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Commit f21cfb25 authored by Magnus Damm's avatar Magnus Damm Committed by Ingo Molnar
Browse files

irq: add remove_irq() for freeing of setup_irq() irqs 



Impact: add new API

This patch adds a remove_irq() function for releasing
interrupts requested with setup_irq().

Without this patch we have no way of releasing such
interrupts since free_irq() today tries to kfree()
the irqaction passed with setup_irq().

Signed-off-by: default avatarMagnus Damm <damm@igel.co.jp>
LKML-Reference: <20090312120542.2926.56609.sendpatchset@rx1.opensource.se>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent f8cb22cb

include/linux/irq.h

+1 −0
Original line number Diff line number Diff line
@@ -236,6 +236,7 @@ typedef struct irq_desc irq_desc_t; 
#include <asm/hw_irq.h>



extern int setup_irq(unsigned int irq, struct irqaction *new);

extern struct irqaction *remove_irq(unsigned int irq, void *dev_id);



#ifdef CONFIG_GENERIC_HARDIRQS

kernel/irq/manage.c

+26 −13
Original line number Diff line number Diff line
@@ -551,20 +551,14 @@ int setup_irq(unsigned int irq, struct irqaction *act) 
}



/**

 *	free_irq - free an interrupt

 *	remove_irq - free an interrupt

 *	@irq: Interrupt line to free

 *	@dev_id: Device identity to free

 *

 *	Remove an interrupt handler. The handler is removed and if the

 *	interrupt line is no longer in use by any driver it is disabled.

 *	On a shared IRQ the caller must ensure the interrupt is disabled

 *	on the card it drives before calling this function. The function

 *	does not return until any executing interrupts for this IRQ

 *	have completed.

 *

 *	This function must not be called from interrupt context.

 * Used to remove interrupts statically setup by the early boot process.

 */

void free_irq(unsigned int irq, void *dev_id)



struct irqaction *remove_irq(unsigned int irq, void *dev_id)

{

	struct irq_desc *desc = irq_to_desc(irq);

	struct irqaction *action, **action_ptr;
@@ -573,7 +567,7 @@ void free_irq(unsigned int irq, void *dev_id) 
	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);



	if (!desc)

		return;

		return NULL;



	spin_lock_irqsave(&desc->lock, flags);
@@ -589,7 +583,7 @@ void free_irq(unsigned int irq, void *dev_id) 
			WARN(1, "Trying to free already-free IRQ %d\n", irq);

			spin_unlock_irqrestore(&desc->lock, flags);



			return;

			return NULL;

		}



		if (action->dev_id == dev_id)
@@ -636,7 +630,26 @@ void free_irq(unsigned int irq, void *dev_id) 
		local_irq_restore(flags);

	}

#endif

	kfree(action);

	return action;

}



/**

 *	free_irq - free an interrupt allocated with request_irq

 *	@irq: Interrupt line to free

 *	@dev_id: Device identity to free

 *

 *	Remove an interrupt handler. The handler is removed and if the

 *	interrupt line is no longer in use by any driver it is disabled.

 *	On a shared IRQ the caller must ensure the interrupt is disabled

 *	on the card it drives before calling this function. The function

 *	does not return until any executing interrupts for this IRQ

 *	have completed.

 *

 *	This function must not be called from interrupt context.

 */

void free_irq(unsigned int irq, void *dev_id)

{

	kfree(remove_irq(irq, dev_id));

}

EXPORT_SYMBOL(free_irq);