[ovs-dev] [PATCH 3/3] datapath: Enable scatter/gather for skb_gso_segment().

[Ben Pfaff]

On Fri, Jun 18, 2010 at 02:46:50PM -0700, Jesse Gross wrote:
> Adding NETIF_F_HW_CSUM (the correct flag since we can handle all types of
> checksums) would work but it doesn't really save anything.  The reason that
> SG is masked out here (and also for devices) is that if you have to go over
> the packet to compute the checksum anyways then the copy is basically free.
> 
> skb_copy_and_csum_datagram_iovec() doesn't really help either because it is
> intended for the receive side but packets with partial checksums are being
> transmit.  This function verifies the checksum but won't fill one in.
> 
> However, I'm a sucker for gold stars and I just love checksumming so I
> implemented the checksumming while copying to userspace.  I'll send that out
> as a separate patch and pushed the first two in the meantime.

You're right, of course.