On Fri, Oct 22, 2021 at 10:16 AM Quentin Monnet <quentin@xxxxxxxxxxxxx> wrote:
>
> BPF programs, maps, and links, can all be listed with their pinned paths
> by bpftool, when the "-f" option is provided. To do so, bpftool builds
> hash maps containing all pinned paths for each kind of objects.
>
> These three hash maps are always initialised in main.c, and exposed
> through main.h. There appear to be no particular reason to do so: we can
> just as well make them static to the files that need them (prog.c,
> map.c, and link.c respectively), and initialise them only when we want
> to show objects and the "-f" switch is provided.
>
> This may prevent unnecessary memory allocations if the implementation of
> the hash maps was to change in the future.
>
> Signed-off-by: Quentin Monnet <quentin@xxxxxxxxxxxxx>
> ---
> tools/bpf/bpftool/link.c | 9 ++++++++-
> tools/bpf/bpftool/main.c | 12 ------------
> tools/bpf/bpftool/main.h | 3 ---
> tools/bpf/bpftool/map.c | 9 ++++++++-
> tools/bpf/bpftool/prog.c | 9 ++++++++-
> 5 files changed, 24 insertions(+), 18 deletions(-)
>
> diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
> index 8cc3e36f8cc6..ebf29be747b3 100644
> --- a/tools/bpf/bpftool/link.c
> +++ b/tools/bpf/bpftool/link.c
> @@ -20,6 +20,8 @@ static const char * const link_type_name[] = {
> [BPF_LINK_TYPE_NETNS] = "netns",
> };
>
> +static struct pinned_obj_table link_table;
> +
> static int link_parse_fd(int *argc, char ***argv)
> {
> int fd;
> @@ -302,8 +304,10 @@ static int do_show(int argc, char **argv)
> __u32 id = 0;
> int err, fd;
>
> - if (show_pinned)
> + if (show_pinned) {
> + hash_init(link_table.table);
> build_pinned_obj_table(&link_table, BPF_OBJ_LINK);
> + }
> build_obj_refs_table(&refs_table, BPF_OBJ_LINK);
>
> if (argc == 2) {
> @@ -384,6 +388,9 @@ static int do_detach(int argc, char **argv)
> if (json_output)
> jsonw_null(json_wtr);
>
> + if (show_pinned)
> + delete_pinned_obj_table(&link_table);
Shouldn't this be in do_show rather than do_detach?
> +
> return 0;
> }
>
[...]
