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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 A089CC433DF for ; Thu, 18 Jun 2020 09:03:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 812F02166E for ; Thu, 18 Jun 2020 09:03:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="NEKpjfzE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728837AbgFRJDn (ORCPT ); Thu, 18 Jun 2020 05:03:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33144 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728588AbgFRJDm (ORCPT ); Thu, 18 Jun 2020 05:03:42 -0400 Received: from mail-ed1-x543.google.com (mail-ed1-x543.google.com [IPv6:2a00:1450:4864:20::543]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1EF27C06174E; Thu, 18 Jun 2020 02:03:37 -0700 (PDT) Received: by mail-ed1-x543.google.com with SMTP id y6so4276204edi.3; Thu, 18 Jun 2020 02:03:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:reply-to:from:date:message-id :subject:to:cc; bh=ukJv09R/Qizrp9nFuZZGIBUbvRYEDs5U5DFimRDckes=; b=NEKpjfzEQnENYtVnTqsPePe6O8sJTbH7i6p7AN/ITECUpn4yRvjc/PUS4iV1OkpOt+ 5b1kDQFzsaMjlyfGpTAmyUIICcldt7izeU//+EV/uSto3CsDJP/f0lyIX14kUMQ2I0J1 9anYbaTihYa8TpdTbBqmVbKPjWb7RCHHE6VNSsWWA+nPLCDK/iVW3TWLoGd2Ret4KwdJ PGrZ67SXlyxNMudF1w03Cod+i2noYosFmMQB8ULHUy/5ZmgMfDdcvLWFjCSmZYdPfB+y j2k69sa7s9R11sgBok/JRrKhWPzgyIjaYgI0MSq7iazYA7G2U+GjWjNAghLjmGDno9le 58ug== 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:reply-to :from:date:message-id:subject:to:cc; bh=ukJv09R/Qizrp9nFuZZGIBUbvRYEDs5U5DFimRDckes=; b=kvjcOzmAsNVXJCKpY9s9zPAJ9bZBmvyWnHkCA8T9Q96zw144qUSAZrCbW27diG1or+ Nlba1Not7WhQGMaxMqeFpafI3Fuz03WQF2bIVlZq2RqQ+sk2ieIJvrHPeSuvpr5lIKPx pMulIRs3S72Db/WFivgdaFE24AIn7K584GhC6BGQD4CFd/BI4B2BbcFnLEVvU4bbupbC 9CrC3tNLJAfQuaMAIKXbcM5cMSNww/lFoiMy/LDuXUH1auwUcCkpkqTagLE85joU9bWb wEJrfmxySvvNfyOr2iV2WLackv+9y8G34/D6A1sVIH+ldVs7ZZhsSUOA5JzpaBIQontp ywbA== X-Gm-Message-State: AOAM5311C9xRtn5Xmik+L8ALYQ9cqMCMvqqVIjsQGsmcYzXSC3Zo3+PB 4yDjsQkEnCpal/Ada/qyGuw1500e+J0vifEafwE= X-Google-Smtp-Source: ABdhPJycBlQ3+qQ1DL1oyfZO7RFqPWELyy0xVggxryiHLBz+jlmSvWJoZWmo84VBTgDwpavlANjslroUBQKec6ojg8o= X-Received: by 2002:aa7:c80c:: with SMTP id a12mr3219176edt.140.1592471016410; Thu, 18 Jun 2020 02:03:36 -0700 (PDT) MIME-Version: 1.0 References: <20200618084543.326605-1-christian.brauner@ubuntu.com> In-Reply-To: <20200618084543.326605-1-christian.brauner@ubuntu.com> Reply-To: mtk.manpages@gmail.com From: "Michael Kerrisk (man-pages)" Date: Thu, 18 Jun 2020 11:03:25 +0200 Message-ID: Subject: Re: [PATCH] nsfs: add NS_GET_INIT_PID ioctl To: Christian Brauner Cc: "linux-fsdevel@vger.kernel.org" , lkml , Wolfgang Bumiller , Serge Hallyn , Alexander Viro Content-Type: text/plain; charset="UTF-8" Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, 18 Jun 2020 at 10:45, Christian Brauner wrote: > > Add an ioctl() to return the PID of the init process/child reaper of a pid > namespace as seen in the caller's pid namespace. What are the pros and cons of returning a PID FD instead of a PID? Thanks, Michael