iwlwifi: mvm: support BAR in reorder buffer

BugLink: http://bugs.launchpad.net/bugs/1638748

commit 9a73a7d upstream.

On default queue we will not receive frame release notification,
but the BAR itself.
Upon receiving the BAR driver should look at the NSSN and adjust
window accordingly.

Fixes: b915c10 ("iwlwifi: mvm: add reorder buffer per queue")
Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c

@@ -598,9 +598,10 @@ static bool iwl_mvm_reorder(struct iwl_mvm *mvm,
 
 	mvm_sta = iwl_mvm_sta_from_mac80211(sta);
 
-	/* not a data packet */
-	if (!ieee80211_is_data_qos(hdr->frame_control) ||
-	    is_multicast_ether_addr(hdr->addr1))
+	/* not a data packet or a bar */
+	if (!ieee80211_is_back_req(hdr->frame_control) &&
+	    (!ieee80211_is_data_qos(hdr->frame_control) ||
+	     is_multicast_ether_addr(hdr->addr1)))
 		return false;
 
 	if (unlikely(!ieee80211_is_data_present(hdr->frame_control)))
@@ -624,6 +625,11 @@ static bool iwl_mvm_reorder(struct iwl_mvm *mvm,
 
 	spin_lock_bh(&buffer->lock);
 
+	if (ieee80211_is_back_req(hdr->frame_control)) {
+		iwl_mvm_release_frames(mvm, sta, napi, buffer, nssn);
+		goto drop;
+	}
+
 	/*
 	 * If there was a significant jump in the nssn - adjust.
 	 * If the SN is smaller than the NSSN it might need to first go into