Shuyu Wei <wsy2220 at gmail.com> :
[...]
> I still have a question, is it possible that tx_clean() run
> between priv->tx_buff[*txbd_curr].skb = skb and dma_wmb()?
A (previous) run can take place after priv->tx_buff[*txbd_curr].skb and
before *info = cpu_to_le32(FOR_EMAC | FIRST_OR_LAST_MASK | len).
So, yes, the driver must check in arc_emac_tx_clean() that 1) either
txbd_dirty != txbd_curr or 2) "info" is not consistent with a still-not-used
status word. Please be patient with me and get rid of the useless "i"
diff --git a/drivers/net/ethernet/arc/emac_main.c b/drivers/net/ethernet/arc/emac_main.c
index a3a9392..337ea3b 100644
--- a/drivers/net/ethernet/arc/emac_main.c
+++ b/drivers/net/ethernet/arc/emac_main.c
@@ -153,9 +153,8 @@ static void arc_emac_tx_clean(struct net_device *ndev)
{
struct arc_emac_priv *priv = netdev_priv(ndev);
struct net_device_stats *stats = &ndev->stats;
- unsigned int i;
- for (i = 0; i < TX_BD_NUM; i++) {
+ while (priv->txbd_dirty != priv->txbd_curr) {
unsigned int *txbd_dirty = &priv->txbd_dirty;
struct arc_emac_bd *txbd = &priv->txbd[*txbd_dirty];
struct buffer_state *tx_buff = &priv->tx_buff[*txbd_dirty];
--
Ueimor
