[Openib-windows] Added ability to change IPoIB mtu size

[Yossi Leybovich]

Hi

Why do we need that?
Just update the inf and the driver will load. ( or you can fake the registry
key ...).

If we go to this direction we should give default values for all the
registry 
keys why just to the payload ?

Thanks
Yossi 

> -----Original Message-----
> From: openib-windows-bounces at openib.org 
> [mailto:openib-windows-bounces at openib.org] On Behalf Of Alex Estrin
> Sent: Wednesday, November 29, 2006 6:05 PM
> To: Yossi Leybovich
> Cc: openib-windows at openib.org
> Subject: Re: [Openib-windows] Added ability to change IPoIB mtu size
> 
> Hi Yossi,
> 
> This patch would allow IPoIB to run even if for any reason 
> payload mtu parameter is missing.
> Please review.
> 
> Thanks,
> Alex
> 
> Index: ipoib_driver.c
> ===================================================================
> --- ipoib_driver.c	(revision 552)
> +++ ipoib_driver.c	(working copy)
> @@ -533,9 +533,13 @@
>  	{
>  		IPOIB_PRINT_EXIT( TRACE_LEVEL_ERROR, IPOIB_DBG_ERROR,
>  			("PayloadMtu parameter missing. Use the 
> default.\n") );
> -		return status;
> +		p_adapter->params.payload_mtu = MAX_PAYLOAD_MTU;
> +		status = NDIS_STATUS_SUCCESS;
>  	}
> -	p_adapter->params.payload_mtu = 
> p_param->ParameterData.IntegerData;
> +	else
> +	{
> +		p_adapter->params.payload_mtu = 
> p_param->ParameterData.IntegerData;
> +	}
>  	p_adapter->params.xfer_block_size = (sizeof(eth_hdr_t) 
> + p_adapter->params.payload_mtu);
>  	NdisReadNetworkAddress( &status, &mac, &len, h_config );
> 
> > -----Original Message-----
> > From: openib-windows-bounces at openib.org 
> > [mailto:openib-windows-bounces at openib.org]On Behalf Of 
> Yossi Leybovich
> > Sent: Wednesday, November 22, 2006 3:29 AM
> > To: Fabian Tillier; Anatoly Lisenko
> > Cc: openib-windows at openib.org
> > Subject: Re: [Openib-windows] Added ability to change IPoIB mtu size
> > 
> > 
> >  
> > 
> > > -----Original Message-----
> > > From: Fabian Tillier [mailto:ftillier.sst at gmail.com]
> > > Sent: Wednesday, November 22, 2006 9:13 AM
> > > To: Anatoly Lisenko
> > > Cc: Yossi Leybovich; openib-windows at openib.org
> > > Subject: Re: [Openib-windows] Added ability to change 
> IPoIB mtu size
> > > 
> > > Hi folks,
> > > 
> > > On 11/19/06, Anatoly Lisenko <anatolyl at voltaire.com> wrote:
> > > >
> > > > Hi Yossi,
> > > >
> > > > This patch add the ability to change MTU size in IPoIB.
> > > >
> > > > Please review.
> > > >
> > > > Thanks,
> > > >
> > > > Anatoly
> > > 
> > > It would be nice to have an explanation of what problem 
> patches are 
> > > trying to solve.  I assume this is done to enable virtualization 
> > > over IPoIB, which requires network packets to be ethernet 
> MTU-sized.
> > > 
> > > I didn't have a chance to look at the patch, but have these
> > thoughts.
> > > Limiting the MTU reported to the OS works fine for 
> outbound packets, 
> > > but care must be exercised for inbound packets.
> > > 
> > > 1. The buffers posted to the receive queue must be the full
> > > 2048 byte IB MTU so that the IPoIB driver can receive any packets 
> > > sent to it without hitting a protection error due to 
> overrunning the 
> > > receive buffers.
> > > 2. If a buffer larger than the configured MTU is 
> received, it must 
> > > be reported to the OS somehow.  I don't know what's 
> required to do 
> > > this, whether you create a new IP header for the data beyond the 
> > > first, or whatnot, but it must be done in such a way that 
> subsequent 
> > > packets don't cause issues with sequence numbers.  This 
> doesn't seem 
> > > like a simple thing to do right, let alone in a performant way.
> > > 
> > Cant we just drop the packets and add that to the statiscs 
> of packet 
> > discards?
> > Wny how I will check that in the code.
> > 
> > > Cheers,
> > > 
> > > - Fab
> > > 
> > 
> > _______________________________________________
> > openib-windows mailing list
> > openib-windows at openib.org
> > http://openib.org/mailman/listinfo/openib-windows
> > 
> > 
>