[RFC] add struct hw_interrupt_type->release

[Chris Wedgwood <cw@f00f.org>]

On Tue, Oct 19, 2004 at 07:31:56PM -0700, Chris Wedgwood wrote:

> +++ b/kernel/irq/manage.c	2004-10-19 17:47:40 -07:00
> @@ -260,6 +260,7 @@
>  				else
>  					desc->handler->disable(irq);
>  			}
                       ^^^
> +			platform_free_irq_notify(irq, dev_id);
>  			spin_unlock_irqrestore(&desc->lock,flags);
>  			unregister_handler_proc(irq, action);
>  

On Wed, Oct 20, 2004 at 02:07:15PM +0100, Christoph Hellwig wrote:

> This looks rather bogus to me.  What prevents UML from doing it's
> work at the struct hw_interrupt_type level?

the ^^^ marked part reads something like if (!desc->action) { ... }
presumably meaning the shutdown/disable is only done when the very
last user of an interrupt source is removed

UML needs to be notified when *any* user is removed so either need
some way to tell the generic code this or perhaps we could introduce
another op to hw_interrupt_type along the lines of ->release like
this:


===== include/linux/irq.h 1.12 vs edited =====
--- 1.12/include/linux/irq.h	2004-10-18 22:26:45 -07:00
+++ edited/include/linux/irq.h	2004-10-20 19:13:01 -07:00
@@ -47,6 +47,7 @@ struct hw_interrupt_type {
 	void (*ack)(unsigned int irq);
 	void (*end)(unsigned int irq);
 	void (*set_affinity)(unsigned int irq, cpumask_t dest);
+	void (*release)(unsigned int irq, void *dev_id);
 };
 
 typedef struct hw_interrupt_type  hw_irq_controller;
===== kernel/irq/manage.c 1.1 vs edited =====
--- 1.1/kernel/irq/manage.c	2004-10-18 22:26:39 -07:00
+++ edited/kernel/irq/manage.c	2004-10-20 18:55:05 -07:00
@@ -253,6 +253,10 @@ void free_irq(unsigned int irq, void *de
 
 			/* Found it - now remove it from the list of entries */
 			*pp = action->next;
+
+			if (desc->handler->release)
+				desc->handler->release(irq, dev_id);
+
 			if (!desc->action) {
 				desc->status |= IRQ_DISABLED;
 				if (desc->handler->shutdown)