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-rw-r--r--drivers/net/ethernet/calxeda/xgmac.c20
1 files changed, 15 insertions, 5 deletions
diff --git a/drivers/net/ethernet/calxeda/xgmac.c b/drivers/net/ethernet/calxeda/xgmac.c
index f630855..5d0b61a 100644
--- a/drivers/net/ethernet/calxeda/xgmac.c
+++ b/drivers/net/ethernet/calxeda/xgmac.c
@@ -410,6 +410,9 @@ struct xgmac_priv {
#define dma_ring_space(h, t, s) CIRC_SPACE(h, t, s)
#define dma_ring_cnt(h, t, s) CIRC_CNT(h, t, s)
+#define tx_dma_ring_space(p) \
+ dma_ring_space((p)->tx_head, (p)->tx_tail, DMA_TX_RING_SZ)
+
/* XGMAC Descriptor Access Helpers */
static inline void desc_set_buf_len(struct xgmac_dma_desc *p, u32 buf_sz)
{
@@ -886,8 +889,10 @@ static void xgmac_tx_complete(struct xgmac_priv *priv)
priv->tx_tail = dma_ring_incr(entry, DMA_TX_RING_SZ);
}
- if (dma_ring_space(priv->tx_head, priv->tx_tail, DMA_TX_RING_SZ) >
- MAX_SKB_FRAGS)
+ /* Ensure tx_tail is visible to xgmac_xmit */
+ smp_mb();
+ if (unlikely(netif_queue_stopped(priv->dev) &&
+ (tx_dma_ring_space(priv) > MAX_SKB_FRAGS)))
netif_wake_queue(priv->dev);
}
@@ -1125,10 +1130,15 @@ static netdev_tx_t xgmac_xmit(struct sk_buff *skb, struct net_device *dev)
priv->tx_head = dma_ring_incr(entry, DMA_TX_RING_SZ);
- if (dma_ring_space(priv->tx_head, priv->tx_tail, DMA_TX_RING_SZ) <
- MAX_SKB_FRAGS)
+ /* Ensure tx_head update is visible to tx completion */
+ smp_mb();
+ if (unlikely(tx_dma_ring_space(priv) <= MAX_SKB_FRAGS)) {
netif_stop_queue(dev);
-
+ /* Ensure netif_stop_queue is visible to tx completion */
+ smp_mb();
+ if (tx_dma_ring_space(priv) > MAX_SKB_FRAGS)
+ netif_start_queue(dev);
+ }
return NETDEV_TX_OK;
}