Thread (21 messages) 21 messages, 2 authors, 2021-03-31

Re: [PATCH v2 1/4] selftests/bpf: test_progs/sockopt_sk: Convert to use BPF skeleton

From: Andrii Nakryiko <hidden>
Date: 2021-03-28 04:59:57

On Fri, Mar 26, 2021 at 5:24 AM Yauheni Kaliuta
[off-list ref] wrote:
Switch the test to use BPF skeleton to save some boilerplate and
make it easy to access bpf program bss segment.

The latter will be used to pass PAGE_SIZE from userspace since there
is no convenient way for bpf program to get it from inside of the
kernel.

Signed-off-by: Yauheni Kaliuta <redacted>
---
It's a nice cleanup. See some suggestion to further clean it up. But
even with this:

Acked-by: Andrii Nakryiko <andrii@kernel.org>
quoted hunk ↗ jump to hunk
 .../selftests/bpf/prog_tests/sockopt_sk.c     | 72 ++++++-------------
 1 file changed, 23 insertions(+), 49 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/sockopt_sk.c b/tools/testing/selftests/bpf/prog_tests/sockopt_sk.c
index d5b44b135c00..114c1a622ffa 100644
--- a/tools/testing/selftests/bpf/prog_tests/sockopt_sk.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockopt_sk.c
@@ -3,6 +3,7 @@
 #include "cgroup_helpers.h"

 #include <linux/tcp.h>
+#include "sockopt_sk.skel.h"

 #ifndef SOL_TCP
 #define SOL_TCP IPPROTO_TCP
@@ -191,60 +192,33 @@ static int getsetsockopt(void)
        return -1;
 }

-static int prog_attach(struct bpf_object *obj, int cgroup_fd, const char *title)
-{
-       enum bpf_attach_type attach_type;
-       enum bpf_prog_type prog_type;
-       struct bpf_program *prog;
-       int err;
-
-       err = libbpf_prog_type_by_name(title, &prog_type, &attach_type);
-       if (err) {
-               log_err("Failed to deduct types for %s BPF program", title);
-               return -1;
-       }
-
-       prog = bpf_object__find_program_by_title(obj, title);
-       if (!prog) {
-               log_err("Failed to find %s BPF program", title);
-               return -1;
-       }
-
-       err = bpf_prog_attach(bpf_program__fd(prog), cgroup_fd,
-                             attach_type, 0);
-       if (err) {
-               log_err("Failed to attach %s BPF program", title);
-               return -1;
-       }
-
-       return 0;
-}
-
 static void run_test(int cgroup_fd)
 {
-       struct bpf_prog_load_attr attr = {
-               .file = "./sockopt_sk.o",
-       };
-       struct bpf_object *obj;
-       int ignored;
-       int err;
-
-       err = bpf_prog_load_xattr(&attr, &obj, &ignored);
-       if (CHECK_FAIL(err))
-               return;
-
-       err = prog_attach(obj, cgroup_fd, "cgroup/getsockopt");
-       if (CHECK_FAIL(err))
-               goto close_bpf_object;
-
-       err = prog_attach(obj, cgroup_fd, "cgroup/setsockopt");
-       if (CHECK_FAIL(err))
-               goto close_bpf_object;
+       struct sockopt_sk *skel;
+       int duration = 0;
+
+       skel = sockopt_sk__open_and_load();
+       if (CHECK(!skel, "skel_load", "sockopt_sk skeleton failed\n"))
+               goto cleanup;
if (!ASSERT_OK_PTR(skel, "skel_load))

is still less boilerplate :)
+
+       skel->links._setsockopt =
+               bpf_program__attach_cgroup(skel->progs._setsockopt, cgroup_fd);
+       if (CHECK(IS_ERR(skel->links._setsockopt),
+                        "setsockopt_attach", "err: %ld\n",
+                        PTR_ERR(skel->links._setsockopt)))
you could save some more boilerplate if you did:

if (!ASSERT_OK_PTR(skel->links._getsockopt), "getsockopt_link")
    goto cleanup;
+               goto cleanup;
+
+       skel->links._getsockopt =
+               bpf_program__attach_cgroup(skel->progs._getsockopt, cgroup_fd);
+       if (CHECK(IS_ERR(skel->links._getsockopt),
+                        "getsockopt_attach", "err: %ld\n",
+                        PTR_ERR(skel->links._getsockopt)))
+               goto cleanup;

        CHECK_FAIL(getsetsockopt());
please switch this to ASSERT_OK() as well.

Once you don't use CHECK/CHECK_FAIL, you also won't need `int duration`, btw.
-close_bpf_object:
-       bpf_object__close(obj);
+cleanup:
+       sockopt_sk__destroy(skel);
 }

 void test_sockopt_sk(void)
--
2.29.2
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