From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754075Ab2AaAMw (ORCPT ); Mon, 30 Jan 2012 19:12:52 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:32995 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752532Ab2AaAMv (ORCPT ); Mon, 30 Jan 2012 19:12:51 -0500 Date: Mon, 30 Jan 2012 16:12:46 -0800 From: Tejun Heo To: "Srivatsa S. Bhat" Cc: rjw@sisk.pl, pavel@ucw.cz, len.brown@intel.com, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/4] PM/Freezer: Make thaw_processes() thaw only userspace tasks Message-ID: <20120131001246.GF27616@google.com> References: <20120130231342.11129.87187.stgit@srivatsabhat.in.ibm.com> <20120130231437.11129.3708.stgit@srivatsabhat.in.ibm.com> <20120130233055.GE27616@google.com> <4F27311C.5020200@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F27311C.5020200@linux.vnet.ibm.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tue, Jan 31, 2012 at 05:39:00AM +0530, Srivatsa S. Bhat wrote: > The thing is that, I wanted to avoid a bug in the patch posted at > https://lkml.org/lkml/2012/1/29/47 as explained in the link. > > So I guess I should have simply done: > > freeze_kernel_threads() calls thaw_kernel_threads() upon error. > The caller of freeze_kernel_threads() will call thaw_processes() if > necessary. > > This way even the SNAPSHOT_CREATE_IMAGE ioctl would remain safe. Yeah, I'd prefer to avoid exporting "userland only" interface to outside. If it's some internal fail path thing, let's handle it inside pm proper. Thanks. -- tejun