[PATCH 4/4] pch_gbe: vlan skb len fix

[PATCH 4/4] pch_gbe: vlan skb len fix

[Andy Cress]

Author: Veaceslav Falico <vfalico@redhat.com>
Date:   Tue Apr 10 08:14:17 2012 +0200

pch_gbe_xmit_frame skb->len verification was incorrect in vlan case 
causing bogus transfer length errors.  One correction could be:
    offset = skb->protocol == htons(ETH_P_8021Q) ? 0 : 4;
    if (unlikely(skb->len > (adapter->hw.mac.max_frame_size - offset))) 
However, this verification is not necessary, so remove it.

Merged-by: Andy Cress <andy.cress@us.kontron.com>
Signed-off-by: Andy Cress <andy.cress@us.kontron.com>

diff --git a/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
b/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
index 2ccdca6..5eaac7f 100644
--- a/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
+++ b/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
@@ -2160,13 +2160,6 @@ static int pch_gbe_xmit_frame(struct sk_buff
*skb, struct net_device *netdev)
 	struct pch_gbe_tx_ring *tx_ring = adapter->tx_ring;
 	unsigned long flags;
 
-	if (unlikely(skb->len > (adapter->hw.mac.max_frame_size - 4))) {
-		pr_err("Transfer length Error: skb len: %d > max: %d\n",
-		       skb->len, adapter->hw.mac.max_frame_size);
-		dev_kfree_skb_any(skb);
-		adapter->stats.tx_length_errors++;
-		return NETDEV_TX_OK;
-	}
 	if (!spin_trylock_irqsave(&tx_ring->tx_lock, flags)) {
 		/* Collision - tell upper layer to requeue */
 		return NETDEV_TX_LOCKED;

RE: [PATCH 4/4] pch_gbe: vlan skb len fix

[Andy Cress]

That's a good idea.  Removing the check is simpler, simpler is better.

Yes, apparently I do need to resubmit with a different email client.

Andy

-----Original Message-----
From: Ben Hutchings [mailto:bhutchings@solarflare.com] 
Sent: Monday, July 09, 2012 4:33 PM
To: Andy Cress
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH 4/4] pch_gbe: vlan skb len fix

On Mon, 2012-07-09 at 06:30 -0700, Andy Cress wrote:
> Author: Veaceslav Falico <vfalico@redhat.com>
> Date:   Tue Apr 10 08:14:17 2012 +0200
> 
>     pch_gbe: correctly verify skb->len in vlan case
>              to avoid bogus transfer length errors.

This check shouldn't be necessary at all.  Maybe you should remove it
instead of correcting the check?

Also, these patches are word-wrapped, and would not be applicable in
this form.  See Documentation/email-clients.txt.

Ben.

Re: [PATCH 4/4] pch_gbe: vlan skb len fix

[Ben Hutchings]

On Mon, 2012-07-09 at 06:30 -0700, Andy Cress wrote:
> Author: Veaceslav Falico <vfalico@redhat.com>
> Date:   Tue Apr 10 08:14:17 2012 +0200
> 
>     pch_gbe: correctly verify skb->len in vlan case
>              to avoid bogus transfer length errors.

This check shouldn't be necessary at all.  Maybe you should remove it
instead of correcting the check?

Also, these patches are word-wrapped, and would not be applicable in
this form.  See Documentation/email-clients.txt.

Ben.

> Signed-off-by: Andy Cress <andy.cress@us.kontron.com>
> 
> diff --git a/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
> b/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
> index 30ef285..04b0e49 100644
> --- a/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
> +++ b/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
> @@ -2158,8 +2158,10 @@ static int pch_gbe_xmit_frame(struct sk_buff
> *skb, struct net_device *netdev)
>  	struct pch_gbe_adapter *adapter = netdev_priv(netdev);
>  	struct pch_gbe_tx_ring *tx_ring = adapter->tx_ring;
>  	unsigned long flags;
> +	int offset;
>  
> -	if (unlikely(skb->len > (adapter->hw.mac.max_frame_size - 4))) {
> +	offset = skb->protocol == htons(ETH_P_8021Q) ? 0 : 4;
> +	if (unlikely(skb->len > (adapter->hw.mac.max_frame_size -
> offset))) {
>  		pr_err("Transfer length Error: skb len: %d > max: %d\n",
>  		       skb->len, adapter->hw.mac.max_frame_size);
>  		dev_kfree_skb_any(skb);

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

[PATCH 4/4] pch_gbe: vlan skb len fix

[Andy Cress]

Author: Veaceslav Falico <vfalico@redhat.com>
Date:   Tue Apr 10 08:14:17 2012 +0200

    pch_gbe: correctly verify skb->len in vlan case
             to avoid bogus transfer length errors.

Signed-off-by: Andy Cress <andy.cress@us.kontron.com>

diff --git a/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
b/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
index 30ef285..04b0e49 100644
--- a/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
+++ b/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
@@ -2158,8 +2158,10 @@ static int pch_gbe_xmit_frame(struct sk_buff
*skb, struct net_device *netdev)
 	struct pch_gbe_adapter *adapter = netdev_priv(netdev);
 	struct pch_gbe_tx_ring *tx_ring = adapter->tx_ring;
 	unsigned long flags;
+	int offset;
 
-	if (unlikely(skb->len > (adapter->hw.mac.max_frame_size - 4))) {
+	offset = skb->protocol == htons(ETH_P_8021Q) ? 0 : 4;
+	if (unlikely(skb->len > (adapter->hw.mac.max_frame_size -
offset))) {
 		pr_err("Transfer length Error: skb len: %d > max: %d\n",
 		       skb->len, adapter->hw.mac.max_frame_size);
 		dev_kfree_skb_any(skb);