samples/bpf: unit test for BPF_MAP_TYPE_PERCPU_HASH

A sanity test for BPF_MAP_TYPE_PERCPU_HASH.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 96 insertions, 0 deletions

diff --git a/samples/bpf/test_maps.c b/samples/bpf/test_maps.c
index 6299ee95cd11..5f5fe5332148 100644
--- a/samples/bpf/test_maps.c
+++ b/samples/bpf/test_maps.c
@@ -89,6 +89,100 @@ static void test_hashmap_sanity(int i, void *data)
         close(map_fd);
 }
 
+/* sanity tests for percpu map API */
+static void test_percpu_hashmap_sanity(int task, void *data)
+{
+        long long key, next_key;
+        int expected_key_mask = 0;
+        unsigned int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
+        long long value[nr_cpus];
+        int map_fd, i;
+
+        map_fd = bpf_create_map(BPF_MAP_TYPE_PERCPU_HASH, sizeof(key),
+                                sizeof(value[0]), 2);
+        if (map_fd < 0) {
+                printf("failed to create hashmap '%s'\n", strerror(errno));
+                exit(1);
+        }
+
+        for (i = 0; i < nr_cpus; i++)
+                value[i] = i + 100;
+        key = 1;
+        /* insert key=1 element */
+        assert(!(expected_key_mask & key));
+        assert(bpf_update_elem(map_fd, &key, value, BPF_ANY) == 0);
+        expected_key_mask |= key;
+
+        /* BPF_NOEXIST means: add new element if it doesn't exist */
+        assert(bpf_update_elem(map_fd, &key, value, BPF_NOEXIST) == -1 &&
+               /* key=1 already exists */
+               errno == EEXIST);
+
+        /* -1 is an invalid flag */
+        assert(bpf_update_elem(map_fd, &key, value, -1) == -1 &&
+               errno == EINVAL);
+
+        /* check that key=1 can be found. value could be 0 if the lookup
+         * was run from a different cpu.
+         */
+        value[0] = 1;
+        assert(bpf_lookup_elem(map_fd, &key, value) == 0 && value[0] == 100);
+
+        key = 2;
+        /* check that key=2 is not found */
+        assert(bpf_lookup_elem(map_fd, &key, value) == -1 && errno == ENOENT);
+
+        /* BPF_EXIST means: update existing element */
+        assert(bpf_update_elem(map_fd, &key, value, BPF_EXIST) == -1 &&
+               /* key=2 is not there */
+               errno == ENOENT);
+
+        /* insert key=2 element */
+        assert(!(expected_key_mask & key));
+        assert(bpf_update_elem(map_fd, &key, value, BPF_NOEXIST) == 0);
+        expected_key_mask |= key;
+
+        /* key=1 and key=2 were inserted, check that key=0 cannot be inserted
+         * due to max_entries limit
+         */
+        key = 0;
+        assert(bpf_update_elem(map_fd, &key, value, BPF_NOEXIST) == -1 &&
+               errno == E2BIG);
+
+        /* check that key = 0 doesn't exist */
+        assert(bpf_delete_elem(map_fd, &key) == -1 && errno == ENOENT);
+
+        /* iterate over two elements */
+        while (!bpf_get_next_key(map_fd, &key, &next_key)) {
+                assert((expected_key_mask & next_key) == next_key);
+                expected_key_mask &= ~next_key;
+
+                assert(bpf_lookup_elem(map_fd, &next_key, value) == 0);
+                for (i = 0; i < nr_cpus; i++)
+                        assert(value[i] == i + 100);
+
+                key = next_key;
+        }
+        assert(errno == ENOENT);
+
+        /* Update with BPF_EXIST */
+        key = 1;
+        assert(bpf_update_elem(map_fd, &key, value, BPF_EXIST) == 0);
+
+        /* delete both elements */
+        key = 1;
+        assert(bpf_delete_elem(map_fd, &key) == 0);
+        key = 2;
+        assert(bpf_delete_elem(map_fd, &key) == 0);
+        assert(bpf_delete_elem(map_fd, &key) == -1 && errno == ENOENT);
+
+        key = 0;
+        /* check that map is empty */
+        assert(bpf_get_next_key(map_fd, &key, &next_key) == -1 &&
+               errno == ENOENT);
+        close(map_fd);
+}
+
 static void test_arraymap_sanity(int i, void *data)
 {
         int key, next_key, map_fd;
@@ -209,6 +303,7 @@ static void run_parallel(int tasks, void (*fn)(int i, void *data), void *data)
 static void test_map_stress(void)
 {
         run_parallel(100, test_hashmap_sanity, NULL);
+        run_parallel(100, test_percpu_hashmap_sanity, NULL);
         run_parallel(100, test_arraymap_sanity, NULL);
 }
 
@@ -282,6 +377,7 @@ static void test_map_parallel(void)
 int main(void)
 {
         test_hashmap_sanity(0, NULL);
+        test_percpu_hashmap_sanity(0, NULL);
         test_arraymap_sanity(0, NULL);
         test_map_large();
         test_map_parallel();