[RFC PATCH bpf-next 5/8] selftests/bpf: Add parallel support for classid

Yafang Shao
2023-10-07T14:03:26Z

Include the current pid in the classid cgroup path. This way, different
testers relying on classid-based configurations will have distinct classid
cgroup directories, enabling them to run concurrently. Additionally, we
leverage the current pid as the classid, ensuring unique identification.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
tools/testing/selftests/bpf/cgroup_helpers.c | 19 ++++++++++++-------
tools/testing/selftests/bpf/cgroup_helpers.h | 2 +-
.../selftests/bpf/prog_tests/cgroup_v1v2.c | 2 +-
3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c b/tools/testing/selftests/bpf/cgroup_helpers.c
index 9c36d1db9f94..e378fa057757 100644
--- a/tools/testing/selftests/bpf/cgroup_helpers.c
+++ b/tools/testing/selftests/bpf/cgroup_helpers.c
@@ -45,9 +45,12 @@
#define format_parent_cgroup_path(buf, path) \
format_cgroup_path_pid(buf, path, getppid())

-#define format_classid_path(buf) \
- snprintf(buf, sizeof(buf), "%s%s", NETCLS_MOUNT_PATH, \
- CGROUP_WORK_DIR)
+#define format_classid_path_pid(buf, pid) \
+ snprintf(buf, sizeof(buf), "%s%s%d", NETCLS_MOUNT_PATH, \
+ CGROUP_WORK_DIR, pid)
+
+#define format_classid_path(buf) \
+ format_classid_path_pid(buf, getpid())

static __thread bool cgroup_workdir_mounted;

@@ -546,15 +549,17 @@ int setup_classid_environment(void)

/**
* set_classid() - Set a cgroupv1 net_cls classid
- * @id: the numeric classid
*
- * Writes the passed classid into the cgroup work dir's net_cls.classid
+ * Writes the classid into the cgroup work dir's net_cls.classid
* file in order to later on trigger socket tagging.
*
+ * To make sure different classid testers have different classids, we use
+ * the current pid as the classid by default.
+ *
* On success, it returns 0, otherwise on failure it returns 1. If there
* is a failure, it prints the error to stderr.
*/
-int set_classid(unsigned int id)
+int set_classid(void)
{
char cgroup_workdir[PATH_MAX - 42];
char cgroup_classid_path[PATH_MAX + 1];
@@ -570,7 +575,7 @@ int set_classid(unsigned int id)
return 1;
}

- if (dprintf(fd, "%u\n", id) < 0) {
+ if (dprintf(fd, "%u\n", getpid()) < 0) {
log_err("Setting cgroup classid");
rc = 1;
}
diff --git a/tools/testing/selftests/bpf/cgroup_helpers.h b/tools/testing/selftests/bpf/cgroup_helpers.h
index 5c2cb9c8b546..92fc41daf4a4 100644
--- a/tools/testing/selftests/bpf/cgroup_helpers.h
+++ b/tools/testing/selftests/bpf/cgroup_helpers.h
@@ -29,7 +29,7 @@ int setup_cgroup_environment(void);
void cleanup_cgroup_environment(void);

/* cgroupv1 related */
-int set_classid(unsigned int id);
+int set_classid(void);
int join_classid(void);

int setup_classid_environment(void);
diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c b/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c
index 9026b42914d3..addf720428f7 100644
--- a/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c
@@ -71,7 +71,7 @@ void test_cgroup_v1v2(void)
}
ASSERT_OK(run_test(cgroup_fd, server_fd, false), "cgroup-v2-only");
setup_classid_environment();
- set_classid(42);
+ set_classid();
ASSERT_OK(run_test(cgroup_fd, server_fd, true), "cgroup-v1v2");
cleanup_classid_environment();
close(server_fd);
--
2.30.1 (Apple Git-130)