rhashtable: Move hash_rnd into bucket_table
Currently hash_rnd is a parameter that users can set. However,
no existing users set this parameter. It is also something that
people are unlikely to want to set directly since it's just a
random number.
In preparation for allowing the reseeding/rehashing of rhashtable,
this patch moves hash_rnd into bucket_table so that it's now an
internal state rather than a parameter.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index b5344ef..ba15dce 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -66,25 +66,28 @@
return hash & (tbl->size - 1);
}
-static u32 obj_raw_hashfn(const struct rhashtable *ht, const void *ptr)
+static u32 obj_raw_hashfn(struct rhashtable *ht, const void *ptr)
{
+ struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
u32 hash;
if (unlikely(!ht->p.key_len))
- hash = ht->p.obj_hashfn(ptr, ht->p.hash_rnd);
+ hash = ht->p.obj_hashfn(ptr, tbl->hash_rnd);
else
hash = ht->p.hashfn(ptr + ht->p.key_offset, ht->p.key_len,
- ht->p.hash_rnd);
+ tbl->hash_rnd);
return hash >> HASH_RESERVED_SPACE;
}
static u32 key_hashfn(struct rhashtable *ht, const void *key, u32 len)
{
- return ht->p.hashfn(key, len, ht->p.hash_rnd) >> HASH_RESERVED_SPACE;
+ struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
+
+ return ht->p.hashfn(key, len, tbl->hash_rnd) >> HASH_RESERVED_SPACE;
}
-static u32 head_hashfn(const struct rhashtable *ht,
+static u32 head_hashfn(struct rhashtable *ht,
const struct bucket_table *tbl,
const struct rhash_head *he)
{
@@ -92,7 +95,7 @@
}
#ifdef CONFIG_PROVE_LOCKING
-static void debug_dump_buckets(const struct rhashtable *ht,
+static void debug_dump_buckets(struct rhashtable *ht,
const struct bucket_table *tbl)
{
struct rhash_head *he;
@@ -385,6 +388,8 @@
if (new_tbl == NULL)
return -ENOMEM;
+ new_tbl->hash_rnd = old_tbl->hash_rnd;
+
atomic_inc(&ht->shift);
/* Make insertions go into the new, empty table right away. Deletions
@@ -476,6 +481,8 @@
if (new_tbl == NULL)
return -ENOMEM;
+ new_tbl->hash_rnd = tbl->hash_rnd;
+
rcu_assign_pointer(ht->future_tbl, new_tbl);
synchronize_rcu();
@@ -1099,14 +1106,13 @@
if (tbl == NULL)
return -ENOMEM;
+ get_random_bytes(&tbl->hash_rnd, sizeof(tbl->hash_rnd));
+
atomic_set(&ht->nelems, 0);
atomic_set(&ht->shift, ilog2(tbl->size));
RCU_INIT_POINTER(ht->tbl, tbl);
RCU_INIT_POINTER(ht->future_tbl, tbl);
- if (!ht->p.hash_rnd)
- get_random_bytes(&ht->p.hash_rnd, sizeof(ht->p.hash_rnd));
-
INIT_WORK(&ht->run_work, rht_deferred_worker);
return 0;