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From: ebiederm@xmission.com (Eric W. Biederman)
To: "Yinghai Lu" <yhlu.kernel@gmail.com>
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Date: Sat, 09 Aug 2008 14:38:50 -0700
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	(Yinghai Lu's message of "Sat, 9 Aug 2008 14:21:45 -0700")
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Subject: Re: [PATCH 08/42] introduce nr_irqs
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"Yinghai Lu" <yhlu.kernel@gmail.com> writes:

> On Sat, Aug 9, 2008 at 9:02 AM, Eric W. Biederman <ebiederm@xmission.com> wrote:
>> "Yinghai Lu" <yhlu.kernel@gmail.com> writes:
>>
>>>> Also, what's the point, if it's just a renaming?
>>>
>>> that is the start point.
>>> nr_irqs is variable, and will be probed later. and use that number to
>>> init dyn_alloc.
>>
>> YH.
>>
>> In my conception the code in kernel/irq.c that today does:
>>
>> struct irq_desc *desc;
>> if (irq >= NR_IRQS)
>>   return -EINVAL;
>> desc = irq_desc + irq;
>>
>> Should become:
>>
>> struct irq_desc *desc;
>> desc = irq_desc(irq);
>> if (!desc)
>>   return -EINVAL;
>>
>
> OK.
>
> also want to introduce dummy
> struct irq_desc
> {
>    unsigned int irq;
> };
>
> in linux/interrupt.h if GENERIC_HARDIRQS is not defined.
> so could have same interface
> irq_desc()
> and
> for_each_irq_desc(irq, desc)

What would use it?  irq_desc doesn't even exist if GENERIC_HARDIRQS are
not defined.

Far far in the future we may want to introduce an opaque type
struct irq.  For use with linux/interrupt.h  Allowing things
like irq_request(struct irq *irq, ...);  For now those kinds
of interfaces should be internal to the genirq code.


Eric