![Herbert Xu](/assets/img/avatar_default.png)
My editor spewed garbage that looked like memory corruption on my screen. It turns out that a number of occurences of "fi" got turned into a ligature. This patch replaces these ligatures with the ASCII letters "fi". Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Cheers, Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
795 lines
20 KiB
C
795 lines
20 KiB
C
/*
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* Resizable, Scalable, Concurrent Hash Table
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*
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* Copyright (c) 2014 Thomas Graf <tgraf@suug.ch>
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* Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
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*
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* Based on the following paper:
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* https://www.usenix.org/legacy/event/atc11/tech/final_files/Triplett.pdf
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*
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* Code partially derived from nft_hash
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/log2.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/mm.h>
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#include <linux/hash.h>
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#include <linux/random.h>
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#include <linux/rhashtable.h>
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#define HASH_DEFAULT_SIZE 64UL
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#define HASH_MIN_SIZE 4UL
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#define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT))
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#ifdef CONFIG_PROVE_LOCKING
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int lockdep_rht_mutex_is_held(const struct rhashtable *ht)
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{
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return ht->p.mutex_is_held();
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}
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EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held);
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#endif
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static void *rht_obj(const struct rhashtable *ht, const struct rhash_head *he)
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{
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return (void *) he - ht->p.head_offset;
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}
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static u32 __hashfn(const struct rhashtable *ht, const void *key,
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u32 len, u32 hsize)
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{
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u32 h;
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h = ht->p.hashfn(key, len, ht->p.hash_rnd);
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return h & (hsize - 1);
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}
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/**
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* rhashtable_hashfn - compute hash for key of given length
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* @ht: hash table to compute for
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* @key: pointer to key
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* @len: length of key
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*
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* Computes the hash value using the hash function provided in the 'hashfn'
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* of struct rhashtable_params. The returned value is guaranteed to be
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* smaller than the number of buckets in the hash table.
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*/
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u32 rhashtable_hashfn(const struct rhashtable *ht, const void *key, u32 len)
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{
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struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
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return __hashfn(ht, key, len, tbl->size);
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}
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EXPORT_SYMBOL_GPL(rhashtable_hashfn);
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static u32 obj_hashfn(const struct rhashtable *ht, const void *ptr, u32 hsize)
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{
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if (unlikely(!ht->p.key_len)) {
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u32 h;
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h = ht->p.obj_hashfn(ptr, ht->p.hash_rnd);
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return h & (hsize - 1);
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}
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return __hashfn(ht, ptr + ht->p.key_offset, ht->p.key_len, hsize);
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}
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/**
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* rhashtable_obj_hashfn - compute hash for hashed object
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* @ht: hash table to compute for
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* @ptr: pointer to hashed object
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*
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* Computes the hash value using the hash function `hashfn` respectively
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* 'obj_hashfn' depending on whether the hash table is set up to work with
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* a fixed length key. The returned value is guaranteed to be smaller than
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* the number of buckets in the hash table.
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*/
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u32 rhashtable_obj_hashfn(const struct rhashtable *ht, void *ptr)
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{
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struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
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return obj_hashfn(ht, ptr, tbl->size);
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}
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EXPORT_SYMBOL_GPL(rhashtable_obj_hashfn);
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static u32 head_hashfn(const struct rhashtable *ht,
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const struct rhash_head *he, u32 hsize)
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{
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return obj_hashfn(ht, rht_obj(ht, he), hsize);
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}
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static struct bucket_table *bucket_table_alloc(size_t nbuckets, gfp_t flags)
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{
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struct bucket_table *tbl;
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size_t size;
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size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
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tbl = kzalloc(size, flags);
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if (tbl == NULL)
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tbl = vzalloc(size);
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if (tbl == NULL)
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return NULL;
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tbl->size = nbuckets;
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return tbl;
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}
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static void bucket_table_free(const struct bucket_table *tbl)
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{
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kvfree(tbl);
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}
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/**
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* rht_grow_above_75 - returns true if nelems > 0.75 * table-size
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* @ht: hash table
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* @new_size: new table size
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*/
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bool rht_grow_above_75(const struct rhashtable *ht, size_t new_size)
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{
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/* Expand table when exceeding 75% load */
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return ht->nelems > (new_size / 4 * 3);
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}
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EXPORT_SYMBOL_GPL(rht_grow_above_75);
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/**
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* rht_shrink_below_30 - returns true if nelems < 0.3 * table-size
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* @ht: hash table
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* @new_size: new table size
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*/
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bool rht_shrink_below_30(const struct rhashtable *ht, size_t new_size)
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{
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/* Shrink table beneath 30% load */
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return ht->nelems < (new_size * 3 / 10);
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}
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EXPORT_SYMBOL_GPL(rht_shrink_below_30);
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static void hashtable_chain_unzip(const struct rhashtable *ht,
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const struct bucket_table *new_tbl,
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struct bucket_table *old_tbl, size_t n)
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{
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struct rhash_head *he, *p, *next;
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unsigned int h;
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/* Old bucket empty, no work needed. */
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p = rht_dereference(old_tbl->buckets[n], ht);
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if (!p)
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return;
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/* Advance the old bucket pointer one or more times until it
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* reaches a node that doesn't hash to the same bucket as the
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* previous node p. Call the previous node p;
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*/
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h = head_hashfn(ht, p, new_tbl->size);
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rht_for_each(he, p->next, ht) {
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if (head_hashfn(ht, he, new_tbl->size) != h)
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break;
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p = he;
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}
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RCU_INIT_POINTER(old_tbl->buckets[n], p->next);
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/* Find the subsequent node which does hash to the same
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* bucket as node P, or NULL if no such node exists.
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*/
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next = NULL;
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if (he) {
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rht_for_each(he, he->next, ht) {
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if (head_hashfn(ht, he, new_tbl->size) == h) {
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next = he;
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break;
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}
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}
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}
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/* Set p's next pointer to that subsequent node pointer,
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* bypassing the nodes which do not hash to p's bucket
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*/
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RCU_INIT_POINTER(p->next, next);
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}
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/**
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* rhashtable_expand - Expand hash table while allowing concurrent lookups
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* @ht: the hash table to expand
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* @flags: allocation flags
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*
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* A secondary bucket array is allocated and the hash entries are migrated
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* while keeping them on both lists until the end of the RCU grace period.
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*
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* This function may only be called in a context where it is safe to call
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* synchronize_rcu(), e.g. not within a rcu_read_lock() section.
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*
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* The caller must ensure that no concurrent table mutations take place.
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* It is however valid to have concurrent lookups if they are RCU protected.
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*/
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int rhashtable_expand(struct rhashtable *ht, gfp_t flags)
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{
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struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht);
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struct rhash_head *he;
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unsigned int i, h;
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bool complete;
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ASSERT_RHT_MUTEX(ht);
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if (ht->p.max_shift && ht->shift >= ht->p.max_shift)
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return 0;
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new_tbl = bucket_table_alloc(old_tbl->size * 2, flags);
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if (new_tbl == NULL)
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return -ENOMEM;
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ht->shift++;
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/* For each new bucket, search the corresponding old bucket
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* for the first entry that hashes to the new bucket, and
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* link the new bucket to that entry. Since all the entries
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* which will end up in the new bucket appear in the same
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* old bucket, this constructs an entirely valid new hash
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* table, but with multiple buckets "zipped" together into a
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* single imprecise chain.
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*/
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for (i = 0; i < new_tbl->size; i++) {
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h = i & (old_tbl->size - 1);
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rht_for_each(he, old_tbl->buckets[h], ht) {
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if (head_hashfn(ht, he, new_tbl->size) == i) {
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RCU_INIT_POINTER(new_tbl->buckets[i], he);
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break;
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}
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}
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}
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/* Publish the new table pointer. Lookups may now traverse
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* the new table, but they will not benefit from any
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* additional efficiency until later steps unzip the buckets.
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*/
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rcu_assign_pointer(ht->tbl, new_tbl);
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/* Unzip interleaved hash chains */
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do {
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/* Wait for readers. All new readers will see the new
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* table, and thus no references to the old table will
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* remain.
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*/
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synchronize_rcu();
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/* For each bucket in the old table (each of which
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* contains items from multiple buckets of the new
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* table): ...
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*/
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complete = true;
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for (i = 0; i < old_tbl->size; i++) {
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hashtable_chain_unzip(ht, new_tbl, old_tbl, i);
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if (old_tbl->buckets[i] != NULL)
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complete = false;
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}
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} while (!complete);
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bucket_table_free(old_tbl);
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return 0;
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}
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EXPORT_SYMBOL_GPL(rhashtable_expand);
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/**
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* rhashtable_shrink - Shrink hash table while allowing concurrent lookups
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* @ht: the hash table to shrink
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* @flags: allocation flags
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*
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* This function may only be called in a context where it is safe to call
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* synchronize_rcu(), e.g. not within a rcu_read_lock() section.
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*
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* The caller must ensure that no concurrent table mutations take place.
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* It is however valid to have concurrent lookups if they are RCU protected.
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*/
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int rhashtable_shrink(struct rhashtable *ht, gfp_t flags)
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{
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struct bucket_table *ntbl, *tbl = rht_dereference(ht->tbl, ht);
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struct rhash_head __rcu **pprev;
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unsigned int i;
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ASSERT_RHT_MUTEX(ht);
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if (ht->shift <= ht->p.min_shift)
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return 0;
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ntbl = bucket_table_alloc(tbl->size / 2, flags);
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if (ntbl == NULL)
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return -ENOMEM;
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ht->shift--;
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/* Link each bucket in the new table to the first bucket
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* in the old table that contains entries which will hash
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* to the new bucket.
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*/
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for (i = 0; i < ntbl->size; i++) {
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ntbl->buckets[i] = tbl->buckets[i];
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/* Link each bucket in the new table to the first bucket
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* in the old table that contains entries which will hash
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* to the new bucket.
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*/
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for (pprev = &ntbl->buckets[i]; *pprev != NULL;
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pprev = &rht_dereference(*pprev, ht)->next)
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;
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RCU_INIT_POINTER(*pprev, tbl->buckets[i + ntbl->size]);
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}
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/* Publish the new, valid hash table */
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rcu_assign_pointer(ht->tbl, ntbl);
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/* Wait for readers. No new readers will have references to the
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* old hash table.
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*/
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synchronize_rcu();
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bucket_table_free(tbl);
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return 0;
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}
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EXPORT_SYMBOL_GPL(rhashtable_shrink);
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/**
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* rhashtable_insert - insert object into hash hash table
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* @ht: hash table
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* @obj: pointer to hash head inside object
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* @flags: allocation flags (table expansion)
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*
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* Will automatically grow the table via rhashtable_expand() if the the
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* grow_decision function specified at rhashtable_init() returns true.
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*
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* The caller must ensure that no concurrent table mutations occur. It is
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* however valid to have concurrent lookups if they are RCU protected.
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*/
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void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj,
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gfp_t flags)
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{
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struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
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u32 hash;
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ASSERT_RHT_MUTEX(ht);
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hash = head_hashfn(ht, obj, tbl->size);
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RCU_INIT_POINTER(obj->next, tbl->buckets[hash]);
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rcu_assign_pointer(tbl->buckets[hash], obj);
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ht->nelems++;
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if (ht->p.grow_decision && ht->p.grow_decision(ht, tbl->size))
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rhashtable_expand(ht, flags);
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}
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EXPORT_SYMBOL_GPL(rhashtable_insert);
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/**
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* rhashtable_remove_pprev - remove object from hash table given previous element
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* @ht: hash table
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* @obj: pointer to hash head inside object
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* @pprev: pointer to previous element
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* @flags: allocation flags (table expansion)
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*
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* Identical to rhashtable_remove() but caller is alreayd aware of the element
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* in front of the element to be deleted. This is in particular useful for
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* deletion when combined with walking or lookup.
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*/
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void rhashtable_remove_pprev(struct rhashtable *ht, struct rhash_head *obj,
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struct rhash_head __rcu **pprev, gfp_t flags)
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{
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struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
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ASSERT_RHT_MUTEX(ht);
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RCU_INIT_POINTER(*pprev, obj->next);
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ht->nelems--;
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if (ht->p.shrink_decision &&
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ht->p.shrink_decision(ht, tbl->size))
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rhashtable_shrink(ht, flags);
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}
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EXPORT_SYMBOL_GPL(rhashtable_remove_pprev);
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/**
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* rhashtable_remove - remove object from hash table
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* @ht: hash table
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* @obj: pointer to hash head inside object
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* @flags: allocation flags (table expansion)
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*
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* Since the hash chain is single linked, the removal operation needs to
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* walk the bucket chain upon removal. The removal operation is thus
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* considerable slow if the hash table is not correctly sized.
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*
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* Will automatically shrink the table via rhashtable_expand() if the the
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* shrink_decision function specified at rhashtable_init() returns true.
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*
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* The caller must ensure that no concurrent table mutations occur. It is
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* however valid to have concurrent lookups if they are RCU protected.
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*/
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bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *obj,
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gfp_t flags)
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{
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struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
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struct rhash_head __rcu **pprev;
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struct rhash_head *he;
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u32 h;
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ASSERT_RHT_MUTEX(ht);
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h = head_hashfn(ht, obj, tbl->size);
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pprev = &tbl->buckets[h];
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rht_for_each(he, tbl->buckets[h], ht) {
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if (he != obj) {
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pprev = &he->next;
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continue;
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}
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rhashtable_remove_pprev(ht, he, pprev, flags);
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return true;
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}
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return false;
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}
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EXPORT_SYMBOL_GPL(rhashtable_remove);
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/**
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* rhashtable_lookup - lookup key in hash table
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* @ht: hash table
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* @key: pointer to key
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*
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* Computes the hash value for the key and traverses the bucket chain looking
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* for a entry with an identical key. The first matching entry is returned.
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*
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* This lookup function may only be used for fixed key hash table (key_len
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* paramter set). It will BUG() if used inappropriately.
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*
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* Lookups may occur in parallel with hash mutations as long as the lookup is
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* guarded by rcu_read_lock(). The caller must take care of this.
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*/
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void *rhashtable_lookup(const struct rhashtable *ht, const void *key)
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{
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const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
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struct rhash_head *he;
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u32 h;
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BUG_ON(!ht->p.key_len);
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h = __hashfn(ht, key, ht->p.key_len, tbl->size);
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rht_for_each_rcu(he, tbl->buckets[h], ht) {
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if (memcmp(rht_obj(ht, he) + ht->p.key_offset, key,
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ht->p.key_len))
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continue;
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return (void *) he - ht->p.head_offset;
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}
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return NULL;
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}
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EXPORT_SYMBOL_GPL(rhashtable_lookup);
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/**
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* rhashtable_lookup_compare - search hash table with compare function
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* @ht: hash table
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* @hash: hash value of desired entry
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* @compare: compare function, must return true on match
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* @arg: argument passed on to compare function
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*
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* Traverses the bucket chain behind the provided hash value and calls the
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* specified compare function for each entry.
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*
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* Lookups may occur in parallel with hash mutations as long as the lookup is
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* guarded by rcu_read_lock(). The caller must take care of this.
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*
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* Returns the first entry on which the compare function returned true.
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*/
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void *rhashtable_lookup_compare(const struct rhashtable *ht, u32 hash,
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bool (*compare)(void *, void *), void *arg)
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{
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const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
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struct rhash_head *he;
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if (unlikely(hash >= tbl->size))
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return NULL;
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|
|
rht_for_each_rcu(he, tbl->buckets[hash], ht) {
|
|
if (!compare(rht_obj(ht, he), arg))
|
|
continue;
|
|
return (void *) he - ht->p.head_offset;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_lookup_compare);
|
|
|
|
static size_t rounded_hashtable_size(struct rhashtable_params *params)
|
|
{
|
|
return max(roundup_pow_of_two(params->nelem_hint * 4 / 3),
|
|
1UL << params->min_shift);
|
|
}
|
|
|
|
/**
|
|
* 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 = arch_fast_hash,
|
|
* .mutex_is_held = &my_mutex_is_held,
|
|
* };
|
|
*
|
|
* Configuration Example 2: Variable length keys
|
|
* struct test_obj {
|
|
* [...]
|
|
* struct rhash_head node;
|
|
* };
|
|
*
|
|
* u32 my_hash_fn(const void *data, u32 seed)
|
|
* {
|
|
* struct test_obj *obj = data;
|
|
*
|
|
* return [... hash ...];
|
|
* }
|
|
*
|
|
* struct rhashtable_params params = {
|
|
* .head_offset = offsetof(struct test_obj, node),
|
|
* .hashfn = arch_fast_hash,
|
|
* .obj_hashfn = my_hash_fn,
|
|
* .mutex_is_held = &my_mutex_is_held,
|
|
* };
|
|
*/
|
|
int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params)
|
|
{
|
|
struct bucket_table *tbl;
|
|
size_t size;
|
|
|
|
size = HASH_DEFAULT_SIZE;
|
|
|
|
if ((params->key_len && !params->hashfn) ||
|
|
(!params->key_len && !params->obj_hashfn))
|
|
return -EINVAL;
|
|
|
|
params->min_shift = max_t(size_t, params->min_shift,
|
|
ilog2(HASH_MIN_SIZE));
|
|
|
|
if (params->nelem_hint)
|
|
size = rounded_hashtable_size(params);
|
|
|
|
tbl = bucket_table_alloc(size, GFP_KERNEL);
|
|
if (tbl == NULL)
|
|
return -ENOMEM;
|
|
|
|
memset(ht, 0, sizeof(*ht));
|
|
ht->shift = ilog2(tbl->size);
|
|
memcpy(&ht->p, params, sizeof(*params));
|
|
RCU_INIT_POINTER(ht->tbl, tbl);
|
|
|
|
if (!ht->p.hash_rnd)
|
|
get_random_bytes(&ht->p.hash_rnd, sizeof(ht->p.hash_rnd));
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_init);
|
|
|
|
/**
|
|
* rhashtable_destroy - destroy hash table
|
|
* @ht: the hash table to destroy
|
|
*
|
|
* 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.
|
|
*/
|
|
void rhashtable_destroy(const struct rhashtable *ht)
|
|
{
|
|
bucket_table_free(ht->tbl);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_destroy);
|
|
|
|
/**************************************************************************
|
|
* Self Test
|
|
**************************************************************************/
|
|
|
|
#ifdef CONFIG_TEST_RHASHTABLE
|
|
|
|
#define TEST_HT_SIZE 8
|
|
#define TEST_ENTRIES 2048
|
|
#define TEST_PTR ((void *) 0xdeadbeef)
|
|
#define TEST_NEXPANDS 4
|
|
|
|
static int test_mutex_is_held(void)
|
|
{
|
|
return 1;
|
|
}
|
|
|
|
struct test_obj {
|
|
void *ptr;
|
|
int value;
|
|
struct rhash_head node;
|
|
};
|
|
|
|
static int __init test_rht_lookup(struct rhashtable *ht)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < TEST_ENTRIES * 2; i++) {
|
|
struct test_obj *obj;
|
|
bool expected = !(i % 2);
|
|
u32 key = i;
|
|
|
|
obj = rhashtable_lookup(ht, &key);
|
|
|
|
if (expected && !obj) {
|
|
pr_warn("Test failed: Could not find key %u\n", key);
|
|
return -ENOENT;
|
|
} else if (!expected && obj) {
|
|
pr_warn("Test failed: Unexpected entry found for key %u\n",
|
|
key);
|
|
return -EEXIST;
|
|
} else if (expected && obj) {
|
|
if (obj->ptr != TEST_PTR || obj->value != i) {
|
|
pr_warn("Test failed: Lookup value mismatch %p!=%p, %u!=%u\n",
|
|
obj->ptr, TEST_PTR, obj->value, i);
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void test_bucket_stats(struct rhashtable *ht,
|
|
struct bucket_table *tbl,
|
|
bool quiet)
|
|
{
|
|
unsigned int cnt, i, total = 0;
|
|
struct test_obj *obj;
|
|
|
|
for (i = 0; i < tbl->size; i++) {
|
|
cnt = 0;
|
|
|
|
if (!quiet)
|
|
pr_info(" [%#4x/%zu]", i, tbl->size);
|
|
|
|
rht_for_each_entry_rcu(obj, tbl->buckets[i], node) {
|
|
cnt++;
|
|
total++;
|
|
if (!quiet)
|
|
pr_cont(" [%p],", obj);
|
|
}
|
|
|
|
if (!quiet)
|
|
pr_cont("\n [%#x] first element: %p, chain length: %u\n",
|
|
i, tbl->buckets[i], cnt);
|
|
}
|
|
|
|
pr_info(" Traversal complete: counted=%u, nelems=%zu, entries=%d\n",
|
|
total, ht->nelems, TEST_ENTRIES);
|
|
}
|
|
|
|
static int __init test_rhashtable(struct rhashtable *ht)
|
|
{
|
|
struct bucket_table *tbl;
|
|
struct test_obj *obj, *next;
|
|
int err;
|
|
unsigned int i;
|
|
|
|
/*
|
|
* Insertion Test:
|
|
* Insert TEST_ENTRIES into table with all keys even numbers
|
|
*/
|
|
pr_info(" Adding %d keys\n", TEST_ENTRIES);
|
|
for (i = 0; i < TEST_ENTRIES; i++) {
|
|
struct test_obj *obj;
|
|
|
|
obj = kzalloc(sizeof(*obj), GFP_KERNEL);
|
|
if (!obj) {
|
|
err = -ENOMEM;
|
|
goto error;
|
|
}
|
|
|
|
obj->ptr = TEST_PTR;
|
|
obj->value = i * 2;
|
|
|
|
rhashtable_insert(ht, &obj->node, GFP_KERNEL);
|
|
}
|
|
|
|
rcu_read_lock();
|
|
tbl = rht_dereference_rcu(ht->tbl, ht);
|
|
test_bucket_stats(ht, tbl, true);
|
|
test_rht_lookup(ht);
|
|
rcu_read_unlock();
|
|
|
|
for (i = 0; i < TEST_NEXPANDS; i++) {
|
|
pr_info(" Table expansion iteration %u...\n", i);
|
|
rhashtable_expand(ht, GFP_KERNEL);
|
|
|
|
rcu_read_lock();
|
|
pr_info(" Verifying lookups...\n");
|
|
test_rht_lookup(ht);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
for (i = 0; i < TEST_NEXPANDS; i++) {
|
|
pr_info(" Table shrinkage iteration %u...\n", i);
|
|
rhashtable_shrink(ht, GFP_KERNEL);
|
|
|
|
rcu_read_lock();
|
|
pr_info(" Verifying lookups...\n");
|
|
test_rht_lookup(ht);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
pr_info(" Deleting %d keys\n", TEST_ENTRIES);
|
|
for (i = 0; i < TEST_ENTRIES; i++) {
|
|
u32 key = i * 2;
|
|
|
|
obj = rhashtable_lookup(ht, &key);
|
|
BUG_ON(!obj);
|
|
|
|
rhashtable_remove(ht, &obj->node, GFP_KERNEL);
|
|
kfree(obj);
|
|
}
|
|
|
|
return 0;
|
|
|
|
error:
|
|
tbl = rht_dereference_rcu(ht->tbl, ht);
|
|
for (i = 0; i < tbl->size; i++)
|
|
rht_for_each_entry_safe(obj, next, tbl->buckets[i], ht, node)
|
|
kfree(obj);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int __init test_rht_init(void)
|
|
{
|
|
struct rhashtable ht;
|
|
struct rhashtable_params params = {
|
|
.nelem_hint = TEST_HT_SIZE,
|
|
.head_offset = offsetof(struct test_obj, node),
|
|
.key_offset = offsetof(struct test_obj, value),
|
|
.key_len = sizeof(int),
|
|
.hashfn = arch_fast_hash,
|
|
.mutex_is_held = &test_mutex_is_held,
|
|
.grow_decision = rht_grow_above_75,
|
|
.shrink_decision = rht_shrink_below_30,
|
|
};
|
|
int err;
|
|
|
|
pr_info("Running resizable hashtable tests...\n");
|
|
|
|
err = rhashtable_init(&ht, ¶ms);
|
|
if (err < 0) {
|
|
pr_warn("Test failed: Unable to initialize hashtable: %d\n",
|
|
err);
|
|
return err;
|
|
}
|
|
|
|
err = test_rhashtable(&ht);
|
|
|
|
rhashtable_destroy(&ht);
|
|
|
|
return err;
|
|
}
|
|
|
|
subsys_initcall(test_rht_init);
|
|
|
|
#endif /* CONFIG_TEST_RHASHTABLE */
|