Commit 88de754a authored by Lennert Buytenhek's avatar Lennert Buytenhek Committed by John W. Linville
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mwl8k: minor transmit quiescing rework 



Minor changes to the transmit quiescing logic:
- Clarify the locking rules for ->tx_wait: only the holder of fw_mutex
  can wait for the TX path to become idle, but tx_wait itself is read
  and cleared by the TX reclaim tasklet under tx_lock.
- Inline mwl8k_txq_busy() in its callers.
- There's no need to kick the transmitter again in
  mwl8k_tx_wait_empty(), since it will have been kicked when the
  packets currently in the TX ring were added to it.
- If the TX ring didn't drain in time, run mwl8k_scan_tx_ring() after
  reading priv->pending_pkts without dropping tx_lock in between.

Signed-off-by: default avatarLennert Buytenhek <buytenh@marvell.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent c2c357ce

drivers/net/wireless/mwl8k.c

+15 −22
Original line number Diff line number Diff line
@@ -142,12 +142,14 @@ struct mwl8k_priv { 
	struct mutex fw_mutex;

	struct task_struct *fw_mutex_owner;

	int fw_mutex_depth;

	struct completion *tx_wait;

	struct completion *hostcmd_wait;



	/* lock held over TX and TX reap */

	spinlock_t tx_lock;



	/* TX quiesce completion, protected by fw_mutex and tx_lock */

	struct completion *tx_wait;



	struct ieee80211_vif *vif;



	struct ieee80211_channel *current_channel;
@@ -1064,11 +1066,6 @@ static inline void mwl8k_tx_start(struct mwl8k_priv *priv) 
	ioread32(priv->regs + MWL8K_HIU_INT_CODE);

}



static inline int mwl8k_txq_busy(struct mwl8k_priv *priv)

{

	return priv->pending_tx_pkts;

}



struct mwl8k_txq_info {

	u32 fw_owned;

	u32 drv_owned;
@@ -1088,7 +1085,6 @@ static int mwl8k_scan_tx_ring(struct mwl8k_priv *priv, 


	memset(txinfo, 0, MWL8K_TX_QUEUES * sizeof(struct mwl8k_txq_info));



	spin_lock_bh(&priv->tx_lock);

	for (count = 0; count < MWL8K_TX_QUEUES; count++) {

		txq = priv->txq + count;

		txinfo[count].len = txq->tx_stats.len;
@@ -1107,30 +1103,26 @@ static int mwl8k_scan_tx_ring(struct mwl8k_priv *priv, 
				txinfo[count].unused++;

		}

	}

	spin_unlock_bh(&priv->tx_lock);



	return ndescs;

}



/*

 * Must be called with hw->fw_mutex held and tx queues stopped.

 * Must be called with priv->fw_mutex held and tx queues stopped.

 */

static int mwl8k_tx_wait_empty(struct ieee80211_hw *hw)

{

	struct mwl8k_priv *priv = hw->priv;

	DECLARE_COMPLETION_ONSTACK(cmd_wait);

	DECLARE_COMPLETION_ONSTACK(tx_wait);

	u32 count;

	unsigned long timeout;



	might_sleep();



	spin_lock_bh(&priv->tx_lock);

	count = mwl8k_txq_busy(priv);

	if (count) {

		priv->tx_wait = &cmd_wait;

		if (priv->radio_on)

			mwl8k_tx_start(priv);

	}

	count = priv->pending_tx_pkts;

	if (count)

		priv->tx_wait = &tx_wait;

	spin_unlock_bh(&priv->tx_lock);



	if (count) {
@@ -1138,20 +1130,20 @@ static int mwl8k_tx_wait_empty(struct ieee80211_hw *hw) 
		int index;

		int newcount;



		timeout = wait_for_completion_timeout(&cmd_wait,

		timeout = wait_for_completion_timeout(&tx_wait,

					msecs_to_jiffies(5000));

		if (timeout)

			return 0;



		spin_lock_bh(&priv->tx_lock);

		priv->tx_wait = NULL;

		newcount = mwl8k_txq_busy(priv);

		newcount = priv->pending_tx_pkts;

		mwl8k_scan_tx_ring(priv, txinfo);

		spin_unlock_bh(&priv->tx_lock);



		printk(KERN_ERR "%s(%u) TIMEDOUT:5000ms Pend:%u-->%u\n",

		       __func__, __LINE__, count, newcount);



		mwl8k_scan_tx_ring(priv, txinfo);

		for (index = 0; index < MWL8K_TX_QUEUES; index++)

			printk(KERN_ERR "TXQ:%u L:%u H:%u T:%u FW:%u "

			       "DRV:%u U:%u\n",
@@ -2397,7 +2389,7 @@ static irqreturn_t mwl8k_interrupt(int irq, void *dev_id) 


	if (status & MWL8K_A2H_INT_QUEUE_EMPTY) {

		if (!mutex_is_locked(&priv->fw_mutex) &&

		    priv->radio_on && mwl8k_txq_busy(priv))

		    priv->radio_on && priv->pending_tx_pkts)

			mwl8k_tx_start(priv);

	}
@@ -2800,7 +2792,7 @@ static void mwl8k_tx_reclaim_handler(unsigned long data) 
	for (i = 0; i < MWL8K_TX_QUEUES; i++)

		mwl8k_txq_reclaim(hw, i, 0);



	if (priv->tx_wait != NULL && mwl8k_txq_busy(priv) == 0) {

	if (priv->tx_wait != NULL && !priv->pending_tx_pkts) {

		complete(priv->tx_wait);

		priv->tx_wait = NULL;

	}
@@ -2932,11 +2924,12 @@ static int __devinit mwl8k_probe(struct pci_dev *pdev, 
	mutex_init(&priv->fw_mutex);

	priv->fw_mutex_owner = NULL;

	priv->fw_mutex_depth = 0;

	priv->tx_wait = NULL;

	priv->hostcmd_wait = NULL;



	spin_lock_init(&priv->tx_lock);



	priv->tx_wait = NULL;



	for (i = 0; i < MWL8K_TX_QUEUES; i++) {

		rc = mwl8k_txq_init(hw, i);

		if (rc)