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mac80211: fix station wakeup powersave race

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Consider the following (relatively unlikely) scenario:
 1) station goes to sleep while frames are buffered in driver
 2) driver blocks wakeup (until no more frames are buffered)
 3) station wakes up again
 4) driver unblocks wakeup

In this case, the current mac80211 code will do the following:
 1) WLAN_STA_PS_STA set
 2) WLAN_STA_PS_DRIVER set
 3) - nothing -
 4) WLAN_STA_PS_DRIVER cleared

As a result, no frames will be delivered to the client, even
though it is awake, until it sends another frame to us that
triggers ieee80211_sta_ps_deliver_wakeup() in sta_ps_end().

Since we now take the PS spinlock, we can fix this while at
the same time removing the complexity with the pending skb
queue function. This was broken since my commit 50a9432dae
("mac80211: fix powersaving clients races") due to removing
the clearing of WLAN_STA_PS_STA in the RX path.

While at it, fix a cleanup path issue when a station is
removed while the driver is still blocking its wakeup.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg
2014-02-20 11:19:58 +01:00
parent 5108ca8280
commit e3685e03b4
4 changed files with 25 additions and 32 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
net/mac80211/util.c
View File

@@ -435,9 +435,8 @@ void ieee80211_add_pending_skb(struct ieee80211_local *local,
spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
}
void ieee80211_add_pending_skbs_fn(struct ieee80211_local *local,
struct sk_buff_head *skbs,
void (*fn)(void *data), void *data)
void ieee80211_add_pending_skbs(struct ieee80211_local *local,
struct sk_buff_head *skbs)
{
struct ieee80211_hw *hw = &local->hw;
struct sk_buff *skb;
@@ -461,9 +460,6 @@ void ieee80211_add_pending_skbs_fn(struct ieee80211_local *local,
__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);