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, 9 insertions, 0 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index dff2239db6e2..b98f1afbfebf 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2471,6 +2471,15 @@ void ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb)
                 return;
         }
 
+        /*
+         * The same happens when we're not even started,
+         * but that's worth a warning.
+         */
+        if (WARN_ON(!local->started)) {
+                kfree_skb(skb);
+                return;
+        }
+
         if (status->flag & RX_FLAG_HT) {
                 /* rate_idx is MCS index */
                 if (WARN_ON(status->rate_idx < 0 ||