rt2x00: fix random stalls
Is possible that we stop queue and then do not wake up it again, especially when packets are transmitted fast. That can be easily reproduced with modified tx queue entry_num to some small value e.g. 16. If mac80211 already hold local->queue_stop_reason_lock, then we can wait on that lock in both rt2x00queue_pause_queue() and rt2x00queue_unpause_queue(). After drooping ->queue_stop_reason_lock is possible that __ieee80211_wake_queue() will be performed before __ieee80211_stop_queue(), hence we stop queue and newer wake up it again. Another race condition is possible when between rt2x00queue_threshold() check and rt2x00queue_pause_queue() we will process all pending tx buffers on different cpu. This might happen if for example interrupt will be triggered on cpu performing rt2x00mac_tx(). To prevent race conditions serialize pause/unpause by queue->tx_lock. Cc: stable@vger.kernel.org Signed-off-by:Stanislaw Gruszka <sgruszka@redhat.com> Acked-by:
Gertjan van Wingerde <gwingerde@gmail.com> Signed-off-by:
John W. Linville <linville@tuxdriver.com>
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210787e8
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