On Sun, Jun 2, 2024 at 5:41 AM Jiri Olsa <olsajiri@xxxxxxxxx> wrote:
>
> On Fri, May 31, 2024 at 06:45:05PM -0700, Andrii Nakryiko wrote:
> > Switch from callback-based iteration over BTF type ID and string offset
> > fields to an iterator-based approach.
> >
> > Switch all existing internal use cases to this new iterator.
> >
> > We have .BTF.ext fields iteration, those could be switched to
> > iterator-based implementation as well, but this is left as a follow up.
> >
> > We also convert bpftool's use of this libbpf-internal API.
> >
> > Cc: Eduard Zingerman <eddyz87@xxxxxxxxx>
> > Cc: Alan Maguire <alan.maguire@xxxxxxxxxx>
> > Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> > ---
> > tools/bpf/bpftool/gen.c | 17 +-
> > tools/lib/bpf/btf.c | 334 ++++++++++++++++++--------------
> > tools/lib/bpf/libbpf_internal.h | 26 ++-
> > tools/lib/bpf/linker.c | 55 +++---
> > 4 files changed, 253 insertions(+), 179 deletions(-)
> >
> > diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
> > index b3979ddc0189..7b9c0255a2cf 100644
> > --- a/tools/bpf/bpftool/gen.c
> > +++ b/tools/bpf/bpftool/gen.c
> > @@ -2379,15 +2379,6 @@ static int btfgen_record_obj(struct btfgen_info *info, const char *obj_path)
> > return err;
> > }
> >
> > -static int btfgen_remap_id(__u32 *type_id, void *ctx)
> > -{
> > - unsigned int *ids = ctx;
> > -
> > - *type_id = ids[*type_id];
> > -
> > - return 0;
> > -}
> > -
> > /* Generate BTF from relocation information previously recorded */
> > static struct btf *btfgen_get_btf(struct btfgen_info *info)
> > {
> > @@ -2466,11 +2457,13 @@ static struct btf *btfgen_get_btf(struct btfgen_info *info)
> >
> > /* second pass: fix up type ids */
> > for (i = 1; i < btf__type_cnt(btf_new); i++) {
> > + struct btf_field_iter it;
> > struct btf_type *btf_type = (struct btf_type *) btf__type_by_id(btf_new, i);
> > + __u32 *type_id;
> >
> > - err = btf_type_visit_type_ids(btf_type, btfgen_remap_id, ids);
> > - if (err)
> > - goto err_out;
> > + btf_field_iter_init(&it, btf_type, BTF_FIELD_ITER_IDS);
>
> lgtm, should we check return value from btf_field_iter_init?
yeah, it should never fail, but if BTF is corrupted it might, so
better safe than sorry, I'll add checks
>
> jirka
>
> > + while ((type_id = btf_field_iter_next(&it)))
> > + *type_id = ids[*type_id];
> > }
> >
> > free(ids);
> > diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
> > index 2d0840ef599a..0c39f9b3f98b 100644
> > --- a/tools/lib/bpf/btf.c
> > +++ b/tools/lib/bpf/btf.c
> > @@ -1739,9 +1739,8 @@ struct btf_pipe {
> > struct hashmap *str_off_map; /* map string offsets from src to dst */
> > };
> >
[...] (trimming is good)
