mac80211: fix powersaving clients races
The code to handle powersaving stations has a race:
when the powersave flag is lifted from a station,
we could transmit a packet that is being processed
for TX at the same time right away, even if there
are other frames queued for it. This would cause
frame reordering. To fix this, lift the flag only
under the appropriate lock that blocks TX.
Additionally, the code to allow drivers to block a
station while frames for it are on the HW queue is
never re-enabled the station, so traffic would get
stuck indefinitely. Fix this by clearing the flag
for this appropriately.
Finally, as an optimisation, don't do anything if
the driver unblocks an already unblocked station.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 59a1d38..3598abf 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1278,6 +1278,9 @@
struct sk_buff *skb);
int ieee80211_add_pending_skbs(struct ieee80211_local *local,
struct sk_buff_head *skbs);
+int ieee80211_add_pending_skbs_fn(struct ieee80211_local *local,
+ struct sk_buff_head *skbs,
+ void (*fn)(void *data), void *data);
void ieee80211_send_auth(struct ieee80211_sub_if_data *sdata,
u16 transaction, u16 auth_alg,
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 902b03ee..d2fcd22 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1102,8 +1102,6 @@
atomic_dec(&sdata->bss->num_sta_ps);
- clear_sta_flags(sta, WLAN_STA_PS_STA);
-
#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);
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 6d8f897..eff5857 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -199,8 +199,11 @@
if (!test_sta_flags(sta, WLAN_STA_PS_STA))
ieee80211_sta_ps_deliver_wakeup(sta);
- else if (test_and_clear_sta_flags(sta, WLAN_STA_PSPOLL))
+ else if (test_and_clear_sta_flags(sta, WLAN_STA_PSPOLL)) {
+ clear_sta_flags(sta, WLAN_STA_PS_DRIVER);
ieee80211_sta_ps_deliver_poll_response(sta);
+ } else
+ clear_sta_flags(sta, WLAN_STA_PS_DRIVER);
}
static int sta_prepare_rate_control(struct ieee80211_local *local,
@@ -880,6 +883,13 @@
}
EXPORT_SYMBOL(ieee80211_find_sta);
+static void clear_sta_ps_flags(void *_sta)
+{
+ struct sta_info *sta = _sta;
+
+ clear_sta_flags(sta, WLAN_STA_PS_DRIVER | WLAN_STA_PS_STA);
+}
+
/* powersave support code */
void ieee80211_sta_ps_deliver_wakeup(struct sta_info *sta)
{
@@ -894,7 +904,8 @@
/* Send all buffered frames to the station */
sent = ieee80211_add_pending_skbs(local, &sta->tx_filtered);
- buffered = ieee80211_add_pending_skbs(local, &sta->ps_tx_buf);
+ buffered = ieee80211_add_pending_skbs_fn(local, &sta->ps_tx_buf,
+ clear_sta_ps_flags, sta);
sent += buffered;
local->total_ps_buffered -= buffered;
@@ -973,7 +984,7 @@
if (block)
set_sta_flags(sta, WLAN_STA_PS_DRIVER);
- else
+ else if (test_sta_flags(sta, WLAN_STA_PS_DRIVER))
ieee80211_queue_work(hw, &sta->drv_unblock_wk);
}
EXPORT_SYMBOL(ieee80211_sta_block_awake);
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 68d0518..e497476 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -368,8 +368,9 @@
spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
}
-int ieee80211_add_pending_skbs(struct ieee80211_local *local,
- struct sk_buff_head *skbs)
+int ieee80211_add_pending_skbs_fn(struct ieee80211_local *local,
+ struct sk_buff_head *skbs,
+ void (*fn)(void *data), void *data)
{
struct ieee80211_hw *hw = &local->hw;
struct sk_buff *skb;
@@ -394,6 +395,9 @@
__skb_queue_tail(&local->pending[queue], skb);
}
+ if (fn)
+ fn(data);
+
for (i = 0; i < hw->queues; i++)
__ieee80211_wake_queue(hw, i,
IEEE80211_QUEUE_STOP_REASON_SKB_ADD);
@@ -402,6 +406,12 @@
return ret;
}
+int ieee80211_add_pending_skbs(struct ieee80211_local *local,
+ struct sk_buff_head *skbs)
+{
+ return ieee80211_add_pending_skbs_fn(local, skbs, NULL, NULL);
+}
+
void ieee80211_stop_queues_by_reason(struct ieee80211_hw *hw,
enum queue_stop_reason reason)
{
