mac80211: remove tasklet enable/disable

Due to the way the tasklets work in mac80211 there's
no need to ever disable them.

However, we need to clear the pending packets when
taking down the last interface because otherwise
the tx_pending_tasklet might be queued if the
driver mucks with the queues (which it shouldn't).

I've had a situation occasionally with ar9170 in
which ksoftirq was using 100% CPU time because
a disabled tasklet was scheduled, and I think that
was due to ar9170 receiving a packet while the
tasklet was disabled. That's strange and it really
should not do that for other reasons, but there's
no need to waste that much CPU time over it, it
should just warn instead.

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

1 files changed, 1 insertions, 8 deletions

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 5940e69fa33..d134bd79972 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -277,11 +277,6 @@ static int ieee80211_open(struct net_device *dev)
                 }
         }
 
-        if (local->open_count == 0) {
-                tasklet_enable(&local->tx_pending_tasklet);
-                tasklet_enable(&local->tasklet);
-        }
-
         /*
          * set_multicast_list will be invoked by the networking core
          * which will check whether any increments here were done in
@@ -552,11 +547,9 @@ static int ieee80211_stop(struct net_device *dev)
         ieee80211_recalc_ps(local, -1);
 
         if (local->open_count == 0) {
+                ieee80211_clear_tx_pending(local);
                 ieee80211_stop_device(local);
 
-                tasklet_disable(&local->tx_pending_tasklet);
-                tasklet_disable(&local->tasklet);
-
                 /* no reconfiguring after stop! */
                 hw_reconf_flags = 0;
         }