[PATCH bpf-next 2/2] selftests/bpf: Add test for bpf_cpumask_weight() kfunc

David Vernet
2023-12-07T21:09:14Z

The new bpf_cpumask_weight() kfunc can be used to count the number of
bits that are set in a struct cpumask* kptr. Let's add a selftest to
verify its behavior.

Signed-off-by: David Vernet <void@manifault.com>
---
.../selftests/bpf/prog_tests/cpumask.c | 1 +
.../selftests/bpf/progs/cpumask_common.h | 1 +
.../selftests/bpf/progs/cpumask_success.c | 43 +++++++++++++++++++
3 files changed, 45 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/cpumask.c b/tools/testing/selftests/bpf/prog_tests/cpumask.c
index 756ea8b590b6..c2e886399e3c 100644
--- a/tools/testing/selftests/bpf/prog_tests/cpumask.c
+++ b/tools/testing/selftests/bpf/prog_tests/cpumask.c
@@ -18,6 +18,7 @@ static const char * const cpumask_success_testcases[] = {
"test_insert_leave",
"test_insert_remove_release",
"test_global_mask_rcu",
+ "test_cpumask_weight",
};

static void verify_success(const char *prog_name)
diff --git a/tools/testing/selftests/bpf/progs/cpumask_common.h b/tools/testing/selftests/bpf/progs/cpumask_common.h
index b15c588ace15..0cd4aebb97cf 100644
--- a/tools/testing/selftests/bpf/progs/cpumask_common.h
+++ b/tools/testing/selftests/bpf/progs/cpumask_common.h
@@ -54,6 +54,7 @@ bool bpf_cpumask_full(const struct cpumask *cpumask) __ksym;
void bpf_cpumask_copy(struct bpf_cpumask *dst, const struct cpumask *src) __ksym;
u32 bpf_cpumask_any_distribute(const struct cpumask *src) __ksym;
u32 bpf_cpumask_any_and_distribute(const struct cpumask *src1, const struct cpumask *src2) __ksym;
+u32 bpf_cpumask_weight(const struct cpumask *cpumask) __ksym;

void bpf_rcu_read_lock(void) __ksym;
void bpf_rcu_read_unlock(void) __ksym;
diff --git a/tools/testing/selftests/bpf/progs/cpumask_success.c b/tools/testing/selftests/bpf/progs/cpumask_success.c
index 674a63424dee..fc3666edf456 100644
--- a/tools/testing/selftests/bpf/progs/cpumask_success.c
+++ b/tools/testing/selftests/bpf/progs/cpumask_success.c
@@ -460,6 +460,49 @@ int BPF_PROG(test_global_mask_rcu, struct task_struct *task, u64 clone_flags)
return 0;
}

+SEC("tp_btf/task_newtask")
+int BPF_PROG(test_cpumask_weight, struct task_struct *task, u64 clone_flags)
+{
+ struct bpf_cpumask *local;
+
+ if (!is_test_task())
+ return 0;
+
+ local = create_cpumask();
+ if (!local)
+ return 0;
+
+ if (bpf_cpumask_weight(cast(local)) != 0) {
+ err = 3;
+ goto out;
+ }
+
+ bpf_cpumask_set_cpu(0, local);
+ if (bpf_cpumask_weight(cast(local)) != 1) {
+ err = 4;
+ goto out;
+ }
+
+ /*
+ * Make sure that adding additional CPUs changes the weight. Test to
+ * see whether the CPU was set to account for running on UP machines.
+ */
+ bpf_cpumask_set_cpu(1, local);
+ if (bpf_cpumask_test_cpu(1, cast(local)) && bpf_cpumask_weight(cast(local)) != 2) {
+ err = 5;
+ goto out;
+ }
+
+ bpf_cpumask_clear(local);
+ if (bpf_cpumask_weight(cast(local)) != 0) {
+ err = 6;
+ goto out;
+ }
+out:
+ bpf_cpumask_release(local);
+ return 0;
+}
+
SEC("tp_btf/task_newtask")
__success
int BPF_PROG(test_refcount_null_tracking, struct task_struct *task, u64 clone_flags)
--
2.42.1