Re: [-mm patch] aic7xxx: check irq validity (was Re: 2.6.18-mm2)

Matthew Wilcox
2006-10-01T14:28:11Z

On Sat, Sep 30, 2006 at 07:58:18PM -0400, Jeff Garzik wrote:
> Actually, rather than adding this check to every driver, I would rather
> do something like the attached patch: create a pci_request_irq(), and
> pass a struct pci_device to it. Then the driver author doesn't have to
> worry about such details.

I like pci_request_irq(), but pci_valid_irq is bad.

> +#ifndef ARCH_VALIDATE_PCI_IRQ
> +int pci_valid_irq(struct pci_dev *pdev)
> +{
> + if (pdev->irq == 0)
> + return -EINVAL;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(pci_valid_irq);
> +#endif /* ARCH_VALIDATE_PCI_IRQ */

Better would be:

#ifndef ARCH_VALIDATE_IRQ
static inline int valid_irq(unsigned int irq)
{
return irq ? 1 : 0;
}
#endif

in linux/interrupt.h (around request_irq).

And it doesn't need to be a __must_check. There's no point -- it has
no side-effects. The only reason to call it is if you want the answer
to the question. You had the sense of the return code wrong too; you
want to use it as:

int pci_request_irq(struct pci_dev *pdev, irq_handler_t handler,
unsigned long flags, const char *name, void *data)
{
if (!valid_irq(pdev->irq)) {
dev_printk(KERN_ERR, &pdev->dev, "invalid irq\n");
return -EINVAL;
}

return request_irq(pdev->irq, handler, flags | IRQF_SHARED, name, data);
}