bpf: Extend libbpf with bpf_map_lookup_and_delete_elem_flags

Add bpf_map_lookup_and_delete_elem_flags() libbpf API in order to use
the BPF_F_LOCK flag with the map_lookup_and_delete_elem() function.
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/15b05dafe46c7e0750d110f233977372029d1f62.1620763117.git.denis.salopek@sartura.hr

tools/lib/bpf/bpf.c

@@ -458,6 +458,19 @@ int bpf_map_lookup_and_delete_elem(int fd, const void *key, void *value)
 	return sys_bpf(BPF_MAP_LOOKUP_AND_DELETE_ELEM, &attr, sizeof(attr));
 }
 
+int bpf_map_lookup_and_delete_elem_flags(int fd, const void *key, void *value, __u64 flags)
+{
+	union bpf_attr attr;
+
+	memset(&attr, 0, 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_AND_DELETE_ELEM, &attr, sizeof(attr));
+}
+
 int bpf_map_delete_elem(int fd, const void *key)
 {
 	union bpf_attr attr;

tools/lib/bpf/bpf.h

@@ -124,6 +124,8 @@ 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_lookup_and_delete_elem_flags(int fd, const void *key,
+						    void *value, __u64 flags);
 LIBBPF_API int bpf_map_delete_elem(int fd, const void *key);
 LIBBPF_API int bpf_map_get_next_key(int fd, const void *key, void *next_key);
 LIBBPF_API int bpf_map_freeze(int fd);

tools/lib/bpf/libbpf.map

@@ -361,6 +361,7 @@ LIBBPF_0.4.0 {
 		bpf_linker__new;
 		bpf_map__initial_value;
 		bpf_map__inner_map;
+		bpf_map_lookup_and_delete_elem_flags;
 		bpf_object__gen_loader;
 		bpf_object__set_kversion;
 		bpf_tc_attach;