On Sat, Oct 23, 2021 at 1:52 PM Quentin Monnet <quentin@xxxxxxxxxxxxx> wrote:
>
> When listing BPF objects, bpftool can print a number of properties about
> items holding references to these objects. For example, it can show pinned
> paths for BPF programs, maps, and links; or programs and maps using a given
> BTF object; or the names and PIDs of processes referencing BPF objects. To
> collect this information, bpftool uses hash maps (to be clear: the data
> structures, inside bpftool - we are not talking of BPF maps). It uses the
> implementation available from the kernel, and picks it up from
> tools/include/linux/hashtable.h.
>
> This patchset converts bpftool's hash maps to a distinct implementation
> instead, the one coming with libbpf. The main motivation for this change is
> that it should ease the path towards a potential out-of-tree mirror for
> bpftool, like the one libbpf already has. Although it's not perfect to
> depend on libbpf's internal components, bpftool is intimately tied with the
> library anyway, and this looks better than depending too much on (non-UAPI)
> kernel headers.
>
> The first two patches contain preparatory work on the Makefile and on the
> initialisation of the hash maps for collecting pinned paths for objects.
> Then the transition is split into several steps, one for each kind of
> properties for which the collection is backed by hash maps.
>
> v2:
> - Move hashmap cleanup for pinned paths for links from do_detach() to
> do_show().
> - Handle errors on hashmap__append() (in three of the patches).
> - Rename bpftool_hash_fn() and bpftool_equal_fn() as hash_fn_for_key_id()
> and equal_fn_for_key_id(), respectively.
> - Add curly braces for hashmap__for_each_key_entry() { } in
> show_btf_plain() and show_btf_json(), where the flow was difficult to
> read.
>
> Quentin Monnet (5):
> bpftool: Remove Makefile dep. on $(LIBBPF) for $(LIBBPF_INTERNAL_HDRS)
> bpftool: Do not expose and init hash maps for pinned path in main.c
> bpftool: Switch to libbpf's hashmap for pinned paths of BPF objects
> bpftool: Switch to libbpf's hashmap for programs/maps in BTF listing
> bpftool: Switch to libbpf's hashmap for PIDs/names references
>
> tools/bpf/bpftool/Makefile | 12 ++--
> tools/bpf/bpftool/btf.c | 132 +++++++++++++++++--------------------
> tools/bpf/bpftool/common.c | 50 ++++++++------
> tools/bpf/bpftool/link.c | 45 ++++++++-----
> tools/bpf/bpftool/main.c | 17 +----
> tools/bpf/bpftool/main.h | 54 +++++++--------
> tools/bpf/bpftool/map.c | 45 ++++++++-----
> tools/bpf/bpftool/pids.c | 90 ++++++++++++++-----------
> tools/bpf/bpftool/prog.c | 45 ++++++++-----
> 9 files changed, 262 insertions(+), 228 deletions(-)
>
> --
> 2.30.2
>
Applied to bpf-next, thanks.
