On 4/20/23 16:41, Andrii Nakryiko wrote:
On Tue, Apr 18, 2023 at 5:37 PM Kui-Feng Lee <thinker.li@xxxxxxxxx> wrote:A new link type, BPF_LINK_TYPE_STRUCT_OPS, was added to attach struct_ops to links. (226bc6ae6405) It would be helpful for users to know which map is associated with the link. The assumption was that every link is associated with a BPF program, but this does not hold true for struct_ops. It would be better to display map_id instead of prog_id for struct_ops links. However, some tools may rely on the old assumption and need a prog_id. The discussion on the mailing list suggests that tools should parse JSON format. We will maintain the existing JSON format by adding a map_id without removing prog_id. As for plain text format, we will remove prog_id from the header line and add a map_id for struct_ops links. Signed-off-by: Kui-Feng Lee <kuifeng@xxxxxxxx> Reviewed-by: Quentin Monnet <quentin@xxxxxxxxxxxxx> --- tools/bpf/bpftool/link.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c index f985b79cca27..8eb8520bd7b4 100644 --- a/tools/bpf/bpftool/link.c +++ b/tools/bpf/bpftool/link.c @@ -195,6 +195,10 @@ static int show_link_close_json(int fd, struct bpf_link_info *info) info->netns.netns_ino); show_link_attach_type_json(info->netns.attach_type, json_wtr); break; + case BPF_LINK_TYPE_STRUCT_OPS: + jsonw_uint_field(json_wtr, "map_id", + info->struct_ops.map_id); + break; default: break; } @@ -227,7 +231,10 @@ static void show_link_header_plain(struct bpf_link_info *info) else printf("type %u ", info->type); - printf("prog %u ", info->prog_id); + if (info->type == BPF_LINK_TYPE_STRUCT_OPS) + printf("map_id %u ", info->struct_ops.map_id); + else + printf("prog %u ", info->prog_id);if we output "prog %u" for prog_id, shouldn't we just output "map %u" for map_id?
"map" make sense to me.
} static void show_link_attach_type_plain(__u32 attach_type) -- 2.34.1
