rhashtable: Round up/down min/max_size to ensure we respect limit

Round up min_size respectively round down max_size to the next power
of two to make sure we always respect the limit specified by the
user. This is required because we compare the table size against the
limit before we expand or shrink.

Also fixes a minor bug where we modified min_size in the params
provided instead of the copy stored in struct rhashtable.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 2 deletions

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 5f8fe3e..e75c48d 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -933,8 +933,6 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params)
 	if (params->nulls_base && params->nulls_base < (1U << RHT_BASE_SHIFT))
 		return -EINVAL;
 
-	params->min_size = max(params->min_size, HASH_MIN_SIZE);
-
 	if (params->nelem_hint)
 		size = rounded_hashtable_size(params);
 
@@ -942,6 +940,14 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params)
 	mutex_init(&ht->mutex);
 	memcpy(&ht->p, params, sizeof(*params));
 
+	if (params->min_size)
+		ht->p.min_size = roundup_pow_of_two(params->min_size);
+
+	if (params->max_size)
+		ht->p.max_size = rounddown_pow_of_two(params->max_size);
+
+	ht->p.min_size = max(params->min_size, HASH_MIN_SIZE);
+
 	if (params->locks_mul)
 		ht->p.locks_mul = roundup_pow_of_two(params->locks_mul);
 	else