mac80211: fix aggregation to not require queue stop

Instead of stopping the entire AC queue when enabling aggregation
(which was only done for hardware with aggregation queues) buffer
the packets for each station, and release them to the pending skb
queue once aggregation is turned on successfully.

We get a little more code, but it becomes conceptually simpler and
we can remove the entire virtual queue mechanism from mac80211 in
a follow-up patch.

This changes how mac80211 behaves towards drivers that support
aggregation but have no hardware queues -- those drivers will now
not be handed packets while the aggregation session is being
established, but only after it has been fully established.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 6ce62e553dc..32345b479ad 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -639,6 +639,14 @@ struct ieee80211_local {
 	struct sk_buff_head pending[IEEE80211_MAX_QUEUES];
 	struct tasklet_struct tx_pending_tasklet;
 
+	/*
+	 * This lock is used to prevent concurrent A-MPDU
+	 * session start/stop processing, this thus also
+	 * synchronises the ->ampdu_action() callback to
+	 * drivers and limits it to one at a time.
+	 */
+	spinlock_t ampdu_lock;
+
 	/* number of interfaces with corresponding IFF_ flags */
 	atomic_t iff_allmultis, iff_promiscs;