From: Stanislaw Gruszka Date: Tue, 19 Dec 2017 11:33:56 +0000 (+0100) Subject: rt2x00: do not pause queue unconditionally on error path X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6dd80efd75ce7c2dbd9f117cf585ee2b33a42ee1;p=linux.git rt2x00: do not pause queue unconditionally on error path Pausing queue without checking threshold is racy with txdone path. Moreover we do not need pause queue on any error, but only if queue is full - in case when we send RTS frame ( other cases of almost full queue are already handled in rt2x00queue_write_tx_frame() ). Patch fixes of theoretically possible problem of pausing empty queue. Signed-off-by: Stanislaw Gruszka Tested-by: Enrico Mioso Signed-off-by: Kalle Valo --- diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c b/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c index c8a6f163102f8..a971bc7a6b639 100644 --- a/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c +++ b/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c @@ -142,22 +142,28 @@ void rt2x00mac_tx(struct ieee80211_hw *hw, if (!rt2x00dev->ops->hw->set_rts_threshold && (tx_info->control.rates[0].flags & (IEEE80211_TX_RC_USE_RTS_CTS | IEEE80211_TX_RC_USE_CTS_PROTECT))) { - if (rt2x00queue_available(queue) <= 1) - goto exit_fail; + if (rt2x00queue_available(queue) <= 1) { + /* + * Recheck for full queue under lock to avoid race + * conditions with rt2x00lib_txdone(). + */ + spin_lock(&queue->tx_lock); + if (rt2x00queue_threshold(queue)) + rt2x00queue_pause_queue(queue); + spin_unlock(&queue->tx_lock); + + goto exit_free_skb; + } if (rt2x00mac_tx_rts_cts(rt2x00dev, queue, skb)) - goto exit_fail; + goto exit_free_skb; } if (unlikely(rt2x00queue_write_tx_frame(queue, skb, control->sta, false))) - goto exit_fail; + goto exit_free_skb; return; - exit_fail: - spin_lock(&queue->tx_lock); - rt2x00queue_pause_queue(queue); - spin_unlock(&queue->tx_lock); exit_free_skb: ieee80211_free_txskb(hw, skb); }