Commit 89d694b9 authored Feb 18, 2008 by Thomas Gleixner

genirq: do not leave interupts enabled on free_irq



The default_disable() function was changed in commit:

 76d21601
 genirq: do not mask interrupts by default

It removed the mask function in favour of the default delayed
interrupt disabling. Unfortunately this also broke the shutdown in
free_irq() when the last handler is removed from the interrupt for
those architectures which rely on the default implementations. Now we
can end up with a enabled interrupt line after the last handler was
removed, which can result in spurious interrupts.

Fix this by adding a default_shutdown function, which is only
installed, when the irqchip implementation does provide neither a
shutdown nor a disable function.

[@stable: affected versions: .21 - .24 ]

Pointed-out-by: Michael Hennerich <Michael.Hennerich@analog.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: stable@kernel.org
Tested-by: Michael Hennerich <Michael.Hennerich@analog.com>

parent 188fd89d

kernel/irq/chip.c

+19 −1

Original line number	Diff line number	Diff line
		@@ -245,6 +245,17 @@ static unsigned int default_startup(unsigned int irq)
		return 0;
		}

		/*
		* default shutdown function
		*/
		static void default_shutdown(unsigned int irq)
		{
		struct irq_desc *desc = irq_desc + irq;

		desc->chip->mask(irq);
		desc->status \|= IRQ_MASKED;
		}

		/*
		* Fixup enable/disable function pointers
		*/
		@@ -256,8 +267,15 @@ void irq_chip_set_defaults(struct irq_chip *chip)
		chip->disable = default_disable;
		if (!chip->startup)
		chip->startup = default_startup;
		/*
		* We use chip->disable, when the user provided its own. When
		* we have default_disable set for chip->disable, then we need
		* to use default_shutdown, otherwise the irq line is not
		* disabled on free_irq():
		*/
		if (!chip->shutdown)
		chip->shutdown = chip->disable;
		chip->shutdown = chip->disable != default_disable ?
		chip->disable : default_shutdown;
		if (!chip->name)
		chip->name = chip->typename;
		if (!chip->end)

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