bpf: Make bpf_link_info.iter similar to bpf_iter_link_info

bpf_link_info.iter is used by link_query to return bpf_iter_link_info
to user space. Fields may be different, e.g., map_fd vs. map_id, so
we cannot reuse the exact structure. But make them similar, e.g.,

  struct bpf_link_info {
     /* common fields */
     union {
	struct { ... } raw_tracepoint;
	struct { ... } tracing;
	...
	struct {
	    /* common fields for iter */
	    union {
		struct {
		    __u32 map_id;
		} map;
		/* other structs for other targets */
	    };
	};
    };
 };

so the structure is extensible the same way as bpf_iter_link_info.

Fixes: 6b0a249a301e ("bpf: Implement link_query for bpf iterators")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200828051922.758950-1-yhs@fb.com

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 0388bc0..ef7af38 100644 (file)
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -4251,8 +4251,10 @@ struct bpf_link_info {
                        __aligned_u64 target_name; /* in/out: target_name buffer ptr */
                        __u32 target_name_len;     /* in/out: target_name buffer len */
                        union {
-                               __u32 map_id;
-                       } map;
+                               struct {
+                                       __u32 map_id;
+                               } map;
+                       };
                } iter;
                struct  {
                        __u32 netns_ino;

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 0388bc0..ef7af38 100644 (file)
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -4251,8 +4251,10 @@ struct bpf_link_info {
                        __aligned_u64 target_name; /* in/out: target_name buffer ptr */
                        __u32 target_name_len;     /* in/out: target_name buffer len */
                        union {
-                               __u32 map_id;
-                       } map;
+                               struct {
+                                       __u32 map_id;
+                               } map;
+                       };
                } iter;
                struct  {
                        __u32 netns_ino;