[PATCH resend -next] lib/rhashtable: consider param->min_size when setting initial table size

[Davidlohr Bueso]

rhashtable_init() currently does not take into account the user-passed
min_size parameter unless param->nelem_hint is set as well. As such,
the default size (number of buckets) will always be HASH_DEFAULT_SIZE
even if the smallest allowed size is larger than that. Remediate this
by unconditionally calling into rounded_hashtable_size() and handling
things accordingly.

Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
---
Resending per Herbert's request with Cc to netdev.

lib/rhashtable.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 62d3a976614e..310e29b51507 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -953,8 +953,16 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_stop);

static size_t rounded_hashtable_size(const struct rhashtable_params *params)
{
-	return max(roundup_pow_of_two(params->nelem_hint * 4 / 3),
-		   (unsigned long)params->min_size);
+	size_t retsize;
+
+	if (params->nelem_hint)
+		retsize = max(roundup_pow_of_two(params->nelem_hint * 4 / 3),
+			      (unsigned long)params->min_size);
+	else
+		retsize = max(HASH_DEFAULT_SIZE,
+			      (unsigned long)params->min_size);
+
+	return retsize;
}

static u32 rhashtable_jhash2(const void *key, u32 length, u32 seed)
@@ -1010,8 +1018,6 @@ int rhashtable_init(struct rhashtable *ht,
	struct bucket_table *tbl;
	size_t size;

-	size = HASH_DEFAULT_SIZE;
-
	if ((!params->key_len && !params->obj_hashfn) ||
	    (params->obj_hashfn && !params->obj_cmpfn))
		return -EINVAL;
@@ -1035,8 +1041,7 @@ int rhashtable_init(struct rhashtable *ht,

	ht->p.min_size = max_t(u16, ht->p.min_size, HASH_MIN_SIZE);

-	if (params->nelem_hint)
-		size = rounded_hashtable_size(&ht->p);
+	size = rounded_hashtable_size(&ht->p);

	if (params->locks_mul)
		ht->p.locks_mul = roundup_pow_of_two(params->locks_mul);
--
2.16.4