From: Alexei Starovoitov <ast@kernel.org>
Date: Wed, 1 Dec 2021 10:10:24 -0800
Subject: libbpf: Replace btf__type_by_id() with btf_type_by_id().
Patch-mainline: v5.17-rc1
Git-commit: 74753e1462e77349525daf9eb60ea21ed92d3a97
References: jsc#PED-1368

To prepare relo_core.c to be compiled in the kernel and the user space
replace btf__type_by_id with btf_type_by_id.

In libbpf btf__type_by_id and btf_type_by_id have different behavior.

bpf_core_apply_relo_insn() needs behavior of uapi btf__type_by_id
vs internal btf_type_by_id, but type_id range check is already done
in bpf_core_apply_relo(), so it's safe to replace it everywhere.
The kernel btf_type_by_id() does the check anyway. It doesn't hurt.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201181040.23337-2-alexei.starovoitov@gmail.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 tools/lib/bpf/btf.c             |    2 +-
 tools/lib/bpf/libbpf_internal.h |    2 +-
 tools/lib/bpf/relo_core.c       |   19 ++++++++-----------
 3 files changed, 10 insertions(+), 13 deletions(-)

--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -454,7 +454,7 @@ const struct btf *btf__base_btf(const st
 }
 
 /* internal helper returning non-const pointer to a type */
-struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id)
+struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id)
 {
 	if (type_id == 0)
 		return &btf_void;
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -172,7 +172,7 @@ static inline void *libbpf_reallocarray(
 struct btf;
 struct btf_type;
 
-struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id);
+struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id);
 const char *btf_kind_str(const struct btf_type *t);
 const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
 
--- a/tools/lib/bpf/relo_core.c
+++ b/tools/lib/bpf/relo_core.c
@@ -51,7 +51,7 @@ static bool is_flex_arr(const struct btf
 		return false;
 
 	/* has to be the last member of enclosing struct */
-	t = btf__type_by_id(btf, acc->type_id);
+	t = btf_type_by_id(btf, acc->type_id);
 	return acc->idx == btf_vlen(t) - 1;
 }
 
@@ -388,7 +388,7 @@ static int bpf_core_match_member(const s
 		return 0;
 
 	local_id = local_acc->type_id;
-	local_type = btf__type_by_id(local_btf, local_id);
+	local_type = btf_type_by_id(local_btf, local_id);
 	local_member = btf_members(local_type) + local_acc->idx;
 	local_name = btf__name_by_offset(local_btf, local_member->name_off);
 
@@ -580,7 +580,7 @@ static int bpf_core_calc_field_relo(cons
 		return -EUCLEAN; /* request instruction poisoning */
 
 	acc = &spec->spec[spec->len - 1];
-	t = btf__type_by_id(spec->btf, acc->type_id);
+	t = btf_type_by_id(spec->btf, acc->type_id);
 
 	/* a[n] accessor needs special handling */
 	if (!acc->name) {
@@ -729,7 +729,7 @@ static int bpf_core_calc_enumval_relo(co
 	case BPF_ENUMVAL_VALUE:
 		if (!spec)
 			return -EUCLEAN; /* request instruction poisoning */
-		t = btf__type_by_id(spec->btf, spec->spec[0].type_id);
+		t = btf_type_by_id(spec->btf, spec->spec[0].type_id);
 		e = btf_enum(t) + spec->spec[0].idx;
 		*val = e->val;
 		break;
@@ -805,8 +805,8 @@ static int bpf_core_calc_relo(const char
 		if (res->orig_sz != res->new_sz) {
 			const struct btf_type *orig_t, *new_t;
 
-			orig_t = btf__type_by_id(local_spec->btf, res->orig_type_id);
-			new_t = btf__type_by_id(targ_spec->btf, res->new_type_id);
+			orig_t = btf_type_by_id(local_spec->btf, res->orig_type_id);
+			new_t = btf_type_by_id(targ_spec->btf, res->new_type_id);
 
 			/* There are two use cases in which it's safe to
 			 * adjust load/store's mem size:
@@ -1054,7 +1054,7 @@ static void bpf_core_dump_spec(int level
 	int i;
 
 	type_id = spec->root_type_id;
-	t = btf__type_by_id(spec->btf, type_id);
+	t = btf_type_by_id(spec->btf, type_id);
 	s = btf__name_by_offset(spec->btf, t->name_off);
 
 	libbpf_print(level, "[%u] %s %s", type_id, btf_kind_str(t), str_is_empty(s) ? "<anon>" : s);
@@ -1158,10 +1158,7 @@ int bpf_core_apply_relo_insn(const char
 	int i, j, err;
 
 	local_id = relo->type_id;
-	local_type = btf__type_by_id(local_btf, local_id);
-	if (!local_type)
-		return -EINVAL;
-
+	local_type = btf_type_by_id(local_btf, local_id);
 	local_name = btf__name_by_offset(local_btf, local_type->name_off);
 	if (!local_name)
 		return -EINVAL;