From patchwork Wed Feb 17 01:08:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Stringer X-Patchwork-Id: 12090797 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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 1AE4FC433E9 for ; Wed, 17 Feb 2021 01:09:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D5AF964EB3 for ; Wed, 17 Feb 2021 01:09:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229707AbhBQBJL (ORCPT ); Tue, 16 Feb 2021 20:09:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47430 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230292AbhBQBJK (ORCPT ); Tue, 16 Feb 2021 20:09:10 -0500 Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 364DAC061574; Tue, 16 Feb 2021 17:08:30 -0800 (PST) Received: by mail-pl1-x630.google.com with SMTP id z7so6498834plk.7; Tue, 16 Feb 2021 17:08:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=vA7yf0zk+T/kB8pnBChx/NJnOYZDQH1veo7XbeOKZhg=; b=SYS1iA85ZA6CTQnNjd1kT0S7tKOPvrWT5jfcqRekx8PY7g0esCw/OGukvmYuOZcYlA 98VnNk79O3XfWIzcyXz4aYqL6siGdPzgAH6lu7bKKRosbbA3u4HWuMlpw8DvfMZ8MdvY zc4Z879xdDgaEqGlWJvT8ytlLKyV4El5ZSE9fgf4JE//9N6jtf8w2/67o+avlFI6Um3y WHi0vd+XXfuUau7DYX8kuz2IvpwnTRLZ+f+hit2yrtG7PTNJM9Zl6UNhXYyaPuqYBPGM Ebvzg5nCQ14R5Wxt4ebdZvpJB1WM9soacfHh1ul/fjbciTSCst+8uJx5b7YVFUYFkNDy Wx3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=vA7yf0zk+T/kB8pnBChx/NJnOYZDQH1veo7XbeOKZhg=; b=muSrxyTEjt+FM48zeKhDn+eQ9qz+HZAh7DNR6C38rj7y3RUnFPvd2CCXyLGBfgnPRu xsmRayZ2ig1uDPy02gtgAOsHjhVHutnYbyDCRMZweV404JfBztDiPCUKkfV7QjaS9Mfg NrwDWMXuQHX+2GmpaGyS9ksjrZRtqdHDYnCL1rOX1bNIhGvsUkvTWkw0Djs8YIB2uxYK a4mF3/Gjf7/sGbrezQCkVgpYGP3Ow2gmNjN4vLCfqWwDfz74r2k6NTrbnIvhcOa4GpVF 2qdXAVlGo5IB3eZxMbqwdBWujCP21kKD1A81nZ4WByFMkDBh1aCcM+mGVNETNKy5uRB2 9ozQ== X-Gm-Message-State: AOAM533ZEgrENX4h0tu4397iNSVJxkUx1Kw81eILuVN1HnH5n3Fw9FrR fLaziePdoBlEmt/HiHpgmw1RSKrJnsq0fA== X-Google-Smtp-Source: ABdhPJxP/4NPeq90Q/Bm7YXAygVT/vf/FljHYezElmVReu02o328iYnecKlVaROM/6rfOi8qZfMzTg== X-Received: by 2002:a17:902:8349:b029:df:d13d:bf83 with SMTP id z9-20020a1709028349b02900dfd13dbf83mr180546pln.69.1613524109369; Tue, 16 Feb 2021 17:08:29 -0800 (PST) Received: from localhost.localdomain (c-73-93-5-123.hsd1.ca.comcast.net. [73.93.5.123]) by smtp.gmail.com with ESMTPSA id c22sm175770pfc.12.2021.02.16.17.08.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Feb 2021 17:08:28 -0800 (PST) Sender: Joe Stringer From: Joe Stringer To: bpf@vger.kernel.org Cc: Joe Stringer , netdev@vger.kernel.org, daniel@iogearbox.net, ast@kernel.org, mtk.manpages@gmail.com, Quentin Monnet Subject: [PATCH bpf-next 01/17] bpf: Import syscall arg documentation Date: Tue, 16 Feb 2021 17:08:05 -0800 Message-Id: <20210217010821.1810741-2-joe@wand.net.nz> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210217010821.1810741-1-joe@wand.net.nz> References: <20210217010821.1810741-1-joe@wand.net.nz> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Joe Stringer These descriptions are present in the man-pages project from the original submissions around 2015-2016. Import them so that they can be kept up to date as developers extend the bpf syscall commands. These descriptions follow the pattern used by scripts/bpf_helpers_doc.py so that we can take advantage of the parser to generate more up-to-date man page writing based upon these headers. Some minor wording adjustments were made to make the descriptions more consistent for the description / return format. Reviewed-by: Quentin Monnet Co-authored-by: Alexei Starovoitov Co-authored-by: Michael Kerrisk Signed-off-by: Joe Stringer --- include/uapi/linux/bpf.h | 119 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 118 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 4c24daa43bac..56d7db0f3daf 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -93,7 +93,124 @@ union bpf_iter_link_info { } map; }; -/* BPF syscall commands, see bpf(2) man-page for details. */ +/* BPF syscall commands, see bpf(2) man-page for more details. + * + * The operation to be performed by the **bpf**\ () system call is determined + * by the *cmd* argument. Each operation takes an accompanying argument, + * provided via *attr*, which is a pointer to a union of type *bpf_attr* (see + * below). The size argument is the size of the union pointed to by *attr*. + * + * Start of BPF syscall commands: + * + * BPF_MAP_CREATE + * Description + * Create a map and return a file descriptor that refers to the + * map. The close-on-exec file descriptor flag (see **fcntl**\ (2)) + * is automatically enabled for the new file descriptor. + * + * Applying **close**\ (2) to the file descriptor returned by + * **BPF_MAP_CREATE** will delete the map (but see NOTES). + * + * Return + * A new file descriptor (a nonnegative integer), or -1 if an + * error occurred (in which case, *errno* is set appropriately). + * + * BPF_MAP_LOOKUP_ELEM + * Description + * Look up an element with a given *key* in the map referred to + * by the file descriptor *map_fd*. + * + * Return + * Returns zero on success. On error, -1 is returned and *errno* + * is set appropriately. + * + * BPF_MAP_UPDATE_ELEM + * Description + * Create or update an element (key/value pair) in a specified map. + * + * The *flags* argument should be specified as one of the + * following: + * + * **BPF_ANY** + * Create a new element or update an existing element. + * **BPF_NOEXIST** + * Create a new element only if it did not exist. + * **BPF_EXIST** + * Update an existing element. + * + * Return + * Returns zero on success. On error, -1 is returned and *errno* + * is set appropriately. + * + * May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**, + * **E2BIG**, **EEXIST**, or **ENOENT**. + * + * **E2BIG** + * The number of elements in the map reached the + * *max_entries* limit specified at map creation time. + * **EEXIST** + * If *flags* specifies **BPF_NOEXIST** and the element + * with *key* already exists in the map. + * **ENOENT** + * If *flags* specifies **BPF_EXIST** and the element with + * *key* does not exist in the map. + * + * BPF_MAP_DELETE_ELEM + * Description + * Look up and delete an element by key in a specified map. + * + * Return + * Returns zero on success. On error, -1 is returned and *errno* + * is set appropriately. + * + * BPF_MAP_GET_NEXT_KEY + * Description + * Look up an element by key in a specified map and return the key + * of the next element. Can be used to iterate over all elements + * in the map. + * + * Return + * Returns zero on success. On error, -1 is returned and *errno* + * is set appropriately. + * + * The following cases can be used to iterate over all elements of + * the map: + * + * * If *key* is not found, the operation returns zero and sets + * the *next_key* pointer to the key of the first element. + * * If *key* is found, the operation returns zero and sets the + * *next_key* pointer to the key of the next element. + * * If *key* is the last element, returns -1 and *errno* is set + * to **ENOENT**. + * + * May set *errno* to **ENOMEM**, **EFAULT**, **EPERM**, or + * **EINVAL** on error. + * + * BPF_PROG_LOAD + * Description + * Verify and load an eBPF program, returning a new file + * descriptor associated with the program. + * + * Applying **close**\ (2) to the file descriptor returned by + * **BPF_PROG_LOAD** will unload the eBPF program (but see NOTES). + * + * The close-on-exec file descriptor flag (see **fcntl**\ (2)) is + * automatically enabled for the new file descriptor. + * + * Return + * A new file descriptor (a nonnegative integer), or -1 if an + * error occurred (in which case, *errno* is set appropriately). + * + * NOTES + * eBPF objects (maps and programs) can be shared between processes. + * For example, after **fork**\ (2), the child inherits file descriptors + * referring to the same eBPF objects. In addition, file descriptors + * referring to eBPF objects can be transferred over UNIX domain sockets. + * File descriptors referring to eBPF objects can be duplicated in the + * usual way, using **dup**\ (2) and similar calls. An eBPF object is + * deallocated only after all file descriptors referring to the object + * have been closed. + */ enum bpf_cmd { BPF_MAP_CREATE, BPF_MAP_LOOKUP_ELEM,