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Commit 988dfbd7 authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
Browse files

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: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Acked-by: default avatarThomas Graf <tgraf@suug.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0ddcf43d

include/linux/rhashtable.h

+2 −2
Original line number Diff line number Diff line
@@ -49,12 +49,14 @@ struct rhash_head { 
/**

 * struct bucket_table - Table of hash buckets

 * @size: Number of hash buckets

 * @hash_rnd: Random seed to fold into hash

 * @locks_mask: Mask to apply before accessing locks[]

 * @locks: Array of spinlocks protecting individual buckets

 * @buckets: size * hash buckets

 */

struct bucket_table {

	size_t			size;

	u32			hash_rnd;

	unsigned int		locks_mask;

	spinlock_t		*locks;
@@ -72,7 +74,6 @@ struct rhashtable; 
 * @key_len: Length of key

 * @key_offset: Offset of key in struct to be hashed

 * @head_offset: Offset of rhash_head in struct to be hashed

 * @hash_rnd: Seed to use while hashing

 * @max_shift: Maximum number of shifts while expanding

 * @min_shift: Minimum number of shifts while shrinking

 * @nulls_base: Base value to generate nulls marker
@@ -85,7 +86,6 @@ struct rhashtable_params { 
	size_t			key_len;

	size_t			key_offset;

	size_t			head_offset;

	u32			hash_rnd;

	size_t			max_shift;

	size_t			min_shift;

	u32			nulls_base;

lib/rhashtable.c

+15 −9
Original line number Diff line number Diff line
@@ -66,25 +66,28 @@ static u32 rht_bucket_index(const struct bucket_table *tbl, u32 hash) 
	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 @@ static u32 head_hashfn(const struct rhashtable *ht, 
}



#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 @@ int rhashtable_expand(struct rhashtable *ht) 
	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 @@ int rhashtable_shrink(struct rhashtable *ht) 
	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 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params) 
	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;