From: Kui-Feng Lee <thinker.li@gmail.com>
To: bpf@vger.kernel.org, ast@kernel.org, martin.lau@linux.dev,
yhs@meta.com, song@kernel.org, kernel-team@meta.com,
andrii@kernel.org
Cc: Kui-Feng Lee <kuifeng@meta.com>, Quentin Monnet <quentin@isovalent.com>
Subject: [PATCH bpf-next v4] bpftool: Show map IDs along with struct_ops links.
Date: Fri, 21 Apr 2023 14:41:31 -0700 [thread overview]
Message-ID: <20230421214131.352662-1-kuifeng@meta.com> (raw)
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@meta.com>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
---
tools/bpf/bpftool/link.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index d98dbc50cf4c..243b74e18e51 100644
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -212,7 +212,10 @@ static int show_link_close_json(int fd, struct bpf_link_info *info)
case BPF_LINK_TYPE_NETFILTER:
netfilter_dump_json(info, json_wtr);
break;
-
+ case BPF_LINK_TYPE_STRUCT_OPS:
+ jsonw_uint_field(json_wtr, "map_id",
+ info->struct_ops.map_id);
+ break;
default:
break;
}
@@ -245,7 +248,10 @@ 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 %u ", info->struct_ops.map_id);
+ else
+ printf("prog %u ", info->prog_id);
}
static void show_link_attach_type_plain(__u32 attach_type)
--
2.34.1
next reply other threads:[~2023-04-21 21:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-21 21:41 Kui-Feng Lee [this message]
2023-04-23 14:33 ` [PATCH bpf-next v4] bpftool: Show map IDs along with struct_ops links John Fastabend
2023-04-27 13:00 ` patchwork-bot+netdevbpf
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