From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrey Ignatov Subject: [PATCH bpf] libbpf: Fix compile error in libbpf_attach_type_by_name Date: Wed, 31 Oct 2018 12:57:18 -0700 Message-ID: <20181031195718.307757-1-rdna@fb.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Andrey Ignatov , , , , To: Return-path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:38352 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729730AbeKAE5j (ORCPT ); Thu, 1 Nov 2018 00:57:39 -0400 Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w9VJt0po029073 for ; Wed, 31 Oct 2018 12:58:06 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2nfjukg10q-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Wed, 31 Oct 2018 12:58:06 -0700 Sender: netdev-owner@vger.kernel.org List-ID: Arnaldo Carvalho de Melo reported build error in libbpf when clang version 3.8.1-24 (tags/RELEASE_381/final) is used: libbpf.c:2201:36: error: comparison of constant -22 with expression of type 'const enum bpf_attach_type' is always false [-Werror,-Wtautological-constant-out-of-range-compare] if (section_names[i].attach_type == -EINVAL) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~ 1 error generated. Fix the error by keeping "is_attachable" property of a program in a separate struct field instead of trying to use attach_type itself. Fixes: commit 956b620fcf0b ("libbpf: Introduce libbpf_attach_type_by_name") Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Andrey Ignatov --- tools/lib/bpf/libbpf.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index b607be7236d3..d6e62e90e8d4 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2084,19 +2084,19 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog, prog->expected_attach_type = type; } -#define BPF_PROG_SEC_IMPL(string, ptype, eatype, atype) \ - { string, sizeof(string) - 1, ptype, eatype, atype } +#define BPF_PROG_SEC_IMPL(string, ptype, eatype, is_attachable, atype) \ + { string, sizeof(string) - 1, ptype, eatype, is_attachable, atype } /* Programs that can NOT be attached. */ -#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, -EINVAL) +#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0) /* Programs that can be attached. */ #define BPF_APROG_SEC(string, ptype, atype) \ - BPF_PROG_SEC_IMPL(string, ptype, 0, atype) + BPF_PROG_SEC_IMPL(string, ptype, 0, 1, atype) /* Programs that must specify expected attach type at load time. */ #define BPF_EAPROG_SEC(string, ptype, eatype) \ - BPF_PROG_SEC_IMPL(string, ptype, eatype, eatype) + BPF_PROG_SEC_IMPL(string, ptype, eatype, 1, eatype) /* Programs that can be attached but attach type can't be identified by section * name. Kept for backward compatibility. @@ -2108,6 +2108,7 @@ static const struct { size_t len; enum bpf_prog_type prog_type; enum bpf_attach_type expected_attach_type; + int is_attachable; enum bpf_attach_type attach_type; } section_names[] = { BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER), @@ -2198,7 +2199,7 @@ int libbpf_attach_type_by_name(const char *name, for (i = 0; i < ARRAY_SIZE(section_names); i++) { if (strncmp(name, section_names[i].sec, section_names[i].len)) continue; - if (section_names[i].attach_type == -EINVAL) + if (!section_names[i].is_attachable) return -EINVAL; *attach_type = section_names[i].attach_type; return 0; -- 2.17.1