return new_tbl;
}
-static int rhashtable_rehash_one(struct rhashtable *ht, unsigned old_hash)
+static int rhashtable_rehash_one(struct rhashtable *ht, unsigned int old_hash)
{
struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht);
struct bucket_table *new_tbl = rhashtable_last_table(ht,
int err = -ENOENT;
struct rhash_head *head, *next, *entry;
spinlock_t *new_bucket_lock;
- unsigned new_hash;
+ unsigned int new_hash;
rht_for_each(entry, old_tbl, old_hash) {
err = 0;
return err;
}
-static void rhashtable_rehash_chain(struct rhashtable *ht, unsigned old_hash)
+static void rhashtable_rehash_chain(struct rhashtable *ht,
+ unsigned int old_hash)
{
struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht);
spinlock_t *old_bucket_lock;
struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht);
struct bucket_table *new_tbl;
struct rhashtable_walker *walker;
- unsigned old_hash;
+ unsigned int old_hash;
new_tbl = rht_dereference(old_tbl->future_tbl, ht);
if (!new_tbl)
static int rhashtable_shrink(struct rhashtable *ht)
{
struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht);
- unsigned size = roundup_pow_of_two(atomic_read(&ht->nelems) * 3 / 2);
+ unsigned int size;
int err;
ASSERT_RHT_MUTEX(ht);
+ size = roundup_pow_of_two(atomic_read(&ht->nelems) * 3 / 2);
if (size < ht->p.min_size)
size = ht->p.min_size;
ht = container_of(work, struct rhashtable, run_work);
mutex_lock(&ht->mutex);
- if (ht->being_destroyed)
- goto unlock;
tbl = rht_dereference(ht->tbl, ht);
tbl = rhashtable_last_table(ht, tbl);
if (rht_grow_above_75(ht, tbl))
rhashtable_expand(ht);
- else if (rht_shrink_below_30(ht, tbl))
+ else if (ht->p.automatic_shrinking && rht_shrink_below_30(ht, tbl))
rhashtable_shrink(ht);
err = rhashtable_rehash_table(ht);
-unlock:
mutex_unlock(&ht->mutex);
if (err)
static bool rhashtable_check_elasticity(struct rhashtable *ht,
struct bucket_table *tbl,
- unsigned hash)
+ unsigned int hash)
{
- unsigned elasticity = ht->elasticity;
+ unsigned int elasticity = ht->elasticity;
struct rhash_head *head;
rht_for_each(head, tbl, hash)
struct bucket_table *tbl)
{
struct rhash_head *head;
- unsigned hash;
+ unsigned int hash;
int err;
tbl = rhashtable_last_table(ht, tbl);
* struct rhash_head node;
* };
*
- * u32 my_hash_fn(const void *data, u32 seed)
+ * u32 my_hash_fn(const void *data, u32 len, u32 seed)
* {
* struct test_obj *obj = data;
*
ht->p.min_size = max(ht->p.min_size, HASH_MIN_SIZE);
+ /* The maximum (not average) chain length grows with the
+ * size of the hash table, at a rate of (log N)/(log log N).
+ * The value of 16 is selected so that even if the hash
+ * table grew to 2^32 you would not expect the maximum
+ * chain length to exceed it unless we are under attack
+ * (or extremely unlucky).
+ *
+ * As this limit is only to detect attacks, we don't need
+ * to set it to a lower value as you'd need the chain
+ * length to vastly exceed 16 to have any real effect
+ * on the system.
+ */
if (!params->insecure_elasticity)
ht->elasticity = 16;
EXPORT_SYMBOL_GPL(rhashtable_init);
/**
- * rhashtable_destroy - destroy hash table
+ * 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.
*
- * Frees the bucket array. This function is not rcu safe, therefore the caller
- * has to make sure that no resizing may happen by unpublishing the hashtable
- * and waiting for the quiescent cycle before releasing 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_destroy(struct rhashtable *ht)
+void rhashtable_free_and_destroy(struct rhashtable *ht,
+ void (*free_fn)(void *ptr, void *arg),
+ void *arg)
{
- ht->being_destroyed = true;
+ const struct bucket_table *tbl;
+ unsigned int i;
cancel_work_sync(&ht->run_work);
mutex_lock(&ht->mutex);
- bucket_table_free(rht_dereference(ht->tbl, ht));
+ 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);
git.openpandora.org / pandora-kernel.git / blobdiff