[ofa-general] [PATCH 3/11] ib_core: add checksum offload support

[Or Gerlitz]

Eli Cohen wrote:
> Add checksum offload support to the core
> A device that publishes IB_DEVICE_IP_CSUM actually supports
> calculating checksum on transmit and provides indication whether
> the checksum is OK on receive.

Hi Eli,

 From the discussion over the "IB/ipoib: S/G and HW checksum support" 
thread, I understand that Linux actually never offloads the IP checksum 
calculation to the HW but rather only the TCP and UDP checksum.

I find it more clear if the device capability (same for the send flag) 
name would follow one of these:
> #define NETIF_F_IP_CSUM     2       /* Can checksum TCP/UDP over IPv4. */
> #define NETIF_F_NO_CSUM     4       /* Does not require checksum. F.e. loopack. */
> #define NETIF_F_HW_CSUM     8       /* Can checksum all the packets. */
> #define NETIF_F_IPV6_CSUM   16      /* Can checksum TCP/UDP over IPV6 */

Or.

> Index: ofa_1_3_dev_kernel/include/rdma/ib_verbs.h

>  enum ib_cq_notify_flags {
> @@ -615,7 +617,9 @@ enum ib_send_flags {
>  	IB_SEND_FENCE		= 1,
>  	IB_SEND_SIGNALED	= (1<<1),
>  	IB_SEND_SOLICITED	= (1<<2),
> -	IB_SEND_INLINE		= (1<<3)
> +	IB_SEND_INLINE		= (1<<3),
> +	IB_SEND_IP_CSUM         = (1<<4),
there's no point for the HW to compute the IP csum, asking this is a 
pure waste, since the stack always does it
> +	IB_SEND_UDP_TCP_CSUM    = (1<<5)
>  };