[Xen-devel] [tip:x86/irq] x86: Don't unmask disabled irqs when migrating them

["tip-bot for Tian, Kevin" <kevin.tian@xxxxxxxxx>]

Commit-ID:  983bbf1af0664b78689612b247acb514300f62c7
Gitweb:     http://git.kernel.org/tip/983bbf1af0664b78689612b247acb514300f62c7
Author:     Tian, Kevin <kevin.tian@xxxxxxxxx>
AuthorDate: Fri, 6 May 2011 14:43:56 +0800
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 19 May 2011 14:51:08 +0200

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@xxxxxxxxx>
Signed-off-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Cc: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
Cc: Jan Beulich <JBeulich@xxxxxxxxxx>
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Link: 
http://lkml.kernel.org/r/%3C625BA99ED14B2D499DC4E29D8138F1505C8ED7F7E3%40shsmsx502.ccr.corp.intel.com%3E
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
 arch/x86/kernel/irq.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 544efe2..6c0802e 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);

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