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Commit 9df86e2e authored by Denis 'GNUtoo' Carikli's avatar Denis 'GNUtoo' Carikli Committed by John W. Linville
Browse files

wl1251: Fix queue stopping/waking for TX path 



This patch was adapted from 06f7bc7d
(from linus's linux-2.6 tree of kernel.org)

here's the original message:
    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: default avatarDenis 'GNUtoo' Carikli <GNUtoo@no-log.org>
Acked-by: default avatarKalle Valo <kvalo@adurom.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 391a200a

drivers/net/wireless/wl12xx/wl1251.h

+4 −1
Original line number Diff line number Diff line
@@ -272,6 +272,8 @@ struct wl1251 { 
	int irq;

	bool use_eeprom;



	spinlock_t wl_lock;



	enum wl1251_state state;

	struct mutex mutex;
@@ -399,7 +401,8 @@ void wl1251_disable_interrupts(struct wl1251 *wl); 


#define WL1251_DEFAULT_POWER_LEVEL 20



#define WL1251_TX_QUEUE_MAX_LENGTH 20

#define WL1251_TX_QUEUE_LOW_WATERMARK  10

#define WL1251_TX_QUEUE_HIGH_WATERMARK 25



#define WL1251_DEFAULT_BEACON_INT 100

#define WL1251_DEFAULT_DTIM_PERIOD 1

drivers/net/wireless/wl12xx/wl1251_main.c

+5 −7
Original line number Diff line number Diff line
@@ -375,6 +375,7 @@ out: 
static int wl1251_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)

{

	struct wl1251 *wl = hw->priv;

	unsigned long flags;



	skb_queue_tail(&wl->tx_queue, skb);
@@ -389,16 +390,13 @@ static int wl1251_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb) 
	 * The workqueue is slow to process the tx_queue and we need stop

	 * the queue here, otherwise the queue will get too long.

	 */

	if (skb_queue_len(&wl->tx_queue) >= WL1251_TX_QUEUE_MAX_LENGTH) {

	if (skb_queue_len(&wl->tx_queue) >= WL1251_TX_QUEUE_HIGH_WATERMARK) {

		wl1251_debug(DEBUG_TX, "op_tx: tx_queue full, stop queues");

		ieee80211_stop_queues(wl->hw);



		/*

		 * FIXME: this is racy, the variable is not properly

		 * protected. Maybe fix this by removing the stupid

		 * variable altogether and checking the real queue state?

		 */

		spin_lock_irqsave(&wl->wl_lock, flags);

		ieee80211_stop_queues(wl->hw);

		wl->tx_queue_stopped = true;

		spin_unlock_irqrestore(&wl->wl_lock, flags);

	}



	return NETDEV_TX_OK;

drivers/net/wireless/wl12xx/wl1251_tx.c

+15 −5
Original line number Diff line number Diff line
@@ -320,11 +320,6 @@ void wl1251_tx_work(struct work_struct *work) 


		ret = wl1251_tx_frame(wl, skb);

		if (ret == -EBUSY) {

			/* firmware buffer is full, stop queues */

			wl1251_debug(DEBUG_TX, "tx_work: fw buffer full, "

				     "stop queues");

			ieee80211_stop_queues(wl->hw);

			wl->tx_queue_stopped = true;

			skb_queue_head(&wl->tx_queue, skb);

			goto out;

		} else if (ret < 0) {
@@ -447,6 +442,7 @@ void wl1251_tx_complete(struct wl1251 *wl) 
{

	int i, result_index, num_complete = 0;

	struct tx_result result[FW_TX_CMPLT_BLOCK_SIZE], *result_ptr;

	unsigned long flags;



	if (unlikely(wl->state != WL1251_STATE_ON))

		return;
@@ -475,6 +471,20 @@ void wl1251_tx_complete(struct wl1251 *wl) 
		}

	}



	if (wl->tx_queue_stopped

	    &&

	    skb_queue_len(&wl->tx_queue) <= WL1251_TX_QUEUE_LOW_WATERMARK){



		/* firmware buffer has space, restart queues */

		wl1251_debug(DEBUG_TX, "tx_complete: waking queues");

		spin_lock_irqsave(&wl->wl_lock, flags);

		ieee80211_wake_queues(wl->hw);

		wl->tx_queue_stopped = false;

		spin_unlock_irqrestore(&wl->wl_lock, flags);

		ieee80211_queue_work(wl->hw, &wl->tx_work);



	}



	/* Every completed frame needs to be acknowledged */

	if (num_complete) {

		/*