Subject: Re: [PATCH 2/2] gianfar: irq_of_parse_and_map() error unnoticed

From: Andrew Morton <[email-masked]>
Date: Mon, 27 Apr 2009 12:23:16 -0700

On Mon, 27 Apr 2009 13:05:30 +0200
Roel Kluin <[email-masked]> wrote:

> priv->interruptTransmit, -Receive and -Error are unsigned, so the error path
> wasn't taken when irq_of_parse_and_map() returned an incorrect irq.
> 
> Signed-off-by: Roel Kluin <[email-masked]> 
> ---
> diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c
> index b2c4967..55c2ce8 100644
> --- a/drivers/net/gianfar.c
> +++ b/drivers/net/gianfar.c
> @@ -203,9 +203,9 @@ static int gfar_of_init(struct net_device *dev)
>  
>  		priv->interruptError = irq_of_parse_and_map(np, 2);
>  
> -		if (priv->interruptTransmit < 0 ||
> -				priv->interruptReceive < 0 ||
> -				priv->interruptError < 0) {
> +		if (priv->interruptTransmit == NO_IRQ ||
> +				priv->interruptReceive == NO_IRQ ||
> +				priv->interruptError == NO_IRQ) {
>  			err = -EINVAL;
>  			goto err_out;
>  		}

I guess that's OK, as gianfar.c appears to be a ppc-only thing, and ppc
does implement NO_IRQ.

However what a lot (all) rtc drivers do is

	if (irq <= 0)

which (afaik) will dtrt in all cases: NO_IRQ==0, NO_IRQ<0,
!defined(NO_IRQ).

Then again, it will dtwt if the platform allows irq numbers of zero.

argh, how did we get into this pickle?