Re: [PATCH v4 6/6] net: sh_eth: use NAPI

2012/05/17 19:33, Francois Romieu wrote:

Shimoda, Yoshihiro [off-list ref] :
[...]

quoted

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index c64a31c..edc7dfe 100644
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c

[...]

< snip >

quoted

@@ -1678,19 +1710,15 @@ static int sh_eth_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	struct sh_eth_private *mdp = netdev_priv(ndev);
 	struct sh_eth_txdesc *txdesc;
 	u32 entry;
-	unsigned long flags;

-	spin_lock_irqsave(&mdp->lock, flags);
 	if ((mdp->cur_tx - mdp->dirty_tx) >= (mdp->num_tx_ring - 4)) {
 		if (!sh_eth_txfree(ndev)) {

There are now two racing sh_eth_txfree and there is no [PATCH v4 7/6].

If I may suggest a slightly different approach, I would apply the patch
below before anything NAPI related:

Thank you very much for the suggestion. I will modify the NAPI patch to fix
the racing using your suggestion.
(Because the original driver (before NAPI) was already locked by mdp->lock
 in sh_eth_interrupt(), I think that the original driver doesn't have the
 racing issue.)

Best regards,
Yoshihiro Shimoda