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: Helmut Schaa <helmut.schaa@xxxxxxxxxxxxxx>
---
net/mac80211/rx.c | 1 -
net/mac80211/sta_info.c | 4 +++-
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 3567586..f89617a 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1147,7 +1147,6 @@ 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",
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 70a0de3..92b894c 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -1007,9 +1007,11 @@ 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 */
--
1.7.7
--
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