ice: propagate xdp_ring onto rx_ring

With rings being split, it is now convenient to introduce a pointer to
XDP ring within the Rx ring. For XDP_TX workloads this means that
xdp_rings array access will be skipped, which was executed per each
processed frame.

Also, read the XDP prog once per NAPI and if prog is present, set up the
local xdp_ring pointer. Reading prog a single time was discussed in [1]
with some concern raised by Toke around dispatcher handling and having
the need for going through the RCU grace period in the ndo_bpf driver
callback, but ice currently is torning down NAPI instances regardless of
the prog presence on VSI.

Although the pointer to XDP ring introduced to Rx ring makes things a
lot slimmer/simpler, I still feel that single prog read per NAPI
lifetime is beneficial.

Further patch that will introduce the fallback path will also get a
profit from that as xdp_ring pointer will be set during the XDP rings
setup.

[1]: https://lore.kernel.org/bpf/87k0oseo6e.fsf@toke.dk/

Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: George Kuruvinakunnel <george.kuruvinakunnel@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 3 insertions, 7 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
index bc64610df7cb..5c2319e0c66d 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
@@ -283,22 +283,18 @@ int ice_xmit_xdp_buff(struct xdp_buff *xdp, struct ice_tx_ring *xdp_ring)
 
 /**
  * ice_finalize_xdp_rx - Bump XDP Tx tail and/or flush redirect map
- * @rx_ring: Rx ring
+ * @xdp_ring: XDP ring
  * @xdp_res: Result of the receive batch
  *
  * This function bumps XDP Tx tail and/or flush redirect map, and
  * should be called when a batch of packets has been processed in the
  * napi loop.
  */
-void ice_finalize_xdp_rx(struct ice_rx_ring *rx_ring, unsigned int xdp_res)
+void ice_finalize_xdp_rx(struct ice_tx_ring *xdp_ring, unsigned int xdp_res)
 {
 	if (xdp_res & ICE_XDP_REDIR)
 		xdp_do_flush_map();
 
-	if (xdp_res & ICE_XDP_TX) {
-		struct ice_tx_ring *xdp_ring =
-			rx_ring->vsi->xdp_rings[smp_processor_id()];
-
+	if (xdp_res & ICE_XDP_TX)
 		ice_xdp_ring_update_tail(xdp_ring);
-	}
 }