From: Magnus Karlsson <magnus.karlsson@intel.com>
Date: Thu, 7 Nov 2019 18:47:38 +0100
Subject: libbpf: Allow for creating Rx or Tx only AF_XDP sockets
Patch-mainline: v5.5-rc1
Git-commit: a68977d269dac0c7aa4a6f650b5e9191dd764861
References: bsc#1177028

The libbpf AF_XDP code is extended to allow for the creation of Rx
only or Tx only sockets. Previously it returned an error if the socket
was not initialized for both Rx and Tx.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: William Tu <u9012063@gmail.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Link: https://lore.kernel.org/bpf/1573148860-30254-4-git-send-email-magnus.karlsson@intel.com
Acked-by: Gary Lin <glin@suse.com>
---
 tools/lib/bpf/xsk.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c
@@ -562,7 +562,8 @@ static int xsk_setup_xdp_prog(struct xsk
 		}
 	}
 
-	err = xsk_set_bpf_maps(xsk);
+	if (xsk->rx)
+		err = xsk_set_bpf_maps(xsk);
 	if (err) {
 		xsk_delete_bpf_maps(xsk);
 		close(xsk->prog_fd);
@@ -583,7 +584,7 @@ int xsk_socket__create(struct xsk_socket
 	struct xsk_socket *xsk;
 	int err;
 
-	if (!umem || !xsk_ptr || !rx || !tx)
+	if (!umem || !xsk_ptr || !(rx || tx))
 		return -EFAULT;
 
 	xsk = calloc(1, sizeof(*xsk));