Skip to content

Commit

Permalink
mac80211: Use rhltable instead of rhashtable
Browse files Browse the repository at this point in the history 
mac80211 currently uses rhashtable with insecure_elasticity set
to true.  The latter is because of duplicate objects.  What's
more, mac80211 walks the rhashtable chains by hand which is broken
as rhashtable may contain multiple tables due to resizing or
rehashing.

This patch fixes it by converting it to the newly added rhltable
interface which is designed for use with duplicate objects.

With rhltable a lookup returns a list of objects instead of a
single one.  This is then fed into the existing for_each_sta_info
macro.

This patch also deletes the sta_addr_hash function since rhashtable
defaults to jhash.

Signed-off-by: Herbert Xu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
  • Loading branch information
@herbertx @davem330
herbertx authored and davem330 committed Sep 20, 2016
1 parent ca26893 commit 83e7e4c
Show file tree
Hide file tree
Showing 5 changed files with 33 additions and 54 deletions.
2 changes: 1 addition & 1 deletion net/mac80211/ieee80211_i.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1213,7 +1213,7 @@ struct ieee80211_local {
spinlock_t tim_lock;
unsigned long num_sta;
struct list_head sta_list;
struct rhashtable sta_hash;
struct rhltable sta_hash;
struct timer_list sta_cleanup;
int sta_generation;

Expand Down
7 changes: 2 additions & 5 deletions net/mac80211/rx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4003,7 +4003,7 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
__le16 fc;
struct ieee80211_rx_data rx;
struct ieee80211_sub_if_data *prev;
struct rhash_head *tmp;
struct rhlist_head *tmp;
int err = 0;

fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
Expand Down Expand Up @@ -4046,13 +4046,10 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
goto out;
} else if (ieee80211_is_data(fc)) {
struct sta_info *sta, *prev_sta;
const struct bucket_table *tbl;

prev_sta = NULL;

tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);

for_each_sta_info(local, tbl, hdr->addr2, sta, tmp) {
for_each_sta_info(local, hdr->addr2, sta, tmp) {
if (!prev_sta) {
prev_sta = sta;
continue;
Expand Down
52 changes: 21 additions & 31 deletions net/mac80211/sta_info.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -67,21 +67,19 @@

static const struct rhashtable_params sta_rht_params = {
.nelem_hint = 3, /* start small */
.insecure_elasticity = true, /* Disable chain-length checks. */
.automatic_shrinking = true,
.head_offset = offsetof(struct sta_info, hash_node),
.key_offset = offsetof(struct sta_info, addr),
.key_len = ETH_ALEN,
.hashfn = sta_addr_hash,
.max_size = CONFIG_MAC80211_STA_HASH_MAX_SIZE,
};

/* Caller must hold local->sta_mtx */
static int sta_info_hash_del(struct ieee80211_local *local,
struct sta_info *sta)
{
return rhashtable_remove_fast(&local->sta_hash, &sta->hash_node,
sta_rht_params);
return rhltable_remove(&local->sta_hash, &sta->hash_node,
sta_rht_params);
}

static void __cleanup_single_sta(struct sta_info *sta)
Expand Down Expand Up @@ -157,19 +155,22 @@ static void cleanup_single_sta(struct sta_info *sta)
sta_info_free(local, sta);
}

struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
const u8 *addr)
{
return rhltable_lookup(&local->sta_hash, addr, sta_rht_params);
}

/* protected by RCU */
struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
const u8 *addr)
{
struct ieee80211_local *local = sdata->local;
struct rhlist_head *tmp;
struct sta_info *sta;
struct rhash_head *tmp;
const struct bucket_table *tbl;

rcu_read_lock();
tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);

for_each_sta_info(local, tbl, addr, sta, tmp) {
for_each_sta_info(local, addr, sta, tmp) {
if (sta->sdata == sdata) {
rcu_read_unlock();
/* this is safe as the caller must already hold
Expand All @@ -190,14 +191,11 @@ struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
const u8 *addr)
{
struct ieee80211_local *local = sdata->local;
struct rhlist_head *tmp;
struct sta_info *sta;
struct rhash_head *tmp;
const struct bucket_table *tbl;

rcu_read_lock();
tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);

for_each_sta_info(local, tbl, addr, sta, tmp) {
for_each_sta_info(local, addr, sta, tmp) {
if (sta->sdata == sdata ||
(sta->sdata->bss && sta->sdata->bss == sdata->bss)) {
rcu_read_unlock();
Expand Down Expand Up @@ -263,8 +261,8 @@ void sta_info_free(struct ieee80211_local *local, struct sta_info *sta)
static int sta_info_hash_add(struct ieee80211_local *local,
struct sta_info *sta)
{
return rhashtable_insert_fast(&local->sta_hash, &sta->hash_node,
sta_rht_params);
return rhltable_insert(&local->sta_hash, &sta->hash_node,
sta_rht_params);
}

static void sta_deliver_ps_frames(struct work_struct *wk)
Expand Down Expand Up @@ -453,9 +451,9 @@ static int sta_info_insert_check(struct sta_info *sta)
is_multicast_ether_addr(sta->sta.addr)))
return -EINVAL;

/* Strictly speaking this isn't necessary as we hold the mutex, but
* the rhashtable code can't really deal with that distinction. We
* do require the mutex for correctness though.
/* The RCU read lock is required by rhashtable due to
* asynchronous resize/rehash. We also require the mutex
* for correctness.
*/
rcu_read_lock();
lockdep_assert_held(&sdata->local->sta_mtx);
Expand Down Expand Up @@ -1043,16 +1041,11 @@ static void sta_info_cleanup(unsigned long data)
round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL));
}

u32 sta_addr_hash(const void *key, u32 length, u32 seed)
{
return jhash(key, ETH_ALEN, seed);
}

int sta_info_init(struct ieee80211_local *local)
{
int err;

err = rhashtable_init(&local->sta_hash, &sta_rht_params);
err = rhltable_init(&local->sta_hash, &sta_rht_params);
if (err)
return err;

Expand All @@ -1068,7 +1061,7 @@ int sta_info_init(struct ieee80211_local *local)
void sta_info_stop(struct ieee80211_local *local)
{
del_timer_sync(&local->sta_cleanup);
rhashtable_destroy(&local->sta_hash);
rhltable_destroy(&local->sta_hash);
}


Expand Down Expand Up @@ -1138,17 +1131,14 @@ struct ieee80211_sta *ieee80211_find_sta_by_ifaddr(struct ieee80211_hw *hw,
const u8 *localaddr)
{
struct ieee80211_local *local = hw_to_local(hw);
struct rhlist_head *tmp;
struct sta_info *sta;
struct rhash_head *tmp;
const struct bucket_table *tbl;

tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);

/*
* Just return a random station if localaddr is NULL
* ... first in list.
*/
for_each_sta_info(local, tbl, addr, sta, tmp) {
for_each_sta_info(local, addr, sta, tmp) {
if (localaddr &&
!ether_addr_equal(sta->sdata->vif.addr, localaddr))
continue;
Expand Down
19 changes: 7 additions & 12 deletions net/mac80211/sta_info.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -455,7 +455,7 @@ struct sta_info {
/* General information, mostly static */
struct list_head list, free_list;
struct rcu_head rcu_head;
struct rhash_head hash_node;
struct rhlist_head hash_node;
u8 addr[ETH_ALEN];
struct ieee80211_local *local;
struct ieee80211_sub_if_data *sdata;
Expand Down Expand Up @@ -638,6 +638,9 @@ rcu_dereference_protected_tid_tx(struct sta_info *sta, int tid)
*/
#define STA_INFO_CLEANUP_INTERVAL (10 * HZ)

struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
const u8 *addr);

/*
* Get a STA info, must be under RCU read lock.
*/
Expand All @@ -647,17 +650,9 @@ 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);

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, 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->addr, (_addr)))
#define for_each_sta_info(local, _addr, _sta, _tmp) \
rhl_for_each_entry_rcu(_sta, _tmp, \
sta_info_hash_lookup(local, _addr), hash_node)

/*
* Get STA info by index, BROKEN!
Expand Down
7 changes: 2 additions & 5 deletions net/mac80211/status.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -746,16 +746,15 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
__le16 fc;
struct ieee80211_supported_band *sband;
struct rhlist_head *tmp;
struct sta_info *sta;
struct rhash_head *tmp;
int retry_count;
int rates_idx;
bool send_to_cooked;
bool acked;
struct ieee80211_bar *bar;
int shift = 0;
int tid = IEEE80211_NUM_TIDS;
const struct bucket_table *tbl;

rates_idx = ieee80211_tx_get_rates(hw, info, &retry_count);

Expand All @@ -764,9 +763,7 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
sband = local->hw.wiphy->bands[info->band];
fc = hdr->frame_control;

tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);

for_each_sta_info(local, tbl, hdr->addr1, sta, tmp) {
for_each_sta_info(local, hdr->addr1, sta, tmp) {
/* skip wrong virtual interface */
if (!ether_addr_equal(hdr->addr2, sta->sdata->vif.addr))
continue;
Expand Down

0 comments on commit 83e7e4c

Please sign in to comment.