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Date: Thu, 13 Nov 2008 12:06:49 -0800
From: Yinghai Lu <yinghai@kernel.org>
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To: Ingo Molnar <mingo@elte.hu>
CC: Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sparse_irq aka dyn_irq v13
References: <49168BD3.5010204@kernel.org> <20081109073813.GA17180@elte.hu> <86802c440811090003g5ac53822y852a4c1096228f8b@mail.gmail.com> <20081110094033.GL22392@elte.hu> <20081110015511.453a801e.akpm@linux-foundation.org> <4918065A.6050402@kernel.org> <20081110100329.GA19970@elte.hu> <491A9F87.8040403@kernel.org> <20081112120814.GG11352@elte.hu> <491BD0BA.5070008@kernel.org> <20081113095345.GM25479@elte.hu>
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Ingo Molnar wrote:

> it still looks ugly to me: couldnt we make it completely #ifdef-free, 
> by just adding the new API variants?
> 
> i.e. leave these present unconditionally:
> 
>>  extern void hpet_msi_unmask(unsigned int irq);
>>  extern void hpet_msi_mask(unsigned int irq);
> 
> and just _add_ these (unconditionally):
> 
>> +extern void hpet_msi_unmask_desc(unsigned int irq, struct irq_desc **descp);
>> +extern void hpet_msi_mask_desc(unsigned int irq, struct irq_desc **descp);
> 
> that gives us zero #ifdefs and much nicer to read patches. Am i 
> missing something why this isnt possible?

in io_apic.c

struct irq_chip hpet_msi_type = {
        .name = "HPET_MSI",
        .unmask = hpet_msi_unmask,
        .mask = hpet_msi_mask,
        .ack = ack_apic_edge,
#ifdef CONFIG_SMP
        .set_affinity = hpet_msi_set_affinity,
#endif
        .retrigger = ioapic_retrigger_irq,
};

so those ack, mask, unmak, eoi field will have different function prototype..when sparseirq is enabled or not.

if you want to remove those #ifdef, we need to go over all irq_chip definition to make all those field to take struct irq_desc *desc (or **descp) instead of unsigned int irq.

actually we only need to pass desc struct instead of irq, because we can get desc->irq in case.

YH