Re: [question] NR_IRQS in genirq

[Paul Mundt <lethal@linux-sh.org>]

On Wed, Nov 24, 2010 at 03:28:37PM +0800, Haojian Zhuang wrote:
> Hi all,
> 
> I'm using the latest kernel 2.6.37-rc1. Now I met some issues on genirq.
> 
> 1. While SPARSE IRQ is enabled, nr_irqs may be larger than NR_IRQS.
> But the allocated_irqs bitmap (kernel/irq/irqdesc.c) is restricted in
> NR_IRQS. Is it an issue?
> 
> 2. irqs_resend bitmap of kernel/irq/resend.c is also restricted in
> NR_IRQS. Is it an issue, too?
> 
Perhaps something like:

diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 9988d03..11bd76c 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -215,6 +215,11 @@ int __init early_irq_init(void)
 	initcnt = arch_probe_nr_irqs();
 	printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d %d\n", NR_IRQS, nr_irqs, initcnt);
 
+	if (unlikely(nr_irqs > NR_IRQS)) {
+		WARN(1, "Probed more than NR_IRQS, chomping.\n");
+		nr_irqs = NR_IRQS;
+	}
+
 	for (i = 0; i < initcnt; i++) {
 		desc = alloc_desc(i, node);
 		set_bit(i, allocated_irqs);

?