case IRQ_DOMAIN_MAP_LINEAR:
                rmap = (unsigned int *)(host + 1);
                for (i = 0; i < revmap_arg; i++)
-                       rmap[i] = NO_IRQ;
+                       rmap[i] = 0;
                host->revmap_data.linear.size = revmap_arg;
                host->revmap_data.linear.revmap = rmap;
                break;
        WARN_ON(host->revmap_type != IRQ_DOMAIN_MAP_NOMAP);
 
        virq = irq_alloc_desc_from(1, 0);
-       if (virq == NO_IRQ) {
+       if (!virq) {
                pr_debug("irq: create_direct virq allocation failed\n");
-               return NO_IRQ;
+               return 0;
        }
        if (virq >= irq_virq_count) {
                pr_err("ERROR: no free irqs available below %i maximum\n",
 
        if (irq_setup_virq(host, virq, virq)) {
                irq_free_desc(virq);
-               return NO_IRQ;
+               return 0;
        }
 
        return virq;
                printk(KERN_WARNING "irq_create_mapping called for"
                       " NULL host, hwirq=%lx\n", hwirq);
                WARN_ON(1);
-               return NO_IRQ;
+               return 0;
        }
        pr_debug("irq: -> using host @%p\n", host);
 
        /* Check if mapping already exists */
        virq = irq_find_mapping(host, hwirq);
-       if (virq != NO_IRQ) {
+       if (virq) {
                pr_debug("irq: -> existing mapping on virq %d\n", virq);
                return virq;
        }
                /* Handle legacy */
                virq = (unsigned int)hwirq;
                if (virq == 0 || virq >= NUM_ISA_INTERRUPTS)
-                       return NO_IRQ;
+                       return 0;
                return virq;
        } else {
                /* Allocate a virtual interrupt number */
                virq = irq_alloc_desc_from(hint, 0);
                if (!virq)
                        virq = irq_alloc_desc_from(1, 0);
-               if (virq == NO_IRQ) {
+               if (!virq) {
                        pr_debug("irq: -> virq allocation failed\n");
-                       return NO_IRQ;
+                       return 0;
                }
        }
 
        if (irq_setup_virq(host, virq, hwirq)) {
                if (host->revmap_type != IRQ_DOMAIN_MAP_LEGACY)
                        irq_free_desc(virq);
-               return NO_IRQ;
+               return 0;
        }
 
        pr_debug("irq: irq %lu on host %s mapped to virtual irq %u\n",
        if (host == NULL) {
                printk(KERN_WARNING "irq: no irq host found for %s !\n",
                       controller->full_name);
-               return NO_IRQ;
+               return 0;
        }
 
        /* If host has no translation, then we assume interrupt line */
        else {
                if (host->ops->xlate(host, controller, intspec, intsize,
                                     &hwirq, &type))
-                       return NO_IRQ;
+                       return 0;
        }
 
        /* Create mapping */
        virq = irq_create_mapping(host, hwirq);
-       if (virq == NO_IRQ)
+       if (!virq)
                return virq;
 
        /* Set type if specified and different than the current one */
        struct irq_domain *host;
        irq_hw_number_t hwirq;
 
-       if (virq == NO_IRQ || !irq_data)
+       if (!virq || !irq_data)
                return;
 
        host = irq_data->domain;
        switch(host->revmap_type) {
        case IRQ_DOMAIN_MAP_LINEAR:
                if (hwirq < host->revmap_data.linear.size)
-                       host->revmap_data.linear.revmap[hwirq] = NO_IRQ;
+                       host->revmap_data.linear.revmap[hwirq] = 0;
                break;
        case IRQ_DOMAIN_MAP_TREE:
                mutex_lock(&revmap_trees_mutex);
        if (host == NULL)
                host = irq_default_host;
        if (host == NULL)
-               return NO_IRQ;
+               return 0;
 
        /* legacy -> bail early */
        if (host->revmap_type == IRQ_DOMAIN_MAP_LEGACY)
                if (i >= irq_virq_count)
                        i = 1;
        } while(i != hint);
-       return NO_IRQ;
+       return 0;
 }
 EXPORT_SYMBOL_GPL(irq_find_mapping);
 
        if (WARN_ON(host->revmap_type != IRQ_DOMAIN_MAP_TREE))
                return;
 
-       if (virq != NO_IRQ) {
+       if (virq) {
                mutex_lock(&revmap_trees_mutex);
                radix_tree_insert(&host->revmap_data.tree, hwirq, irq_data);
                mutex_unlock(&revmap_trees_mutex);
                return irq_find_mapping(host, hwirq);
 
        /* Fill up revmap with slow path if no mapping found */
-       if (unlikely(revmap[hwirq] == NO_IRQ))
+       if (unlikely(!revmap[hwirq]))
                revmap[hwirq] = irq_find_mapping(host, hwirq);
 
        return revmap[hwirq];