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authorJohannes Berg <johannes.berg@intel.com>2015-02-13 21:55:15 +0100
committerJohannes Berg <johannes.berg@intel.com>2015-04-01 10:06:26 +0200
commit7bedd0cfad4e122bc0ddaf3fc955a38c88c95d35 (patch)
treef156540ff672dec031e81a64fc60796dd34ea867 /net/mac80211/sta_info.h
parent9911674fcf1f239ff3c87e56177c4826e33dfd95 (diff)
downloadlinux-sh-7bedd0cfad4e122bc0ddaf3fc955a38c88c95d35.tar.gz
mac80211: use rhashtable for station table
We currently have a hand-rolled table with 256 entries and are using the last byte of the MAC address as the hash. This hash is obviously very fast, but collisions are easily created and we waste a lot of space in the common case of just connecting as a client to an AP where we just have a single station. The other common case of an AP is also suboptimal due to the size of the hash table and the ease of causing collisions. Convert all of this to use rhashtable with jhash, which gives us the advantage of a far better hash function (with random perturbation to avoid hash collision attacks) and of course that the hash table grows and shrinks dynamically with chain length, improving both cases above. Use a specialised hash function (using jhash, but with fixed length) to achieve better compiler optimisation as suggested by Sergey Ryazanov. Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211/sta_info.h')
-rw-r--r--net/mac80211/sta_info.h38
1 files changed, 12 insertions, 26 deletions
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 248f56e59ebc..97f25b9e52be 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -16,6 +16,7 @@
#include <linux/workqueue.h>
#include <linux/average.h>
#include <linux/etherdevice.h>
+#include <linux/rhashtable.h>
#include "key.h"
/**
@@ -246,7 +247,7 @@ struct sta_ampdu_mlme {
*
* @list: global linked list entry
* @free_list: list entry for keeping track of stations to free
- * @hnext: hash table linked list pointer
+ * @hash_node: hash node for rhashtable
* @local: pointer to the global information
* @sdata: virtual interface this station belongs to
* @ptk: peer keys negotiated with this station, if any
@@ -339,7 +340,7 @@ struct sta_info {
/* General information, mostly static */
struct list_head list, free_list;
struct rcu_head rcu_head;
- struct sta_info __rcu *hnext;
+ struct rhash_head hash_node;
struct ieee80211_local *local;
struct ieee80211_sub_if_data *sdata;
struct ieee80211_key __rcu *gtk[NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS];
@@ -535,10 +536,6 @@ rcu_dereference_protected_tid_tx(struct sta_info *sta, int tid)
lockdep_is_held(&sta->ampdu_mlme.mtx));
}
-#define STA_HASH_SIZE 256
-#define STA_HASH(sta) (sta[5])
-
-
/* Maximum number of frames to buffer per power saving station per AC */
#define STA_MAX_TX_BUFFER 64
@@ -559,26 +556,15 @@ struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
const u8 *addr);
-static inline
-void for_each_sta_info_type_check(struct ieee80211_local *local,
- const u8 *addr,
- struct sta_info *sta,
- struct sta_info *nxt)
-{
-}
+u32 sta_addr_hash(const void *key, u32 length, u32 seed);
+
+#define _sta_bucket_idx(_tbl, _a) \
+ rht_bucket_index(_tbl, sta_addr_hash(_a, ETH_ALEN, (_tbl)->hash_rnd))
-#define for_each_sta_info(local, _addr, _sta, nxt) \
- for ( /* initialise loop */ \
- _sta = rcu_dereference(local->sta_hash[STA_HASH(_addr)]),\
- nxt = _sta ? rcu_dereference(_sta->hnext) : NULL; \
- /* typecheck */ \
- for_each_sta_info_type_check(local, (_addr), _sta, nxt),\
- /* continue condition */ \
- _sta; \
- /* advance loop */ \
- _sta = nxt, \
- nxt = _sta ? rcu_dereference(_sta->hnext) : NULL \
- ) \
+#define for_each_sta_info(local, tbl, _addr, _sta, _tmp) \
+ rht_for_each_entry_rcu(_sta, _tmp, tbl, \
+ _sta_bucket_idx(tbl, _addr), \
+ hash_node) \
/* compare address and run code only if it matches */ \
if (ether_addr_equal(_sta->sta.addr, (_addr)))
@@ -615,7 +601,7 @@ int sta_info_destroy_addr_bss(struct ieee80211_sub_if_data *sdata,
void sta_info_recalc_tim(struct sta_info *sta);
-void sta_info_init(struct ieee80211_local *local);
+int sta_info_init(struct ieee80211_local *local);
void sta_info_stop(struct ieee80211_local *local);
/**