On 11/24/20 6:33 AM, Jesper Dangaard Brouer wrote:
On Fri, 20 Nov 2020 23:41:11 -0800
Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> wrote:
On Fri, Nov 20, 2020 at 8:21 AM Jesper Dangaard Brouer
<brouer@xxxxxxxxxx> wrote:
Adding selftest for BPF-helper bpf_check_mtu(). Making sure
it can be used from both XDP and TC.
Signed-off-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
---
tools/testing/selftests/bpf/prog_tests/check_mtu.c | 37 ++++++++++++++++++++
tools/testing/selftests/bpf/progs/test_check_mtu.c | 33 ++++++++++++++++++
2 files changed, 70 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/check_mtu.c
create mode 100644 tools/testing/selftests/bpf/progs/test_check_mtu.c
diff --git a/tools/testing/selftests/bpf/prog_tests/check_mtu.c b/tools/testing/selftests/bpf/prog_tests/check_mtu.c
new file mode 100644
index 000000000000..09b8f986a17b
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/check_mtu.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Red Hat */
+#include <uapi/linux/bpf.h>
+#include <linux/if_link.h>
+#include <test_progs.h>
+
+#include "test_check_mtu.skel.h"
+#define IFINDEX_LO 1
+
+void test_check_mtu_xdp(struct test_check_mtu *skel)
this should be static func, otherwise it's treated as an independent selftest.
Ok, fixed.
+{
+ int err = 0;
+ int fd;
+
+ fd = bpf_program__fd(skel->progs.xdp_use_helper);
+ err = bpf_set_link_xdp_fd(IFINDEX_LO, fd, XDP_FLAGS_SKB_MODE);
+ if (CHECK_FAIL(err))
please use CHECK() or one of ASSERT_xxx() helpers. CHECK_FAIL() should
be used for high-volume unlikely to fail test (i.e., very rarely).
I could not get CHECK() macro working. I now realize that this is
because I've not defined a global static variable named 'duration'.
static __u32 duration;
I wonder, are there any best-practice documentation or blogpost on
howto write these bpf-selftests?
The 'duration' in old days is used to measure performance. Today most
of selftests actually do not need this. We do not have doc/blogpost
for this. The best is to look at other files under prog_tests to see
how they handle duration ...
Below signature is the compile error for others to Google for, and
solution above.
-
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
$ make
TEST-OBJ [test_progs] check_mtu.test.o
In file included from /home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/prog_tests/check_mtu.c:6:
/home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/prog_tests/check_mtu.c: In function ‘test_check_mtu’:
./test_progs.h:129:25: error: ‘duration’ undeclared (first use in this function)
129 | _CHECK(condition, tag, duration, format)
| ^~~~~~~~
./test_progs.h:111:25: note: in definition of macro ‘_CHECK’
111 | __func__, tag, duration); \
| ^~~~~~~~
/home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/prog_tests/check_mtu.c:33:6: note: in expansion of macro ‘CHECK’
33 | if (CHECK(!skel, "open and load skel", "failed"))
| ^~~~~
./test_progs.h:129:25: note: each undeclared identifier is reported only once for each function it appears in
129 | _CHECK(condition, tag, duration, format)
| ^~~~~~~~
./test_progs.h:111:25: note: in definition of macro ‘_CHECK’
111 | __func__, tag, duration); \
| ^~~~~~~~
/home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/prog_tests/check_mtu.c:33:6: note: in expansion of macro ‘CHECK’
33 | if (CHECK(!skel, "open and load skel", "failed"))
| ^~~~~
make: *** [Makefile:396: /home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/check_mtu.test.o] Error 1
