From: Jesper Dangaard Brouer <brouer@redhat.com>
Date: Thu, 14 May 2020 12:51:40 +0200
Subject: selftests/bpf: Adjust BPF selftest for xdp_adjust_tail
Patch-mainline: v5.8-rc1
Git-commit: 68545fb6f2ff621de26d96a3f15868abfb6897b0
References: bsc#1177028

Current selftest for BPF-helper xdp_adjust_tail only shrink tail.
Make it more clear that this is a shrink test case.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/158945350058.97035.17280775016196207372.stgit@firesoul
Acked-by: Gary Lin <glin@suse.com>
---
 tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c        |    9 ++-
 tools/testing/selftests/bpf/progs/test_adjust_tail.c            |   30 ----------
 tools/testing/selftests/bpf/progs/test_xdp_adjust_tail_shrink.c |   30 ++++++++++
 3 files changed, 37 insertions(+), 32 deletions(-)
 rename tools/testing/selftests/bpf/progs/{test_adjust_tail.c => test_xdp_adjust_tail_shrink.c} (70%)

--- a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
@@ -2,9 +2,9 @@
 #include <test_progs.h>
 #include <network_helpers.h>
 
-void test_xdp_adjust_tail(void)
+void test_xdp_adjust_tail_shrink(void)
 {
-	const char *file = "./test_adjust_tail.o";
+	const char *file = "./test_xdp_adjust_tail_shrink.o";
 	struct bpf_object *obj;
 	char buf[128];
 	__u32 duration, retval, size;
@@ -28,3 +28,8 @@ void test_xdp_adjust_tail(void)
 	      err, errno, retval, size);
 	bpf_object__close(obj);
 }
+
+void test_xdp_adjust_tail(void)
+{
+	test_xdp_adjust_tail_shrink();
+}
--- a/tools/testing/selftests/bpf/progs/test_adjust_tail.c
+++ /dev/null
@@ -1,30 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0
- * Copyright (c) 2018 Facebook
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- */
-#include <linux/bpf.h>
-#include <linux/if_ether.h>
-#include <bpf/bpf_helpers.h>
-
-int _version SEC("version") = 1;
-
-SEC("xdp_adjust_tail")
-int _xdp_adjust_tail(struct xdp_md *xdp)
-{
-	void *data_end = (void *)(long)xdp->data_end;
-	void *data = (void *)(long)xdp->data;
-	int offset = 0;
-
-	if (data_end - data == 54)
-		offset = 256;
-	else
-		offset = 20;
-	if (bpf_xdp_adjust_tail(xdp, 0 - offset))
-		return XDP_DROP;
-	return XDP_TX;
-}
-
-char _license[] SEC("license") = "GPL";
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xdp_adjust_tail_shrink.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2018 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include <linux/bpf.h>
+#include <linux/if_ether.h>
+#include <bpf/bpf_helpers.h>
+
+int _version SEC("version") = 1;
+
+SEC("xdp_adjust_tail_shrink")
+int _xdp_adjust_tail_shrink(struct xdp_md *xdp)
+{
+	void *data_end = (void *)(long)xdp->data_end;
+	void *data = (void *)(long)xdp->data;
+	int offset = 0;
+
+	if (data_end - data == 54) /* sizeof(pkt_v4) */
+		offset = 256; /* shrink too much */
+	else
+		offset = 20;
+	if (bpf_xdp_adjust_tail(xdp, 0 - offset))
+		return XDP_DROP;
+	return XDP_TX;
+}
+
+char _license[] SEC("license") = "GPL";