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Commit f32bfb9a authored by Sergei Shtylyov's avatar Sergei Shtylyov Committed by David S. Miller
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sh_eth: use DMA barriers 



Commit  7d7355f5 ("sh_eth: Ensure proper ordering of descriptor active
bit write/read") did the right thing  but used too "heavy" barriers while
there were already "lighter" DMA barriers exactly  for this case...

Signed-off-by: default avatarSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 73186df8

drivers/net/ethernet/renesas/sh_eth.c

+4 −4
Original line number Diff line number Diff line
@@ -1416,7 +1416,7 @@ static int sh_eth_txfree(struct net_device *ndev) 
		if (txdesc->status & cpu_to_edmac(mdp, TD_TACT))

			break;

		/* TACT bit must be checked before all the following reads */

		rmb();

		dma_rmb();

		netif_info(mdp, tx_done, ndev,

			   "tx entry %d status 0x%08x\n",

			   entry, edmac_to_cpu(mdp, txdesc->status));
@@ -1458,7 +1458,7 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota) 
	rxdesc = &mdp->rx_ring[entry];

	while (!(rxdesc->status & cpu_to_edmac(mdp, RD_RACT))) {

		/* RACT bit must be checked before all the following reads */

		rmb();

		dma_rmb();

		desc_status = edmac_to_cpu(mdp, rxdesc->status);

		pkt_len = rxdesc->frame_length;
@@ -1544,7 +1544,7 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota) 
			skb_checksum_none_assert(skb);

			rxdesc->addr = dma_addr;

		}

		wmb(); /* RACT bit must be set after all the above writes */

		dma_wmb(); /* RACT bit must be set after all the above writes */

		if (entry >= mdp->num_rx_ring - 1)

			rxdesc->status |=

				cpu_to_edmac(mdp, RD_RACT | RD_RFP | RD_RDLE);
@@ -2403,7 +2403,7 @@ static int sh_eth_start_xmit(struct sk_buff *skb, struct net_device *ndev) 
	}

	txdesc->buffer_length = skb->len;



	wmb(); /* TACT bit must be set after all the above writes */

	dma_wmb(); /* TACT bit must be set after all the above writes */

	if (entry >= mdp->num_tx_ring - 1)

		txdesc->status |= cpu_to_edmac(mdp, TD_TACT | TD_TDLE);

	else