From patchwork Sun Feb 20 13:47:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kumar Kartikeya Dwivedi X-Patchwork-Id: 12752703 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D84D7C433FE for ; Sun, 20 Feb 2022 13:48:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241184AbiBTNsp (ORCPT ); Sun, 20 Feb 2022 08:48:45 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:48384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229884AbiBTNsl (ORCPT ); Sun, 20 Feb 2022 08:48:41 -0500 Received: from mail-pl1-x644.google.com (mail-pl1-x644.google.com [IPv6:2607:f8b0:4864:20::644]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4523921813; Sun, 20 Feb 2022 05:48:20 -0800 (PST) Received: by mail-pl1-x644.google.com with SMTP id l8so10858885pls.7; Sun, 20 Feb 2022 05:48:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=PzcNo+2Cl6iYUCYcvpUBH3gr0tfx0tpOlkynbpKJJzs=; b=gnkR8SFne9AxfmrY6l1U3pCSAtxEEohSpRVSFpn4eHh0ml4Jme0rYQTjuVFoDLakMh N4eQNTxJkoRY+/myDHc96XRvuVXV5Jujoy7Cq2Ruk5e00DC5/VQEpl9oXD/Grlf7RbrR cPy3ZAFPgyA0l09vRq5MECIRYXovWC3s9sGWkTrBiKElJCKDZjD0nesWncdFN8m39Kar uvPvX3XiCwpsduDJ0IineI1MF62YDqT3fAUKwJPUGv9n9Lq3JjlLKCcRFmr0jje4kX69 UpvDtq0CX6UjbnQxen/FOQYStpjDzyUnbx5iwZughSYpJGRhhpmOncefnA8rXhsmrRHT qm3Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=PzcNo+2Cl6iYUCYcvpUBH3gr0tfx0tpOlkynbpKJJzs=; b=EgMqZUllYqhhlHhK2l8oP03ADEhScGhM09lo6A6qdAjzPDCn0drRTfHM3HKr9491/n x+yx05BCNTANSWR3lqneL7PnKnwQwYUrJLfff/w+bXCJuTZtc/WF0187I9jiW28U7VQd kaaq0LnaZS3WwKCsgGG75g+nDE7JoImla/Inl82HYN7LVmIrF1OJL8JngzNa9evpRxjk atKNM+3+j0Ut5Djg360CtEPrieAfWgCyVVWqFoZqXdGj825lk6VdD8R6iIBvIfZVp5qG iVGDqRzyx8s2vw5IL7qyW7fILI0PpKtmnMA3jXnRb8o5x1ARrocXlSdI9SyqidGbIV80 6acg== X-Gm-Message-State: AOAM530NXBrzMJLgLyvWv9FcSlY7FAhiGOI183DW7NtZqSv4tryVEfJ2 bj+g1ZL7gNs30oDzoeU2Km4Ek0kpfeo= X-Google-Smtp-Source: ABdhPJxqFb7mKuV/HBOE8jJordIDkenzpU+FOrtk0NuYyxSbBgqwHYFumCCvdIjy4oBUBuMqkzlYeA== X-Received: by 2002:a17:903:2283:b0:14d:b86b:165b with SMTP id b3-20020a170903228300b0014db86b165bmr15171985plh.41.1645364899656; Sun, 20 Feb 2022 05:48:19 -0800 (PST) Received: from localhost ([2405:201:6014:d0c0:6243:316e:a9e1:adda]) by smtp.gmail.com with ESMTPSA id g63sm9060558pfb.65.2022.02.20.05.48.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 20 Feb 2022 05:48:19 -0800 (PST) From: Kumar Kartikeya Dwivedi To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , =?utf-8?q?Toke_H=C3=B8iland-J=C3=B8?= =?utf-8?q?rgensen?= , Jesper Dangaard Brouer , netfilter-devel@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH bpf-next v1 01/15] bpf: Factor out fd returning from bpf_btf_find_by_name_kind Date: Sun, 20 Feb 2022 19:17:59 +0530 Message-Id: <20220220134813.3411982-2-memxor@gmail.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220220134813.3411982-1-memxor@gmail.com> References: <20220220134813.3411982-1-memxor@gmail.com> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2938; h=from:subject; bh=/DfuqiVvvM+Atumhzb4HyEeRwNtGOpOsgZS5ZW8b5tQ=; b=owEBbQKS/ZANAwAIAUzgyIZIvxHKAcsmYgBiEkZXkMyYe/Lt+F66RQ4bL9Z/mevwOrvjMnzoNuHb UewkETyJAjMEAAEIAB0WIQRLvip+Buz51YI8YRFM4MiGSL8RygUCYhJGVwAKCRBM4MiGSL8RyhZEEA C65AeyeTfBXOEkpFn9Eq6xuZtpdc9omJPpWReu529cRJRFrjUYDvFK0KN+F9rNDwJsC2O0Hxicpy6B CX7BOpIrOKrrlbiGluICkOiEB+GiCyndtyJ+UC71Po2tbAaEm2Yz1evJL41M2ovtdUCLHPG/q7QA3O Zql7ooRamhF9UD86tNobw5esP7xJXDa8BCkX+M/8bnIloKXZZvMd4sFeVdhZTPHPUws6jTA88hvNYL AF/S5SVAf2Sa0vz5+yWB5tAQUvKhlVJba4zuaYngd8eq68u36hFhMZLI0j8Us0AUsSIN1aCrzPAgXQ 9s2Qf0nTw3HzBDNwwi6o3ybUvfq7QXTp8Dyp/01x8+EJQSCNt94fCIKbVSxoE+S7j5wrLcx+XJp5O1 A7mQT+eA/GCBFU32NP93PIcqsi0izNtyfNuGPjY2Xj55QxF9/mJMxesFgpvlVU1I89rKvUNgQANaKs MS7ImcUoiz+nA46oQqueVemKYom36FY+Yt8rY60N+yiMuoDuq0dp9wbCRu7TMiEEHtPCwT8CONw2Bq 419k3FJ7RN9oJJ3MQftXr43AZcO7VCnu0V/lV3dCsbD7M8TcQLaTqxk4c2z+Vay+CuKcazISe9Z51a EO0pTAYniMtdqUdRaYX/2WU55kj+Qh4R60p+ubbAx0E1YXDQxkWql+7AnAHA== X-Developer-Key: i=memxor@gmail.com; a=openpgp; fpr=4BBE2A7E06ECF9D5823C61114CE0C88648BF11CA Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net In next few patches, we need a helper that searches all kernel BTFs (vmlinux and module BTFs), and finds the type denoted by 'name' and 'kind'. Turns out bpf_btf_find_by_name_kind already does the same thing, but it instead returns a BTF ID and optionally fd (if module BTF). This is used for relocating ksyms in BPF loader code (bpftool gen skel -L). We extract the core code out into a new helper btf_find_by_name_kind_all, which returns the BTF ID and BTF pointer in an out parameter. The reference for the returned BTF pointer is only bumped if it is a module BTF, this needs to be kept in mind when using this helper. Hence, the user must release the BTF reference iff btf_is_module is true, otherwise transfer the ownership to e.g. an fd. In case of the helper, the fd is only allocated for module BTFs, so no extra handling for btf_vmlinux case is required. Signed-off-by: Kumar Kartikeya Dwivedi --- kernel/bpf/btf.c | 47 +++++++++++++++++++++++++++++++---------------- 1 file changed, 31 insertions(+), 16 deletions(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 2c4c5dbe2abe..3645d8c14a18 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6545,16 +6545,10 @@ static struct btf *btf_get_module_btf(const struct module *module) return btf; } -BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags) +static s32 btf_find_by_name_kind_all(const char *name, u32 kind, struct btf **btfp) { struct btf *btf; - long ret; - - if (flags) - return -EINVAL; - - if (name_sz <= 1 || name[name_sz - 1]) - return -EINVAL; + s32 ret; btf = bpf_get_btf_vmlinux(); if (IS_ERR(btf)) @@ -6580,19 +6574,40 @@ BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int spin_unlock_bh(&btf_idr_lock); ret = btf_find_by_name_kind(mod_btf, name, kind); if (ret > 0) { - int btf_obj_fd; - - btf_obj_fd = __btf_new_fd(mod_btf); - if (btf_obj_fd < 0) { - btf_put(mod_btf); - return btf_obj_fd; - } - return ret | (((u64)btf_obj_fd) << 32); + *btfp = mod_btf; + return ret; } spin_lock_bh(&btf_idr_lock); btf_put(mod_btf); } spin_unlock_bh(&btf_idr_lock); + } else { + *btfp = btf; + } + return ret; +} + +BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags) +{ + struct btf *btf = NULL; + int btf_obj_fd = 0; + long ret; + + if (flags) + return -EINVAL; + + if (name_sz <= 1 || name[name_sz - 1]) + return -EINVAL; + + ret = btf_find_by_name_kind_all(name, kind, &btf); + if (ret > 0 && btf_is_module(btf)) { + /* reference for btf is only raised if module BTF */ + btf_obj_fd = __btf_new_fd(btf); + if (btf_obj_fd < 0) { + btf_put(btf); + return btf_obj_fd; + } + return ret | (((u64)btf_obj_fd) << 32); } return ret; }