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SubjectRe: [PATCH] vmxnet3: Use correct minimum MTU value
On Tue, Oct 17, 2017 at 04:33:43PM +0200, Mohammed Gamal wrote:
> Currently the vmxnet3 driver has a minimum MTU value of 60. Which
> goes against the RFC791 spec which specifies it at 68.
>
> Setting MTU to values between 60 <= MTU <= 67 causes the network
> interface to lose its IP, and it fails to restart.
>
> This sets the minimum value to ETH_MIN_MTU (68) which is compatible
> with is according to spec.

Hi Mohammed

I'm not sure this is actually correct. Yes, IP sets a minimum of 68,
and the IP address will be removed if you set a smaller MTU. But the
interface should still usable for other protocols. It can still send
and receive frames.

Is the hardware happy to send 60 byte frames?

Andrew

>
> Reported-by: Bo Yang <boyang@redhat.com>
> Signed-off-by: Mohammed Gamal <mgamal@redhat.com>
> ---
> drivers/net/vmxnet3/vmxnet3_defs.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/vmxnet3/vmxnet3_defs.h b/drivers/net/vmxnet3/vmxnet3_defs.h
> index c3a3164..4ad905a 100644
> --- a/drivers/net/vmxnet3/vmxnet3_defs.h
> +++ b/drivers/net/vmxnet3/vmxnet3_defs.h
> @@ -749,7 +749,7 @@ struct Vmxnet3_DriverShared {
> ((vfTable[vid >> 5] & (1 << (vid & 31))) != 0)
>
> #define VMXNET3_MAX_MTU 9000
> -#define VMXNET3_MIN_MTU 60
> +#define VMXNET3_MIN_MTU ETH_MIN_MTU
>
> #define VMXNET3_LINK_UP (10000 << 16 | 1) /* 10 Gbps, up */
> #define VMXNET3_LINK_DOWN 0
> --
> 1.8.3.1
>

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