acpi-devel@lists.sourceforge.net, linux-ia64@vger.kernel.orgRe:[PATCH] Updated patches for PCI IRQ resource deallocation support [3/3]

[Zwane Mwaikambo]

Hello Kenji,

On Fri, 24 Sep 2004, Kenji Kaneshige wrote:

> +		/*
> +		 * If interrupt handlers still exists on the irq
> +		 * associated with the gsi, don't unregister the
> +		 * interrupt.
> +		 */
> +		if (unlikely(idesc->action)) {
> +			iosapic_intr_info[vector].refcnt++;
> +			spin_unlock_irqrestore(&idesc->lock, flags);
> +			printk(KERN_WARNING "Cannot unregister GSI. IRQ %u is still in use.\n", irq);
> +			return;
> +		}
> +
> +		/* Clear the interrupt controller descriptor. */
> +		idesc->handler = &no_irq_type;

Hmm, what happens here if that vector was queued just before the local irq 
disable in spin_lock_irqsave(idesc->lock...) ? Then when we unlock we'll 
call do_IRQ to handle the irq associated with that vector. I haven't seen 
the usage but it appears that iosapic_unregister_intr requires some 
serialisation.

Thanks,
	Zwane
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