[PATCH 01/03] Add remove_irq() for freeing of setup_irq() irqs

Magnus Damm
2009-03-12T12:09:19Z

From: Magnus Damm <damm@igel.co.jp>

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: Magnus Damm <damm@igel.co.jp>
---

Changes since V2:
- name the function remove_irq() instead of __free_irq(), thanks Thomas!

Changes since V1:
- break out a __free_irq() function, thanks Ingo!

include/linux/irq.h | 1 +
kernel/irq/manage.c | 39 ++++++++++++++++++++++++++-------------
2 files changed, 27 insertions(+), 13 deletions(-)

--- 0001/include/linux/irq.h
+++ work/include/linux/irq.h 2009-03-12 18:36:20.000000000 +0900
@@ -228,6 +228,7 @@ 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

--- 0001/kernel/irq/manage.c
+++ work/kernel/irq/manage.c 2009-03-12 20:29:17.000000000 +0900
@@ -551,20 +551,14 @@ int setup_irq(unsigned int irq, struct i
}

/**
- * 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 *de
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 *de
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 *de
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));