[patch] fix intr-remap with dyn_array/nr_irqs changes

[Suresh Siddha <suresh.b.siddha@intel.com>]

I didn't find time to closely review the dyn_array/nr_irqs changes. But
the appended patch is needed to fix the broken intr-remapping support on
x86/tip

And also, I don't see any locks used in to_irq_desc_with_new(). How are
we handling the concurrent usage scenarios. And also, this code can use
some cleanups (like the names, to_irq_desc_with_new()?) etc.

thanks,
suresh
---

In irq_2_iommu_with_new() and set_irte_irq(), irq_desc or
irq_2_iommu pointers may not be allocated. So use the routines which
will allocate them if they are not already allocated.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
---

diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c
index 3593f0f..fbd82ff 100644
--- a/drivers/pci/intr_remapping.c
+++ b/drivers/pci/intr_remapping.c
@@ -76,7 +76,10 @@ static struct irq_2_iommu *irq_2_iommu_with_new(unsigned int irq)
 	struct irq_desc *desc;
 	struct irq_2_iommu *irq_iommu;
 
-	desc = to_irq_desc(irq);
+	/*
+	 * alloc irq desc if not allocated already.
+	 */
+	desc = to_irq_desc_with_new(irq);
 
 	BUG_ON(!desc);
 
@@ -255,11 +258,7 @@ int set_irte_irq(int irq, struct intel_iommu *iommu, u16 index, u16 subhandle)
 	struct irq_2_iommu *irq_iommu;
 
 	spin_lock(&irq_2_ir_lock);
-	irq_iommu = valid_irq_2_iommu(irq);
-	if (!irq_iommu) {
-		spin_unlock(&irq_2_ir_lock);
-		return -1;
-	}
+	irq_iommu = irq_2_iommu_with_new(irq);
 
 	irq_iommu->iommu = iommu;
 	irq_iommu->irte_index = index;