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mac80211: use DECLARE_EWMA for ave_beacon_signal

Browse source 
It doesn't seem problematic to change the weight for the average
beacon signal from 3 to 4, so use DECLARE_EWMA. This also makes
the code easier to maintain since bugs like the one fixed in the
previous patch can't happen as easily.

With a fix from Avraham Stern to invert the sign since EMWA uses
unsigned values only.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg 2015-08-28 10:52:54 +02:00
parent 8ec6d97871
commit 338c17ae31
3 changed files with 10 additions and 22 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
net/mac80211/ieee80211_i.h
View file

@ -419,6 +419,8 @@ struct ieee80211_sta_tx_tspec {
bool downgraded;
};
DECLARE_EWMA(beacon_signal, 16, 4)
struct ieee80211_if_managed {
struct timer_list timer;
struct timer_list conn_mon_timer;
@ -490,13 +492,7 @@ struct ieee80211_if_managed {
s16 p2p_noa_index;
/*
* Weighted average of the signal strength from Beacon frames in the
* current BSS. This is in units of 1/16 of the signal unit to maintain
* accuracy and to speed up calculations, i.e., the value need to be
* divided by 16 to get the actual value.
*/
int ave_beacon_signal;
struct ewma_beacon_signal ave_beacon_signal;
/*
* Number of Beacon frames used in ave_beacon_signal. This can be used

20
net/mac80211/mlme.c
View file

@ -81,13 +81,6 @@ MODULE_PARM_DESC(probe_wait_ms,
"Maximum time(ms) to wait for probe response"
" before disconnecting (reason 4).");
/*
* Weight given to the latest Beacon frame when calculating average signal
* strength for Beacon frames received in the current BSS. This must be
* between 1 and 15.
*/
#define IEEE80211_SIGNAL_AVE_WEIGHT 3
/*
* How many Beacon frames need to have been used in average signal strength
* before starting to indicate signal change events.
@ -3366,21 +3359,19 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
/* Track average RSSI from the Beacon frames of the current AP */
if (ifmgd->flags & IEEE80211_STA_RESET_SIGNAL_AVE) {
ifmgd->flags &= ~IEEE80211_STA_RESET_SIGNAL_AVE;
ifmgd->ave_beacon_signal = rx_status->signal * 16;
ewma_beacon_signal_init(&ifmgd->ave_beacon_signal);
ifmgd->last_cqm_event_signal = 0;
ifmgd->count_beacon_signal = 1;
ifmgd->last_ave_beacon_signal = 0;
} else {
ifmgd->ave_beacon_signal =
(IEEE80211_SIGNAL_AVE_WEIGHT * rx_status->signal * 16 +
(16 - IEEE80211_SIGNAL_AVE_WEIGHT) *
ifmgd->ave_beacon_signal) / 16;
ifmgd->count_beacon_signal++;
}
ewma_beacon_signal_add(&ifmgd->ave_beacon_signal, -rx_status->signal);
if (ifmgd->rssi_min_thold != ifmgd->rssi_max_thold &&
ifmgd->count_beacon_signal >= IEEE80211_SIGNAL_AVE_MIN_COUNT) {
int sig = ifmgd->ave_beacon_signal / 16;
int sig = -ewma_beacon_signal_read(&ifmgd->ave_beacon_signal);
int last_sig = ifmgd->last_ave_beacon_signal;
struct ieee80211_event event = {
.type = RSSI_EVENT,
@ -3407,10 +3398,11 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
if (bss_conf->cqm_rssi_thold &&
ifmgd->count_beacon_signal >= IEEE80211_SIGNAL_AVE_MIN_COUNT &&
!(sdata->vif.driver_flags & IEEE80211_VIF_SUPPORTS_CQM_RSSI)) {
int sig = ifmgd->ave_beacon_signal / 16;
int sig = -ewma_beacon_signal_read(&ifmgd->ave_beacon_signal);
int last_event = ifmgd->last_cqm_event_signal;
int thold = bss_conf->cqm_rssi_thold;
int hyst = bss_conf->cqm_rssi_hyst;
if (sig < thold &&
(last_event == 0 || sig < last_event - hyst)) {
ifmgd->last_cqm_event_signal = sig;

2
net/mac80211/util.c
View file

@ -2543,7 +2543,7 @@ int ieee80211_ave_rssi(struct ieee80211_vif *vif)
/* non-managed type inferfaces */
return 0;
}
return ifmgd->ave_beacon_signal / 16;
return -ewma_beacon_signal_read(&ifmgd->ave_beacon_signal);
}
EXPORT_SYMBOL_GPL(ieee80211_ave_rssi);