Commit ca32723a authored Aug 30, 2013 by Rob Herring Committed by David S. Miller Sep 03, 2013

net: calxedaxgmac: update ring buffer tx_head after barriers



Ensure that the descriptor writes are visible before the ring buffer head
is updated. Since writel is a barrier, we can simply update the head after
the writel.

Reported-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 1a1d4d2f

drivers/net/ethernet/calxeda/xgmac.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1121,9 +1121,10 @@ static netdev_tx_t xgmac_xmit(struct sk_buff skb, struct net_device dev)
		wmb();
		desc_set_tx_owner(first, desc_flags \| TXDESC_FIRST_SEG);

		writel(1, priv->base + XGMAC_DMA_TX_POLL);

		priv->tx_head = dma_ring_incr(entry, DMA_TX_RING_SZ);

		writel(1, priv->base + XGMAC_DMA_TX_POLL);
		if (dma_ring_space(priv->tx_head, priv->tx_tail, DMA_TX_RING_SZ) <
		MAX_SKB_FRAGS)
		netif_stop_queue(dev);