Re: [PATCH v3 2/4] genirq: Inform handler about line sharing state

Jan Kiszka
2010-12-15T09:38:20Z

Am 15.12.2010 09:05, Thomas Gleixner wrote:
> On Wed, 15 Dec 2010, Jan Kiszka wrote:
>
>> Am 14.12.2010 22:46, Thomas Gleixner wrote:
>>> On Mon, 13 Dec 2010, Jan Kiszka wrote:
>>>> From: Jan Kiszka <jan.kiszka@siemens.com>
>>>> chip_bus_lock(desc);
>>>> retval = __setup_irq(irq, desc, action);
>>>> chip_bus_sync_unlock(desc);
>>>>
>>>> - if (retval)
>>>> + if (retval) {
>>>> + if (desc->action && !desc->action->next)
>>>> + desc->irq_data.drv_status &= ~IRQS_SHARED;
>>>
>>> This is redundant. IRQS_SHARED gets set in a code path where all
>>> checks are done already.
>>
>> Nope, it's also set before entry of __setup_irq in case we call an
>> IRQF_ADAPTIVE handler.
>>
>> We need to set it that early as we may race with IRQ events for the
>> already registered handler happening between the sharing notification
>> and the actual registration of the second handler.
>
> Hmm, ok. Though the MAKE_SHAREABLE flag should be sufficient to do the
> notification.

For notification, yes. But we need SHARED once we reenable the line
after the notification.

Jan

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