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| author | Ben Hutchings <ben.hutchings@codethink.co.uk> | 2015-03-03 01:52:00 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-03-03 03:30:56 +0100 |
| commit | 7d7355f58ba4f9d68d2fb79864bab4ccb618e4e1 (patch) | |
| tree | 79a7efdc9a433f1c5f05651adc70c2579760c313 | |
| parent | Merge branch 'mlx4' (diff) | |
| download | linux-7d7355f58ba4f9d68d2fb79864bab4ccb618e4e1.tar.xz linux-7d7355f58ba4f9d68d2fb79864bab4ccb618e4e1.zip | |
sh_eth: Ensure proper ordering of descriptor active bit write/read
When submitting a DMA descriptor, the active bit must be written last.
When reading a completed DMA descriptor, the active bit must be read
first.
Add memory barriers to ensure that this ordering is maintained.
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/ethernet/renesas/sh_eth.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index 654b48d1e61a..5c212a833bcf 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -1410,6 +1410,8 @@ static int sh_eth_txfree(struct net_device *ndev) txdesc = &mdp->tx_ring[entry]; if (txdesc->status & cpu_to_edmac(mdp, TD_TACT)) break; + /* TACT bit must be checked before all the following reads */ + rmb(); /* Free the original skb. */ if (mdp->tx_skbuff[entry]) { dma_unmap_single(&ndev->dev, txdesc->addr, @@ -1447,6 +1449,8 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota) limit = boguscnt; 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(); desc_status = edmac_to_cpu(mdp, rxdesc->status); pkt_len = rxdesc->frame_length; @@ -1526,6 +1530,7 @@ 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 */ if (entry >= mdp->num_rx_ring - 1) rxdesc->status |= cpu_to_edmac(mdp, RD_RACT | RD_RFP | RD_RDEL); @@ -2195,6 +2200,7 @@ 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 */ if (entry >= mdp->num_tx_ring - 1) txdesc->status |= cpu_to_edmac(mdp, TD_TACT | TD_TDLE); else |