selftests/bpf: Add bpf_lookup_and_delete_elem tests

Add bpf selftests and extend existing ones for a new function
bpf_lookup_and_delete_elem() for (percpu) hash and (percpu) LRU hash map
types.
In test_lru_map and test_maps we add an element, lookup_and_delete it,
then check whether it's deleted.
The newly added lookup_and_delete prog tests practically do the same
thing but additionally use a BPF program to change the value of the
element for LRU maps.

Signed-off-by: Denis Salopek <denis.salopek@sartura.hr>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/d30d3e0060c1f750e133579623cf1c60ff58f3d9.1620763117.git.denis.salopek@sartura.hr

1 files changed, 288 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/lookup_and_delete.c b/tools/testing/selftests/bpf/prog_tests/lookup_and_delete.c
new file mode 100644
index 000000000000..beebfa9730e1
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/lookup_and_delete.c
@@ -0,0 +1,288 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <test_progs.h>
+#include "test_lookup_and_delete.skel.h"
+
+#define START_VALUE 1234
+#define NEW_VALUE 4321
+#define MAX_ENTRIES 2
+
+static int duration;
+static int nr_cpus;
+
+static int fill_values(int map_fd)
+{
+	__u64 key, value = START_VALUE;
+	int err;
+
+	for (key = 1; key < MAX_ENTRIES + 1; key++) {
+		err = bpf_map_update_elem(map_fd, &key, &value, BPF_NOEXIST);
+		if (!ASSERT_OK(err, "bpf_map_update_elem"))
+			return -1;
+	}
+
+	return 0;
+}
+
+static int fill_values_percpu(int map_fd)
+{
+	__u64 key, value[nr_cpus];
+	int i, err;
+
+	for (i = 0; i < nr_cpus; i++)
+		value[i] = START_VALUE;
+
+	for (key = 1; key < MAX_ENTRIES + 1; key++) {
+		err = bpf_map_update_elem(map_fd, &key, value, BPF_NOEXIST);
+		if (!ASSERT_OK(err, "bpf_map_update_elem"))
+			return -1;
+	}
+
+	return 0;
+}
+
+static struct test_lookup_and_delete *setup_prog(enum bpf_map_type map_type,
+						 int *map_fd)
+{
+	struct test_lookup_and_delete *skel;
+	int err;
+
+	skel = test_lookup_and_delete__open();
+	if (!ASSERT_OK_PTR(skel, "test_lookup_and_delete__open"))
+		return NULL;
+
+	err = bpf_map__set_type(skel->maps.hash_map, map_type);
+	if (!ASSERT_OK(err, "bpf_map__set_type"))
+		goto cleanup;
+
+	err = bpf_map__set_max_entries(skel->maps.hash_map, MAX_ENTRIES);
+	if (!ASSERT_OK(err, "bpf_map__set_max_entries"))
+		goto cleanup;
+
+	err = test_lookup_and_delete__load(skel);
+	if (!ASSERT_OK(err, "test_lookup_and_delete__load"))
+		goto cleanup;
+
+	*map_fd = bpf_map__fd(skel->maps.hash_map);
+	if (!ASSERT_GE(*map_fd, 0, "bpf_map__fd"))
+		goto cleanup;
+
+	return skel;
+
+cleanup:
+	test_lookup_and_delete__destroy(skel);
+	return NULL;
+}
+
+/* Triggers BPF program that updates map with given key and value */
+static int trigger_tp(struct test_lookup_and_delete *skel, __u64 key,
+		      __u64 value)
+{
+	int err;
+
+	skel->bss->set_pid = getpid();
+	skel->bss->set_key = key;
+	skel->bss->set_value = value;
+
+	err = test_lookup_and_delete__attach(skel);
+	if (!ASSERT_OK(err, "test_lookup_and_delete__attach"))
+		return -1;
+
+	syscall(__NR_getpgid);
+
+	test_lookup_and_delete__detach(skel);
+
+	return 0;
+}
+
+static void test_lookup_and_delete_hash(void)
+{
+	struct test_lookup_and_delete *skel;
+	__u64 key, value;
+	int map_fd, err;
+
+	/* Setup program and fill the map. */
+	skel = setup_prog(BPF_MAP_TYPE_HASH, &map_fd);
+	if (!ASSERT_OK_PTR(skel, "setup_prog"))
+		return;
+
+	err = fill_values(map_fd);
+	if (!ASSERT_OK(err, "fill_values"))
+		goto cleanup;
+
+	/* Lookup and delete element. */
+	key = 1;
+	err = bpf_map_lookup_and_delete_elem(map_fd, &key, &value);
+	if (!ASSERT_OK(err, "bpf_map_lookup_and_delete_elem"))
+		goto cleanup;
+
+	/* Fetched value should match the initially set value. */
+	if (CHECK(value != START_VALUE, "bpf_map_lookup_and_delete_elem",
+		  "unexpected value=%lld\n", value))
+		goto cleanup;
+
+	/* Check that the entry is non existent. */
+	err = bpf_map_lookup_elem(map_fd, &key, &value);
+	if (!ASSERT_ERR(err, "bpf_map_lookup_elem"))
+		goto cleanup;
+
+cleanup:
+	test_lookup_and_delete__destroy(skel);
+}
+
+static void test_lookup_and_delete_percpu_hash(void)
+{
+	struct test_lookup_and_delete *skel;
+	__u64 key, val, value[nr_cpus];
+	int map_fd, err, i;
+
+	/* Setup program and fill the map. */
+	skel = setup_prog(BPF_MAP_TYPE_PERCPU_HASH, &map_fd);
+	if (!ASSERT_OK_PTR(skel, "setup_prog"))
+		return;
+
+	err = fill_values_percpu(map_fd);
+	if (!ASSERT_OK(err, "fill_values_percpu"))
+		goto cleanup;
+
+	/* Lookup and delete element. */
+	key = 1;
+	err = bpf_map_lookup_and_delete_elem(map_fd, &key, value);
+	if (!ASSERT_OK(err, "bpf_map_lookup_and_delete_elem"))
+		goto cleanup;
+
+	for (i = 0; i < nr_cpus; i++) {
+		val = value[i];
+
+		/* Fetched value should match the initially set value. */
+		if (CHECK(val != START_VALUE, "map value",
+			  "unexpected for cpu %d: %lld\n", i, val))
+			goto cleanup;
+	}
+
+	/* Check that the entry is non existent. */
+	err = bpf_map_lookup_elem(map_fd, &key, value);
+	if (!ASSERT_ERR(err, "bpf_map_lookup_elem"))
+		goto cleanup;
+
+cleanup:
+	test_lookup_and_delete__destroy(skel);
+}
+
+static void test_lookup_and_delete_lru_hash(void)
+{
+	struct test_lookup_and_delete *skel;
+	__u64 key, value;
+	int map_fd, err;
+
+	/* Setup program and fill the LRU map. */
+	skel = setup_prog(BPF_MAP_TYPE_LRU_HASH, &map_fd);
+	if (!ASSERT_OK_PTR(skel, "setup_prog"))
+		return;
+
+	err = fill_values(map_fd);
+	if (!ASSERT_OK(err, "fill_values"))
+		goto cleanup;
+
+	/* Insert new element at key=3, should reuse LRU element. */
+	key = 3;
+	err = trigger_tp(skel, key, NEW_VALUE);
+	if (!ASSERT_OK(err, "trigger_tp"))
+		goto cleanup;
+
+	/* Lookup and delete element 3. */
+	err = bpf_map_lookup_and_delete_elem(map_fd, &key, &value);
+	if (!ASSERT_OK(err, "bpf_map_lookup_and_delete_elem"))
+		goto cleanup;
+
+	/* Value should match the new value. */
+	if (CHECK(value != NEW_VALUE, "bpf_map_lookup_and_delete_elem",
+		  "unexpected value=%lld\n", value))
+		goto cleanup;
+
+	/* Check that entries 3 and 1 are non existent. */
+	err = bpf_map_lookup_elem(map_fd, &key, &value);
+	if (!ASSERT_ERR(err, "bpf_map_lookup_elem"))
+		goto cleanup;
+
+	key = 1;
+	err = bpf_map_lookup_elem(map_fd, &key, &value);
+	if (!ASSERT_ERR(err, "bpf_map_lookup_elem"))
+		goto cleanup;
+
+cleanup:
+	test_lookup_and_delete__destroy(skel);
+}
+
+static void test_lookup_and_delete_lru_percpu_hash(void)
+{
+	struct test_lookup_and_delete *skel;
+	__u64 key, val, value[nr_cpus];
+	int map_fd, err, i, cpucnt = 0;
+
+	/* Setup program and fill the LRU map. */
+	skel = setup_prog(BPF_MAP_TYPE_LRU_PERCPU_HASH, &map_fd);
+	if (!ASSERT_OK_PTR(skel, "setup_prog"))
+		return;
+
+	err = fill_values_percpu(map_fd);
+	if (!ASSERT_OK(err, "fill_values_percpu"))
+		goto cleanup;
+
+	/* Insert new element at key=3, should reuse LRU element 1. */
+	key = 3;
+	err = trigger_tp(skel, key, NEW_VALUE);
+	if (!ASSERT_OK(err, "trigger_tp"))
+		goto cleanup;
+
+	/* Clean value. */
+	for (i = 0; i < nr_cpus; i++)
+		value[i] = 0;
+
+	/* Lookup and delete element 3. */
+	err = bpf_map_lookup_and_delete_elem(map_fd, &key, value);
+	if (!ASSERT_OK(err, "bpf_map_lookup_and_delete_elem")) {
+		goto cleanup;
+	}
+
+	/* Check if only one CPU has set the value. */
+	for (i = 0; i < nr_cpus; i++) {
+		val = value[i];
+		if (val) {
+			if (CHECK(val != NEW_VALUE, "map value",
+				  "unexpected for cpu %d: %lld\n", i, val))
+				goto cleanup;
+			cpucnt++;
+		}
+	}
+	if (CHECK(cpucnt != 1, "map value", "set for %d CPUs instead of 1!\n",
+		  cpucnt))
+		goto cleanup;
+
+	/* Check that entries 3 and 1 are non existent. */
+	err = bpf_map_lookup_elem(map_fd, &key, &value);
+	if (!ASSERT_ERR(err, "bpf_map_lookup_elem"))
+		goto cleanup;
+
+	key = 1;
+	err = bpf_map_lookup_elem(map_fd, &key, &value);
+	if (!ASSERT_ERR(err, "bpf_map_lookup_elem"))
+		goto cleanup;
+
+cleanup:
+	test_lookup_and_delete__destroy(skel);
+}
+
+void test_lookup_and_delete(void)
+{
+	nr_cpus = bpf_num_possible_cpus();
+
+	if (test__start_subtest("lookup_and_delete"))
+		test_lookup_and_delete_hash();
+	if (test__start_subtest("lookup_and_delete_percpu"))
+		test_lookup_and_delete_percpu_hash();
+	if (test__start_subtest("lookup_and_delete_lru"))
+		test_lookup_and_delete_lru_hash();
+	if (test__start_subtest("lookup_and_delete_lru_percpu"))
+		test_lookup_and_delete_lru_percpu_hash();
+}