Re: [Xen-devel] [PATCH 4/4] xen/events: Add WARN_ON when quick lookup found invalid type.

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

On Wed, 23 May 2012, Konrad Rzeszutek Wilk wrote:
> All of the bind_XYZ_to_irq do a quick lookup to see if the
> event exists. And if they that value is returned instead of

                           ^

> initialized. This patch adds an extra logic to check that the
> type returned is the proper one and we can use it to find
> drivers that are doing something naught.
> 
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
>  drivers/xen/events.c |   11 +++++++++--
>  1 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/xen/events.c b/drivers/xen/events.c
> index faae2f9..093851b 100644
> --- a/drivers/xen/events.c
> +++ b/drivers/xen/events.c
> @@ -827,6 +827,9 @@ int bind_evtchn_to_irq(unsigned int evtchn)
>  					      handle_edge_irq, "event");
>  
>  		xen_irq_info_evtchn_init(irq, evtchn);
> +	} else {
> +		struct irq_info *info = info_for_irq(irq);
> +		WARN_ON(info && info->type != IRQT_EVTCHN);
>  	}

considering that when evtchn_to_irq[evtchn] is != -1, a corresponding
struct irq_info is always supposed to exists, shouldn't this be:

WARN_ON(info == NULL || info->type != IRQT_EVTCHN);

?


>  out:
> @@ -862,8 +865,10 @@ static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
>  		xen_irq_info_ipi_init(cpu, irq, evtchn, ipi);
>  
>  		bind_evtchn_to_cpu(evtchn, cpu);
> +	} else {
> +		struct irq_info *info = info_for_irq(irq);
> +		WARN_ON(info && info->type != IRQT_IPI);
>  	}
> -
>   out:
>  	mutex_unlock(&irq_mapping_update_lock);
>  	return irq;
> @@ -939,8 +944,10 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
>  		xen_irq_info_virq_init(cpu, irq, evtchn, virq);
>  
>  		bind_evtchn_to_cpu(evtchn, cpu);
> +	} else {
> +		struct irq_info *info = info_for_irq(irq);
> +		WARN_ON(info && info->type != IRQT_VIRQ);
>  	}
> -
>  out:
>  	mutex_unlock(&irq_mapping_update_lock);

same here