[Intel-wired-lan] [PATCH net-next] i40e: xsk: read the XDP program once per NAPI

[Ciara Loftus <ciara.loftus@intel.com>]

Similar to how it's done in the ice driver since 'eb087cd82864 ("ice:
propagate xdp_ring onto rx_ring")', read the XDP program once per NAPI
instead of once per descriptor cleaned. I measured an improvement in
throughput of 2% for the AF_XDP xdpsock l2fwd benchmark in busy polling
mode on my platform.

Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
---
 drivers/net/ethernet/intel/i40e/i40e_xsk.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
index af3e7e6afc85..2f422c61ac11 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
@@ -146,17 +146,13 @@ int i40e_xsk_pool_setup(struct i40e_vsi *vsi, struct xsk_buff_pool *pool,
  *
  * Returns any of I40E_XDP_{PASS, CONSUMED, TX, REDIR}
  **/
-static int i40e_run_xdp_zc(struct i40e_ring *rx_ring, struct xdp_buff *xdp)
+static int i40e_run_xdp_zc(struct i40e_ring *rx_ring, struct xdp_buff *xdp,
+			   struct bpf_prog *xdp_prog)
 {
 	int err, result = I40E_XDP_PASS;
 	struct i40e_ring *xdp_ring;
-	struct bpf_prog *xdp_prog;
 	u32 act;
 
-	/* NB! xdp_prog will always be !NULL, due to the fact that
-	 * this path is enabled by setting an XDP program.
-	 */
-	xdp_prog = READ_ONCE(rx_ring->xdp_prog);
 	act = bpf_prog_run_xdp(xdp_prog, xdp);
 
 	if (likely(act == XDP_REDIRECT)) {
@@ -339,9 +335,15 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget)
 	u16 next_to_clean = rx_ring->next_to_clean;
 	u16 count_mask = rx_ring->count - 1;
 	unsigned int xdp_res, xdp_xmit = 0;
+	struct bpf_prog *xdp_prog;
 	bool failure = false;
 	u16 cleaned_count;
 
+	/* NB! xdp_prog will always be !NULL, due to the fact that
+	 * this path is enabled by setting an XDP program.
+	 */
+	xdp_prog = READ_ONCE(rx_ring->xdp_prog);
+
 	while (likely(total_rx_packets < (unsigned int)budget)) {
 		union i40e_rx_desc *rx_desc;
 		unsigned int rx_packets;
@@ -378,7 +380,7 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget)
 		xsk_buff_set_size(bi, size);
 		xsk_buff_dma_sync_for_cpu(bi, rx_ring->xsk_pool);
 
-		xdp_res = i40e_run_xdp_zc(rx_ring, bi);
+		xdp_res = i40e_run_xdp_zc(rx_ring, bi, xdp_prog);
 		i40e_handle_xdp_result_zc(rx_ring, bi, rx_desc, &rx_packets,
 					  &rx_bytes, size, xdp_res, &failure);
 		if (failure)
-- 
2.25.1

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