From: Kevin Laatz <kevin.laatz@intel.com>
Date: Tue, 27 Aug 2019 02:25:21 +0000
Subject: ixgbe: simplify Rx buffer recycle
Patch-mainline: v5.4-rc1
Git-commit: b35a2d3e895600d8a1273b44f68128491faab3b8
References: jsc#SLE-7979 jsc#SLE-7981

Currently, the dma, addr and handle are modified when we reuse Rx buffers
in zero-copy mode. However, this is not required as the inputs to the
function are copies, not the original values themselves. As we use the
copies within the function, we can use the original 'obi' values
directly without having to mask and add the headroom.

Signed-off-by: Kevin Laatz <kevin.laatz@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 |   13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
@@ -201,8 +201,6 @@ ixgbe_rx_buffer *ixgbe_get_rx_buffer_zc(
 static void ixgbe_reuse_rx_buffer_zc(struct ixgbe_ring *rx_ring,
 				     struct ixgbe_rx_buffer *obi)
 {
-	unsigned long mask = (unsigned long)rx_ring->xsk_umem->chunk_mask;
-	u64 hr = rx_ring->xsk_umem->headroom + XDP_PACKET_HEADROOM;
 	u16 nta = rx_ring->next_to_alloc;
 	struct ixgbe_rx_buffer *nbi;
 
@@ -212,14 +210,9 @@ static void ixgbe_reuse_rx_buffer_zc(str
 	rx_ring->next_to_alloc = (nta < rx_ring->count) ? nta : 0;
 
 	/* transfer page from old buffer to new buffer */
-	nbi->dma = obi->dma & mask;
-	nbi->dma += hr;
-
-	nbi->addr = (void *)((unsigned long)obi->addr & mask);
-	nbi->addr += hr;
-
-	nbi->handle = obi->handle & mask;
-	nbi->handle += rx_ring->xsk_umem->headroom;
+	nbi->dma = obi->dma;
+	nbi->addr = obi->addr;
+	nbi->handle = obi->handle;
 
 	obi->addr = NULL;
 	obi->skb = NULL;