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: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c
index 25982b02f0ea388bda148755fbc17887392df5e9..4dfc93fe9744f6b2c7be3a35816c90e106c63ee5 100644 (file)
--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c
@@ -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;
 }