From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755278Ab1LAVu1 (ORCPT ); Thu, 1 Dec 2011 16:50:27 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:38140 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754555Ab1LAVu0 (ORCPT ); Thu, 1 Dec 2011 16:50:26 -0500 From: "Rafael J. Wysocki" To: "Srivatsa S. Bhat" Subject: Re: [PATCH] PM / Hibernate: Thaw processes in SNAPSHOT_CREATE_IMAGE ioctl error/test paths Date: Thu, 1 Dec 2011 22:53:20 +0100 User-Agent: KMail/1.13.6 (Linux/3.2.0-rc3+; KDE/4.6.0; x86_64; ; ) Cc: Tejun Heo , pavel@ucw.cz, len.brown@intel.com, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org References: <20111201131532.21615.86479.stgit@srivatsabhat.in.ibm.com> <20111201154722.GB12668@google.com> <4ED7AB26.4080804@linux.vnet.ibm.com> In-Reply-To: <4ED7AB26.4080804@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201112012253.20250.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday, December 01, 2011, Srivatsa S. Bhat wrote: > 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 Applied to linux-pm/linux-next. Thanks, Rafael > --- > > 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: > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > >