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rhashtable: remove insecure_elasticity 

commit 83e7e4ce9e ("mac80211: Use rhltable instead of rhashtable")
removed the last user that made use of 'insecure_elasticity' parameter,
i.e. the default of 16 is used everywhere.

Replace it with a constant.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
zero-colors
Florian Westphal 2017-04-16 02:55:09 +02:00 committed by David S. Miller
parent 3a9ca1e2cb
commit 5f8ddeab10
2 changed files with 17 additions and 21 deletions
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21
include/linux/rhashtable.h
View File

@ -49,6 +49,21 @@
/* Base bits plus 1 bit for nulls marker */
#define RHT_HASH_RESERVED_SPACE (RHT_BASE_BITS + 1)
/* Maximum chain length before rehash
*
* The maximum (not average) chain length grows with the size of the hash
* table, at a rate of (log N)/(log log N).
*
* The value of 16 is selected so that even if the hash table grew to
* 2^32 you would not expect the maximum chain length to exceed it
* unless we are under attack (or extremely unlucky).
*
* As this limit is only to detect attacks, we don't need to set it to a
* lower value as you'd need the chain length to vastly exceed 16 to have
* any real effect on the system.
*/
#define RHT_ELASTICITY 16u
struct rhash_head {
struct rhash_head __rcu *next;
};
@ -114,7 +129,6 @@ struct rhashtable;
* @max_size: Maximum size while expanding
* @min_size: Minimum size while shrinking
* @nulls_base: Base value to generate nulls marker
* @insecure_elasticity: Set to true to disable chain length checks
* @automatic_shrinking: Enable automatic shrinking of tables
* @locks_mul: Number of bucket locks to allocate per cpu (default: 128)
* @hashfn: Hash function (default: jhash2 if !(key_len % 4), or jhash)
@ -130,7 +144,6 @@ struct rhashtable_params {
unsigned int max_size;
unsigned int min_size;
u32 nulls_base;
bool insecure_elasticity;
bool automatic_shrinking;
size_t locks_mul;
rht_hashfn_t hashfn;
@ -143,7 +156,6 @@ struct rhashtable_params {
* @tbl: Bucket table
* @nelems: Number of elements in table
* @key_len: Key length for hashfn
* @elasticity: Maximum chain length before rehash
* @p: Configuration parameters
* @rhlist: True if this is an rhltable
* @run_work: Deferred worker to expand/shrink asynchronously
@ -154,7 +166,6 @@ struct rhashtable {
struct bucket_table __rcu *tbl;
atomic_t nelems;
unsigned int key_len;
unsigned int elasticity;
struct rhashtable_params p;
bool rhlist;
struct work_struct run_work;
@ -726,7 +737,7 @@ slow_path:
return rhashtable_insert_slow(ht, key, obj);
}
elasticity = ht->elasticity;
elasticity = RHT_ELASTICITY;
pprev = rht_bucket_insert(ht, tbl, hash);
data = ERR_PTR(-ENOMEM);
if (!pprev)

17
lib/rhashtable.c
View File

@ -535,7 +535,7 @@ static void *rhashtable_lookup_one(struct rhashtable *ht,
struct rhash_head *head;
int elasticity;
elasticity = ht->elasticity;
elasticity = RHT_ELASTICITY;
pprev = rht_bucket_var(tbl, hash);
rht_for_each_continue(head, *pprev, tbl, hash) {
struct rhlist_head *list;
@ -972,21 +972,6 @@ int rhashtable_init(struct rhashtable *ht,
if (params->nelem_hint)
size = rounded_hashtable_size(&ht->p);
/* The maximum (not average) chain length grows with the
* size of the hash table, at a rate of (log N)/(log log N).
* The value of 16 is selected so that even if the hash
* table grew to 2^32 you would not expect the maximum
* chain length to exceed it unless we are under attack
* (or extremely unlucky).
*
* As this limit is only to detect attacks, we don't need
* to set it to a lower value as you'd need the chain
* length to vastly exceed 16 to have any real effect
* on the system.
*/
if (!params->insecure_elasticity)
ht->elasticity = 16;
if (params->locks_mul)
ht->p.locks_mul = roundup_pow_of_two(params->locks_mul);
else