A test case is added for hashmap and percpu hashmap. The test
also exercises nested bpf_for_each_map_elem() calls like
bpf_prog:
bpf_for_each_map_elem(func1)
func1:
bpf_for_each_map_elem(func2)
func2:
$ ./test_progs -n 44
#44/1 hash_map:OK
#44 for_each:OK
Summary: 1/1 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Yonghong Song <yhs@xxxxxx>
---
.../selftests/bpf/prog_tests/for_each.c | 91 ++++++++++++++++
.../bpf/progs/for_each_hash_map_elem.c | 103 ++++++++++++++++++
2 files changed, 194 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/for_each.c
create mode 100644 tools/testing/selftests/bpf/progs/for_each_hash_map_elem.c
diff --git a/tools/testing/selftests/bpf/prog_tests/for_each.c b/tools/testing/selftests/bpf/prog_tests/for_each.c
new file mode 100644
index 000000000000..7a399fbc89a4
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/for_each.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+#include <test_progs.h>
+#include "for_each_hash_map_elem.skel.h"
+
+static int duration;
+
+static void do_dummy_read(struct bpf_program *prog)
+{
+ struct bpf_link *link;
+ char buf[16] = {};
+ int iter_fd, len;
+
+ link = bpf_program__attach_iter(prog, NULL);
+ if (CHECK(IS_ERR(link), "attach_iter", "attach_iter failed\n"))
+ return;
+
+ iter_fd = bpf_iter_create(bpf_link__fd(link));
+ if (CHECK(iter_fd < 0, "create_iter", "create_iter failed\n"))
+ goto free_link;
+
+ /* not check contents, but ensure read() ends without error */
+ while ((len = read(iter_fd, buf, sizeof(buf))) > 0)
+ ;
+ CHECK(len < 0, "read", "read failed: %s\n", strerror(errno));
+
+ close(iter_fd);
+
+free_link:
+ bpf_link__destroy(link);
+}
+
+static void test_hash_map(void)
+{
+ int i, hashmap_fd, percpu_map_fd, err;
+ struct for_each_hash_map_elem *skel;
+ __u64 *percpu_valbuf = NULL;
+ __u32 key, num_cpus;
+ __u64 val;
+
+ skel = for_each_hash_map_elem__open_and_load();
+ if (CHECK(!skel, "for_each_hash_map_elem__open_and_load",
+ "skeleton open_and_load failed\n"))
+ return;
+
+ hashmap_fd = bpf_map__fd(skel->maps.hashmap);
+ for (i = 0; i < bpf_map__max_entries(skel->maps.hashmap); i++) {
+ key = i;
+ val = i + 1;
+ err = bpf_map_update_elem(hashmap_fd, &key, &val, BPF_ANY);
+ if (CHECK(err, "map_update", "map_update failed\n"))
+ goto out;
+ }
+
+ num_cpus = bpf_num_possible_cpus();
+ percpu_map_fd = bpf_map__fd(skel->maps.percpu_map);
+ percpu_valbuf = malloc(sizeof(__u64) * num_cpus);
+ if (CHECK_FAIL(!percpu_valbuf))
+ goto out;
+
+ key = 1;
+ for (i = 0; i < num_cpus; i++)
+ percpu_valbuf[i] = i + 1;
+ err = bpf_map_update_elem(percpu_map_fd, &key, percpu_valbuf, BPF_ANY);
+ if (CHECK(err, "percpu_map_update", "map_update failed\n"))
+ goto out;
+
+ do_dummy_read(skel->progs.dump_task);
+
+ ASSERT_EQ(skel->bss->called, 1, "called");
+ ASSERT_EQ(skel->bss->hashmap_output, 4, "output_val");
+
+ key = 1;
+ err = bpf_map_lookup_elem(hashmap_fd, &key, &val);
+ ASSERT_ERR(err, "hashmap_lookup");
+
+ ASSERT_EQ(skel->bss->percpu_called, 1, "percpu_called");
+ CHECK_FAIL(skel->bss->cpu >= num_cpus);
+ ASSERT_EQ(skel->bss->percpu_key, 1, "percpu_key");
+ ASSERT_EQ(skel->bss->percpu_val, skel->bss->cpu + 1, "percpu_val");
+ ASSERT_EQ(skel->bss->percpu_output, 100, "percpu_output");
+out:
+ free(percpu_valbuf);
+ for_each_hash_map_elem__destroy(skel);
+}
+
+void test_for_each(void)
+{
+ if (test__start_subtest("hash_map"))
+ test_hash_map();
+}
diff --git a/tools/testing/selftests/bpf/progs/for_each_hash_map_elem.c b/tools/testing/selftests/bpf/progs/for_each_hash_map_elem.c
new file mode 100644
index 000000000000..7808a5aa75e7
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/for_each_hash_map_elem.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+#include "bpf_iter.h"
+#include <bpf/bpf_helpers.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct {
+ __uint(type, BPF_MAP_TYPE_HASH);
+ __uint(max_entries, 3);
+ __type(key, __u32);
+ __type(value, __u64);
+} hashmap SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_HASH);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, __u64);
+} percpu_map SEC(".maps");
+
+struct callback_ctx {
+ struct bpf_iter__task *ctx;
+ int input;
+ int output;
+};
+
+static __u64
+check_hash_elem(struct bpf_map *map, __u32 *key, __u64 *val,
+ struct callback_ctx *data)
+{
+ struct bpf_iter__task *ctx = data->ctx;
+ __u32 k;
+ __u64 v;
+
+ if (ctx) {
+ k = *key;
+ v = *val;
+ if (ctx->meta->seq_num == 10 && k == 10 && v == 10)
+ data->output = 3; /* impossible path */
+ else
+ data->output = 4;
+ } else {
+ data->output = data->input;
+ bpf_map_delete_elem(map, key);
+ }
+
+ return 0;
+}
+
+__u32 cpu = 0;
+__u32 percpu_called = 0;
+__u32 percpu_key = 0;
+__u64 percpu_val = 0;
+
+static __u64
+check_percpu_elem(struct bpf_map *map, __u32 *key, __u64 *val,
+ struct callback_ctx *data)
+{
+ percpu_called++;
+ cpu = bpf_get_smp_processor_id();
+ percpu_key = *key;
+ percpu_val = *val;
+
+ bpf_for_each_map_elem(&hashmap, check_hash_elem, data, 0);
+ return 0;
+}
+
+int called = 0;
+int hashmap_output = 0;
+int percpu_output = 0;
+
+SEC("iter/task")
+int dump_task(struct bpf_iter__task *ctx)
+{
+ struct seq_file *seq = ctx->meta->seq;
+ struct task_struct *task = ctx->task;
+ struct callback_ctx data;
+ int ret;
+
+ /* only call once since we will delete map elements */
+ if (task == (void *)0 || called > 0)
+ return 0;
+
+ called++;
+
+ data.ctx = ctx;
+ data.input = task->tgid;
+ data.output = 0;
+ ret = bpf_for_each_map_elem(&hashmap, check_hash_elem, &data, 0);
+ if (ret)
+ return 0;
+
+ hashmap_output = data.output;
+
+ data.ctx = 0;
+ data.input = 100;
+ data.output = 0;
+ bpf_for_each_map_elem(&percpu_map, check_percpu_elem, &data, 0);
+ percpu_output = data.output;
+
+ return 0;
+}
--
2.24.1
