mac80211: also expire filtered frames
mac80211 will expire normal PS-buffered frames, but
if the device rejected some frames for a sleeping
station, these won't be on the ps_tx_buf queue but
on the tx_filtered queue instead; this is done to
avoid reordering.
However, mac80211 will not expire frames from the
filtered queue, let's fix that.
Also add a more comments to what all this expiry is
doing and how it works.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 863d59f..8dabe66 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -709,6 +709,39 @@
if (!sta->sdata->bss)
return false;
+ /*
+ * First check for frames that should expire on the filtered
+ * queue. Frames here were rejected by the driver and are on
+ * a separate queue to avoid reordering with normal PS-buffered
+ * frames. They also aren't accounted for right now in the
+ * total_ps_buffered counter.
+ */
+ for (;;) {
+ spin_lock_irqsave(&sta->tx_filtered.lock, flags);
+ skb = skb_peek(&sta->tx_filtered);
+ if (sta_info_buffer_expired(sta, skb))
+ skb = __skb_dequeue(&sta->tx_filtered);
+ else
+ skb = NULL;
+ spin_unlock_irqrestore(&sta->tx_filtered.lock, flags);
+
+ /*
+ * Frames are queued in order, so if this one
+ * hasn't expired yet we can stop testing. If
+ * we actually reached the end of the queue we
+ * also need to stop, of course.
+ */
+ if (!skb)
+ break;
+ dev_kfree_skb(skb);
+ }
+
+ /*
+ * Now also check the normal PS-buffered queue, this will
+ * only find something if the filtered queue was emptied
+ * since the filtered frames are all before the normal PS
+ * buffered frames.
+ */
for (;;) {
spin_lock_irqsave(&sta->ps_tx_buf.lock, flags);
skb = skb_peek(&sta->ps_tx_buf);
@@ -718,6 +751,11 @@
skb = NULL;
spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags);
+ /*
+ * frames are queued in order, so if this one
+ * hasn't expired yet (or we reached the end of
+ * the queue) we can stop testing
+ */
if (!skb)
break;
@@ -727,13 +765,22 @@
sta->sta.addr);
#endif
dev_kfree_skb(skb);
-
- /* if the queue is now empty recalc TIM bit */
- if (skb_queue_empty(&sta->ps_tx_buf))
- sta_info_recalc_tim(sta);
}
- return !skb_queue_empty(&sta->ps_tx_buf);
+ /*
+ * Finally, recalculate the TIM bit for this station -- it might
+ * now be clear because the station was too slow to retrieve its
+ * frames.
+ */
+ sta_info_recalc_tim(sta);
+
+ /*
+ * Return whether there are any frames still buffered, this is
+ * used to check whether the cleanup timer still needs to run,
+ * if there are no frames we don't need to rearm the timer.
+ */
+ return !(skb_queue_empty(&sta->ps_tx_buf) &&
+ skb_queue_empty(&sta->tx_filtered));
}
static int __must_check __sta_info_destroy(struct sta_info *sta)