On 10/23/09 04:39, Han, Weidong wrote:
> From 9c91f23076c555690488cbd81f889f279d4cf2fa Mon Sep 17 00:00:00 2001
> From: Weidong Han <weidong.han@xxxxxxxxx>
> Date: Sat, 24 Oct 2009 03:18:30 +0800
> Subject: [PATCH] pv-ops: fix shared irq device passthrough
>
> In driver/xen/events.c, whether bind_pirq is shareable or not is
> determined by desc->action is NULL or not. But in __setup_irq,
> startup(irq) is invoked before desc->action is assigned with
> new action. So desc->action in startup_irq is alwasy NULL, and
> bind_pirq is always not shareable. This results in pt_irq_create_bind
> failure when passthrough a device which shares irq to other devices.
>
> This patch move desc->action before startup(irq), therefore fix
> the problem.
>
Hm, not sure about this. The logic in __setup_irq already looks pretty
tortured, and I'd like to avoid touching it unless there's definitively
a bug in there.
I think the right question is whether probe_irq() is really doing the
right test, and whether it could do something else instead?
J
> Signed-off-by: Weidong Han <weidong.han@xxxxxxxxx>
> ---
> kernel/irq/manage.c | 14 ++++++++++----
> 1 files changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index 07a11dc..3b85b72 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -565,6 +565,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc,
> struct irqaction *new)
> {
> struct irqaction *old, **old_ptr;
> const char *old_name = NULL;
> + int old_irq;
> unsigned long flags;
> int shared = 0;
> int ret;
> @@ -644,6 +645,11 @@ __setup_irq(unsigned int irq, struct irq_desc *desc,
> struct irqaction *new)
> shared = 1;
> }
>
> + old = *old_ptr;
> + old_irq = new->irq;
> + new->irq = irq;
> + *old_ptr = new;
> +
> if (!shared) {
> irq_chip_set_defaults(desc->chip);
>
> @@ -654,8 +660,11 @@ __setup_irq(unsigned int irq, struct irq_desc *desc,
> struct irqaction *new)
> ret = __irq_set_trigger(desc, irq,
> new->flags & IRQF_TRIGGER_MASK);
>
> - if (ret)
> + if (ret) {
> + new->irq = old_irq;
> + *old_ptr = old;
> goto out_thread;
> + }
> } else
> compat_irq_chip_set_default_handler(desc);
> #if defined(CONFIG_IRQ_PER_CPU)
> @@ -690,9 +699,6 @@ __setup_irq(unsigned int irq, struct irq_desc *desc,
> struct irqaction *new)
> (int)(new->flags & IRQF_TRIGGER_MASK));
> }
>
> - new->irq = irq;
> - *old_ptr = new;
> -
> /* Reset broken irq detection when installing new handler */
> desc->irq_count = 0;
> desc->irqs_unhandled = 0;
>
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