[PATCH 1/2] igb: Allow extra 4 bytes on RX for vlan tags.

[PATCH 1/2] igb: Allow extra 4 bytes on RX for vlan tags.

[greearb]

From: Ben Greear <greearb@candelatech.com>

This allows the NIC to receive 1518 byte (not counting
FCS) packets when MTU is 1500, thus allowing 1500 MTU
VLAN frames to be received.  Please note that no VLANs
were actually configured on the NIC...it was just acting
as pass-through device.

Signed-off-by: Ben Greear <greearb@candelatech.com>
---
:100644 100644 58c665b... 30c9cc6... M	drivers/net/igb/igb_main.c
 drivers/net/igb/igb_main.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index 58c665b..30c9cc6 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -2281,7 +2281,8 @@ static int __devinit igb_sw_init(struct igb_adapter *adapter)
 	adapter->rx_itr_setting = IGB_DEFAULT_ITR;
 	adapter->tx_itr_setting = IGB_DEFAULT_ITR;
 
-	adapter->max_frame_size = netdev->mtu + ETH_HLEN + ETH_FCS_LEN;
+	adapter->max_frame_size = (netdev->mtu + ETH_HLEN + ETH_FCS_LEN
+				   + VLAN_HLEN);
 	adapter->min_frame_size = ETH_ZLEN + ETH_FCS_LEN;
 
 	spin_lock_init(&adapter->stats64_lock);
@@ -4303,7 +4304,7 @@ static int igb_change_mtu(struct net_device *netdev, int new_mtu)
 {
 	struct igb_adapter *adapter = netdev_priv(netdev);
 	struct pci_dev *pdev = adapter->pdev;
-	int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN;
+	int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
 	u32 rx_buffer_len, i;
 
 	if ((new_mtu < 68) || (max_frame > MAX_JUMBO_FRAME_SIZE)) {
-- 
1.7.2.3

[PATCH 2/2] network: Allow af_packet to transmit +4 bytes for VLAN packets.

[greearb]

From: Ben Greear <greearb@candelatech.com>

This allows user-space to send a '1500' MTU VLAN packet on a
1500 MTU ethernet frame.  The extra 4 bytes of a VLAN header is
not usually charged against the MTU when other parts of the
network stack is transmitting vlans...

Signed-off-by: Ben Greear <greearb@candelatech.com>
---
:100644 100644 91cb1d7... ef7f378... M	net/packet/af_packet.c
 net/packet/af_packet.c |   31 +++++++++++++++++++++++++++++--
 1 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 91cb1d7..ef7f378 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -466,7 +466,7 @@ retry:
 	 */
 
 	err = -EMSGSIZE;
-	if (len > dev->mtu + dev->hard_header_len)
+	if (len > dev->mtu + dev->hard_header_len + VLAN_HLEN)
 		goto out_unlock;
 
 	if (!skb) {
@@ -497,6 +497,19 @@ retry:
 		goto retry;
 	}
 
+	if (len > (dev->mtu + dev->hard_header_len)) {
+		/* Earlier code assumed this would be a VLAN pkt,
+		 * double-check this now that we have the actual
+		 * packet in hand.
+		 */
+		struct ethhdr *ehdr;
+		skb_reset_mac_header(skb);
+		ehdr = eth_hdr(skb);
+		if (ehdr->h_proto != htons(ETH_P_8021Q)) {
+			err = -EMSGSIZE;
+			goto out_unlock;
+		}
+	}
 
 	skb->protocol = proto;
 	skb->dev = dev;
@@ -1200,7 +1213,7 @@ static int packet_snd(struct socket *sock,
 	}
 
 	err = -EMSGSIZE;
-	if (!gso_type && (len > dev->mtu+reserve))
+	if (!gso_type && (len > dev->mtu + reserve + ETH_HLEN))
 		goto out_unlock;
 
 	err = -ENOBUFS;
@@ -1225,6 +1238,20 @@ static int packet_snd(struct socket *sock,
 	if (err < 0)
 		goto out_free;
 
+	if (!gso_type && (len > dev->mtu + reserve)) {
+		/* Earlier code assumed this would be a VLAN pkt,
+		 * double-check this now that we have the actual
+		 * packet in hand.
+		 */
+		struct ethhdr *ehdr;
+		skb_reset_mac_header(skb);
+		ehdr = eth_hdr(skb);
+		if (ehdr->h_proto != htons(ETH_P_8021Q)) {
+			err = -EMSGSIZE;
+			goto out_free;
+		}
+	}
+
 	skb->protocol = proto;
 	skb->dev = dev;
 	skb->priority = sk->sk_priority;
-- 
1.7.2.3

Re: [PATCH 2/2] network: Allow af_packet to transmit +4 bytes for VLAN packets.

[Eric Dumazet]

Le jeudi 10 février 2011 à 13:59 -0800, greearb@candelatech.com a
écrit :
> From: Ben Greear <greearb@candelatech.com>
> 
> This allows user-space to send a '1500' MTU VLAN packet on a
> 1500 MTU ethernet frame.  The extra 4 bytes of a VLAN header is
> not usually charged against the MTU when other parts of the
> network stack is transmitting vlans...
> 
> Signed-off-by: Ben Greear <greearb@candelatech.com>
> ---
> :100644 100644 91cb1d7... ef7f378... M	net/packet/af_packet.c
>  net/packet/af_packet.c |   31 +++++++++++++++++++++++++++++--
>  1 files changed, 29 insertions(+), 2 deletions(-)
> 
> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> index 91cb1d7..ef7f378 100644
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -466,7 +466,7 @@ retry:
>  	 */
>  
>  	err = -EMSGSIZE;
> -	if (len > dev->mtu + dev->hard_header_len)
> +	if (len > dev->mtu + dev->hard_header_len + VLAN_HLEN)
>  		goto out_unlock;
>  
>  	if (!skb) {
> @@ -497,6 +497,19 @@ retry:
>  		goto retry;
>  	}
>  
> +	if (len > (dev->mtu + dev->hard_header_len)) {
> +		/* Earlier code assumed this would be a VLAN pkt,
> +		 * double-check this now that we have the actual
> +		 * packet in hand.
> +		 */
> +		struct ethhdr *ehdr;
> +		skb_reset_mac_header(skb);
> +		ehdr = eth_hdr(skb);
> +		if (ehdr->h_proto != htons(ETH_P_8021Q)) {
> +			err = -EMSGSIZE;
> +			goto out_unlock;

This would leak skb.

> +		}
> +	}
>  
>  	skb->protocol = proto;
>  	skb->dev = dev;

Re: [PATCH 1/2] igb: Allow extra 4 bytes on RX for vlan tags.

[Jeff Kirsher]

On Thu, Feb 10, 2011 at 13:59,  <greearb@candelatech.com> wrote:
> From: Ben Greear <greearb@candelatech.com>
>
> This allows the NIC to receive 1518 byte (not counting
> FCS) packets when MTU is 1500, thus allowing 1500 MTU
> VLAN frames to be received.  Please note that no VLANs
> were actually configured on the NIC...it was just acting
> as pass-through device.
>
> Signed-off-by: Ben Greear <greearb@candelatech.com>
> ---
> :100644 100644 58c665b... 30c9cc6... M  drivers/net/igb/igb_main.c
>  drivers/net/igb/igb_main.c |    5 +++--
>  1 files changed, 3 insertions(+), 2 deletions(-)
>

Thanks Ben, I have added the patch to my queue of igb patches.

-- 
Cheers,
Jeff

Re: [PATCH 2/2] network: Allow af_packet to transmit +4 bytes for VLAN packets.

[Ben Greear]

On 02/10/2011 10:57 PM, Eric Dumazet wrote:
> Le jeudi 10 février 2011 à 13:59 -0800, greearb@candelatech.com a
> écrit :
>> From: Ben Greear<greearb@candelatech.com>
>>
>> This allows user-space to send a '1500' MTU VLAN packet on a
>> 1500 MTU ethernet frame.  The extra 4 bytes of a VLAN header is
>> not usually charged against the MTU when other parts of the
>> network stack is transmitting vlans...
>>
>> Signed-off-by: Ben Greear<greearb@candelatech.com>
>> ---
>> :100644 100644 91cb1d7... ef7f378... M	net/packet/af_packet.c
>>   net/packet/af_packet.c |   31 +++++++++++++++++++++++++++++--
>>   1 files changed, 29 insertions(+), 2 deletions(-)
>>
>> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
>> index 91cb1d7..ef7f378 100644
>> --- a/net/packet/af_packet.c
>> +++ b/net/packet/af_packet.c
>> @@ -466,7 +466,7 @@ retry:
>>   	 */
>>
>>   	err = -EMSGSIZE;
>> -	if (len>  dev->mtu + dev->hard_header_len)
>> +	if (len>  dev->mtu + dev->hard_header_len + VLAN_HLEN)
>>   		goto out_unlock;
>>
>>   	if (!skb) {
>> @@ -497,6 +497,19 @@ retry:
>>   		goto retry;
>>   	}
>>
>> +	if (len>  (dev->mtu + dev->hard_header_len)) {
>> +		/* Earlier code assumed this would be a VLAN pkt,
>> +		 * double-check this now that we have the actual
>> +		 * packet in hand.
>> +		 */
>> +		struct ethhdr *ehdr;
>> +		skb_reset_mac_header(skb);
>> +		ehdr = eth_hdr(skb);
>> +		if (ehdr->h_proto != htons(ETH_P_8021Q)) {
>> +			err = -EMSGSIZE;
>> +			goto out_unlock;
>
> This would leak skb.
>
>> +		}
>> +	}
>>
>>   	skb->protocol = proto;
>>   	skb->dev = dev;

Can you double-check that?  Seems to me that in that method the out_unlock
falls through to the out_free case.  The other method is the opposite, funny
enough...

Thanks,
Ben

>
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: [PATCH 2/2] network: Allow af_packet to transmit +4 bytes for VLAN packets.

[Eric Dumazet]

Le vendredi 11 février 2011 à 09:38 -0800, Ben Greear a écrit :

> Can you double-check that?  Seems to me that in that method the out_unlock
> falls through to the out_free case.  The other method is the opposite, funny
> enough...

Oops you're right, sorry.

Reading again your patch, I see you used one ETH_HLEN instead of
VLAN_HLEN in packet_snd()

Re: [PATCH 1/2] igb: Allow extra 4 bytes on RX for vlan tags.

[Jeff Kirsher]

On Thu, Feb 10, 2011 at 13:59,  <greearb@candelatech.com> wrote:
> From: Ben Greear <greearb@candelatech.com>
>
> This allows the NIC to receive 1518 byte (not counting
> FCS) packets when MTU is 1500, thus allowing 1500 MTU
> VLAN frames to be received.  Please note that no VLANs
> were actually configured on the NIC...it was just acting
> as pass-through device.
>
> Signed-off-by: Ben Greear <greearb@candelatech.com>
> ---
> :100644 100644 58c665b... 30c9cc6... M  drivers/net/igb/igb_main.c
>  drivers/net/igb/igb_main.c |    5 +++--
>  1 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
> index 58c665b..30c9cc6 100644
> --- a/drivers/net/igb/igb_main.c
> +++ b/drivers/net/igb/igb_main.c
> @@ -2281,7 +2281,8 @@ static int __devinit igb_sw_init(struct igb_adapter *adapter)
>        adapter->rx_itr_setting = IGB_DEFAULT_ITR;
>        adapter->tx_itr_setting = IGB_DEFAULT_ITR;
>
> -       adapter->max_frame_size = netdev->mtu + ETH_HLEN + ETH_FCS_LEN;
> +       adapter->max_frame_size = (netdev->mtu + ETH_HLEN + ETH_FCS_LEN
> +                                  + VLAN_HLEN);
>        adapter->min_frame_size = ETH_ZLEN + ETH_FCS_LEN;
>
>        spin_lock_init(&adapter->stats64_lock);
> @@ -4303,7 +4304,7 @@ static int igb_change_mtu(struct net_device *netdev, int new_mtu)
>  {
>        struct igb_adapter *adapter = netdev_priv(netdev);
>        struct pci_dev *pdev = adapter->pdev;
> -       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN;
> +       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
>        u32 rx_buffer_len, i;
>
>        if ((new_mtu < 68) || (max_frame > MAX_JUMBO_FRAME_SIZE)) {

While testing this patch, validation found that the patch reduces the
maximum mtu size
by 4 bytes (reduces it from 9216 to 9212).  This is not a desired side
effect of this patch.

Thoughts?

-- 
Cheers,
Jeff

Re: [PATCH 1/2] igb: Allow extra 4 bytes on RX for vlan tags.

[Ben Greear]

On 02/17/2011 03:04 AM, Jeff Kirsher wrote:
> On Thu, Feb 10, 2011 at 13:59,<greearb@candelatech.com>  wrote:
>> From: Ben Greear<greearb@candelatech.com>
>>
>> This allows the NIC to receive 1518 byte (not counting
>> FCS) packets when MTU is 1500, thus allowing 1500 MTU
>> VLAN frames to be received.  Please note that no VLANs
>> were actually configured on the NIC...it was just acting
>> as pass-through device.
>>
>> Signed-off-by: Ben Greear<greearb@candelatech.com>
>> ---
>> :100644 100644 58c665b... 30c9cc6... M  drivers/net/igb/igb_main.c
>>   drivers/net/igb/igb_main.c |    5 +++--
>>   1 files changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
>> index 58c665b..30c9cc6 100644
>> --- a/drivers/net/igb/igb_main.c
>> +++ b/drivers/net/igb/igb_main.c
>> @@ -2281,7 +2281,8 @@ static int __devinit igb_sw_init(struct igb_adapter *adapter)
>>         adapter->rx_itr_setting = IGB_DEFAULT_ITR;
>>         adapter->tx_itr_setting = IGB_DEFAULT_ITR;
>>
>> -       adapter->max_frame_size = netdev->mtu + ETH_HLEN + ETH_FCS_LEN;
>> +       adapter->max_frame_size = (netdev->mtu + ETH_HLEN + ETH_FCS_LEN
>> +                                  + VLAN_HLEN);
>>         adapter->min_frame_size = ETH_ZLEN + ETH_FCS_LEN;
>>
>>         spin_lock_init(&adapter->stats64_lock);
>> @@ -4303,7 +4304,7 @@ static int igb_change_mtu(struct net_device *netdev, int new_mtu)
>>   {
>>         struct igb_adapter *adapter = netdev_priv(netdev);
>>         struct pci_dev *pdev = adapter->pdev;
>> -       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN;
>> +       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
>>         u32 rx_buffer_len, i;
>>
>>         if ((new_mtu<  68) || (max_frame>  MAX_JUMBO_FRAME_SIZE)) {
>
> While testing this patch, validation found that the patch reduces the
> maximum mtu size
> by 4 bytes (reduces it from 9216 to 9212).  This is not a desired side
> effect of this patch.

You could add handling for that case and have it act as it used to when
new_mtu is greater than 9212?

I tested e1000e and it worked w/out hacking at 1500 MTU, so maybe
check how it does it?

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: [PATCH 1/2] igb: Allow extra 4 bytes on RX for vlan tags.

[Jesse Gross]

On Thu, Feb 17, 2011 at 9:28 AM, Ben Greear <greearb@candelatech.com> wrote:
> On 02/17/2011 03:04 AM, Jeff Kirsher wrote:
>>
>> On Thu, Feb 10, 2011 at 13:59,<greearb@candelatech.com>  wrote:
>>>
>>> From: Ben Greear<greearb@candelatech.com>
>>>
>>> This allows the NIC to receive 1518 byte (not counting
>>> FCS) packets when MTU is 1500, thus allowing 1500 MTU
>>> VLAN frames to be received.  Please note that no VLANs
>>> were actually configured on the NIC...it was just acting
>>> as pass-through device.
>>>
>>> Signed-off-by: Ben Greear<greearb@candelatech.com>
>>> ---
>>> :100644 100644 58c665b... 30c9cc6... M  drivers/net/igb/igb_main.c
>>>  drivers/net/igb/igb_main.c |    5 +++--
>>>  1 files changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
>>> index 58c665b..30c9cc6 100644
>>> --- a/drivers/net/igb/igb_main.c
>>> +++ b/drivers/net/igb/igb_main.c
>>> @@ -2281,7 +2281,8 @@ static int __devinit igb_sw_init(struct igb_adapter
>>> *adapter)
>>>        adapter->rx_itr_setting = IGB_DEFAULT_ITR;
>>>        adapter->tx_itr_setting = IGB_DEFAULT_ITR;
>>>
>>> -       adapter->max_frame_size = netdev->mtu + ETH_HLEN + ETH_FCS_LEN;
>>> +       adapter->max_frame_size = (netdev->mtu + ETH_HLEN + ETH_FCS_LEN
>>> +                                  + VLAN_HLEN);
>>>        adapter->min_frame_size = ETH_ZLEN + ETH_FCS_LEN;
>>>
>>>        spin_lock_init(&adapter->stats64_lock);
>>> @@ -4303,7 +4304,7 @@ static int igb_change_mtu(struct net_device
>>> *netdev, int new_mtu)
>>>  {
>>>        struct igb_adapter *adapter = netdev_priv(netdev);
>>>        struct pci_dev *pdev = adapter->pdev;
>>> -       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN;
>>> +       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
>>>        u32 rx_buffer_len, i;
>>>
>>>        if ((new_mtu<  68) || (max_frame>  MAX_JUMBO_FRAME_SIZE)) {
>>
>> While testing this patch, validation found that the patch reduces the
>> maximum mtu size
>> by 4 bytes (reduces it from 9216 to 9212).  This is not a desired side
>> effect of this patch.
>
> You could add handling for that case and have it act as it used to when
> new_mtu is greater than 9212?
>
> I tested e1000e and it worked w/out hacking at 1500 MTU, so maybe
> check how it does it?

I just wanted to bring this up again to see if any progress had been
made.  We were looking at this driver and trying to figure out the
best way to convert it to use the new vlan model but I'm not familiar
enough with the hardware to know.  It seems that all of the other
Intel drivers unconditionally add space for the vlan tag to the
receive buffer (and would therefore have similar effects as this
patch), is there something different about this card?

I believe that Alex was working on something in this area (in the
context of one of my patches from a long time ago) but I'm not sure
what came of that.

Re: [PATCH 1/2] igb: Allow extra 4 bytes on RX for vlan tags.

[Ben Greear]

On 07/20/2011 05:18 PM, Jesse Gross wrote:
> On Thu, Feb 17, 2011 at 9:28 AM, Ben Greear<greearb@candelatech.com>  wrote:
>> On 02/17/2011 03:04 AM, Jeff Kirsher wrote:
>>>
>>> On Thu, Feb 10, 2011 at 13:59,<greearb@candelatech.com>    wrote:
>>>>
>>>> From: Ben Greear<greearb@candelatech.com>
>>>>
>>>> This allows the NIC to receive 1518 byte (not counting
>>>> FCS) packets when MTU is 1500, thus allowing 1500 MTU
>>>> VLAN frames to be received.  Please note that no VLANs
>>>> were actually configured on the NIC...it was just acting
>>>> as pass-through device.
>>>>
>>>> Signed-off-by: Ben Greear<greearb@candelatech.com>
>>>> ---
>>>> :100644 100644 58c665b... 30c9cc6... M  drivers/net/igb/igb_main.c
>>>>   drivers/net/igb/igb_main.c |    5 +++--
>>>>   1 files changed, 3 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
>>>> index 58c665b..30c9cc6 100644
>>>> --- a/drivers/net/igb/igb_main.c
>>>> +++ b/drivers/net/igb/igb_main.c
>>>> @@ -2281,7 +2281,8 @@ static int __devinit igb_sw_init(struct igb_adapter
>>>> *adapter)
>>>>         adapter->rx_itr_setting = IGB_DEFAULT_ITR;
>>>>         adapter->tx_itr_setting = IGB_DEFAULT_ITR;
>>>>
>>>> -       adapter->max_frame_size = netdev->mtu + ETH_HLEN + ETH_FCS_LEN;
>>>> +       adapter->max_frame_size = (netdev->mtu + ETH_HLEN + ETH_FCS_LEN
>>>> +                                  + VLAN_HLEN);
>>>>         adapter->min_frame_size = ETH_ZLEN + ETH_FCS_LEN;
>>>>
>>>>         spin_lock_init(&adapter->stats64_lock);
>>>> @@ -4303,7 +4304,7 @@ static int igb_change_mtu(struct net_device
>>>> *netdev, int new_mtu)
>>>>   {
>>>>         struct igb_adapter *adapter = netdev_priv(netdev);
>>>>         struct pci_dev *pdev = adapter->pdev;
>>>> -       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN;
>>>> +       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
>>>>         u32 rx_buffer_len, i;
>>>>
>>>>         if ((new_mtu<    68) || (max_frame>    MAX_JUMBO_FRAME_SIZE)) {
>>>
>>> While testing this patch, validation found that the patch reduces the
>>> maximum mtu size
>>> by 4 bytes (reduces it from 9216 to 9212).  This is not a desired side
>>> effect of this patch.
>>
>> You could add handling for that case and have it act as it used to when
>> new_mtu is greater than 9212?
>>
>> I tested e1000e and it worked w/out hacking at 1500 MTU, so maybe
>> check how it does it?
>
> I just wanted to bring this up again to see if any progress had been
> made.  We were looking at this driver and trying to figure out the
> best way to convert it to use the new vlan model but I'm not familiar

I've been watching :)

> enough with the hardware to know.  It seems that all of the other
> Intel drivers unconditionally add space for the vlan tag to the
> receive buffer (and would therefore have similar effects as this
> patch), is there something different about this card?
>
> I believe that Alex was working on something in this area (in the
> context of one of my patches from a long time ago) but I'm not sure
> what came of that.

Truth is, I don't really see why it's a problem to decrease the
maximum MTU slightly in order to make it work with VLANs.

I'm not sure if there is some way to make it work with VLANs
and not decrease the maximum MTU.

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: [PATCH 1/2] igb: Allow extra 4 bytes on RX for vlan tags.

[Jeff Kirsher]

[-- Attachment #1: Type: text/plain, Size: 3800 bytes --]

On Wed, 2011-07-20 at 17:27 -0700, Ben Greear wrote:
> On 07/20/2011 05:18 PM, Jesse Gross wrote:
> > On Thu, Feb 17, 2011 at 9:28 AM, Ben Greear<greearb@candelatech.com>  wrote:
> >> On 02/17/2011 03:04 AM, Jeff Kirsher wrote:
> >>>
> >>> On Thu, Feb 10, 2011 at 13:59,<greearb@candelatech.com>    wrote:
> >>>>
> >>>> From: Ben Greear<greearb@candelatech.com>
> >>>>
> >>>> This allows the NIC to receive 1518 byte (not counting
> >>>> FCS) packets when MTU is 1500, thus allowing 1500 MTU
> >>>> VLAN frames to be received.  Please note that no VLANs
> >>>> were actually configured on the NIC...it was just acting
> >>>> as pass-through device.
> >>>>
> >>>> Signed-off-by: Ben Greear<greearb@candelatech.com>
> >>>> ---
> >>>> :100644 100644 58c665b... 30c9cc6... M  drivers/net/igb/igb_main.c
> >>>>   drivers/net/igb/igb_main.c |    5 +++--
> >>>>   1 files changed, 3 insertions(+), 2 deletions(-)
> >>>>
> >>>> diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
> >>>> index 58c665b..30c9cc6 100644
> >>>> --- a/drivers/net/igb/igb_main.c
> >>>> +++ b/drivers/net/igb/igb_main.c
> >>>> @@ -2281,7 +2281,8 @@ static int __devinit igb_sw_init(struct igb_adapter
> >>>> *adapter)
> >>>>         adapter->rx_itr_setting = IGB_DEFAULT_ITR;
> >>>>         adapter->tx_itr_setting = IGB_DEFAULT_ITR;
> >>>>
> >>>> -       adapter->max_frame_size = netdev->mtu + ETH_HLEN + ETH_FCS_LEN;
> >>>> +       adapter->max_frame_size = (netdev->mtu + ETH_HLEN + ETH_FCS_LEN
> >>>> +                                  + VLAN_HLEN);
> >>>>         adapter->min_frame_size = ETH_ZLEN + ETH_FCS_LEN;
> >>>>
> >>>>         spin_lock_init(&adapter->stats64_lock);
> >>>> @@ -4303,7 +4304,7 @@ static int igb_change_mtu(struct net_device
> >>>> *netdev, int new_mtu)
> >>>>   {
> >>>>         struct igb_adapter *adapter = netdev_priv(netdev);
> >>>>         struct pci_dev *pdev = adapter->pdev;
> >>>> -       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN;
> >>>> +       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
> >>>>         u32 rx_buffer_len, i;
> >>>>
> >>>>         if ((new_mtu<    68) || (max_frame>    MAX_JUMBO_FRAME_SIZE)) {
> >>>
> >>> While testing this patch, validation found that the patch reduces the
> >>> maximum mtu size
> >>> by 4 bytes (reduces it from 9216 to 9212).  This is not a desired side
> >>> effect of this patch.
> >>
> >> You could add handling for that case and have it act as it used to when
> >> new_mtu is greater than 9212?
> >>
> >> I tested e1000e and it worked w/out hacking at 1500 MTU, so maybe
> >> check how it does it?
> >
> > I just wanted to bring this up again to see if any progress had been
> > made.  We were looking at this driver and trying to figure out the
> > best way to convert it to use the new vlan model but I'm not familiar
> 
> I've been watching :)
> 
> > enough with the hardware to know.  It seems that all of the other
> > Intel drivers unconditionally add space for the vlan tag to the
> > receive buffer (and would therefore have similar effects as this
> > patch), is there something different about this card?
> >
> > I believe that Alex was working on something in this area (in the
> > context of one of my patches from a long time ago) but I'm not sure
> > what came of that.
> 
> Truth is, I don't really see why it's a problem to decrease the
> maximum MTU slightly in order to make it work with VLANs.
> 
> I'm not sure if there is some way to make it work with VLANs
> and not decrease the maximum MTU.

This was the reason this did not get accepted.  I was looking into what
could be done so that we did not decease the maximum MTU, but I got
side-tracked and have not done anything on it in several months.

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Re: [PATCH 1/2] igb: Allow extra 4 bytes on RX for vlan tags.

[Alexander Duyck]

On Wed, Jul 20, 2011 at 6:21 PM, Jeff Kirsher
<jeffrey.t.kirsher@intel.com> wrote:
> On Wed, 2011-07-20 at 17:27 -0700, Ben Greear wrote:
>> On 07/20/2011 05:18 PM, Jesse Gross wrote:
>> > On Thu, Feb 17, 2011 at 9:28 AM, Ben Greear<greearb@candelatech.com>  wrote:
>> >> On 02/17/2011 03:04 AM, Jeff Kirsher wrote:
>> >>>
>> >>> On Thu, Feb 10, 2011 at 13:59,<greearb@candelatech.com>    wrote:
>> >>>>
>> >>>> From: Ben Greear<greearb@candelatech.com>
>> >>>>
>> >>>> This allows the NIC to receive 1518 byte (not counting
>> >>>> FCS) packets when MTU is 1500, thus allowing 1500 MTU
>> >>>> VLAN frames to be received.  Please note that no VLANs
>> >>>> were actually configured on the NIC...it was just acting
>> >>>> as pass-through device.
>> >>>>
>> >>>> Signed-off-by: Ben Greear<greearb@candelatech.com>
>> >>>> ---
>> >>>> :100644 100644 58c665b... 30c9cc6... M  drivers/net/igb/igb_main.c
>> >>>>   drivers/net/igb/igb_main.c |    5 +++--
>> >>>>   1 files changed, 3 insertions(+), 2 deletions(-)
>> >>>>
>> >>>> diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
>> >>>> index 58c665b..30c9cc6 100644
>> >>>> --- a/drivers/net/igb/igb_main.c
>> >>>> +++ b/drivers/net/igb/igb_main.c
>> >>>> @@ -2281,7 +2281,8 @@ static int __devinit igb_sw_init(struct igb_adapter
>> >>>> *adapter)
>> >>>>         adapter->rx_itr_setting = IGB_DEFAULT_ITR;
>> >>>>         adapter->tx_itr_setting = IGB_DEFAULT_ITR;
>> >>>>
>> >>>> -       adapter->max_frame_size = netdev->mtu + ETH_HLEN + ETH_FCS_LEN;
>> >>>> +       adapter->max_frame_size = (netdev->mtu + ETH_HLEN + ETH_FCS_LEN
>> >>>> +                                  + VLAN_HLEN);
>> >>>>         adapter->min_frame_size = ETH_ZLEN + ETH_FCS_LEN;
>> >>>>
>> >>>>         spin_lock_init(&adapter->stats64_lock);
>> >>>> @@ -4303,7 +4304,7 @@ static int igb_change_mtu(struct net_device
>> >>>> *netdev, int new_mtu)
>> >>>>   {
>> >>>>         struct igb_adapter *adapter = netdev_priv(netdev);
>> >>>>         struct pci_dev *pdev = adapter->pdev;
>> >>>> -       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN;
>> >>>> +       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
>> >>>>         u32 rx_buffer_len, i;
>> >>>>
>> >>>>         if ((new_mtu<    68) || (max_frame>    MAX_JUMBO_FRAME_SIZE)) {
>> >>>
>> >>> While testing this patch, validation found that the patch reduces the
>> >>> maximum mtu size
>> >>> by 4 bytes (reduces it from 9216 to 9212).  This is not a desired side
>> >>> effect of this patch.
>> >>
>> >> You could add handling for that case and have it act as it used to when
>> >> new_mtu is greater than 9212?
>> >>
>> >> I tested e1000e and it worked w/out hacking at 1500 MTU, so maybe
>> >> check how it does it?
>> >
>> > I just wanted to bring this up again to see if any progress had been
>> > made.  We were looking at this driver and trying to figure out the
>> > best way to convert it to use the new vlan model but I'm not familiar
>>
>> I've been watching :)
>>
>> > enough with the hardware to know.  It seems that all of the other
>> > Intel drivers unconditionally add space for the vlan tag to the
>> > receive buffer (and would therefore have similar effects as this
>> > patch), is there something different about this card?
>> >
>> > I believe that Alex was working on something in this area (in the
>> > context of one of my patches from a long time ago) but I'm not sure
>> > what came of that.
>>
>> Truth is, I don't really see why it's a problem to decrease the
>> maximum MTU slightly in order to make it work with VLANs.
>>
>> I'm not sure if there is some way to make it work with VLANs
>> and not decrease the maximum MTU.
>
> This was the reason this did not get accepted.  I was looking into what
> could be done so that we did not decease the maximum MTU, but I got
> side-tracked and have not done anything on it in several months.
>

I can take a look at fixing this most likely tomorrow.  I have some
work planned for igb anyway over the next few days.

Odds are it is just a matter of where the VLAN_HLEN is added.  As I
recall for our drivers the correct spot is in the setting of
rx_buffer_len since that is the area more concerned with maximum
receive frame size versus the mtu section which is more concerned with
the transmit side of things.

Thanks,

Alex

Re: [PATCH 1/2] igb: Allow extra 4 bytes on RX for vlan tags.

[Jesse Gross]

On Wed, Jul 20, 2011 at 11:35 PM, Alexander Duyck
<alexander.duyck@gmail.com> wrote:
> On Wed, Jul 20, 2011 at 6:21 PM, Jeff Kirsher
> <jeffrey.t.kirsher@intel.com> wrote:
>> On Wed, 2011-07-20 at 17:27 -0700, Ben Greear wrote:
>>> On 07/20/2011 05:18 PM, Jesse Gross wrote:
>>> > On Thu, Feb 17, 2011 at 9:28 AM, Ben Greear<greearb@candelatech.com>  wrote:
>>> >> On 02/17/2011 03:04 AM, Jeff Kirsher wrote:
>>> >>>
>>> >>> On Thu, Feb 10, 2011 at 13:59,<greearb@candelatech.com>    wrote:
>>> >>>>
>>> >>>> From: Ben Greear<greearb@candelatech.com>
>>> >>>>
>>> >>>> This allows the NIC to receive 1518 byte (not counting
>>> >>>> FCS) packets when MTU is 1500, thus allowing 1500 MTU
>>> >>>> VLAN frames to be received.  Please note that no VLANs
>>> >>>> were actually configured on the NIC...it was just acting
>>> >>>> as pass-through device.
>>> >>>>
>>> >>>> Signed-off-by: Ben Greear<greearb@candelatech.com>
>>> >>>> ---
>>> >>>> :100644 100644 58c665b... 30c9cc6... M  drivers/net/igb/igb_main.c
>>> >>>>   drivers/net/igb/igb_main.c |    5 +++--
>>> >>>>   1 files changed, 3 insertions(+), 2 deletions(-)
>>> >>>>
>>> >>>> diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
>>> >>>> index 58c665b..30c9cc6 100644
>>> >>>> --- a/drivers/net/igb/igb_main.c
>>> >>>> +++ b/drivers/net/igb/igb_main.c
>>> >>>> @@ -2281,7 +2281,8 @@ static int __devinit igb_sw_init(struct igb_adapter
>>> >>>> *adapter)
>>> >>>>         adapter->rx_itr_setting = IGB_DEFAULT_ITR;
>>> >>>>         adapter->tx_itr_setting = IGB_DEFAULT_ITR;
>>> >>>>
>>> >>>> -       adapter->max_frame_size = netdev->mtu + ETH_HLEN + ETH_FCS_LEN;
>>> >>>> +       adapter->max_frame_size = (netdev->mtu + ETH_HLEN + ETH_FCS_LEN
>>> >>>> +                                  + VLAN_HLEN);
>>> >>>>         adapter->min_frame_size = ETH_ZLEN + ETH_FCS_LEN;
>>> >>>>
>>> >>>>         spin_lock_init(&adapter->stats64_lock);
>>> >>>> @@ -4303,7 +4304,7 @@ static int igb_change_mtu(struct net_device
>>> >>>> *netdev, int new_mtu)
>>> >>>>   {
>>> >>>>         struct igb_adapter *adapter = netdev_priv(netdev);
>>> >>>>         struct pci_dev *pdev = adapter->pdev;
>>> >>>> -       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN;
>>> >>>> +       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
>>> >>>>         u32 rx_buffer_len, i;
>>> >>>>
>>> >>>>         if ((new_mtu<    68) || (max_frame>    MAX_JUMBO_FRAME_SIZE)) {
>>> >>>
>>> >>> While testing this patch, validation found that the patch reduces the
>>> >>> maximum mtu size
>>> >>> by 4 bytes (reduces it from 9216 to 9212).  This is not a desired side
>>> >>> effect of this patch.
>>> >>
>>> >> You could add handling for that case and have it act as it used to when
>>> >> new_mtu is greater than 9212?
>>> >>
>>> >> I tested e1000e and it worked w/out hacking at 1500 MTU, so maybe
>>> >> check how it does it?
>>> >
>>> > I just wanted to bring this up again to see if any progress had been
>>> > made.  We were looking at this driver and trying to figure out the
>>> > best way to convert it to use the new vlan model but I'm not familiar
>>>
>>> I've been watching :)
>>>
>>> > enough with the hardware to know.  It seems that all of the other
>>> > Intel drivers unconditionally add space for the vlan tag to the
>>> > receive buffer (and would therefore have similar effects as this
>>> > patch), is there something different about this card?
>>> >
>>> > I believe that Alex was working on something in this area (in the
>>> > context of one of my patches from a long time ago) but I'm not sure
>>> > what came of that.
>>>
>>> Truth is, I don't really see why it's a problem to decrease the
>>> maximum MTU slightly in order to make it work with VLANs.
>>>
>>> I'm not sure if there is some way to make it work with VLANs
>>> and not decrease the maximum MTU.
>>
>> This was the reason this did not get accepted.  I was looking into what
>> could be done so that we did not decease the maximum MTU, but I got
>> side-tracked and have not done anything on it in several months.
>>
>
> I can take a look at fixing this most likely tomorrow.  I have some
> work planned for igb anyway over the next few days.
>
> Odds are it is just a matter of where the VLAN_HLEN is added.  As I
> recall for our drivers the correct spot is in the setting of
> rx_buffer_len since that is the area more concerned with maximum
> receive frame size versus the mtu section which is more concerned with
> the transmit side of things.

Thanks Alex.

Re: [PATCH 1/2] igb: Allow extra 4 bytes on RX for vlan tags.

[Ben Greear]

On 07/20/2011 11:35 PM, Alexander Duyck wrote:
> On Wed, Jul 20, 2011 at 6:21 PM, Jeff Kirsher
> <jeffrey.t.kirsher@intel.com>  wrote:
>> On Wed, 2011-07-20 at 17:27 -0700, Ben Greear wrote:
>>> On 07/20/2011 05:18 PM, Jesse Gross wrote:
>>>> On Thu, Feb 17, 2011 at 9:28 AM, Ben Greear<greearb@candelatech.com>    wrote:
>>>>> On 02/17/2011 03:04 AM, Jeff Kirsher wrote:
>>>>>>
>>>>>> On Thu, Feb 10, 2011 at 13:59,<greearb@candelatech.com>      wrote:
>>>>>>>
>>>>>>> From: Ben Greear<greearb@candelatech.com>
>>>>>>>
>>>>>>> This allows the NIC to receive 1518 byte (not counting
>>>>>>> FCS) packets when MTU is 1500, thus allowing 1500 MTU
>>>>>>> VLAN frames to be received.  Please note that no VLANs
>>>>>>> were actually configured on the NIC...it was just acting
>>>>>>> as pass-through device.
>>>>>>>
>>>>>>> Signed-off-by: Ben Greear<greearb@candelatech.com>
>>>>>>> ---
>>>>>>> :100644 100644 58c665b... 30c9cc6... M  drivers/net/igb/igb_main.c
>>>>>>>    drivers/net/igb/igb_main.c |    5 +++--
>>>>>>>    1 files changed, 3 insertions(+), 2 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
>>>>>>> index 58c665b..30c9cc6 100644
>>>>>>> --- a/drivers/net/igb/igb_main.c
>>>>>>> +++ b/drivers/net/igb/igb_main.c
>>>>>>> @@ -2281,7 +2281,8 @@ static int __devinit igb_sw_init(struct igb_adapter
>>>>>>> *adapter)
>>>>>>>          adapter->rx_itr_setting = IGB_DEFAULT_ITR;
>>>>>>>          adapter->tx_itr_setting = IGB_DEFAULT_ITR;
>>>>>>>
>>>>>>> -       adapter->max_frame_size = netdev->mtu + ETH_HLEN + ETH_FCS_LEN;
>>>>>>> +       adapter->max_frame_size = (netdev->mtu + ETH_HLEN + ETH_FCS_LEN
>>>>>>> +                                  + VLAN_HLEN);
>>>>>>>          adapter->min_frame_size = ETH_ZLEN + ETH_FCS_LEN;
>>>>>>>
>>>>>>>          spin_lock_init(&adapter->stats64_lock);
>>>>>>> @@ -4303,7 +4304,7 @@ static int igb_change_mtu(struct net_device
>>>>>>> *netdev, int new_mtu)
>>>>>>>    {
>>>>>>>          struct igb_adapter *adapter = netdev_priv(netdev);
>>>>>>>          struct pci_dev *pdev = adapter->pdev;
>>>>>>> -       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN;
>>>>>>> +       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
>>>>>>>          u32 rx_buffer_len, i;
>>>>>>>
>>>>>>>          if ((new_mtu<      68) || (max_frame>      MAX_JUMBO_FRAME_SIZE)) {
>>>>>>
>>>>>> While testing this patch, validation found that the patch reduces the
>>>>>> maximum mtu size
>>>>>> by 4 bytes (reduces it from 9216 to 9212).  This is not a desired side
>>>>>> effect of this patch.
>>>>>
>>>>> You could add handling for that case and have it act as it used to when
>>>>> new_mtu is greater than 9212?
>>>>>
>>>>> I tested e1000e and it worked w/out hacking at 1500 MTU, so maybe
>>>>> check how it does it?
>>>>
>>>> I just wanted to bring this up again to see if any progress had been
>>>> made.  We were looking at this driver and trying to figure out the
>>>> best way to convert it to use the new vlan model but I'm not familiar
>>>
>>> I've been watching :)
>>>
>>>> enough with the hardware to know.  It seems that all of the other
>>>> Intel drivers unconditionally add space for the vlan tag to the
>>>> receive buffer (and would therefore have similar effects as this
>>>> patch), is there something different about this card?
>>>>
>>>> I believe that Alex was working on something in this area (in the
>>>> context of one of my patches from a long time ago) but I'm not sure
>>>> what came of that.
>>>
>>> Truth is, I don't really see why it's a problem to decrease the
>>> maximum MTU slightly in order to make it work with VLANs.
>>>
>>> I'm not sure if there is some way to make it work with VLANs
>>> and not decrease the maximum MTU.
>>
>> This was the reason this did not get accepted.  I was looking into what
>> could be done so that we did not decease the maximum MTU, but I got
>> side-tracked and have not done anything on it in several months.
>>
>
> I can take a look at fixing this most likely tomorrow.  I have some
> work planned for igb anyway over the next few days.
>
> Odds are it is just a matter of where the VLAN_HLEN is added.  As I
> recall for our drivers the correct spot is in the setting of
> rx_buffer_len since that is the area more concerned with maximum
> receive frame size versus the mtu section which is more concerned with
> the transmit side of things.

Did a patch for this ever get posted?  I'll be happy to test it
if so...

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: [PATCH 1/2] igb: Allow extra 4 bytes on RX for vlan tags.

[Alexander Duyck]

On 08/25/2011 11:51 AM, Ben Greear wrote:
> On 07/20/2011 11:35 PM, Alexander Duyck wrote:
>> On Wed, Jul 20, 2011 at 6:21 PM, Jeff Kirsher
>> <jeffrey.t.kirsher@intel.com>  wrote:
>>> On Wed, 2011-07-20 at 17:27 -0700, Ben Greear wrote:
>>>> On 07/20/2011 05:18 PM, Jesse Gross wrote:
>>>>> On Thu, Feb 17, 2011 at 9:28 AM, Ben 
>>>>> Greear<greearb@candelatech.com>    wrote:
>>>>>> On 02/17/2011 03:04 AM, Jeff Kirsher wrote:
>>>>>>>
>>>>>>> On Thu, Feb 10, 2011 at 13:59,<greearb@candelatech.com>      wrote:
>>>>>>>>
>>>>>>>> From: Ben Greear<greearb@candelatech.com>
>>>>>>>>
>>>>>>>> This allows the NIC to receive 1518 byte (not counting
>>>>>>>> FCS) packets when MTU is 1500, thus allowing 1500 MTU
>>>>>>>> VLAN frames to be received.  Please note that no VLANs
>>>>>>>> were actually configured on the NIC...it was just acting
>>>>>>>> as pass-through device.
>>>>>>>>
>>>>>>>> Signed-off-by: Ben Greear<greearb@candelatech.com>
>>>>>>>> ---
>>>>>>>> :100644 100644 58c665b... 30c9cc6... M  drivers/net/igb/igb_main.c
>>>>>>>>    drivers/net/igb/igb_main.c |    5 +++--
>>>>>>>>    1 files changed, 3 insertions(+), 2 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/drivers/net/igb/igb_main.c 
>>>>>>>> b/drivers/net/igb/igb_main.c
>>>>>>>> index 58c665b..30c9cc6 100644
>>>>>>>> --- a/drivers/net/igb/igb_main.c
>>>>>>>> +++ b/drivers/net/igb/igb_main.c
>>>>>>>> @@ -2281,7 +2281,8 @@ static int __devinit igb_sw_init(struct 
>>>>>>>> igb_adapter
>>>>>>>> *adapter)
>>>>>>>>          adapter->rx_itr_setting = IGB_DEFAULT_ITR;
>>>>>>>>          adapter->tx_itr_setting = IGB_DEFAULT_ITR;
>>>>>>>>
>>>>>>>> -       adapter->max_frame_size = netdev->mtu + ETH_HLEN + 
>>>>>>>> ETH_FCS_LEN;
>>>>>>>> +       adapter->max_frame_size = (netdev->mtu + ETH_HLEN + 
>>>>>>>> ETH_FCS_LEN
>>>>>>>> +                                  + VLAN_HLEN);
>>>>>>>>          adapter->min_frame_size = ETH_ZLEN + ETH_FCS_LEN;
>>>>>>>>
>>>>>>>>          spin_lock_init(&adapter->stats64_lock);
>>>>>>>> @@ -4303,7 +4304,7 @@ static int igb_change_mtu(struct net_device
>>>>>>>> *netdev, int new_mtu)
>>>>>>>>    {
>>>>>>>>          struct igb_adapter *adapter = netdev_priv(netdev);
>>>>>>>>          struct pci_dev *pdev = adapter->pdev;
>>>>>>>> -       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN;
>>>>>>>> +       int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN + 
>>>>>>>> VLAN_HLEN;
>>>>>>>>          u32 rx_buffer_len, i;
>>>>>>>>
>>>>>>>>          if ((new_mtu<      68) || (max_frame>      
>>>>>>>> MAX_JUMBO_FRAME_SIZE)) {
>>>>>>>
>>>>>>> While testing this patch, validation found that the patch 
>>>>>>> reduces the
>>>>>>> maximum mtu size
>>>>>>> by 4 bytes (reduces it from 9216 to 9212).  This is not a 
>>>>>>> desired side
>>>>>>> effect of this patch.
>>>>>>
>>>>>> You could add handling for that case and have it act as it used 
>>>>>> to when
>>>>>> new_mtu is greater than 9212?
>>>>>>
>>>>>> I tested e1000e and it worked w/out hacking at 1500 MTU, so maybe
>>>>>> check how it does it?
>>>>>
>>>>> I just wanted to bring this up again to see if any progress had been
>>>>> made.  We were looking at this driver and trying to figure out the
>>>>> best way to convert it to use the new vlan model but I'm not familiar
>>>>
>>>> I've been watching :)
>>>>
>>>>> enough with the hardware to know.  It seems that all of the other
>>>>> Intel drivers unconditionally add space for the vlan tag to the
>>>>> receive buffer (and would therefore have similar effects as this
>>>>> patch), is there something different about this card?
>>>>>
>>>>> I believe that Alex was working on something in this area (in the
>>>>> context of one of my patches from a long time ago) but I'm not sure
>>>>> what came of that.
>>>>
>>>> Truth is, I don't really see why it's a problem to decrease the
>>>> maximum MTU slightly in order to make it work with VLANs.
>>>>
>>>> I'm not sure if there is some way to make it work with VLANs
>>>> and not decrease the maximum MTU.
>>>
>>> This was the reason this did not get accepted.  I was looking into what
>>> could be done so that we did not decease the maximum MTU, but I got
>>> side-tracked and have not done anything on it in several months.
>>>
>>
>> I can take a look at fixing this most likely tomorrow.  I have some
>> work planned for igb anyway over the next few days.
>>
>> Odds are it is just a matter of where the VLAN_HLEN is added.  As I
>> recall for our drivers the correct spot is in the setting of
>> rx_buffer_len since that is the area more concerned with maximum
>> receive frame size versus the mtu section which is more concerned with
>> the transmit side of things.
>
> Did a patch for this ever get posted?  I'll be happy to test it
> if so...
>
> Thanks,
> Ben
>
We haven't posted one yet.  I have one written up but it is currently 
mixed in with a set of 30 patches that I am testing/cleaning 
up/formatting before submitting to our formal validation team.  I will 
likely be submitting it to Jeff Kirsher sometime next week and the 
patches will probably be available a few weeks after that.

Thanks,

Alex