* [PATCH v4 bpf-next 8/9] libbpf: introduce bpf_map_lookup_elem_flags()
@ 2019-01-24 4:31 Alexei Starovoitov
2019-01-24 4:31 ` [PATCH v4 bpf-next 9/9] selftests/bpf: test for BPF_F_LOCK Alexei Starovoitov
0 siblings, 1 reply; 2+ messages in thread
From: Alexei Starovoitov @ 2019-01-24 4:31 UTC (permalink / raw)
To: davem; +Cc: daniel, jakub.kicinski, netdev, kernel-team
Introduce
int bpf_map_lookup_elem_flags(int fd, const void *key, void *value, __u64 flags)
helper to lookup array/hash/cgroup_local_storage elements with BPF_F_LOCK flag.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
tools/lib/bpf/bpf.c | 13 +++++++++++++
tools/lib/bpf/bpf.h | 2 ++
tools/lib/bpf/libbpf.map | 1 +
3 files changed, 16 insertions(+)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 3caaa3428774..d55a77a05d5f 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -357,6 +357,19 @@ int bpf_map_lookup_elem(int fd, const void *key, void *value)
return sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
}
+int bpf_map_lookup_elem_flags(int fd, const void *key, void *value, __u64 flags)
+{
+ union bpf_attr attr;
+
+ bzero(&attr, sizeof(attr));
+ attr.map_fd = fd;
+ attr.key = ptr_to_u64(key);
+ attr.value = ptr_to_u64(value);
+ attr.flags = flags;
+
+ return sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
+}
+
int bpf_map_lookup_and_delete_elem(int fd, const void *key, void *value)
{
union bpf_attr attr;
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 8f09de482839..ed09eed2dc3b 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -110,6 +110,8 @@ LIBBPF_API int bpf_map_update_elem(int fd, const void *key, const void *value,
__u64 flags);
LIBBPF_API int bpf_map_lookup_elem(int fd, const void *key, void *value);
+LIBBPF_API int bpf_map_lookup_elem_flags(int fd, const void *key, void *value,
+ __u64 flags);
LIBBPF_API int bpf_map_lookup_and_delete_elem(int fd, const void *key,
void *value);
LIBBPF_API int bpf_map_delete_elem(int fd, const void *key);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 266bc95d0142..f6f96fc38c50 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -130,4 +130,5 @@ LIBBPF_0.0.2 {
bpf_probe_helper;
bpf_probe_map_type;
bpf_probe_prog_type;
+ bpf_map_lookup_elem_flags;
} LIBBPF_0.0.1;
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH v4 bpf-next 9/9] selftests/bpf: test for BPF_F_LOCK
2019-01-24 4:31 [PATCH v4 bpf-next 8/9] libbpf: introduce bpf_map_lookup_elem_flags() Alexei Starovoitov
@ 2019-01-24 4:31 ` Alexei Starovoitov
0 siblings, 0 replies; 2+ messages in thread
From: Alexei Starovoitov @ 2019-01-24 4:31 UTC (permalink / raw)
To: davem; +Cc: daniel, jakub.kicinski, netdev, kernel-team
Add C based test that runs 4 bpf programs in parallel
that update the same hash and array maps.
And another 2 threads that read from these two maps
via lookup(key, value, BPF_F_LOCK) api
to make sure the user space sees consistent value in both
hash and array elements while user space races with kernel bpf progs.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
tools/testing/selftests/bpf/Makefile | 2 +-
tools/testing/selftests/bpf/test_map_lock.c | 66 ++++++++++++++++++
tools/testing/selftests/bpf/test_progs.c | 74 +++++++++++++++++++++
3 files changed, 141 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/bpf/test_map_lock.c
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index fcfda51406f9..368ca8249732 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -39,7 +39,7 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
get_cgroup_id_kern.o socket_cookie_prog.o test_select_reuseport_kern.o \
test_skb_cgroup_id_kern.o bpf_flow.o netcnt_prog.o \
test_sk_lookup_kern.o test_xdp_vlan.o test_queue_map.o test_stack_map.o \
- xdp_dummy.o test_map_in_map.o test_spin_lock.o
+ xdp_dummy.o test_map_in_map.o test_spin_lock.o test_map_lock.o
# Order correspond to 'make run_tests' order
TEST_PROGS := test_kmod.sh \
diff --git a/tools/testing/selftests/bpf/test_map_lock.c b/tools/testing/selftests/bpf/test_map_lock.c
new file mode 100644
index 000000000000..af8cc68ed2f9
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_map_lock.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+#include <linux/bpf.h>
+#include <linux/version.h>
+#include "bpf_helpers.h"
+
+#define VAR_NUM 16
+
+struct hmap_elem {
+ struct bpf_spin_lock lock;
+ int var[VAR_NUM];
+};
+
+struct bpf_map_def SEC("maps") hash_map = {
+ .type = BPF_MAP_TYPE_HASH,
+ .key_size = sizeof(int),
+ .value_size = sizeof(struct hmap_elem),
+ .max_entries = 1,
+};
+
+BPF_ANNOTATE_KV_PAIR(hash_map, int, struct hmap_elem);
+
+struct array_elem {
+ struct bpf_spin_lock lock;
+ int var[VAR_NUM];
+};
+
+struct bpf_map_def SEC("maps") array_map = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .key_size = sizeof(int),
+ .value_size = sizeof(struct array_elem),
+ .max_entries = 1,
+};
+
+BPF_ANNOTATE_KV_PAIR(array_map, int, struct array_elem);
+
+SEC("map_lock_demo")
+int bpf_map_lock_test(struct __sk_buff *skb)
+{
+ struct hmap_elem zero = {}, *val;
+ int rnd = bpf_get_prandom_u32();
+ int key = 0, err = 1, i;
+ struct array_elem *q;
+
+ val = bpf_map_lookup_elem(&hash_map, &key);
+ if (!val)
+ goto err;
+ /* spin_lock in hash map */
+ bpf_spin_lock(&val->lock);
+ for (i = 0; i < VAR_NUM; i++)
+ val->var[i] = rnd;
+ bpf_spin_unlock(&val->lock);
+
+ /* spin_lock in array */
+ q = bpf_map_lookup_elem(&array_map, &key);
+ if (!q)
+ goto err;
+ bpf_spin_lock(&q->lock);
+ for (i = 0; i < VAR_NUM; i++)
+ q->var[i] = rnd;
+ bpf_spin_unlock(&q->lock);
+ err = 0;
+err:
+ return err;
+}
+char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index 6425e95c3f16..1427338f14a2 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -1922,6 +1922,79 @@ static void test_spin_lock(void)
bpf_object__close(obj);
}
+static void *parallel_map_access(void *arg)
+{
+ int err, map_fd = *(u32 *) arg;
+ int vars[17], i, j, rnd, key = 0;
+
+ for (i = 0; i < 10000; i++) {
+ err = bpf_map_lookup_elem_flags(map_fd, &key, vars, BPF_F_LOCK);
+ if (err) {
+ printf("lookup failed\n");
+ error_cnt++;
+ goto out;
+ }
+ if (vars[0] != 0) {
+ printf("lookup #%d var[0]=%d\n", i, vars[0]);
+ error_cnt++;
+ goto out;
+ }
+ rnd = vars[1];
+ for (j = 2; j < 17; j++) {
+ if (vars[j] == rnd)
+ continue;
+ printf("lookup #%d var[1]=%d var[%d]=%d\n",
+ i, rnd, j, vars[j]);
+ error_cnt++;
+ goto out;
+ }
+ }
+out:
+ pthread_exit(arg);
+}
+
+static void test_map_lock(void)
+{
+ const char *file = "./test_map_lock.o";
+ int prog_fd, map_fd[2], vars[17] = {};
+ pthread_t thread_id[6];
+ struct bpf_object *obj;
+ int err = 0, key = 0, i;
+ void *ret;
+
+ err = bpf_prog_load(file, BPF_PROG_TYPE_CGROUP_SKB, &obj, &prog_fd);
+ if (err) {
+ printf("test_map_lock:bpf_prog_load errno %d\n", errno);
+ goto close_prog;
+ }
+ map_fd[0] = bpf_find_map(__func__, obj, "hash_map");
+ if (map_fd[0] < 0)
+ goto close_prog;
+ map_fd[1] = bpf_find_map(__func__, obj, "array_map");
+ if (map_fd[1] < 0)
+ goto close_prog;
+
+ bpf_map_update_elem(map_fd[0], &key, vars, BPF_F_LOCK);
+
+ for (i = 0; i < 4; i++)
+ assert(pthread_create(&thread_id[i], NULL,
+ ¶llel_bpf_prog_test_run, &prog_fd) == 0);
+ for (i = 4; i < 6; i++)
+ assert(pthread_create(&thread_id[i], NULL,
+ ¶llel_map_access, &map_fd[i - 4]) == 0);
+ for (i = 0; i < 4; i++)
+ assert(pthread_join(thread_id[i], &ret) == 0 &&
+ ret == (void *)&prog_fd);
+ for (i = 4; i < 6; i++)
+ assert(pthread_join(thread_id[i], &ret) == 0 &&
+ ret == (void *)&map_fd[i - 4]);
+ goto close_prog_noerr;
+close_prog:
+ error_cnt++;
+close_prog_noerr:
+ bpf_object__close(obj);
+}
+
int main(void)
{
srand(time(NULL));
@@ -1950,6 +2023,7 @@ int main(void)
test_queue_stack_map(QUEUE);
test_queue_stack_map(STACK);
test_spin_lock();
+ test_map_lock();
printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt);
return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS;
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
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2019-01-24 4:31 [PATCH v4 bpf-next 8/9] libbpf: introduce bpf_map_lookup_elem_flags() Alexei Starovoitov
2019-01-24 4:31 ` [PATCH v4 bpf-next 9/9] selftests/bpf: test for BPF_F_LOCK Alexei Starovoitov
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