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Date: Fri, 16 Nov 2012 00:36:12 +0000
From: "Liu, Chuansheng" <chuansheng.liu@...el.com>
To: "mingo@...hat.com" <mingo@...hat.com>,
"tglx@...utronix.de" <tglx@...utronix.de>
CC: "x86@...nel.org" <x86@...nel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"Liu, Chuansheng" <chuansheng.liu@...el.com>
Subject: RE: [PATCH] x86/irq,io_apic: Fix wrong unmask_ioapic calling when
the irq is masked
Hi Thomas and Ingo,
Could you have a look for this patch? It fix the wrong unmask action.
Thanks.
> -----Original Message-----
> From: Liu, Chuansheng
> Sent: Thursday, November 15, 2012 12:53 AM
> To: mingo@...hat.com; tglx@...utronix.de
> Cc: x86@...nel.org; linux-kernel@...r.kernel.org; Liu, Chuansheng
> Subject: [PATCH] x86/irq,io_apic: Fix wrong unmask_ioapic calling when the irq
> is masked
>
>
> There is one typical case will cause this issue, that is:
> One io-apic interrupt with ONE_SHOT and threaded, when interrupt is coming:
> handle_fasteoi_irq()
> --> mask_irq(desc)
> ...
> desc->irq_data.chip->irq_eoi(&desc->irq_data)[ack_apic_level]
> --> ioapic_irqd_mask()
> ...
> ioapic_irqd_unmask()
>
> After that, the irq will be in unmasked state.
>
> It will break the ONE_SHOT and threaded irq, and brings some unwanted
> issues.
> Here adding the irqd_irq_masked() condition to know if unmasking action is
> needed.
>
> Signed-off-by: liu chuansheng <chuansheng.liu@...el.com>
> ---
> arch/x86/kernel/apic/io_apic.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> index 1817fa9..d963e76 100644
> --- a/arch/x86/kernel/apic/io_apic.c
> +++ b/arch/x86/kernel/apic/io_apic.c
> @@ -2479,7 +2479,8 @@ static inline void ioapic_irqd_unmask(struct irq_data
> *data,
> */
> if (!io_apic_level_ack_pending(cfg))
> irq_move_masked_irq(data);
> - unmask_ioapic(cfg);
> + if (!irqd_irq_masked(data))
> + unmask_ioapic(cfg);
> }
> }
> #else
> --
> 1.7.0.4
>
>
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