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SubjectRe: [PATCH]: Staging: hv: Allocate the vmbus irq dynamically
On Tue, 15 Feb 2011, K. Y. Srinivasan wrote:
> -/* FIXME! We need to do this dynamically for PIC and APIC system */
> -#define VMBUS_IRQ 0x5
> -#define VMBUS_IRQ_VECTOR IRQ5_VECTOR
> +static int vmbus_irq;
>
> /* Main vmbus driver data structure */
> struct vmbus_driver_context {
> @@ -57,6 +55,27 @@ struct vmbus_driver_context {
> struct vm_device device_ctx;
> };
>
> +/*
> + * Find an un-used IRQ that the VMBUS can use. If none is available;
> + * return -EBUSY.
> + */
> +static int vmbus_get_irq(void)
> +{
> + unsigned int avail_irq_mask;
> + int irq = -EBUSY;
> +
> + /*
> + * Pick the first unused interrupt. HyperV can
> + * interrupt us on any interrupt line we specify.
> + */
> +
> + avail_irq_mask = probe_irq_on();
> + if (avail_irq_mask != 0)
> + irq = ffs(avail_irq_mask);
> + probe_irq_off(avail_irq_mask);
> + return irq;


Please do not use probe_irq_on for dynamic irq allocation. Highjacking
the lower PIC irqs is really not a good idea. Depending on when this
runs, you might grab an irq required by a driver which gets loaded
later.

Could you please explain what you're trying to do here ?

Thanks,

tglx


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