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=-4.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 94931C43381 for ; Wed, 20 Mar 2019 21:23:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 63B55218AE for ; Wed, 20 Mar 2019 21:23:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=netronome-com.20150623.gappssmtp.com header.i=@netronome-com.20150623.gappssmtp.com header.b="IF7AL/YR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727635AbfCTVXw (ORCPT ); Wed, 20 Mar 2019 17:23:52 -0400 Received: from mail-qt1-f194.google.com ([209.85.160.194]:34674 "EHLO mail-qt1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727381AbfCTVXw (ORCPT ); Wed, 20 Mar 2019 17:23:52 -0400 Received: by mail-qt1-f194.google.com with SMTP id k2so4411160qtm.1 for ; Wed, 20 Mar 2019 14:23:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netronome-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :organization:mime-version:content-transfer-encoding; bh=Aj6nIkn/AI1AWOF6wEFthrXZBX84FY8wDZnSJigal8g=; b=IF7AL/YRhbpaZdHqMetud8t7yiazxqXvtQnXKunLy4VNyxr7P4CnBV1c9PoknNhA3L tZ/DGlqxfElhkjbZcsJvNhaRyCX5FP1R8EHA5zj+Wko3imaXTtBhvq4BbOo7wl2r+Y6y 5VJOMQm87TlhLNM6qC7TW59kAYjnIKPhmMUgQ42hkxkMzklQVRNBMVkwjGlBXYhG/dYd 4oLnYJ7RVGVc3VPFG3gUw2wQ99e+BWZo/4K8vXj55/eO92kRWFnRON1Sgo78vtmjEvIS nf7TsZVGZsTQx5LAWeR9e91SmEbHUIlFX8YlSyTvXK+eIoIM68Rnh7A8EQ3XfDNXCWNb 1YiQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:organization:mime-version:content-transfer-encoding; bh=Aj6nIkn/AI1AWOF6wEFthrXZBX84FY8wDZnSJigal8g=; b=i/99JFBzfIuVTxUlOFFbadCF5jegYIBSdOQ7nZrgpw16nm4riKOFDLsWobjvHtNdG7 L2qWQY0lbCaLBWTcDq7UV8A6/rH/B8gXQfcsGaBwtuungpQUdUBNfegeWN/ik5b/4O6O 3xXCqowQ5omAIu/MtFFY1gXMnJhRbqBwrToxbq0Pcj5XWMDLYC2Vd1qzg5b6yDpDj9I5 QVhtlltmseGOZrnS1NecWMov0qPJXkr63DQV/dJsJD1F1ZNES0rmlLYRzzZwaWgi41Ac hoGiYXtyJ1UpZ4j7XaOZcYd8G5kBAJY1FdlA1AocW70Tna6zfdP7SHkj8zPs0mWcR9Z3 JOEw== X-Gm-Message-State: APjAAAXvoDvRPenfYeQuPcQqphiiaILvwNIX4qaUVIkLVeAJWgMJHIyn MUMHGq0ErLgKxYcNdnghg9ssFA== X-Google-Smtp-Source: APXvYqwidp8PK88SKWHfQz18wyMml4ciS0Q2gHGtN8xR2rx5uBD6FtZh7fyEinqsVOpP6EvS1/zhzw== X-Received: by 2002:a0c:81fa:: with SMTP id 55mr151252qve.91.1553117031341; Wed, 20 Mar 2019 14:23:51 -0700 (PDT) Received: from cakuba.netronome.com ([66.60.152.14]) by smtp.gmail.com with ESMTPSA id v8sm1881599qtv.81.2019.03.20.14.23.49 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 20 Mar 2019 14:23:50 -0700 (PDT) Date: Wed, 20 Mar 2019 14:23:46 -0700 From: Jakub Kicinski To: Alban Crequy Cc: ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, alban@kinvolk.io, iago@kinvolk.io Subject: Re: [PATCH bpf-next v1 4/7] tools: bpftool: implement map exec command Message-ID: <20190320142346.3b552895@cakuba.netronome.com> In-Reply-To: <20190320173332.18105-4-alban@kinvolk.io> References: <20190320173332.18105-1-alban@kinvolk.io> <20190320173332.18105-4-alban@kinvolk.io> Organization: Netronome Systems, Ltd. MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 20 Mar 2019 18:33:29 +0100, Alban Crequy wrote: > From: Alban Crequy > > The map exec commands allows to open an existing map and pass the file > descriptor to a child process. This enables applications to use an > existing BPF map even when they don't support bpffs. > > Example of usage: > # bpftool map exec pinned /sys/fs/bpf/foo fd 99 cmd -- readlink /proc/self/fd/99 > anon_inode:bpf-map Would you mind telling us a little more about the use for this feature? It seems fairly limited. If it's about probing objects (finding out if they are a map or a program) perhaps we can add a command just for that? (I guess bpftool -f isn't really the cleanest way of getting at that info.) > Documentation and bash completion updated as well. > > Signed-off-by: Alban Crequy