read_lock(); - - spin_lock(&ht->lock); - if (iter->walker->tbl) - list_del(&iter->walker->list); - spin_unlock(&ht->lock); - - if (!iter->walker->tbl) { - iter->walker->tbl = rht_dereference_rcu(ht->tbl, ht); - return -EAGAIN; - } - - return 0; -} -EXPORT_SYMBOL_GPL(rhashtable_walk_start); - -/** - * rhashtable_walk_next - Return the next object and advance the iterator - * @iter: Hash table iterator - * - * Note that you must call rhashtable_walk_stop when you are finished - * with the walk. - * - * Returns the next object or NULL when the end of the table is reached. - * - * Returns -EAGAIN if resize event occured. Note that the iterator - * will rewind back to the beginning and you may continue to use it. - */ -void *rhashtable_walk_next(struct rhashtable_iter *iter) -{ - struct bucket_table *tbl = iter->walker->tbl; - struct rhashtable *ht = iter->ht; - struct rhash_head *p = iter->p; - - if (p) { - p = rht_dereference_bucket_rcu(p->next, tbl, iter->slot); - goto next; - } - - for (; iter->slot < tbl->size; iter->slot++) { - int skip = iter->skip; - - rht_for_each_rcu(p, tbl, iter->slot) { - if (!skip) - break; - skip--; - } - -next: - if (!rht_is_a_nulls(p)) { - iter->skip++; - iter->p = p; - return rht_obj(ht, p); - } - - iter->skip = 0; - } - - iter->p = NULL; - - /* Ensure we see any new tables. */ - smp_rmb(); - - iter->walker->tbl = rht_dereference_rcu(tbl->future_tbl, ht); - if (iter->walker->tbl) { - iter->slot = 0; - iter->skip = 0; - return ERR_PTR(-EAGAIN); - } - - return NULL; -} -EXPORT_SYMBOL_GPL(rhashtable_walk_next); - -/** - * rhashtable_walk_stop - Finish a hash table walk - * @iter: Hash table iterator - * - * Finish a hash table walk. - */ -void rhashtable_walk_stop(struct rhashtable_iter *iter) - __releases(RCU) -{ - struct rhashtable *ht; - struct bucket_table *tbl = iter->walker->tbl; - - if (!tbl) - goto out; - - ht = iter->ht; - - spin_lock(&ht->lock); - if (tbl->rehash < tbl->size) - list_add(&iter->walker->list, &tbl->walkers); - else - iter->walker->tbl = NULL; - spin_unlock(&ht->lock); - - iter->p = NULL; - -out: - rcu_read_unlock(); -} -EXPORT_SYMBOL_GPL(rhashtable_walk_stop); static size_t rounded_hashtable_size(const struct rhashtable_params *params) { @@ -683,49 +431,6 @@ static u32 rhashtable_jhash2(const void *key, u32 length, u32 seed) return jhash2(key, length, seed); } -/** - * rhashtable_init - initialize a new hash table - * @ht: hash table to be initialized - * @params: configuration parameters - * - * Initializes a new hash table based on the provided configuration - * parameters. A table can be configured either with a variable or - * fixed length key: - * - * Configuration Example 1: Fixed length keys - * struct test_obj { - * int key; - * void * my_member; - * struct rhash_head node; - * }; - * - * struct rhashtable_params params = { - * .head_offset = offsetof(struct test_obj, node), - * .key_offset = offsetof(struct test_obj, key), - * .key_len = sizeof(int), - * .hashfn = jhash, - * .nulls_base = (1U << RHT_BASE_SHIFT), - * }; - * - * Configuration Example 2: Variable length keys - * struct test_obj { - * [...] - * struct rhash_head node; - * }; - * - * u32 my_hash_fn(const void *data, u32 len, u32 seed) - * { - * struct test_obj *obj = data; - * - * return [... hash ...]; - * } - * - * struct rhashtable_params params = { - * .head_offset = offsetof(struct test_obj, node), - * .hashfn = jhash, - * .obj_hashfn = my_hash_fn, - * }; - */ int rhashtable_init(struct rhashtable *ht, const struct rhashtable_params *params) { @@ -805,56 +510,15 @@ int rhashtable_init(struct rhashtable *ht, return 0; } -EXPORT_SYMBOL_GPL(rhashtable_init); -/** - * rhashtable_free_and_destroy - free elements and destroy hash table - * @ht: the hash table to destroy - * @free_fn: callback to release resources of element - * @arg: pointer passed to free_fn - * - * Stops an eventual async resize. If defined, invokes free_fn for each - * element to releasal resources. Please note that RCU protected - * readers may still be accessing the elements. Releasing of resources - * must occur in a compatible manner. Then frees the bucket array. - * - * This function will eventually sleep to wait for an async resize - * to complete. The caller is responsible that no further write operations - * occurs in parallel. - */ -void rhashtable_free_and_destroy(struct rhashtable *ht, - void (*free_fn)(void *ptr, void *arg), - void *arg) +void rhashtable_destroy(struct rhashtable *ht) { struct bucket_table *tbl; - unsigned int i; cancel_work_sync(&ht->run_work); mutex_lock(&ht->mutex); tbl = rht_dereference(ht->tbl, ht); - if (free_fn) { - for (i = 0; i < tbl->size; i++) { - struct rhash_head *pos, *next; - - for (pos = rht_dereference(tbl->buckets[i], ht), - next = !rht_is_a_nulls(pos) ? - rht_dereference(pos->next, ht) : NULL; - !rht_is_a_nulls(pos); - pos = next, - next = !rht_is_a_nulls(pos) ? - rht_dereference(pos->next, ht) : NULL) - free_fn(rht_obj(ht, pos), arg); - } - } - bucket_table_free(tbl); mutex_unlock(&ht->mutex); } -EXPORT_SYMBOL_GPL(rhashtable_free_and_destroy); - -void rhashtable_destroy(struct rhashtable *ht) -{ - return rhashtable_free_and_destroy(ht, NULL, NULL); -} -EXPORT_SYMBOL_GPL(rhashtable_destroy); |