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Commit 608383bf authored by Helmut Schaa's avatar Helmut Schaa Committed by John W. Linville
Browse files

mac80211: Fix incorrect num_sta_ps decrement in ap_sta_ps_end 



If the driver blocked this specific STA with the help of
ieee80211_sta_block_awake we won't clear WLAN_STA_PS_STA later but
still decrement num_sta_ps. Hence, the next data frame from this
STA will trigger ap_sta_ps_end again and also decrement num_sta_ps
again leading to an incorrect num_sta_ps counter.

This can result in problems with powersaving clients not waking up
from PS because the TIM calculation might be skipped due to the
incorrect num_sta_ps counter.

Signed-off-by: default avatarHelmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 2ab694d3

net/mac80211/rx.c

+2 −6
Original line number Diff line number Diff line
@@ -1145,19 +1145,15 @@ static void ap_sta_ps_start(struct sta_info *sta) 


static void ap_sta_ps_end(struct sta_info *sta)

{

	struct ieee80211_sub_if_data *sdata = sta->sdata;



	atomic_dec(&sdata->bss->num_sta_ps);



#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG

	printk(KERN_DEBUG "%s: STA %pM aid %d exits power save mode\n",

	       sdata->name, sta->sta.addr, sta->sta.aid);

	       sta->sdata->name, sta->sta.addr, sta->sta.aid);

#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */



	if (test_sta_flag(sta, WLAN_STA_PS_DRIVER)) {

#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG

		printk(KERN_DEBUG "%s: STA %pM aid %d driver-ps-blocked\n",

		       sdata->name, sta->sta.addr, sta->sta.aid);

		       sta->sdata->name, sta->sta.addr, sta->sta.aid);

#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */

		return;

	}

net/mac80211/sta_info.c

+3 −1
Original line number Diff line number Diff line
@@ -997,9 +997,11 @@ EXPORT_SYMBOL(ieee80211_find_sta); 
static void clear_sta_ps_flags(void *_sta)

{

	struct sta_info *sta = _sta;

	struct ieee80211_sub_if_data *sdata = sta->sdata;



	clear_sta_flag(sta, WLAN_STA_PS_DRIVER);

	clear_sta_flag(sta, WLAN_STA_PS_STA);

	if (test_and_clear_sta_flag(sta, WLAN_STA_PS_STA))

		atomic_dec(&sdata->bss->num_sta_ps);

}



/* powersave support code */