Re: [PATCH 1/4] x86_64 io_apic: Implement remove_pin_to_irq

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

"Lu, Yinghai" <yinghai.lu@amd.com> writes:

> -----Original Message-----
> From: ebiederm@xmission.com [mailto:ebiederm@xmission.com] 
> Sent: Monday, January 08, 2007 7:50 AM
> To: Linus Torvalds
> Cc: Tobias Diedrich; Lu, Yinghai; Andrew Morton; Adrian Bunk; Andi
> Kleen; Linux Kernel Mailing List
> Subject: [PATCH 1/4] x86_64 io_apic: Implement remove_pin_to_irq
>
> +static void remove_pin_to_irq(unsigned int irq, int apic, int pin)
> +{
> +	struct irq_pin_list *entry = irq_2_pin + irq;
>
> You may need to update add_pin_to_irq to avoid multi entries for irq 0.

Any updates to add_pin_to_irq are wrong.  It works fine.  If there
is something wrong we need to fix remove_pin_to_irq.

What is the problem you see?  Sorry I'm dense at the moment.

I preserve the invariant that irq_2_pin + irq is always the first
entry in the chain.  I do this when I delete a multi chain entry
by copying the next entry over the current entry, and then freeing
(and leaking) the second entry in the chain.

Is there something wrong with that?  I came within an inch of deleting
this multiple apic, pin to irq mapping code but the comments said it
is needed for some ioapic case.  So in resurrecting this variant I may
have goofed somewhere.

Eric