mac80211: implement basic background scanning

Introduce a new scan flag "SCAN_OFF_CHANNEL" which basically tells us
that we are currently on a different channel for scanning and cannot
RX/TX. "SCAN_SW_SCANNING" tells us that we are currently running a
software scan but we might as well be on the operating channel to RX/TX.
While "SCAN_SW_SCANNING" is set during the whole scan "SCAN_OFF_CHANNEL"
is set when leaving the operating channel and unset when coming back.

Introduce two new scan states "SCAN_LEAVE_OPER_CHANNEL" and
"SCAN_ENTER_OPER_CHANNEL" which basically implement the functionality we
need to leave the operating channel (send a nullfunc to the AP and stop
the queues) and enter it again (send a nullfunc to the AP and start the
queues again).

Enhance the scan state "SCAN_DECISION" to switch back to the operating
channel after each scanned channel. In the future it sould be simple
to enhance the decision state to scan as much channels in a row as the
qos latency allows us.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index d7491dc2a65c..70ff4f065665 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -192,7 +192,7 @@ ieee80211_tx_h_check_assoc(struct ieee80211_tx_data *tx)
         if (unlikely(info->flags & IEEE80211_TX_CTL_INJECTED))
                 return TX_CONTINUE;
 
-        if (unlikely(test_bit(SCAN_SW_SCANNING, &tx->local->scanning)) &&
+        if (unlikely(test_bit(SCAN_OFF_CHANNEL, &tx->local->scanning)) &&
             !ieee80211_is_probe_req(hdr->frame_control) &&
             !ieee80211_is_nullfunc(hdr->frame_control))
                 /*