* Re: [PATCH] xen/events/fifo: Add missing hotplug notifier transition
[not found] <1457686822-39117-1-git-send-email-anna-maria@linutronix.de>
@ 2016-03-11 10:53 ` David Vrabel
[not found] ` <56E2A3B6.2060208@citrix.com>
1 sibling, 0 replies; 3+ messages in thread
From: David Vrabel @ 2016-03-11 10:53 UTC (permalink / raw)
To: Anna-Maria Gleixner, linux-kernel
Cc: xen-devel, Boris Ostrovsky, David Vrabel, rt
On 11/03/16 09:00, Anna-Maria Gleixner wrote:
> The evtchn_fifo_cpu_notification() hotplug callback lacks handling of
> the CPU_UP_CANCELED case. That means, if CPU_UP_PREPARE fails, the
> handle of the fifo events is not dropped.
>
> Add handling for CPU_UP_CANCELED transition to drop the fifo events
> handle.
__evtchn_fifo_handle_events() does not releases resources, it processes
any pending events for this CPU.
This patch would only be necessary if a CPU in CPU_UP_CANCELED state may
have had unmasked interrupts. If so you would need:
case CPU_UP_CANCELED:
if (per_cpu(cpu_control_block, cpu))
__evtchn_fifo_handle_events(cpu, true);
break;
To handle the case where the control block allocation or initialization
failed during CPU_UP_PREPARE.
David
>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Cc: David Vrabel <david.vrabel@citrix.com>
> Cc: xen-devel@lists.xenproject.org
> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
> ---
> drivers/xen/events/events_fifo.c | 1 +
> 1 file changed, 1 insertion(+)
>
> --- a/drivers/xen/events/events_fifo.c
> +++ b/drivers/xen/events/events_fifo.c
> @@ -432,6 +432,7 @@ static int evtchn_fifo_cpu_notification(
> ret = evtchn_fifo_alloc_control_block(cpu);
> break;
> case CPU_DEAD:
> + case CPU_UP_CANCELED:
> __evtchn_fifo_handle_events(cpu, true);
> break;
> default:
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
>
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] xen/events/fifo: Add missing hotplug notifier transition
[not found] ` <56E2A3B6.2060208@citrix.com>
@ 2016-03-11 11:26 ` Anna-Maria Gleixner
0 siblings, 0 replies; 3+ messages in thread
From: Anna-Maria Gleixner @ 2016-03-11 11:26 UTC (permalink / raw)
To: David Vrabel; +Cc: xen-devel, Boris Ostrovsky, linux-kernel, rt
On Fri, 11 Mar 2016, David Vrabel wrote:
> On 11/03/16 09:00, Anna-Maria Gleixner wrote:
> > The evtchn_fifo_cpu_notification() hotplug callback lacks handling of
> > the CPU_UP_CANCELED case. That means, if CPU_UP_PREPARE fails, the
> > handle of the fifo events is not dropped.
> >
> > Add handling for CPU_UP_CANCELED transition to drop the fifo events
> > handle.
>
> __evtchn_fifo_handle_events() does not releases resources, it processes
> any pending events for this CPU.
>
> This patch would only be necessary if a CPU in CPU_UP_CANCELED state may
> have had unmasked interrupts. If so you would need:
Thanks for the explanation
> case CPU_UP_CANCELED:
> if (per_cpu(cpu_control_block, cpu))
> __evtchn_fifo_handle_events(cpu, true);
> break;
>
> To handle the case where the control block allocation or initialization
> failed during CPU_UP_PREPARE.
This would not be necessary, because if the CPU_UP_PREPARE of this
notifier fails, the CPU_UP_CANCELLED of this notifier will not be
invoked.
Anna-Maria
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] xen/events/fifo: Add missing hotplug notifier transition
@ 2016-03-11 9:00 Anna-Maria Gleixner
0 siblings, 0 replies; 3+ messages in thread
From: Anna-Maria Gleixner @ 2016-03-11 9:00 UTC (permalink / raw)
To: linux-kernel
Cc: David Vrabel, xen-devel, Boris Ostrovsky, Anna-Maria Gleixner, rt
The evtchn_fifo_cpu_notification() hotplug callback lacks handling of
the CPU_UP_CANCELED case. That means, if CPU_UP_PREPARE fails, the
handle of the fifo events is not dropped.
Add handling for CPU_UP_CANCELED transition to drop the fifo events
handle.
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: xen-devel@lists.xenproject.org
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
---
drivers/xen/events/events_fifo.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -432,6 +432,7 @@ static int evtchn_fifo_cpu_notification(
ret = evtchn_fifo_alloc_control_block(cpu);
break;
case CPU_DEAD:
+ case CPU_UP_CANCELED:
__evtchn_fifo_handle_events(cpu, true);
break;
default:
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-03-11 10:53 ` [PATCH] xen/events/fifo: Add missing hotplug notifier transition David Vrabel
[not found] ` <56E2A3B6.2060208@citrix.com>
2016-03-11 11:26 ` Anna-Maria Gleixner
2016-03-11 9:00 Anna-Maria Gleixner
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