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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 6A62BC04AA8 for ; Tue, 30 Apr 2019 09:08:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3765320652 for ; Tue, 30 Apr 2019 09:08:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="KCIillAx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726539AbfD3JIL (ORCPT ); Tue, 30 Apr 2019 05:08:11 -0400 Received: from mail-lf1-f68.google.com ([209.85.167.68]:36754 "EHLO mail-lf1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725938AbfD3JIL (ORCPT ); Tue, 30 Apr 2019 05:08:11 -0400 Received: by mail-lf1-f68.google.com with SMTP id u17so10279000lfi.3 for ; Tue, 30 Apr 2019 02:08:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=9HjQ88MY4ZiDc1bI5n4MIBBh4bZ2A3E/q/QZEBk7alU=; b=KCIillAxrZrXB5w7B79fb19nYg7F3YCwf/ztmA9aoE9VUD7WLkEyGA1XTGj7Kk7I9I Q513ZwfxLRI6HJ4DrN1ZMjXfa842QSSs6yPwd0FUt+xZKwllptZpyag00LUFcGYK3EsC XdEbFchQbx1GNf/krTIlE74LPo3MefjF2xV0uZ5Rt9BcNTBf/J2/0tgE/CjrS+/46uwD ARjeDWBBqlnHHRKTKdiGH05RWZ9Qh2z5qOAaNQx9+9uWyCnSM+J6HGsn9mtkAkyisNb6 WLz5Pn17WNGE47oaQuTDdvGZvJ9oPYfrIEusa3M0SiUmfS8nh2ODl35nGOliRsB/77U5 zOrQ== 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:references :mime-version:content-disposition:in-reply-to:user-agent; bh=9HjQ88MY4ZiDc1bI5n4MIBBh4bZ2A3E/q/QZEBk7alU=; b=CRs2/jDPmNgUUM1lD+017iprN+Uxzi4z7yp1t0bS55eSukG9f7VrrTMHfzQhhwBqDd Yfw1jRKUDIVXVMTSq9/LGeUJ+FVEQVmvEpXDx4hKld+qb+VrcUgKMC4MCf/wXlvCWirA ZjjICN/cBW3tvuqS1Eojvjb+cLZGy+2dLeoOOsLqaxZYSIHl/LWiocQKfR1nprRgvET/ Uojb2KhRFCrMVHh+xNuK7YScXZB5/IDKTbk5YBjMseBxeYjvUTtLJ3aEiGvMvJAgD/hQ YANyIuH8IJQbSQBFXTjblitW7H5vZ2zgOLHFy1e55nAAHRBDVVUXkUMZWlsghCJz7HW6 RNgQ== X-Gm-Message-State: APjAAAXEsdq5kpuBP2HyOIkpSLuE/QYr1LmUVq5rKUshcFIB350xrOID +YPci3TsxVRvnliG5mQ5uCc= X-Google-Smtp-Source: APXvYqxC1zZd7LprV/dgF44Ba5ne0SfC/5gxd6UPTeJBnWPoKvFHoqjjCKTMw2d90XkBC0hQgb2Gkw== X-Received: by 2002:a19:f50f:: with SMTP id j15mr36291099lfb.135.1556615289352; Tue, 30 Apr 2019 02:08:09 -0700 (PDT) Received: from uranus.localdomain ([5.18.103.226]) by smtp.gmail.com with ESMTPSA id u22sm1374696lji.40.2019.04.30.02.08.08 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 30 Apr 2019 02:08:08 -0700 (PDT) Received: by uranus.localdomain (Postfix, from userid 1000) id 45A444603CA; Tue, 30 Apr 2019 12:08:08 +0300 (MSK) Date: Tue, 30 Apr 2019 12:08:08 +0300 From: Cyrill Gorcunov To: Kirill Tkhai Cc: Michal =?iso-8859-1?Q?Koutn=FD?= , akpm@linux-foundation.org, arunks@codeaurora.org, brgl@bgdev.pl, geert+renesas@glider.be, ldufour@linux.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mguzik@redhat.com, mhocko@kernel.org, rppt@linux.ibm.com, vbabka@suse.cz Subject: Re: [PATCH 3/3] prctl_set_mm: downgrade mmap_sem to read lock Message-ID: <20190430090808.GC2673@uranus.lan> References: <20190418182321.GJ3040@uranus.lan> <20190430081844.22597-1-mkoutny@suse.com> <20190430081844.22597-4-mkoutny@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 30, 2019 at 11:55:45AM +0300, Kirill Tkhai wrote: > > - up_write(&mm->mmap_sem); > > + spin_unlock(&mm->arg_lock); > > + up_read(&mm->mmap_sem); > > return error; > > Hm, shouldn't spin_lock()/spin_unlock() pair go as a fixup to existing code > in a separate patch? > > Without them, the existing code has a problem at least in get_mm_cmdline(). Seems reasonable to merge it into patch 1.