libeth: xsk: add XSk xmit functions

Reuse core sending functions to send XSk xmit frames.
Both metadata and no metadata pools/driver are supported. libeth_xdp
also provides generic XSk metadata ops, currently with the checksum
offload only and for cases when HW doesn't require supplying L3/L4
checksum offsets. Drivers are free to pass their own ops.
&libeth_xdp_tx_bulk is not used here as it would be redundant;
pool->tx_descs are accessed directly.
Fake "libeth_xsktmo" is needed to hide implementation details from the
drivers when they want to use the generic ops: the original struct is
defined in the same file where dev->xsk_tx_metadata_ops gets set to
avoid duplication of slowpath; at the same time; XSk xmit functions
use local "fast" copy to inline XMO callbacks.
Tx descriptor filling loop is unrolled by 8.

Suggested-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> # optimizations
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/libeth/priv.h b/drivers/net/ethernet/intel/libeth/priv.h
index ebcb26f24401..03e74382b2cb 100644
--- a/drivers/net/ethernet/intel/libeth/priv.h
+++ b/drivers/net/ethernet/intel/libeth/priv.h
@@ -13,6 +13,8 @@ struct libeth_xdp_tx_frame;
 struct skb_shared_info;
 struct xdp_frame_bulk;
 
+extern const struct xsk_tx_metadata_ops libeth_xsktmo_slow;
+
 void libeth_xsk_tx_return_bulk(const struct libeth_xdp_tx_frame *bq,
 			       u32 count);