Commit c2641123 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Daniel Borkmann
Browse files

libbpf: Make use of BTF field iterator in BTF handling code 



Use new BTF field iterator logic to replace all the callback-based
visitor calls. There is still a .BTF.ext callback-based visitor APIs
that should be converted, which will happens as a follow up.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Tested-by: default avatarAlan Maguire <alan.maguire@oracle.com>
Acked-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20240605001629.4061937-4-andrii@kernel.org
parent 2bce2c1c

tools/lib/bpf/btf.c

+54 −22
Original line number Diff line number Diff line
@@ -1739,9 +1739,8 @@ struct btf_pipe { 
	struct hashmap *str_off_map; /* map string offsets from src to dst */

};



static int btf_rewrite_str(__u32 *str_off, void *ctx)

static int btf_rewrite_str(struct btf_pipe *p, __u32 *str_off)

{

	struct btf_pipe *p = ctx;

	long mapped_off;

	int off, err;
@@ -1774,7 +1773,9 @@ static int btf_rewrite_str(__u32 *str_off, void *ctx) 
int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_type *src_type)

{

	struct btf_pipe p = { .src = src_btf, .dst = btf };

	struct btf_field_iter it;

	struct btf_type *t;

	__u32 *str_off;

	int sz, err;



	sz = btf_type_size(src_type);
@@ -1791,26 +1792,17 @@ int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_t 


	memcpy(t, src_type, sz);



	err = btf_type_visit_str_offs(t, btf_rewrite_str, &p);

	err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS);

	if (err)

		return libbpf_err(err);



	return btf_commit_type(btf, sz);

	while ((str_off = btf_field_iter_next(&it))) {

		err = btf_rewrite_str(&p, str_off);

		if (err)

			return libbpf_err(err);

	}



static int btf_rewrite_type_ids(__u32 *type_id, void *ctx)

{

	struct btf *btf = ctx;



	if (!*type_id) /* nothing to do for VOID references */

		return 0;



	/* we haven't updated btf's type count yet, so

	 * btf->start_id + btf->nr_types - 1 is the type ID offset we should

	 * add to all newly added BTF types

	 */

	*type_id += btf->start_id + btf->nr_types - 1;

	return 0;

	return btf_commit_type(btf, sz);

}



static size_t btf_dedup_identity_hash_fn(long key, void *ctx);
@@ -1858,6 +1850,9 @@ int btf__add_btf(struct btf *btf, const struct btf *src_btf) 
	memcpy(t, src_btf->types_data, data_sz);



	for (i = 0; i < cnt; i++) {

		struct btf_field_iter it;

		__u32 *type_id, *str_off;



		sz = btf_type_size(t);

		if (sz < 0) {

			/* unlikely, has to be corrupted src_btf */
@@ -1869,15 +1864,31 @@ int btf__add_btf(struct btf *btf, const struct btf *src_btf) 
		*off = t - btf->types_data;



		/* add, dedup, and remap strings referenced by this BTF type */

		err = btf_type_visit_str_offs(t, btf_rewrite_str, &p);

		err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS);

		if (err)

			goto err_out;

		while ((str_off = btf_field_iter_next(&it))) {

			err = btf_rewrite_str(&p, str_off);

			if (err)

				goto err_out;

		}



		/* remap all type IDs referenced from this BTF type */

		err = btf_type_visit_type_ids(t, btf_rewrite_type_ids, btf);

		err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS);

		if (err)

			goto err_out;



		while ((type_id = btf_field_iter_next(&it))) {

			if (!*type_id) /* nothing to do for VOID references */

				continue;



			/* we haven't updated btf's type count yet, so

			 * btf->start_id + btf->nr_types - 1 is the type ID offset we should

			 * add to all newly added BTF types

			 */

			*type_id += btf->start_id + btf->nr_types - 1;

		}



		/* go to next type data and type offset index entry */

		t += sz;

		off++;
@@ -3453,12 +3464,20 @@ static int btf_for_each_str_off(struct btf_dedup *d, str_off_visit_fn fn, void * 
	int i, r;



	for (i = 0; i < d->btf->nr_types; i++) {

		struct btf_field_iter it;

		struct btf_type *t = btf_type_by_id(d->btf, d->btf->start_id + i);

		__u32 *str_off;



		r = btf_type_visit_str_offs(t, fn, ctx);

		r = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS);

		if (r)

			return r;



		while ((str_off = btf_field_iter_next(&it))) {

			r = fn(str_off, ctx);

			if (r)

				return r;

		}

	}



	if (!d->btf_ext)

		return 0;
@@ -4919,10 +4938,23 @@ static int btf_dedup_remap_types(struct btf_dedup *d) 


	for (i = 0; i < d->btf->nr_types; i++) {

		struct btf_type *t = btf_type_by_id(d->btf, d->btf->start_id + i);

		struct btf_field_iter it;

		__u32 *type_id;



		r = btf_type_visit_type_ids(t, btf_dedup_remap_type_id, d);

		r = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS);

		if (r)

			return r;



		while ((type_id = btf_field_iter_next(&it))) {

			__u32 resolved_id, new_id;



			resolved_id = resolve_type_id(d, *type_id);

			new_id = d->hypot_map[resolved_id];

			if (new_id > BTF_MAX_NR_TYPES)

				return -EINVAL;



			*type_id = new_id;

		}

	}



	if (!d->btf_ext)