wifi: mac80211: Do not schedule stopped TXQs

Ignore TXQs with the flag IEEE80211_TXQ_STOP when scheduling a queue.

The flag is only set after all fragments have been dequeued and won't
allow dequeueing other frames as long as the flag is set.

For drivers using ieee80211_txq_schedule_start() this prevents an
loop trying to push the queued frames while IEEE80211_TXQ_STOP is set:

After setting IEEE80211_TXQ_STOP the driver will call
ieee80211_return_txq(). Which calls __ieee80211_schedule_txq(), detects
that there sill are frames in the queue and immediately restarts the
stopped TXQ. Which can't dequeue any frame and thus starts over the loop.

Signed-off-by: Alexander Wetzel <Alexander@wetzel-home.de>
Fixes: ba8c3d6f16a1 ("mac80211: add an intermediate software queue implementation")
Link: https://patch.msgid.link/20250717162547.94582-2-Alexander@wetzel-home.de
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index f3a065313a31a615c40611cc5030cd6a5fddc526..adbd640b56725f0446395c80d645c6212f01e61a 100644 (file)
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -4099,7 +4099,9 @@ void __ieee80211_schedule_txq(struct ieee80211_hw *hw,
 
        spin_lock_bh(&local->active_txq_lock[txq->ac]);
 
-       has_queue = force || txq_has_queue(txq);
+       has_queue = force ||
+                   (!test_bit(IEEE80211_TXQ_STOP, &txqi->flags) &&
+                    txq_has_queue(txq));
        if (list_empty(&txqi->schedule_order) &&
            (has_queue || ieee80211_txq_keep_active(txqi))) {
                /* If airtime accounting is active, always enqueue STAs at the