irqchip/armada-370-xp: Fix support for Multi-MSI interrupts

commit d0a553502e upstream.

irq-armada-370-xp driver already sets MSI_FLAG_MULTI_PCI_MSI flag into
msi_domain_info structure. But allocated interrupt numbers for Multi-MSI
needs to be properly aligned otherwise devices send MSI interrupt with
wrong number.

Fix this issue by using function bitmap_find_free_region() instead of
bitmap_find_next_zero_area() to allocate aligned interrupt numbers.

Signed-off-by: Pali Rohár <pali@kernel.org>
Fixes: a71b9412c9 ("irqchip/armada-370-xp: Allow allocation of multiple MSIs")
Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211125130057.26705-2-pali@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/irqchip/irq-armada-370-xp.c

@@ -232,17 +232,13 @@ static int armada_370_xp_msi_alloc(struct irq_domain *domain, unsigned int virq,
 	int hwirq, i;
 
 	mutex_lock(&msi_used_lock);
-
-	hwirq = bitmap_find_next_zero_area(msi_used, PCI_MSI_DOORBELL_NR,
-					   0, nr_irqs, 0);
-	if (hwirq >= PCI_MSI_DOORBELL_NR) {
-		mutex_unlock(&msi_used_lock);
-		return -ENOSPC;
-	}
-
-	bitmap_set(msi_used, hwirq, nr_irqs);
+	hwirq = bitmap_find_free_region(msi_used, PCI_MSI_DOORBELL_NR,
+					order_base_2(nr_irqs));
 	mutex_unlock(&msi_used_lock);
 
+	if (hwirq < 0)
+		return -ENOSPC;
+
 	for (i = 0; i < nr_irqs; i++) {
 		irq_domain_set_info(domain, virq + i, hwirq + i,
 				    &armada_370_xp_msi_bottom_irq_chip,
@@ -259,7 +255,7 @@ static void armada_370_xp_msi_free(struct irq_domain *domain,
 	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
 
 	mutex_lock(&msi_used_lock);
-	bitmap_clear(msi_used, d->hwirq, nr_irqs);
+	bitmap_release_region(msi_used, d->hwirq, order_base_2(nr_irqs));
 	mutex_unlock(&msi_used_lock);
 }