Messages in this thread | | | Subject | Re: [PATCH] platform: finally disallow IRQ0 in platform_get_irq() and its ilk | From | Sergey Shtylyov <> | Date | Wed, 12 Jan 2022 20:53:51 +0300 |
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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)?
> M.
MBR, Sergey
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