[ofw] RE: [IPoIB CM][Patch] receive Chksum flags

[Alex Naslednikov]

 Hello, Alex,
I would like to point your attention on the following issue.
When CSUM is enabled, you take the value of CSUM from the WQE, thus
supposing that HW will put 0 (zero) there:
> +			NDIS_PER_PACKET_INFO_FROM_PACKET( p_packet,
TcpIpChecksumPacketInfo ) =
> +
(void*)(uintn_t)(p_desc->ndis_csum.Value);

This is right for the new versions of our HW, but we can't assume this
generally. There are 2 possible solutions.
The best one (IMHO) is simply verify that CM mode and CSUM_ENABLED are
not set on simultaneously. 
That is, simply unite 2 cases: CSUM_DISABLED and CSUM_ENABLED.

The other is to check (in qp.c) which kind of QP we are working and each
time set 0 in appropriate place.
The problem with this solution is that it will have influence on
DataPath flow, which is not desirable. 

Thanks,
XaleX

-----Original Message-----
From: Alex Estrin [mailto:alex.estrin at qlogic.com] 
Sent: Tuesday, February 10, 2009 2:45 PM
To: ofw at lists.openfabrics.org; Alex Naslednikov
Subject: RE: [IPoIB CM][Patch] receive Chksum flags

Applied in revision 1937.

Thanks,
Alex.

> -----Original Message-----
> From: ofw-bounces at lists.openfabrics.org 
> [mailto:ofw-bounces at lists.openfabrics.org] On Behalf Of Alex Estrin
> Sent: Monday, February 09, 2009 1:06 PM
> To: ofw at lists.openfabrics.org; Alex Naslednikov
> Subject: [ofw] [IPoIB CM][Patch] receive Chksum flags
> 
> Hello,
> 
> Here is a patch to replace hardcoded TCP/IP Chksum flags indication 
> with the same algorithm as used for datagram mode.
> 
> Please review.
> 
> Thanks,
> Alex.
> 
> Index: kernel/ipoib_endpoint.c
> ===================================================================
> --- kernel/ipoib_endpoint.c	(revision 1933)
> +++ kernel/ipoib_endpoint.c	(working copy)
> @@ -791,6 +791,7 @@
>  	ipoib_cm_desc_t		*p_desc;
>  	uint32_t				i = 0;
>  	NDIS_PACKET				*p_packet;
> +	NDIS_TCP_IP_CHECKSUM_PACKET_INFO	chksum;
> 
>  	IPOIB_ENTER( IPOIB_DBG_RECV );
>  	UNUSED_PARAM( p_endpt );
> @@ -813,12 +814,31 @@
>  			p_port->cm_recv_mgr.depth--;
>  			continue;
>  		}
> -		p_desc->ndis_csum.Value = 0;
> -		p_desc->ndis_csum.Receive.NdisPacketTcpChecksumSucceeded
= TRUE;
> -		p_desc->ndis_csum.Receive.NdisPacketUdpChecksumSucceeded
= TRUE;
> -		p_desc->ndis_csum.Receive.NdisPacketIpChecksumSucceeded
= TRUE;
> -		NDIS_PER_PACKET_INFO_FROM_PACKET( p_packet,
TcpIpChecksumPacketInfo ) =
> -
(void*)(uintn_t)p_desc-
> >ndis_csum.Value;
> +		chksum.Value = 0;
> +		switch( p_port->p_adapter->params.recv_chksum_offload )
> +		{
> +		default:
> +			CL_ASSERT( FALSE );
> +		case CSUM_DISABLED:
> +			NDIS_PER_PACKET_INFO_FROM_PACKET( p_packet,
TcpIpChecksumPacketInfo ) =
> +				(void*)(uintn_t)chksum.Value;
> +			break;
> +		case CSUM_ENABLED:
> +			/* Get the checksums directly from packet
information. */
> +			/* In this case, no one of cheksum's cat get
false value */
> +			/* If hardware checksum failed or wasn't
calculated, NDIS will 
> +recalculate it again
> */
> +			NDIS_PER_PACKET_INFO_FROM_PACKET( p_packet,
TcpIpChecksumPacketInfo ) =
> +
(void*)(uintn_t)(p_desc->ndis_csum.Value);
> +			break;
> +		case CSUM_BYPASS:
> +			/* Flag the checksums as having been calculated.
*/
> +			chksum.Receive.NdisPacketTcpChecksumSucceeded =
TRUE;
> +			chksum.Receive.NdisPacketUdpChecksumSucceeded =
TRUE;
> +			chksum.Receive.NdisPacketIpChecksumSucceeded =
TRUE;
> +			NDIS_PER_PACKET_INFO_FROM_PACKET( p_packet,
TcpIpChecksumPacketInfo ) =
> +				(void*)(uintn_t)chksum.Value;
> +			break;
> +		}
> 
>  		NDIS_SET_PACKET_STATUS(	p_packet, NDIS_STATUS_SUCCESS );
>  		p_port->cm_recv_mgr.recv_pkt_array[i] = p_packet;
> Index: kernel/ipoib_port.c
> ===================================================================
> --- kernel/ipoib_port.c	(revision 1933)
> +++ kernel/ipoib_port.c	(working copy)
> @@ -1082,16 +1082,6 @@
>  			NdisWriteErrorLogEntry(
p_port->p_adapter->h_adapter,
>  				EVENT_IPOIB_CONNECTED_MODE_ERR, 1,
0xbadc0de2 );
>  		}
> -		else
> -		{
> -			/* now we can adjust csum capabilities */
> -		if (p_port->p_adapter->params.send_chksum_offload )
> -			p_port->p_adapter->params.send_chksum_offload =
CSUM_DISABLED;
> -
> -		if (p_port->p_adapter->params.recv_chksum_offload ==
CSUM_ENABLED)
> -			p_port->p_adapter->params.recv_chksum_offload =
CSUM_BYPASS;
> -		}
> -
>  	}
>  	IPOIB_EXIT( IPOIB_DBG_INIT );
>  	return IB_SUCCESS;
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