[PATCH v3 bpf-next 8/9] libbpf: introduce bpf_map_lookup_elem_flags()

[Alexei Starovoitov]

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 <a...@kernel.org>
---
 tools/lib/bpf/bpf.c      | 13 +++++++++++++
 tools/lib/bpf/bpf.h      |  2 ++
 tools/lib/bpf/libbpf.map |  4 ++++
 3 files changed, 19 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 cd02cd4e2cc3..ca5155409a15 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -124,3 +124,7 @@ LIBBPF_0.0.1 {
        local:
                *;
 };
+LIBBPF_0.0.2 {
+       global:
+               bpf_map_lookup_elem_flags;
+} LIBBPF_0.0.1;
-- 
2.17.1