From: Ciara Loftus <ciara.loftus@intel.com>
Date: Fri, 13 Sep 2019 10:39:48 +0000
Subject: samples/bpf: fix xdpsock l2fwd tx for unaligned mode
Patch-mainline: v5.4-rc1
Git-commit: 5a712e1363c8ecb4b504a888833ef91416314c36
References: bsc#1155518

Preserve the offset of the address of the received descriptor, and include
it in the address set for the tx descriptor, so the kernel can correctly
locate the start of the packet data.

Fixes: 03895e63ff97 ("samples/bpf: add buffer recycling for unaligned chunks to xdpsock")
Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Gary Lin <glin@suse.com>
---
 samples/bpf/xdpsock_user.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/samples/bpf/xdpsock_user.c
+++ b/samples/bpf/xdpsock_user.c
@@ -685,7 +685,7 @@ static void l2fwd(struct xsk_socket_info
 	for (i = 0; i < rcvd; i++) {
 		u64 addr = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx)->addr;
 		u32 len = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx++)->len;
-		u64 orig = xsk_umem__extract_addr(addr);
+		u64 orig = addr;
 
 		addr = xsk_umem__add_offset_to_addr(addr);
 		char *pkt = xsk_umem__get_data(xsk->umem->buffer, addr);