* [PATCH net] ibmveth: Fix max MTU limit
@ 2020-06-18 15:43 Thomas Falcon
2020-06-18 15:57 ` Jakub Kicinski
2020-06-20 3:22 ` David Miller
0 siblings, 2 replies; 4+ messages in thread
From: Thomas Falcon @ 2020-06-18 15:43 UTC (permalink / raw)
To: netdev; +Cc: Thomas Falcon, linuxppc-dev
The max MTU limit defined for ibmveth is not accounting for
virtual ethernet buffer overhead, which is twenty-two additional
bytes set aside for the ethernet header and eight additional bytes
of an opaque handle reserved for use by the hypervisor. Update the
max MTU to reflect this overhead.
Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
---
drivers/net/ethernet/ibm/ibmveth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index 96d36ae5049e..c5c732601e35 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -1715,7 +1715,7 @@ static int ibmveth_probe(struct vio_dev *dev, const struct vio_device_id *id)
}
netdev->min_mtu = IBMVETH_MIN_MTU;
- netdev->max_mtu = ETH_MAX_MTU;
+ netdev->max_mtu = ETH_MAX_MTU - IBMVETH_BUFF_OH;
memcpy(netdev->dev_addr, mac_addr_p, ETH_ALEN);
--
2.26.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH net] ibmveth: Fix max MTU limit
2020-06-18 15:43 [PATCH net] ibmveth: Fix max MTU limit Thomas Falcon
@ 2020-06-18 15:57 ` Jakub Kicinski
2020-06-18 20:51 ` Thomas Falcon
2020-06-20 3:22 ` David Miller
1 sibling, 1 reply; 4+ messages in thread
From: Jakub Kicinski @ 2020-06-18 15:57 UTC (permalink / raw)
To: Thomas Falcon; +Cc: netdev, linuxppc-dev
On Thu, 18 Jun 2020 10:43:46 -0500 Thomas Falcon wrote:
> The max MTU limit defined for ibmveth is not accounting for
> virtual ethernet buffer overhead, which is twenty-two additional
> bytes set aside for the ethernet header and eight additional bytes
> of an opaque handle reserved for use by the hypervisor. Update the
> max MTU to reflect this overhead.
>
> Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
How about
Fixes: d894be57ca92 ("ethernet: use net core MTU range checking in more drivers")
Fixes: 110447f8269a ("ethernet: fix min/max MTU typos")
?
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH net] ibmveth: Fix max MTU limit
2020-06-18 15:57 ` Jakub Kicinski
@ 2020-06-18 20:51 ` Thomas Falcon
0 siblings, 0 replies; 4+ messages in thread
From: Thomas Falcon @ 2020-06-18 20:51 UTC (permalink / raw)
To: Jakub Kicinski; +Cc: netdev, linuxppc-dev
On 6/18/20 10:57 AM, Jakub Kicinski wrote:
> On Thu, 18 Jun 2020 10:43:46 -0500 Thomas Falcon wrote:
>> The max MTU limit defined for ibmveth is not accounting for
>> virtual ethernet buffer overhead, which is twenty-two additional
>> bytes set aside for the ethernet header and eight additional bytes
>> of an opaque handle reserved for use by the hypervisor. Update the
>> max MTU to reflect this overhead.
>>
>> Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
> How about
>
> Fixes: d894be57ca92 ("ethernet: use net core MTU range checking in more drivers")
> Fixes: 110447f8269a ("ethernet: fix min/max MTU typos")
>
> ?
Thanks, do you need me to send a v2 with those tags?
Tom
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net] ibmveth: Fix max MTU limit
2020-06-18 15:43 [PATCH net] ibmveth: Fix max MTU limit Thomas Falcon
2020-06-18 15:57 ` Jakub Kicinski
@ 2020-06-20 3:22 ` David Miller
1 sibling, 0 replies; 4+ messages in thread
From: David Miller @ 2020-06-20 3:22 UTC (permalink / raw)
To: tlfalcon; +Cc: netdev, linuxppc-dev
From: Thomas Falcon <tlfalcon@linux.ibm.com>
Date: Thu, 18 Jun 2020 10:43:46 -0500
> The max MTU limit defined for ibmveth is not accounting for
> virtual ethernet buffer overhead, which is twenty-two additional
> bytes set aside for the ethernet header and eight additional bytes
> of an opaque handle reserved for use by the hypervisor. Update the
> max MTU to reflect this overhead.
>
> Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Applied with Fixes: tags added and queued up for -stable.
Thank you.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-06-18 15:43 [PATCH net] ibmveth: Fix max MTU limit Thomas Falcon
2020-06-18 15:57 ` Jakub Kicinski
2020-06-18 20:51 ` Thomas Falcon
2020-06-20 3:22 ` David Miller
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