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SubjectRe: [PATCH v2] platform: finally disallow IRQ0 in platform_get_irq() and its ilk
On Fri, Mar 11, 2022 at 10:35:29PM +0300, Sergey Shtylyov wrote:
> The commit a85a6c86c25b ("driver core: platform: Clarify that IRQ 0 is
> invalid") only calls WARN() when IRQ0 is about to be returned, however
> using IRQ0 is considered invalid (according to Linus) outside the arch/
> code where it's used by the i8253 drivers. Many driver subsystems treat
> 0 specially (e.g. as an indication of the polling mode by libata), so
> the users of platform_get_irq[_byname]() in them would have to filter
> out IRQ0 explicitly and this (quite obviously) doesn't scale...
> Let's finally get this straight and return -EINVAL instead of IRQ0!
>
> Fixes: a85a6c86c25b ("driver core: platform: Clarify that IRQ 0 is invalid")
> Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
> Acked-by: Marc Zyngier <maz@kernel.org>
>
> ---
> The patch is against the 'driver-core-next' branch of Greg Kroah-Hartman's
> 'driver-core.git' repo.
>
> Changes in version 2:
> - added Marc's ACK.
>
> drivers/base/platform.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> Index: driver-core/drivers/base/platform.c
> ===================================================================
> --- driver-core.orig/drivers/base/platform.c
> +++ driver-core/drivers/base/platform.c
> @@ -231,7 +231,8 @@ int platform_get_irq_optional(struct pla
> out_not_found:
> ret = -ENXIO;
> out:
> - WARN(ret == 0, "0 is an invalid IRQ number\n");
> + if (WARN(!ret, "0 is an invalid IRQ number\n"))
> + return -EINVAL;
> return ret;
> }
> EXPORT_SYMBOL_GPL(platform_get_irq_optional);
> @@ -446,7 +447,8 @@ static int __platform_get_irq_byname(str
>
> r = platform_get_resource_byname(dev, IORESOURCE_IRQ, name);
> if (r) {
> - WARN(r->start == 0, "0 is an invalid IRQ number\n");
> + if (WARN(!r->start, "0 is an invalid IRQ number\n"))
> + return -EINVAL;
> return r->start;
> }
>

Ok, let's try this now. Worst case, we revert it later :)

thanks,

greg k-h

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