[bpf-next V2 PATCH 3/8] ixgbe: implement flush flag for ndo_xdp_xmit

[Jesper Dangaard Brouer]

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 <bro...@redhat.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |   20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c 
b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 87f088f4af52..4fd77c9067f2 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -10022,6 +10022,15 @@ static int ixgbe_xdp(struct net_device *dev, struct 
netdev_bpf *xdp)
        }
 }
 
+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)
 {
@@ -10033,7 +10042,7 @@ static int ixgbe_xdp_xmit(struct net_device *dev, int n,
        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
@@ -10054,6 +10063,9 @@ static int ixgbe_xdp_xmit(struct net_device *dev, int n,
                }
        }
 
+       if (unlikely(flags & XDP_XMIT_FLUSH))
+               ixgbe_xdp_ring_update_tail(ring);
+
        return n - drops;
 }
 
@@ -10072,11 +10084,7 @@ static void ixgbe_xdp_flush(struct net_device *dev)
        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;
 }