From: Kei Tokunaga <ktokunag@redhat.com>
Subject: [RHEL5 PATCH] CPEI gets warning at kernel/irq/migration.c:27/move_native_irq()
Date: Mon, 18 Dec 2006 11:45:25 -0500
Bugzilla: 218520
Message-Id: <4586C5A5.1050603@redhat.com>
Changelog: CPEI - prevent relocating hotplug irqs


BZ218520
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=218520

This is a backported upstream patch to suppress unnecessary
warnings on CPEI.

CPEI is PER_CPU irq but it has set_affinity handler for a special
use (hotplug).  Function irq_affinity_write_proc() only checks
the existence of handler to determine whether the irq can be
relocated.

Therefore this function allows users (ex. irqbalance) to attempt
to move CPEI which is not relocatable PER_CPU irq.  Once such
an attempt is done with CPEI, every CPEI gets warnings because
it hits WARN_ON() at end of every interruption process.

Thanks,
Kei




---

 linux-2.6.18-1.2878.el5-kei/kernel/irq/proc.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff -puN kernel/irq/proc.c~bz218520-suppress_CPEI_warning kernel/irq/proc.c
--- linux-2.6.18-1.2878.el5/kernel/irq/proc.c~bz218520-suppress_CPEI_warning	2006-12-15 09:40:43.000000000 -0500
+++ linux-2.6.18-1.2878.el5-kei/kernel/irq/proc.c	2006-12-15 09:40:43.000000000 -0500
@@ -54,7 +54,8 @@ static int irq_affinity_write_proc(struc
 	unsigned int irq = (int)(long)data, full_count = count, err;
 	cpumask_t new_value, tmp;
 
-	if (!irq_desc[irq].chip->set_affinity || no_irq_affinity)
+	if (!irq_desc[irq].chip->set_affinity || no_irq_affinity ||
+				CHECK_IRQ_PER_CPU(irq_desc[irq].status))
 		return -EIO;
 
 	err = cpumask_parse(buffer, count, new_value);

_