[PATCH bpf-next 2/3] selftests/bpf: Tests for single-cpu updates of per-cpu maps

[Paul Chaignon <paul.chaignon@orange.com>]

This patch adds test cases for single-cpu updates of per-cpu maps.  It
updates values for the first and last CPUs and checks that only their
values were updated.

Signed-off-by: Paul Chaignon <paul.chaignon@orange.com>
---
 tools/testing/selftests/bpf/test_maps.c | 34 ++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c
index 02eae1e864c2..e3d3b15e1b91 100644
--- a/tools/testing/selftests/bpf/test_maps.c
+++ b/tools/testing/selftests/bpf/test_maps.c
@@ -150,6 +150,7 @@ static void test_hashmap_percpu(unsigned int task, void *data)
 	BPF_DECLARE_PERCPU(long, value);
 	long long key, next_key, first_key;
 	int expected_key_mask = 0;
+	long new_value = 42;
 	int fd, i;
 
 	fd = bpf_create_map(BPF_MAP_TYPE_PERCPU_HASH, sizeof(key),
@@ -232,6 +233,23 @@ static void test_hashmap_percpu(unsigned int task, void *data)
 	key = 1;
 	assert(bpf_map_update_elem(fd, &key, value, BPF_EXIST) == 0);
 
+	/* Update value for a single CPU. */
+	assert(bpf_map_update_elem(fd, &key, &new_value,
+				   BPF_NOEXIST | BPF_CPU) == -1 &&
+	       errno == EEXIST);
+	assert(bpf_map_update_elem(fd, &key, &new_value,
+				   ((__u64)nr_cpus) << 32 | BPF_CPU) == -1 &&
+	       errno == EINVAL);
+	assert(bpf_map_update_elem(fd, &key, &new_value,
+				   BPF_EXIST | BPF_CPU) == 0);
+	assert(bpf_map_update_elem(fd, &key, &new_value,
+				   (nr_cpus - 1ULL) << 32 | BPF_CPU) == 0);
+	assert(bpf_map_lookup_elem(fd, &key, value) == 0);
+	assert(bpf_percpu(value, 0) == new_value);
+	for (i = 1; i < nr_cpus - 1; i++)
+		assert(bpf_percpu(value, i) == i + 100);
+	assert(bpf_percpu(value, nr_cpus - 1) == new_value);
+
 	/* Delete both elements. */
 	key = 1;
 	assert(bpf_map_delete_elem(fd, &key) == 0);
@@ -402,6 +420,7 @@ static void test_arraymap_percpu(unsigned int task, void *data)
 	unsigned int nr_cpus = bpf_num_possible_cpus();
 	BPF_DECLARE_PERCPU(long, values);
 	int key, next_key, fd, i;
+	long new_value = 42;
 
 	fd = bpf_create_map(BPF_MAP_TYPE_PERCPU_ARRAY, sizeof(key),
 			    sizeof(bpf_percpu(values, 0)), 2, 0);
@@ -449,8 +468,21 @@ static void test_arraymap_percpu(unsigned int task, void *data)
 	assert(bpf_map_get_next_key(fd, &next_key, &next_key) == -1 &&
 	       errno == ENOENT);
 
-	/* Delete shouldn't succeed. */
+	/* Update value for a single CPU */
 	key = 1;
+	assert(bpf_map_update_elem(fd, &key, &new_value,
+				   ((__u64)nr_cpus) << 32 | BPF_CPU) == -1 &&
+	       errno == EINVAL);
+	assert(bpf_map_update_elem(fd, &key, &new_value, BPF_CPU) == 0);
+	assert(bpf_map_update_elem(fd, &key, &new_value,
+				   (nr_cpus - 1ULL) << 32 | BPF_CPU) == 0);
+	assert(bpf_map_lookup_elem(fd, &key, values) == 0);
+	assert(bpf_percpu(values, 0) == new_value);
+	for (i = 1; i < nr_cpus - 1; i++)
+		assert(bpf_percpu(values, i) == i + 100);
+	assert(bpf_percpu(values, nr_cpus - 1) == new_value);
+
+	/* Delete shouldn't succeed. */
 	assert(bpf_map_delete_elem(fd, &key) == -1 && errno == EINVAL);
 
 	close(fd);
-- 
2.24.0