mac80211: allow drivers to sleep in ampdu_action

Allow drivers to sleep, and indicate this in
the documentation. ath9k has some locking I
don't understand, so keep it safe and disable
BHs in it, all other drivers look fine with
the context change.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/main.c

@@ -1769,6 +1769,8 @@ static int ath9k_ampdu_action(struct ieee80211_hw *hw,
 	struct ath_softc *sc = aphy->sc;
 	int ret = 0;
 
+	local_bh_disable();
+
 	switch (action) {
 	case IEEE80211_AMPDU_RX_START:
 		if (!(sc->sc_flags & SC_OP_RXAGGR))
@@ -1798,6 +1800,8 @@ static int ath9k_ampdu_action(struct ieee80211_hw *hw,
 			  "Unknown AMPDU action\n");
 	}
 
+	local_bh_enable();
+
 	return ret;
 }
 

include/net/mac80211.h

@@ -1640,7 +1640,7 @@ enum ieee80211_ampdu_mlme_action {
  * 	is the first frame we expect to perform the action on. Notice
  * 	that TX/RX_STOP can pass NULL for this parameter.
  *	Returns a negative error code on failure.
- *	The callback must be atomic.
+ *	The callback can sleep.
  *
  * @get_survey: Return per-channel survey information
  *

net/mac80211/driver-ops.h

@@ -352,11 +352,10 @@ static inline int drv_ampdu_action(struct ieee80211_local *local,
 
 	might_sleep();
 
-	local_bh_disable();
 	if (local->ops->ampdu_action)
 		ret = local->ops->ampdu_action(&local->hw, &sdata->vif, action,
 					       sta, tid, ssn);
-	local_bh_enable();
+
 	trace_drv_ampdu_action(local, sdata, action, sta, tid, ssn, ret);
 	return ret;
 }