* [Ocfs2-devel] FW: [PATCH] workqueue: cancel_delayed_work() should return %NULL if work item is idle
@ 2012-10-19 17:56 Dan Magenheimer
2012-10-23 8:50 ` Joel Becker
0 siblings, 1 reply; 3+ messages in thread
From: Dan Magenheimer @ 2012-10-19 17:56 UTC (permalink / raw)
To: ocfs2-devel
FYI, it is likely that ocfs2 will not work on 3.7-rcN until
the following one-line patch is merged, as the code in ramster
that provoked it is directly leveraged from ocfs2 o2net.
> From: Tejun Heo [mailto:tj at kernel.org]
> Sent: Thursday, October 18, 2012 5:39 PM
> To: Dan Magenheimer
> Cc: linux-kernel at vger.kernel.org; Konrad Wilk
> Subject: [PATCH] workqueue: cancel_delayed_work() should return %NULL if work item is idle
>
> From e65120fcfc1cb9697655d29ecd7982451c05d3c2 Mon Sep 17 00:00:00 2001
> From: Dan Magenheimer <dan.magenheimer@oracle.com>
> Date: Thu, 18 Oct 2012 16:31:37 -0700
>
> 57b30ae77b ("workqueue: reimplement cancel_delayed_work() using
> try_to_grab_pending()") made cancel_delayed_work() always return %true
> unless someone else is also trying to cancel the work item, which is
> broken - if the target work item is idle, the return value should be
> %false.
>
> try_to_grab_pending() indicates that the target work item was idle by
> zero return value. Use it for return. Note that this brings
> cancel_delayed_work() in line with __cancel_work_timer() in return
> value handling.
>
> Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> LKML-Reference: <444a6439-b1a4-4740-9e7e-bc37267cfe73@default>
> ---
> kernel/workqueue.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index d951daa..042d221 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -2982,7 +2982,7 @@ bool cancel_delayed_work(struct delayed_work *dwork)
>
> set_work_cpu_and_clear_pending(&dwork->work, work_cpu(&dwork->work));
> local_irq_restore(flags);
> - return true;
> + return ret;
> }
> EXPORT_SYMBOL(cancel_delayed_work);
>
> --
> 1.7.7.3
>
^ permalink raw reply [flat|nested] 3+ messages in thread* [Ocfs2-devel] FW: [PATCH] workqueue: cancel_delayed_work() should return %NULL if work item is idle
2012-10-19 17:56 [Ocfs2-devel] FW: [PATCH] workqueue: cancel_delayed_work() should return %NULL if work item is idle Dan Magenheimer
@ 2012-10-23 8:50 ` Joel Becker
2012-10-23 15:46 ` Dan Magenheimer
0 siblings, 1 reply; 3+ messages in thread
From: Joel Becker @ 2012-10-23 8:50 UTC (permalink / raw)
To: ocfs2-devel
Help me understand the issue. Who broke this? Do I need to push this
patch, or is someone else?
Thanks,
Joel
On Fri, Oct 19, 2012 at 10:56:42AM -0700, Dan Magenheimer wrote:
> FYI, it is likely that ocfs2 will not work on 3.7-rcN until
> the following one-line patch is merged, as the code in ramster
> that provoked it is directly leveraged from ocfs2 o2net.
>
> > From: Tejun Heo [mailto:tj at kernel.org]
> > Sent: Thursday, October 18, 2012 5:39 PM
> > To: Dan Magenheimer
> > Cc: linux-kernel at vger.kernel.org; Konrad Wilk
> > Subject: [PATCH] workqueue: cancel_delayed_work() should return %NULL if work item is idle
> >
> > From e65120fcfc1cb9697655d29ecd7982451c05d3c2 Mon Sep 17 00:00:00 2001
> > From: Dan Magenheimer <dan.magenheimer@oracle.com>
> > Date: Thu, 18 Oct 2012 16:31:37 -0700
> >
> > 57b30ae77b ("workqueue: reimplement cancel_delayed_work() using
> > try_to_grab_pending()") made cancel_delayed_work() always return %true
> > unless someone else is also trying to cancel the work item, which is
> > broken - if the target work item is idle, the return value should be
> > %false.
> >
> > try_to_grab_pending() indicates that the target work item was idle by
> > zero return value. Use it for return. Note that this brings
> > cancel_delayed_work() in line with __cancel_work_timer() in return
> > value handling.
> >
> > Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
> > Signed-off-by: Tejun Heo <tj@kernel.org>
> > LKML-Reference: <444a6439-b1a4-4740-9e7e-bc37267cfe73@default>
> > ---
> > kernel/workqueue.c | 2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> > index d951daa..042d221 100644
> > --- a/kernel/workqueue.c
> > +++ b/kernel/workqueue.c
> > @@ -2982,7 +2982,7 @@ bool cancel_delayed_work(struct delayed_work *dwork)
> >
> > set_work_cpu_and_clear_pending(&dwork->work, work_cpu(&dwork->work));
> > local_irq_restore(flags);
> > - return true;
> > + return ret;
> > }
> > EXPORT_SYMBOL(cancel_delayed_work);
> >
> > --
> > 1.7.7.3
> >
>
> _______________________________________________
> Ocfs2-devel mailing list
> Ocfs2-devel at oss.oracle.com
> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
--
Life's Little Instruction Book #139
"Never deprive someone of hope; it might be all they have."
http://www.jlbec.org/
jlbec at evilplan.org
^ permalink raw reply [flat|nested] 3+ messages in thread* [Ocfs2-devel] FW: [PATCH] workqueue: cancel_delayed_work() should return %NULL if work item is idle
2012-10-23 8:50 ` Joel Becker
@ 2012-10-23 15:46 ` Dan Magenheimer
0 siblings, 0 replies; 3+ messages in thread
From: Dan Magenheimer @ 2012-10-23 15:46 UTC (permalink / raw)
To: ocfs2-devel
> From: Joel Becker [mailto:jlbec at evilplan.org]
> Sent: Tuesday, October 23, 2012 2:51 AM
> To: Dan Magenheimer
> Cc: ocfs2-devel at oss.oracle.com
> Subject: Re: [Ocfs2-devel] FW: [PATCH] workqueue: cancel_delayed_work() should return %NULL if work
> item is idle
>
> Help me understand the issue. Who broke this? Do I need to push this
> patch, or is someone else?
Tejun's new workqueue implementation which was just merged in 3.7
had a bug in it. See this thread:
https://lkml.org/lkml/2012/10/18/592
It appears the patch didn't get into 3.7-rc2. Cc'ing Tejun.
Hopefully it will be merged for -rc3 since
ramster is completely broken without the patch because a reference
counter on a socket gets miscounted. I expect the same to be
true of ocfs2... Srini was going to check.
Dan
> On Fri, Oct 19, 2012 at 10:56:42AM -0700, Dan Magenheimer wrote:
> > FYI, it is likely that ocfs2 will not work on 3.7-rcN until
> > the following one-line patch is merged, as the code in ramster
> > that provoked it is directly leveraged from ocfs2 o2net.
> >
> > > From: Tejun Heo [mailto:tj at kernel.org]
> > > Sent: Thursday, October 18, 2012 5:39 PM
> > > To: Dan Magenheimer
> > > Cc: linux-kernel at vger.kernel.org; Konrad Wilk
> > > Subject: [PATCH] workqueue: cancel_delayed_work() should return %NULL if work item is idle
> > >
> > > From e65120fcfc1cb9697655d29ecd7982451c05d3c2 Mon Sep 17 00:00:00 2001
> > > From: Dan Magenheimer <dan.magenheimer@oracle.com>
> > > Date: Thu, 18 Oct 2012 16:31:37 -0700
> > >
> > > 57b30ae77b ("workqueue: reimplement cancel_delayed_work() using
> > > try_to_grab_pending()") made cancel_delayed_work() always return %true
> > > unless someone else is also trying to cancel the work item, which is
> > > broken - if the target work item is idle, the return value should be
> > > %false.
> > >
> > > try_to_grab_pending() indicates that the target work item was idle by
> > > zero return value. Use it for return. Note that this brings
> > > cancel_delayed_work() in line with __cancel_work_timer() in return
> > > value handling.
> > >
> > > Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
> > > Signed-off-by: Tejun Heo <tj@kernel.org>
> > > LKML-Reference: <444a6439-b1a4-4740-9e7e-bc37267cfe73@default>
> > > ---
> > > kernel/workqueue.c | 2 +-
> > > 1 files changed, 1 insertions(+), 1 deletions(-)
> > >
> > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> > > index d951daa..042d221 100644
> > > --- a/kernel/workqueue.c
> > > +++ b/kernel/workqueue.c
> > > @@ -2982,7 +2982,7 @@ bool cancel_delayed_work(struct delayed_work *dwork)
> > >
> > > set_work_cpu_and_clear_pending(&dwork->work, work_cpu(&dwork->work));
> > > local_irq_restore(flags);
> > > - return true;
> > > + return ret;
> > > }
> > > EXPORT_SYMBOL(cancel_delayed_work);
> > >
> > > --
> > > 1.7.7.3
> > >
> >
> > _______________________________________________
> > Ocfs2-devel mailing list
> > Ocfs2-devel at oss.oracle.com
> > https://oss.oracle.com/mailman/listinfo/ocfs2-devel
>
> --
>
> Life's Little Instruction Book #139
>
> "Never deprive someone of hope; it might be all they have."
>
> http://www.jlbec.org/
> jlbec at evilplan.org
^ permalink raw reply [flat|nested] 3+ messages in thread
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2012-10-19 17:56 [Ocfs2-devel] FW: [PATCH] workqueue: cancel_delayed_work() should return %NULL if work item is idle Dan Magenheimer
2012-10-23 8:50 ` Joel Becker
2012-10-23 15:46 ` Dan Magenheimer
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