On 4/16/21 2:58 AM, Denis Salopek wrote:
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.
Cc: Juraj Vijtiuk <juraj.vijtiuk@xxxxxxxxxx>
Cc: Luka Oreskovic <luka.oreskovic@xxxxxxxxxx>
Cc: Luka Perkov <luka.perkov@xxxxxxxxxx>
Cc: Yonghong Song <yhs@xxxxxx>
Cc: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Signed-off-by: Denis Salopek <denis.salopek@xxxxxxxxxx>
---
v5: Use more appropriate macros. Better check for changed value.
---
.../bpf/prog_tests/lookup_and_delete.c | 292 ++++++++++++++++++
.../bpf/progs/test_lookup_and_delete.c | 26 ++
tools/testing/selftests/bpf/test_lru_map.c | 8 +
tools/testing/selftests/bpf/test_maps.c | 19 +-
4 files changed, 344 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/lookup_and_delete.c
create mode 100644 tools/testing/selftests/bpf/progs/test_lookup_and_delete.c
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..fb46d9082e98
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/lookup_and_delete.c
@@ -0,0 +1,292 @@
+// 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)
+{
+ BPF_DECLARE_PERCPU(__u64, value);
+ int i, err;
+ u64 key;
+
+ for (i = 0; i < nr_cpus; i++)
+ bpf_percpu(value, i) = START_VALUE;
There is an ongoing effort to remove bpf_percpu() macro and recommend to
use explicit percpu encoding, see:
https://lore.kernel.org/bpf/20210415174619.51229-3-pctammela@xxxxxxxxxxxx/T/#u
I would suggest to make a change in the next revision to avoid
possibly another round of change of either this patch set or the percpu
patch set. The same for above BPF_DECLARE_PERCPU.
+
+ 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(!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, 2);
Maybe change 2 to 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_LT(0, *map_fd, "bpf_map__fd"))
Theoretically *map_fd = 0 should be fine too and I don't think kernel
checks map_fd value in this case. Also comparison "0 < *map_fd" is kind
of anti-pattern. Could you add an ASSERT_GE
to test_progs.h, using
!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;
+ BPF_DECLARE_PERCPU(__u64, value);
change here.
+ int map_fd, err, i;
+ __u64 key, val;
+
+ /* 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 = bpf_percpu(value, i);
here.
+
+ /* 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;
+ BPF_DECLARE_PERCPU(__u64, value);
here.
+ int map_fd, err, i, cpucnt = 0;
+ __u64 key, val;
+
+ /* 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++)
+ bpf_percpu(value, i) = 0;
here.
+
+ /* 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")) {
+ CHECK(1 == 0, "errno = ", "%d\n", errno);
The condition is "1 == 0"? What is the purpose here?
+ goto cleanup;
+ }
+
+ /* Check if only one CPU has set the value. */
+ for (i = 0; i < nr_cpus; i++) {
+ val = bpf_percpu(value, i);
here.
+ 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();
+}
diff --git a/tools/testing/selftests/bpf/progs/test_lookup_and_delete.c b/tools/testing/selftests/bpf/progs/test_lookup_and_delete.c
new file mode 100644
index 000000000000..3a193f42c7e7
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_lookup_and_delete.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+
+__u32 set_pid = 0;
+__u64 set_key = 0;
+__u64 set_value = 0;
+
+struct {
+ __uint(type, BPF_MAP_TYPE_HASH);
+ __uint(max_entries, 2);
+ __type(key, __u64);
+ __type(value, __u64);
+} hash_map SEC(".maps");
+
+SEC("tp/syscalls/sys_enter_getpgid")
+int bpf_lookup_and_delete_test(const void *ctx)
+{
+ if (set_pid == bpf_get_current_pid_tgid() >> 32)
+ bpf_map_update_elem(&hash_map, &set_key, &set_value, BPF_NOEXIST);
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/test_lru_map.c b/tools/testing/selftests/bpf/test_lru_map.c
index 6a5349f9eb14..7e9049fa3edf 100644
--- a/tools/testing/selftests/bpf/test_lru_map.c
+++ b/tools/testing/selftests/bpf/test_lru_map.c
@@ -231,6 +231,14 @@ static void test_lru_sanity0(int map_type, int map_flags)
assert(bpf_map_lookup_elem(lru_map_fd, &key, value) == -1 &&
errno == ENOENT);
+ /* lookup elem key=1 and delete it, then check it doesn't exist */
+ key = 1;
+ assert(!bpf_map_lookup_and_delete_elem(lru_map_fd, &key, &value));
+ assert(value[0] == 1234);
+
+ /* remove the same element from the expected map */
+ assert(!bpf_map_delete_elem(expected_map_fd, &key));
+
assert(map_equal(lru_map_fd, expected_map_fd));
close(expected_map_fd);
diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c
index 51adc42b2b40..dbd5f95e8bde 100644
--- a/tools/testing/selftests/bpf/test_maps.c
+++ b/tools/testing/selftests/bpf/test_maps.c
@@ -65,6 +65,13 @@ static void test_hashmap(unsigned int task, void *data)
assert(bpf_map_lookup_elem(fd, &key, &value) == 0 && value == 1234);
key = 2;
+ value = 1234;
+ /* Insert key=2 element. */
+ assert(bpf_map_update_elem(fd, &key, &value, BPF_ANY) == 0);
+
+ /* Check that key=2 matches the value and delete it */
+ assert(bpf_map_lookup_and_delete_elem(fd, &key, &value) == 0 && value == 1234);
+
/* Check that key=2 is not found. */
assert(bpf_map_lookup_elem(fd, &key, &value) == -1 && errno == ENOENT);
@@ -164,8 +171,18 @@ static void test_hashmap_percpu(unsigned int task, void *data)
key = 1;
/* Insert key=1 element. */
- assert(!(expected_key_mask & key));
there is no need to move this line below, right?
assert(bpf_map_update_elem(fd, &key, value, BPF_ANY) == 0);
+
+ /* Lookup and delete elem key=1 and check value. */
+ assert(bpf_map_lookup_and_delete_elem(fd, &key, value) == 0 &&
+ bpf_percpu(value, 0) == 100);
bpf_percpu here.
+
+ for (i = 0; i < nr_cpus; i++)
+ bpf_percpu(value, i) = i + 100;
bpf_percpu here.
+
+ /* Insert key=1 element which should not exist. */
+ assert(!(expected_key_mask & key));
+ assert(bpf_map_update_elem(fd, &key, value, BPF_NOEXIST) == 0);
expected_key_mask |= key;
/* BPF_NOEXIST means add new element if it doesn't exist. */
