Re: [tip:irq/urgent] irq: Ensure irq_exit() code runs with interrupts disabled

[Frederic Weisbecker]

2013/2/21 tip-bot for Thomas Gleixner <tipbot@xxxxxxxxx>:
> Commit-ID:  630e7580f681475d92d87e78373e4136096e12f2
> Gitweb:     http://git.kernel.org/tip/630e7580f681475d92d87e78373e4136096e12f2
> Author:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> AuthorDate: Wed, 20 Feb 2013 22:00:48 +0100
> Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> CommitDate: Thu, 21 Feb 2013 18:32:44 +0100
>
> irq: Ensure irq_exit() code runs with interrupts disabled
>
> We had already a few problems with code called from irq_exit() when
> interrupted from a nesting interrupt. This can happen on architectures
> which do not define __ARCH_IRQ_EXIT_IRQS_DISABLED.
>
> __ARCH_IRQ_EXIT_IRQS_DISABLED should go away and we want to make it
> mandatory to call irq_exit() with interrupts disabled.
>
> As a temporary protection disable interrupts for those architectures
> which do not define __ARCH_IRQ_EXIT_IRQS_DISABLED and add a WARN_ONCE
> when an architecture which defines __ARCH_IRQ_EXIT_IRQS_DISABLED calls
> irq_exit() with interrupts enabled.
>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxx>
> Link: alpine.LFD.2.02.1302202155320.22263@ionos">http://lkml.kernel.org/r/alpine.LFD.2.02.1302202155320.22263@ionos
>
> ---
>  kernel/softirq.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/kernel/softirq.c b/kernel/softirq.c
> index f5cc25f..d1f7943 100644
> --- a/kernel/softirq.c
> +++ b/kernel/softirq.c
> @@ -341,6 +341,14 @@ static inline void invoke_softirq(void)
>   */
>  void irq_exit(void)
>  {
> +#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED
> +       unsigned long flags;
> +
> +       local_irq_save(flags);
> +#else
> +       WARN_ON_ONCE(!irqs_disabled();

Missing closing parenthesis.
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