bpf: Add map_name to bpf_map_info

This patch allows userspace to specify a name for a map
during BPF_MAP_CREATE.

The map's name can later be exported to user space
via BPF_OBJ_GET_INFO_BY_FD.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index bd63482..6d2137b 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -190,6 +190,7 @@ union bpf_attr {
 		__u32	numa_node;	/* numa node (effective only if
 					 * BPF_F_NUMA_NODE is set).
 					 */
+		__u8	map_name[BPF_OBJ_NAME_LEN];
 	};
 
 	struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
@@ -829,6 +830,7 @@ struct bpf_map_info {
 	__u32 value_size;
 	__u32 max_entries;
 	__u32 map_flags;
+	__u8  name[BPF_OBJ_NAME_LEN];
 } __attribute__((aligned(8)));
 
 /* User bpf_sock_ops struct to access socket values and specify request ops