From: Jesper Dangaard Brouer <brouer@redhat.com>
Date: Thu, 31 May 2018 10:59:57 +0200
Subject: ixgbe: implement flush flag for ndo_xdp_xmit
Patch-mainline: v4.18-rc1
Git-commit: 5e2e609522d67750d4b3c0321d1917bb109ac41b
References: bsc#1113994 FATE#326315 FATE#326317

When passed the XDP_XMIT_FLUSH flag ixgbe_xdp_xmit now performs the
same kind of ring tail update as in ixgbe_xdp_flush.  The update tail
code in ixgbe_xdp_flush is generalized and shared with ixgbe_xdp_xmit.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |   20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -10048,6 +10048,15 @@ static int ixgbe_xdp(struct net_device *
 	}
 }
 
+static void ixgbe_xdp_ring_update_tail(struct ixgbe_ring *ring)
+{
+	/* Force memory writes to complete before letting h/w know there
+	 * are new descriptors to fetch.
+	 */
+	wmb();
+	writel(ring->next_to_use, ring->tail);
+}
+
 static int ixgbe_xdp_xmit(struct net_device *dev, int n,
 			  struct xdp_frame **frames, u32 flags)
 {
@@ -10059,7 +10068,7 @@ static int ixgbe_xdp_xmit(struct net_dev
 	if (unlikely(test_bit(__IXGBE_DOWN, &adapter->state)))
 		return -ENETDOWN;
 
-	if (unlikely(flags & ~XDP_XMIT_FLAGS_NONE))
+	if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
 		return -EINVAL;
 
 	/* During program transitions its possible adapter->xdp_prog is assigned
@@ -10080,6 +10089,9 @@ static int ixgbe_xdp_xmit(struct net_dev
 		}
 	}
 
+	if (unlikely(flags & XDP_XMIT_FLUSH))
+		ixgbe_xdp_ring_update_tail(ring);
+
 	return n - drops;
 }
 
@@ -10098,11 +10110,7 @@ static void ixgbe_xdp_flush(struct net_d
 	if (unlikely(!ring))
 		return;
 
-	/* Force memory writes to complete before letting h/w know there
-	 * are new descriptors to fetch.
-	 */
-	wmb();
-	writel(ring->next_to_use, ring->tail);
+	ixgbe_xdp_ring_update_tail(ring);
 
 	return;
 }