-static int xen_allocate_irq_dynamic(void)
-{
- struct irq_data *data;
- int irq, res;
- int bottom = get_nr_hw_irqs();
- int top = nr_irqs-1;
-
- if (bottom == nr_irqs)
- goto no_irqs;
-
- /* This loop starts from the top of IRQ space and goes down.
- * We need this b/c if we have a PCI device in a Xen PV guest
- * we do not have an IO-APIC (though the backend might have them)
- * mapped in. To not have a collision of physical IRQs with the Xen
- * event channels start at the top of the IRQ space for virtual IRQs.
- */
- for (irq = top; irq > bottom; irq--) {
- data = irq_get_irq_data(irq);
- /* only 15->0 have init'd desc; handle irq > 16 */
- if (!data)
- break;
- if (data->chip == &no_irq_chip)
- break;
- if (data->chip != &xen_dynamic_chip)
- continue;
- if (irq_info[irq].type == IRQT_UNBOUND)
- return irq;
+ if (irq == -ENOMEM && first > NR_IRQS_LEGACY) {
+ printk(KERN_ERR "Out of dynamic IRQ space and eating into GSI space. You should increase nr_irqs\n");
+ first = max(NR_IRQS_LEGACY, first - NR_IRQS_LEGACY);
+ goto retry;