mac80211: Optimize scans on current operating channel.

This should decrease un-necessary flushes, on/off channel work,
and channel changes in cases where the only scanned channel is
the current operating channel.

* Removes SCAN_OFF_CHANNEL flag, uses SDATA_STATE_OFFCHANNEL
  and is-scanning flags instead.

* Add helper method to determine if we are currently configured
  for the operating channel.

* Do no blindly go off/on channel in work.c  Instead, only call
  appropriate on/off code when we really need to change channels.
  Always enable offchannel-ps mode when starting work,
  and disable it when we are done.

* Consolidate ieee80211_offchannel_stop_station and
  ieee80211_offchannel_stop_beaconing, call it
  ieee80211_offchannel_stop_vifs instead.

* Accept non-beacon frames when scanning on operating channel.

* Scan state machine optimized to minimize on/off channel
  transitions.  Also, when going on-channel, go ahead and
  re-enable beaconing.  We're going to be there for 200ms,
  so seems like some useful beaconing could happen.
  Always enable offchannel-ps mode when starting software
  scan, and disable it when we are done.

* Grab local->mtx earlier in __ieee80211_scan_completed_finish
  so that we are protected when calling hw_config(), etc.

* Pass probe-responses up the stack if scanning on local
  channel, so that mlme can take a look.

Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 3 insertions, 9 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 753ffc41c1aa..b5f59ed24000 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -409,16 +409,10 @@ ieee80211_rx_h_passive_scan(struct ieee80211_rx_data *rx)
         if (likely(!(status->rx_flags & IEEE80211_RX_IN_SCAN)))
                 return RX_CONTINUE;
 
-        if (test_bit(SCAN_HW_SCANNING, &local->scanning))
+        if (test_bit(SCAN_HW_SCANNING, &local->scanning) ||
+            test_bit(SCAN_SW_SCANNING, &local->scanning))
                 return ieee80211_scan_rx(rx->sdata, skb);
 
-        if (test_bit(SCAN_SW_SCANNING, &local->scanning)) {
-                /* drop all the other packets during a software scan anyway */
-                if (ieee80211_scan_rx(rx->sdata, skb) != RX_QUEUED)
-                        dev_kfree_skb(skb);
-                return RX_QUEUED;
-        }
-
         /* scanning finished during invoking of handlers */
         I802_DEBUG_INC(local->rx_handlers_drop_passive_scan);
         return RX_DROP_UNUSABLE;
@@ -2793,7 +2787,7 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
                 local->dot11ReceivedFragmentCount++;
 
         if (unlikely(test_bit(SCAN_HW_SCANNING, &local->scanning) ||
-                     test_bit(SCAN_OFF_CHANNEL, &local->scanning)))
+                     test_bit(SCAN_SW_SCANNING, &local->scanning)))
                 status->rx_flags |= IEEE80211_RX_IN_SCAN;
 
         if (ieee80211_is_mgmt(fc))