x86: Don't unmask disabled irqs when migrating them

It doesn't make sense to unconditionally unmask a disabled irq when
migrating it from offlined cpu to another. If the irq triggers then it
will be disabled in the interrupt handler anyway. So we can just avoid
unmasking it.

[ tglx: Made masking unconditional again and fixed the changelog ]

Signed-off-by: Fengzhe Zhang <fengzhe.zhang@intel.com>
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Link: http://lkml.kernel.org/r/%3C625BA99ED14B2D499DC4E29D8138F1505C8ED7F7E3%40shsmsx502.ccr.corp.intel.com%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 544efe2741be..6c0802eb2f7f 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -276,7 +276,8 @@ void fixup_irqs(void)
                 else if (!(warned++))
                         set_affinity = 0;
 
-                if (!irqd_can_move_in_process_context(data) && chip->irq_unmask)
+                if (!irqd_can_move_in_process_context(data) &&
+                    !irqd_irq_disabled(data) && chip->irq_unmask)
                         chip->irq_unmask(data);
 
                 raw_spin_unlock(&desc->lock);