Messages in this thread | | | Date | Wed, 12 Jan 2022 18:08:43 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH] platform: finally disallow IRQ0 in platform_get_irq() and its ilk |
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On 2022-01-12 17:53, Sergey Shtylyov wrote: > On 1/4/22 12:26 PM, Marc Zyngier wrote: > >> [Adding Geert] >> >> On Sat, 06 Nov 2021 20:26:47 +0000, >> Sergey Shtylyov <s.shtylyov@omp.ru> 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> >>> >>> --- >>> The patch is against the 'driver-core-linus' branch of Greg >>> Kroah-Hartman's >>> 'driver-core.git' repo. >>> >>> 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); >>> @@ -445,7 +446,8 @@ 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; >>> } >> >> Geert recently mentioned that a few architectures (such as sh?) still >> use IRQ0 as something valid in limited cases. >> >> From my PoV, this patch is fine, but please be prepared to fix things >> in a couple of years when someone decides to boot a recent kernel on >> their pet dinosaur. With that in mind: >> >> Acked-by: Marc Zyngier <maz@kernel.org> > > Greg, so would that ACK be enough? Is there a chance this patch > gets finally included > into 5.17-rc1? Or should I look into fixing the recently found > arch/sh/ issue 1st (as you > can see, just WARN()'ing about IRQ0 wasn't enough to get this fixed)?
Fixing SH would be a good thing.
Thanks,
M. -- Jazz is not dead. It just smells funny...
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