From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A764C4338F for ; Mon, 26 Jul 2021 22:49:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2556A60F6C for ; Mon, 26 Jul 2021 22:49:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233463AbhGZWJZ (ORCPT ); Mon, 26 Jul 2021 18:09:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60778 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233380AbhGZWJY (ORCPT ); Mon, 26 Jul 2021 18:09:24 -0400 Received: from mail-yb1-xb33.google.com (mail-yb1-xb33.google.com [IPv6:2607:f8b0:4864:20::b33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5411BC061757 for ; Mon, 26 Jul 2021 15:49:52 -0700 (PDT) Received: by mail-yb1-xb33.google.com with SMTP id x192so17573685ybe.0 for ; Mon, 26 Jul 2021 15:49:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=En4cdfSQAaaiPItfg3Kc9yjWGHLCniATF74AUkHAIf8=; b=rXml6LrGneLAj0vFNEsfSLLg593BlgH3jJrg2CnIcGOnJDbW5TA7C8WoV4KIU5zgWg 5wNedPz6Z7VF2depmyPhbRY+QDOIud7VkPAhb36WjBeEDwMRU79gOWdmtJN3i8bA/pFR Ku1fc0ewcs6UMDxfXweY0n3DUAtJZp/ZFkSAkQBxYVQn6wGU6xUwjUz2gJw5q1pq3dx0 bgPvtTMPD+4SfyWx/nmR7O0UXhjHRJJvBOwO6vwtoOjPC39UkfT0Lo3P39P6SGsEKSKH Dku69tTPprqmUfiY5izzJwkP+RnbBz8hnzCrrsi/ddlZRPANJb2XGuGONw3WLw2AohNR 8MFQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=En4cdfSQAaaiPItfg3Kc9yjWGHLCniATF74AUkHAIf8=; b=h5Xthz5WptwJI4+YPJv07DxjEVoMliy4kqI7ZOMBJ5H7vwNrCtyuxGMPi0gdMbCWqd Azh507xyoTc7fvDLKJ0suZ6MV1dX3DGbDmRAXwfAHBNzIqSXK5DRwoJHWft/fFxaeE8t jAm+s9r7QzwNO8p2b2QICLtD1liZpifXSrio7ybkDJqOZN59dQaL/9fe5C2ngA264Spx banurDOPl7TU7h2b5HU6rs34Q3+yWi3wI81L4vgz4bN7Nux7H0jwSlrjNeU9fCNdU2yM SIvBRlQER9EuN7zhwpu2mQcm2vU29EI2n6Yi+g7f9iS56G8bGa01leFFVj4tLs0+DSkz +7yA== X-Gm-Message-State: AOAM531D/VwrVQVgetBr0Vw+4fm/m19LHNDJUxPUNhXMa7c9XiS0UZze HUK/VjnymHbD8/6KApx9TkgJR68SuqhkHtloiAo= X-Google-Smtp-Source: ABdhPJyYpDBI0tAHKSx9qbayeZ4Kh7VCV6WFcBjvF8qFopW2cPjaxhYAQdaMB7wcugFFFqi8W3iAncAqQ1tRtX+iQzk= X-Received: by 2002:a25:cdc7:: with SMTP id d190mr26466696ybf.425.1627339791520; Mon, 26 Jul 2021 15:49:51 -0700 (PDT) MIME-Version: 1.0 References: <20210724051256.1629110-1-hengqi.chen@gmail.com> In-Reply-To: <20210724051256.1629110-1-hengqi.chen@gmail.com> From: Andrii Nakryiko Date: Mon, 26 Jul 2021 15:49:40 -0700 Message-ID: Subject: Re: [PATCH bpf-next] libbpf: add libbpf_load_vmlinux_btf/libbpf_load_module_btf APIs To: Hengqi Chen Cc: bpf , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Yonghong Song , john fastabend Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Fri, Jul 23, 2021 at 10:13 PM Hengqi Chen wrote: > > Add libbpf_load_vmlinux_btf/libbpf_load_module_btf APIs. > This is part of the libbpf v1.0. [1] > > [1] https://github.com/libbpf/libbpf/issues/280 Saying it's part of libbpf 1.0 effort and given a link to Github PR is not really a sufficient commit message. Please expand on what you are doing in the patch and why. > > Signed-off-by: Hengqi Chen > --- > tools/lib/bpf/btf.c | 24 +++++++++++++++++++++++- > tools/lib/bpf/btf.h | 2 ++ > tools/lib/bpf/libbpf.c | 8 ++++---- > tools/lib/bpf/libbpf.map | 2 ++ > 4 files changed, 31 insertions(+), 5 deletions(-) > > diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c > index b46760b93bb4..414e1c5635ef 100644 > --- a/tools/lib/bpf/btf.c > +++ b/tools/lib/bpf/btf.c > @@ -4021,7 +4021,7 @@ static void btf_dedup_merge_hypot_map(struct btf_dedup *d) > */ > if (d->hypot_adjust_canon) > continue; > - > + > if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD) > d->map[t_id] = c_id; > > @@ -4395,6 +4395,11 @@ static int btf_dedup_remap_types(struct btf_dedup *d) > * data out of it to use for target BTF. > */ > struct btf *libbpf_find_kernel_btf(void) > +{ > + return libbpf_load_vmlinux_btf(); > +} > + > +struct btf *libbpf_load_vmlinux_btf(void) > { > struct { > const char *path_fmt; > @@ -4440,6 +4445,23 @@ struct btf *libbpf_find_kernel_btf(void) > return libbpf_err_ptr(-ESRCH); > } > > +struct btf *libbpf_load_module_btf(const char *mod) So we probably need to allow user to pre-load and re-use vmlinux BTF for efficiency, especially if they have some use-case to load a lot of BTFs. > +{ > + char path[80]; > + struct btf *base; > + int err; > + > + base = libbpf_load_vmlinux_btf(); > + err = libbpf_get_error(base); > + if (err) { > + pr_warn("Error loading vmlinux BTF: %d\n", err); > + return base; libbpf_err_ptr() needs to be used here, pr_warn() could have destroyed errno already > + } > + > + snprintf(path, sizeof(path), "/sys/kernel/btf/%s", mod); > + return btf__parse_split(path, base); so who's freeing base BTF in this case? > +} > + > int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx) > { > int i, n, err; [...]