From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stanislav Fomichev Subject: [PATCH bpf-next] bpf: libbpf: retry map creation without the name Date: Mon, 19 Nov 2018 13:35:09 -0800 Message-ID: <20181119213509.16417-1-sdf@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: vladum@google.com, Stanislav Fomichev To: netdev@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net Return-path: Received: from mail-it1-f201.google.com ([209.85.166.201]:50779 "EHLO mail-it1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725898AbeKTIAs (ORCPT ); Tue, 20 Nov 2018 03:00:48 -0500 Received: by mail-it1-f201.google.com with SMTP id p66so273607itc.0 for ; Mon, 19 Nov 2018 13:35:13 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: Since commit 88cda1c9da02 ("bpf: libbpf: Provide basic API support to specify BPF obj name"), libbpf unconditionally sets bpf_attr->name for maps. Pre v4.14 kernels don't know about map names and return an error about unexpected non-zero data. Retry sys_bpf without a map name to cover older kernels. Signed-off-by: Stanislav Fomichev --- tools/lib/bpf/bpf.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 03f9bcc4ef50..673175bc06ee 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -69,6 +69,7 @@ int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr) { __u32 name_len = create_attr->name ? strlen(create_attr->name) : 0; union bpf_attr attr; + int ret; memset(&attr, '\0', sizeof(attr)); @@ -86,7 +87,15 @@ int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr) attr.map_ifindex = create_attr->map_ifindex; attr.inner_map_fd = create_attr->inner_map_fd; - return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr)); + ret = sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr)); + if (ret < 0 && create_attr->name) { + /* Retry the same syscall, but without the name. + * Pre v4.14 kernels don't support map names. + */ + memset(attr.map_name, 0, sizeof(attr.map_name)); + return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr)); + } + return ret; } int bpf_create_map_node(enum bpf_map_type map_type, const char *name, -- 2.19.1.1215.g8438c0b245-goog