From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755400Ab1LAQ2h (ORCPT ); Thu, 1 Dec 2011 11:28:37 -0500 Received: from e28smtp04.in.ibm.com ([122.248.162.4]:54462 "EHLO e28smtp04.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752882Ab1LAQ2f (ORCPT ); Thu, 1 Dec 2011 11:28:35 -0500 Message-ID: <4ED7AB26.4080804@linux.vnet.ibm.com> Date: Thu, 01 Dec 2011 21:58:22 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux i686; rv:7.0) Gecko/20110927 Thunderbird/7.0 MIME-Version: 1.0 To: Tejun Heo CC: rjw@sisk.pl, pavel@ucw.cz, len.brown@intel.com, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Subject: Re: [PATCH] PM / Hibernate: Thaw processes in SNAPSHOT_CREATE_IMAGE ioctl error/test paths References: <20111201131532.21615.86479.stgit@srivatsabhat.in.ibm.com> <20111201154722.GB12668@google.com> In-Reply-To: <20111201154722.GB12668@google.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit x-cbid: 11120116-5564-0000-0000-000000570E29 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/01/2011 09:17 PM, Tejun Heo wrote: > On Thu, Dec 01, 2011 at 06:45:37PM +0530, Srivatsa S. Bhat wrote: >> Commit 2aede851ddf08666f68ffc17be446420e9d2a056 (PM / Hibernate: Freeze >> kernel threads after preallocating memory) moved the freezing of kernel >> threads to hibernation_snapshot() function. >> >> So now, if the call to hibernation_snapshot() fails or returns early due >> to a successful hibernation test, the caller has to thaw processes to >> ensure that the system gets back to its original state. >> >> But in SNAPSHOT_CREATE_IMAGE hibernation ioctl, the caller does not thaw >> processes. Fix this issue. But note that if hibernation_snapshot() returned >> due to a successful freezer test, we still send the value of 'in_suspend' >> (which is now 0) to userspace, because we are not in an error path per-se, >> and moreover, the value of in_suspend correctly depicts the situation here. >> >> Signed-off-by: Srivatsa S. Bhat > > Is this still applicable on top of pm-freezer branch? > Well, yes, but not in this form. Thanks for bringing that up! If the call to hibernation_snapshot() returns an error, we need not do anything since your freezer changes handle that case and call thaw_processes() automatically. But in case of return due to a successful freezer test, we would need to explicitly thaw processes since the freezer successfully froze them in the previous step. So the following patch would do that, for the pm-freezer branch: --- From: Srivatsa S. Bhat Subject: [PATCH] PM / Hibernate: Thaw processes in SNAPSHOT_CREATE_IMAGE ioctl test path Commit 2aede851ddf08666f68ffc17be446420e9d2a056 (PM / Hibernate: Freeze kernel threads after preallocating memory) moved the freezing of kernel threads to hibernation_snapshot() function. So now, if the call to hibernation_snapshot() returns early due to a successful hibernation test, the caller has to thaw processes to ensure that the system gets back to its original state. But in SNAPSHOT_CREATE_IMAGE hibernation ioctl, the caller does not thaw processes in case hibernation_snapshot() returned due to a successful freezer test. Fix this issue. But note we still send the value of 'in_suspend' (which is now 0) to userspace, because we are not in an error path per-se, and moreover, the value of in_suspend correctly depicts the situation here. Signed-off-by: Srivatsa S. Bhat --- kernel/power/hibernate.c | 2 +- kernel/power/power.h | 2 ++ kernel/power/user.c | 11 ++++++++--- 3 files changed, 11 insertions(+), 4 deletions(-) diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 80c2d90..57bab63 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -55,7 +55,7 @@ enum { static int hibernation_mode = HIBERNATION_SHUTDOWN; -static bool freezer_test_done; +bool freezer_test_done; static const struct platform_hibernation_ops *hibernation_ops; diff --git a/kernel/power/power.h b/kernel/power/power.h index 23a2db1..0c4defe 100644 --- a/kernel/power/power.h +++ b/kernel/power/power.h @@ -50,6 +50,8 @@ static inline char *check_image_kernel(struct swsusp_info *info) #define SPARE_PAGES ((1024 * 1024) >> PAGE_SHIFT) /* kernel/power/hibernate.c */ +extern bool freezer_test_done; + extern int hibernation_snapshot(int platform_mode); extern int hibernation_restore(int platform_mode); extern int hibernation_platform_enter(void); diff --git a/kernel/power/user.c b/kernel/power/user.c index 7cc3f5b..c202e2e 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -281,10 +281,15 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, } pm_restore_gfp_mask(); error = hibernation_snapshot(data->platform_support); - if (!error) + if (!error) { error = put_user(in_suspend, (int __user *)arg); - if (!error) - data->ready = 1; + if (!error && !freezer_test_done) + data->ready = 1; + if (freezer_test_done) { + freezer_test_done = false; + thaw_processes(); + } + } break; case SNAPSHOT_ATOMIC_RESTORE: