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: Magnus Damm <damm@igel.co.jp> LKML-Reference: <20090312120542.2926.56609.sendpatchset@rx1.opensource.se> Signed-off-by: Ingo Molnar <mingo@elte.hu>

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: Magnus Damm <damm@igel.co.jp> LKML-Reference: <20090312120542.2926.56609.sendpatchset@rx1.opensource.se> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Magnus Damm · Ingo Molnar
1 parent f8cb22cbb8
Showing 2 changed files with 27 additions and 13 deletions Side-by-side Diff
include/linux/irq.h
kernel/irq/manage.c
@@ -236,6 +236,7 @@
 #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
  
@@ -551,20 +551,14 @@
 }
  
 /**
- *	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 @@
 	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 @@
 			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 @@
 		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);
...	...	@@ -236,6 +236,7 @@
236	236	#include <asm/hw_irq.h>
237	237
238	238	extern int setup_irq(unsigned int irq, struct irqaction *new);
	239	+extern struct irqaction remove_irq(unsigned int irq, void dev_id);
239	240
240	241	#ifdef CONFIG_GENERIC_HARDIRQS
241	242
...	...	@@ -551,20 +551,14 @@
551	551	}
552	552
553	553	/**
554		- * free_irq - free an interrupt
	554	+ * remove_irq - free an interrupt
555	555	* @irq: Interrupt line to free
556	556	* @dev_id: Device identity to free
557	557	*
558		- * Remove an interrupt handler. The handler is removed and if the
559		- * interrupt line is no longer in use by any driver it is disabled.
560		- * On a shared IRQ the caller must ensure the interrupt is disabled
561		- * on the card it drives before calling this function. The function
562		- * does not return until any executing interrupts for this IRQ
563		- * have completed.
564		- *
565		- * This function must not be called from interrupt context.
	558	+ * Used to remove interrupts statically setup by the early boot process.
566	559	*/
567		-void free_irq(unsigned int irq, void *dev_id)
	560	+
	561	+struct irqaction remove_irq(unsigned int irq, void dev_id)
568	562	{
569	563	struct irq_desc *desc = irq_to_desc(irq);
570	564	struct irqaction action, *action_ptr;
...	...	@@ -573,7 +567,7 @@
573	567	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
574	568
575	569	if (!desc)
576		- return;
	570	+ return NULL;
577	571
578	572	spin_lock_irqsave(&desc->lock, flags);
579	573
...	...	@@ -589,7 +583,7 @@
589	583	WARN(1, "Trying to free already-free IRQ %d\n", irq);
590	584	spin_unlock_irqrestore(&desc->lock, flags);
591	585
592		- return;
	586	+ return NULL;
593	587	}
594	588
595	589	if (action->dev_id == dev_id)
...	...	@@ -636,7 +630,26 @@
636	630	local_irq_restore(flags);
637	631	}
638	632	#endif
639		- kfree(action);
	633	+ return action;
	634	+}
	635	+
	636	+/**
	637	+ * free_irq - free an interrupt allocated with request_irq
	638	+ * @irq: Interrupt line to free
	639	+ * @dev_id: Device identity to free
	640	+ *
	641	+ * Remove an interrupt handler. The handler is removed and if the
	642	+ * interrupt line is no longer in use by any driver it is disabled.
	643	+ * On a shared IRQ the caller must ensure the interrupt is disabled
	644	+ * on the card it drives before calling this function. The function
	645	+ * does not return until any executing interrupts for this IRQ
	646	+ * have completed.
	647	+ *
	648	+ * This function must not be called from interrupt context.
	649	+ */
	650	+void free_irq(unsigned int irq, void *dev_id)
	651	+{
	652	+ kfree(remove_irq(irq, dev_id));
640	653	}
641	654	EXPORT_SYMBOL(free_irq);
642	655