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From: Alan Maguire <alan.maguire@oracle.com>
To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org
Cc: kafai@fb.com, songliubraving@fb.com, yhs@fb.com,
	john.fastabend@gmail.com, kpsingh@chromium.org,
	rostedt@goodmis.org, mingo@redhat.com, haoluo@google.com,
	jolsa@kernel.org, quentin@isovalent.com,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	bpf@vger.kernel.org
Subject: [RFC bpf-next 2/3] libbpf: bpf__find_by_name[_kind] should use btf__get_nr_types()
Date: Fri, 13 Nov 2020 18:10:12 +0000	[thread overview]
Message-ID: <1605291013-22575-3-git-send-email-alan.maguire@oracle.com> (raw)
In-Reply-To: <1605291013-22575-1-git-send-email-alan.maguire@oracle.com>

When operating on split BTF, btf__find_by_name[_kind] will not
iterate over all types since they use btf->nr_types to show
the number of types to iterate over.  For split BTF this is
the number of types _on top of base BTF_, so it will
underestimate the number of types to iterate over, especially
for vmlinux + module BTF, where the latter is much smaller.

Use btf__get_nr_types() instead.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
---
 tools/lib/bpf/btf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 2d0d064..0fccf4b 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -679,7 +679,7 @@ __s32 btf__find_by_name(const struct btf *btf, const char *type_name)
 	if (!strcmp(type_name, "void"))
 		return 0;
 
-	for (i = 1; i <= btf->nr_types; i++) {
+	for (i = 1; i <= btf__get_nr_types(btf); i++) {
 		const struct btf_type *t = btf__type_by_id(btf, i);
 		const char *name = btf__name_by_offset(btf, t->name_off);
 
@@ -698,7 +698,7 @@ __s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name,
 	if (kind == BTF_KIND_UNKN || !strcmp(type_name, "void"))
 		return 0;
 
-	for (i = 1; i <= btf->nr_types; i++) {
+	for (i = 1; i <= btf__get_nr_types(btf); i++) {
 		const struct btf_type *t = btf__type_by_id(btf, i);
 		const char *name;
 
-- 
1.8.3.1


  parent reply	other threads:[~2020-11-13 18:11 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-13 18:10 [RFC bpf-next 0/3] bpf: support module BTF in btf display helpers Alan Maguire
2020-11-13 18:10 ` [RFC bpf-next 1/3] bpf: add module support to " Alan Maguire
2020-11-14  6:58   ` Andrii Nakryiko
2020-11-14 16:04     ` Alexei Starovoitov
2020-11-15  4:13       ` Yonghong Song
2020-11-15 10:53         ` Alan Maguire
2020-11-17 23:56           ` Andrii Nakryiko
2020-11-13 18:10 ` Alan Maguire [this message]
2020-11-14  6:46   ` [RFC bpf-next 2/3] libbpf: bpf__find_by_name[_kind] should use btf__get_nr_types() Andrii Nakryiko
2020-11-13 18:10 ` [RFC bpf-next 3/3] selftests/bpf: verify module-specific types can be shown via bpf_snprintf_btf Alan Maguire
2020-11-14  7:01   ` Andrii Nakryiko

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