Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753004AbbGWJ6J (ORCPT ); Thu, 23 Jul 2015 05:58:09 -0400 Received: from mail-wi0-f177.google.com ([209.85.212.177]:38090 "EHLO mail-wi0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751497AbbGWJ6F (ORCPT ); Thu, 23 Jul 2015 05:58:05 -0400 Message-ID: <55B0BAA9.4020106@gmail.com> Date: Thu, 23 Jul 2015 11:58:01 +0200 From: "Michael Kerrisk (man-pages)" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Alexei Starovoitov , Daniel Borkmann CC: mtk.manpages@gmail.com, linux-man , linux-kernel@vger.kernel.org, Silvan Jegen , Walter Harms Subject: Re: Draft 3 of bpf(2) man page for review References: <55AFE46F.3090800@gmail.com> <55AFED75.2030208@plumgrid.com> <55AFF8BF.3050204@gmail.com> <55B01535.4080809@plumgrid.com> In-Reply-To: <55B01535.4080809@plumgrid.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2347 Lines: 57 On 07/23/2015 12:12 AM, Alexei Starovoitov wrote: > On 7/22/15 1:10 PM, Michael Kerrisk (man-pages) wrote: >> BPF maps are a generic data structure for storage of different >> data types. A user process can create multiple maps (with >> key/value-pairs being opaque bytes of data) and access them via >> file descriptors. Differnt eBPF programs can access the same >> maps in parallel. It's up to the user process and eBPF program >> to decide what they store inside maps. > > typo in 'Different' Fixed. >> eBPF program types >> By picking prog_type, the program author selects a set of helper >> functions that can be called from the eBPF program and the corre‐ >> sponding format of struct bpf_context (which is the data blob >> passed into the eBPF program as the first argument). For exam‐ >> ple, programs loaded with a prog_type of >> BPF_PROG_TYPE_SOCKET_FILTER may call the bpf_map_lookup_elem() >> helper, whereas some other program types may not be able to >> employ this helper. The set of functions available to eBPF pro‐ >> grams of a given type may increase in the future. > > overall it's all correct, but today bpf_map_lookup_elem() is allowed > for all program types. May be change that to: > "BPF_PROG_TYPE_KPROBE may call the bpf_probe_read() helper" > since only type_kprobe programs can call it. > type_sockets/type_sched_* cannot. Changed, as you suggest. >> The bpf_context argument is a pointer to a struct sk_buff. >> Programs cannot access the fields of sk_buff directly. > > Probably drop last sentence and replace 'sk_buff' with '__sk_buff' > in the first? Or for the first version we can drop both sentences. I did the former. > The rest looks great. Thank you much! Thanks, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/