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Date: Wed, 4 Nov 2009 20:49:41 +0800
Message-ID: <2674af740911040449h14eaac35y2ec3016862479bc6@mail.gmail.com>
Subject: Re: [PATCH]: use spin_lock_irqsave in try_one_irq()
From: Yong Zhang <yong.zhang0@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Prarit Bhargava <prarit@redhat.com>, linux-kernel@vger.kernel.org,
       ebiederm@xmission.com, akpm@linux-foundation.org,
       Ingo Molnar <mingo@elte.hu>
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On Wed, Nov 4, 2009 at 5:18 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> On Tue, 3 Nov 2009, Yong Zhang wrote:
>
>> > This happens because the &desc->lock is taken with spin_lock_irqsave and
>> > just a spin_lock.  In the try_one_irq(), this lock really should be a
>> > spin_lock_irqsave().
>> >

>> So I think the following patch is also workable to you.
>
> Yes, that's sufficient.
>
>> diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c
>> index 114e704..11affbc 100644
>> --- a/kernel/irq/spurious.c
>> +++ b/kernel/irq/spurious.c
>> @@ -111,6 +111,7 @@ static void poll_all_shared_irqs(void)
>>
>>       for_each_irq_desc(i, desc) {
>>               unsigned int status;
>> +             unsigned long flags;
>>
>>               if (!i)
>>                        continue;
>> @@ -121,7 +122,9 @@ static void poll_all_shared_irqs(void)
>>               if (!(status & IRQ_SPURIOUS_DISABLED))
>>                       continue;
>>
>> +             local_irq_save(flags);
>>               try_one_irq(i, desc);
>> +             local_irq_restore(flags);
>
>  You can even use local_irq_en/disable() here.

Yup, I will resend the patch later.

Thanks,
Yong

>
> Thanks,
>
>        tglx