wl1271: Fix queue stopping/waking for TX path
The queue stopping/waking functionality was broken in a way that could cause huge latencies in TX transfers and even cause the TX to stall in the right circumstances. Correct these problems. Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com> Reviewed-by: Kalle Valo <kalle.valo@nokia.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Родитель
15305498a4
Коммит
06f7bc7db7
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@ -491,7 +491,8 @@ int wl1271_plt_stop(struct wl1271 *wl);
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#define WL1271_DEFAULT_POWER_LEVEL 0
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#define WL1271_TX_QUEUE_MAX_LENGTH 20
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#define WL1271_TX_QUEUE_LOW_WATERMARK 10
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#define WL1271_TX_QUEUE_HIGH_WATERMARK 25
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/* WL1271 needs a 200ms sleep after power on, and a 20ms sleep before power
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on in case is has been shut down shortly before */
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@ -791,15 +791,13 @@ static int wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
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* The workqueue is slow to process the tx_queue and we need stop
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* the queue here, otherwise the queue will get too long.
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*/
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if (skb_queue_len(&wl->tx_queue) >= WL1271_TX_QUEUE_MAX_LENGTH) {
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ieee80211_stop_queues(wl->hw);
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if (skb_queue_len(&wl->tx_queue) >= WL1271_TX_QUEUE_HIGH_WATERMARK) {
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wl1271_debug(DEBUG_TX, "op_tx: stopping queues");
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/*
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* FIXME: this is racy, the variable is not properly
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* protected. Maybe fix this by removing the stupid
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* variable altogether and checking the real queue state?
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*/
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spin_lock_irqsave(&wl->wl_lock, flags);
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ieee80211_stop_queues(wl->hw);
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set_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags);
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spin_unlock_irqrestore(&wl->wl_lock, flags);
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}
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return NETDEV_TX_OK;
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@ -278,22 +278,12 @@ void wl1271_tx_work(struct work_struct *work)
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ret = wl1271_tx_frame(wl, skb);
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if (ret == -EBUSY) {
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/* firmware buffer is full, stop queues */
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wl1271_debug(DEBUG_TX, "tx_work: fw buffer full, "
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"stop queues");
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ieee80211_stop_queues(wl->hw);
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set_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags);
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/* firmware buffer is full, lets stop transmitting. */
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skb_queue_head(&wl->tx_queue, skb);
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goto out_ack;
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} else if (ret < 0) {
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dev_kfree_skb(skb);
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goto out_ack;
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} else if (test_and_clear_bit(WL1271_FLAG_TX_QUEUE_STOPPED,
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&wl->flags)) {
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/* firmware buffer has space, restart queues */
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wl1271_debug(DEBUG_TX,
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"complete_packet: waking queues");
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ieee80211_wake_queues(wl->hw);
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}
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}
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@ -380,8 +370,6 @@ void wl1271_tx_complete(struct wl1271 *wl)
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u32 count, fw_counter;
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u32 i;
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wl1271_debug(DEBUG_TX, "tx_complete received, packets: %d", count);
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/* read the tx results from the chipset */
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wl1271_read(wl, le32_to_cpu(memmap->tx_result),
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wl->tx_res_if, sizeof(*wl->tx_res_if), false);
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@ -393,6 +381,7 @@ void wl1271_tx_complete(struct wl1271 *wl)
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tx_result_host_counter), fw_counter);
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count = fw_counter - wl->tx_results_count;
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wl1271_debug(DEBUG_TX, "tx_complete received, packets: %d", count);
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/* verify that the result buffer is not getting overrun */
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if (unlikely(count > TX_HW_RESULT_QUEUE_LEN))
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@ -409,6 +398,19 @@ void wl1271_tx_complete(struct wl1271 *wl)
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wl->tx_results_count++;
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}
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if (test_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags) &&
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skb_queue_len(&wl->tx_queue) <= WL1271_TX_QUEUE_LOW_WATERMARK) {
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unsigned long flags;
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/* firmware buffer has space, restart queues */
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wl1271_debug(DEBUG_TX, "tx_complete: waking queues");
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spin_lock_irqsave(&wl->wl_lock, flags);
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ieee80211_wake_queues(wl->hw);
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clear_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags);
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spin_unlock_irqrestore(&wl->wl_lock, flags);
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ieee80211_queue_work(wl->hw, &wl->tx_work);
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}
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}
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/* caller must hold wl->mutex */
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