From: Krzysztof Kazimierczak <krzysztof.kazimierczak@intel.com>
Date: Thu, 13 Feb 2020 13:31:22 -0800
Subject: ice: Support XDP UMEM wake up mechanism
Patch-mainline: v5.7-rc1
Git-commit: 5fa23e0b23fb14364a396593a4e083606a6d6893
References: jsc#SLE-12878

Add support for a new AF_XDP feature that has already been introduced in
upstreamed Intel NIC drivers. If a user space application signals 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: Krzysztof Kazimierczak <krzysztof.kazimierczak@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/intel/ice/ice_xsk.c |   18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

--- a/drivers/net/ethernet/intel/ice/ice_xsk.c
+++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
@@ -937,6 +937,15 @@ int ice_clean_rx_irq_zc(struct ice_ring
 	ice_finalize_xdp_rx(rx_ring, xdp_xmit);
 	ice_update_rx_ring_stats(rx_ring, total_rx_packets, 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;
 }
 
@@ -988,6 +997,8 @@ static bool ice_xmit_zc(struct ice_ring
 	if (tx_desc) {
 		ice_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 > 0 && work_done;
@@ -1063,6 +1074,13 @@ bool ice_clean_tx_irq_zc(struct ice_ring
 	if (xsk_frames)
 		xsk_umem_complete_tx(xdp_ring->xsk_umem, xsk_frames);
 
+	if (xsk_umem_uses_need_wakeup(xdp_ring->xsk_umem)) {
+		if (xdp_ring->next_to_clean == xdp_ring->next_to_use)
+			xsk_set_tx_need_wakeup(xdp_ring->xsk_umem);
+		else
+			xsk_clear_tx_need_wakeup(xdp_ring->xsk_umem);
+	}
+
 	ice_update_tx_ring_stats(xdp_ring, total_packets, total_bytes);
 	xmit_done = ice_xmit_zc(xdp_ring, ICE_DFLT_IRQ_WORK);