Re: [git patch] free_irq() fixes

[ebiederm@xmission.com (Eric W. Biederman)]

Jeff Garzik <jeff@garzik.org> writes:

> Eric W. Biederman wrote:
>> And on x86 at least the hardware maps the MSI write into an interrupt.
>> So there is not an opportunity to get any metdata/OOB data from the
>> MSI message.  Instead we just potentially get a boatload more irq
>> sources.  Which is one of the things making a static NR_IRQS painful.
>>
>> To be safe we have to make NR_IRQS 10x+ or so bigger then people use
>> today.  Just in case they decide to plug in some really irq hungry
>> cards.
>
>
> Just to be clear, irq_chip/irq_desc and metadata/OOB data are two very different
> beasts.  irq_chip/irq_desc is more a system attribute as Linus notes.  Also, it
> doesn't change very often.
>
> metadata/OOB, on the other hand, is different -for each interrupt-, and is
> highly relevant to drivers.  Thus should be part of the driver API somehow.

I'm not certain I follow so I will ask.

Do you mean information that is different each time an interrupt is fires?

Or do you mean information that differs for each different interrupt?
Something like the current dev_id?

To my knowledge there is not any information that varies each time an
interrupt fires.

Eric