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rhashtable: optimize rhashtable_lookup routine

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Define an internal compare function and relevant compare argument,
and then make use of rhashtable_lookup_compare() to lookup key in
hash table, reducing duplicated code between rhashtable_lookup()
and rhashtable_lookup_compare().

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Cc: Thomas Graf <tgraf@suug.ch>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ying Xue 2015-01-07 13:41:52 +08:00 committed by David S. Miller
parent 7c1b70234e
commit efb975a67e
1 changed files with 18 additions and 23 deletions
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41
lib/rhashtable.c
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@ -612,6 +612,19 @@ bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *obj)
}
EXPORT_SYMBOL_GPL(rhashtable_remove);
struct rhashtable_compare_arg {
struct rhashtable *ht;
const void *key;
};
static bool rhashtable_compare(void *ptr, void *arg)
{
struct rhashtable_compare_arg *x = arg;
struct rhashtable *ht = x->ht;
return !memcmp(ptr + ht->p.key_offset, x->key, ht->p.key_len);
}
/**
* rhashtable_lookup - lookup key in hash table
* @ht: hash table
@ -627,32 +640,14 @@ EXPORT_SYMBOL_GPL(rhashtable_remove);
*/
void *rhashtable_lookup(struct rhashtable *ht, const void *key)
{
const struct bucket_table *tbl, *old_tbl;
struct rhash_head *he;
u32 hash;
struct rhashtable_compare_arg arg = {
.ht = ht,
.key = key,
};
BUG_ON(!ht->p.key_len);
rcu_read_lock();
old_tbl = rht_dereference_rcu(ht->tbl, ht);
tbl = rht_dereference_rcu(ht->future_tbl, ht);
hash = key_hashfn(ht, key, ht->p.key_len);
restart:
rht_for_each_rcu(he, tbl, rht_bucket_index(tbl, hash)) {
if (memcmp(rht_obj(ht, he) + ht->p.key_offset, key,
ht->p.key_len))
continue;
rcu_read_unlock();
return rht_obj(ht, he);
}
if (unlikely(tbl != old_tbl)) {
tbl = old_tbl;
goto restart;
}
rcu_read_unlock();
return NULL;
return rhashtable_lookup_compare(ht, key, &rhashtable_compare, &arg);
}
EXPORT_SYMBOL_GPL(rhashtable_lookup);