From: Magnus Karlsson <magnus.karlsson@intel.com>
Date: Wed, 14 Aug 2019 09:27:19 +0200
Subject: ixgbe: add support for AF_XDP need_wakeup feature
Patch-mainline: v5.4-rc1
Git-commit: 5c129241e2de79f09cb4e50bbca09e1c14ad787d
References: jsc#SLE-7979 jsc#SLE-7981

This patch adds support for the need_wakeup feature of AF_XDP. If the
application has told the kernel that it might sleep using the new bind
flag XDP_USE_NEED_WAKEUP, the driver will then set this flag if it has
no more buffers on the NIC Rx ring and yield to the application. For
Tx, it will set the flag if it has no outstanding Tx completion
interrupts and return to the application.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c |   17 +++++++++++++++++
 1 file changed, 17 insertions(+)

--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
@@ -547,6 +547,14 @@ int ixgbe_clean_rx_irq_zc(struct ixgbe_q
 	q_vector->rx.total_packets += total_rx_packets;
 	q_vector->rx.total_bytes += total_rx_bytes;
 
+	if (xsk_umem_uses_need_wakeup(rx_ring->xsk_umem)) {
+		if (failure || rx_ring->next_to_clean == rx_ring->next_to_use)
+			xsk_set_rx_need_wakeup(rx_ring->xsk_umem);
+		else
+			xsk_clear_rx_need_wakeup(rx_ring->xsk_umem);
+
+		return (int)total_rx_packets;
+	}
 	return failure ? budget : (int)total_rx_packets;
 }
 
@@ -615,6 +623,8 @@ static bool ixgbe_xmit_zc(struct ixgbe_r
 	if (tx_desc) {
 		ixgbe_xdp_ring_update_tail(xdp_ring);
 		xsk_umem_consume_tx_done(xdp_ring->xsk_umem);
+		if (xsk_umem_uses_need_wakeup(xdp_ring->xsk_umem))
+			xsk_clear_tx_need_wakeup(xdp_ring->xsk_umem);
 	}
 
 	return !!budget && work_done;
@@ -682,6 +692,13 @@ bool ixgbe_clean_xdp_tx_irq(struct ixgbe
 	if (xsk_frames)
 		xsk_umem_complete_tx(umem, xsk_frames);
 
+	if (xsk_umem_uses_need_wakeup(tx_ring->xsk_umem)) {
+		if (tx_ring->next_to_clean == tx_ring->next_to_use)
+			xsk_set_tx_need_wakeup(tx_ring->xsk_umem);
+		else
+			xsk_clear_tx_need_wakeup(tx_ring->xsk_umem);
+	}
+
 	return ixgbe_xmit_zc(tx_ring, q_vector->tx.work_limit);
 }