f53c3fe8da
This patch introduces grant mapping on netback TX path. It replaces grant copy operations, ditching grant copy coalescing along the way. Another solution for copy coalescing is introduced in "xen-netback: Handle guests with too many frags", older guests and Windows can broke before that patch applies. There is a callback (xenvif_zerocopy_callback) from core stack to release the slots back to the guests when kfree_skb or skb_orphan_frags called. It feeds a separate dealloc thread, as scheduling NAPI instance from there is inefficient, therefore we can't do dealloc from the instance. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>