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Commit d8498088 authored by Florian Fainelli's avatar Florian Fainelli Committed by David S. Miller
Browse files

net: systemport: fix transmit locking scheme 



Our transmit locking scheme did not account for the TX ring full
interrupt. If a TX ring full interrupt fires while we are attempting to
transmit, we will cause a deadlock to occur. Fix this by making sure
that we properly disable interrupts while acquiring the spinlock.

Signed-off-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6934e79e

drivers/net/ethernet/broadcom/bcmsysport.c

+7 −5
Original line number Diff line number Diff line
@@ -637,10 +637,11 @@ static unsigned int bcm_sysport_tx_reclaim(struct bcm_sysport_priv *priv, 
					   struct bcm_sysport_tx_ring *ring)

{

	unsigned int released;

	unsigned long flags;



	spin_lock(&ring->lock);

	spin_lock_irqsave(&ring->lock, flags);

	released = __bcm_sysport_tx_reclaim(priv, ring);

	spin_unlock(&ring->lock);

	spin_unlock_irqrestore(&ring->lock, flags);



	return released;

}
@@ -822,6 +823,7 @@ static netdev_tx_t bcm_sysport_xmit(struct sk_buff *skb, 
	struct netdev_queue *txq;

	struct dma_desc *desc;

	unsigned int skb_len;

	unsigned long flags;

	dma_addr_t mapping;

	u32 len_status;

	u16 queue;
@@ -831,8 +833,8 @@ static netdev_tx_t bcm_sysport_xmit(struct sk_buff *skb, 
	txq = netdev_get_tx_queue(dev, queue);

	ring = &priv->tx_rings[queue];



	/* lock against tx reclaim in BH context */

	spin_lock(&ring->lock);

	/* lock against tx reclaim in BH context and TX ring full interrupt */

	spin_lock_irqsave(&ring->lock, flags);

	if (unlikely(ring->desc_count == 0)) {

		netif_tx_stop_queue(txq);

		netdev_err(dev, "queue %d awake and ring full!\n", queue);
@@ -914,7 +916,7 @@ static netdev_tx_t bcm_sysport_xmit(struct sk_buff *skb, 


	ret = NETDEV_TX_OK;

out:

	spin_unlock(&ring->lock);

	spin_unlock_irqrestore(&ring->lock, flags);

	return ret;

}