Re: [PATCH v2] platform: finally disallow IRQ0 in platform_get_irq() and its ilk

From: Sergey Shtylyov
Date: Thu Apr 28 2022 - 15:59:24 EST

On 4/28/22 9:13 AM, Greg Kroah-Hartman 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@xxxxxx>
>>>> Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
>> [...]
>>> Ok, let's try this now.
>> Well, better late than never! :-)
>>> Worst case, we revert it later :)
>> Please just don't revert it outright on the 1st issue report -- give me time
>> to look at the issue(s) reported...
>> BTW, I've CC'ed you on the SH patch that avoids using IRQ0. Please help to
>> merge it (v1/v2 were posted on February 11th and there was no motion since then)!
> I can't merge that until a sh maintainer acks it.

Hm, looking at the arch/sh/ commit history, you've recently merged couple patches
without any ACKs from the SH people. ;-) What concerns you in this case, me touching
the assembly code? Who's worth looping in on that patch, do you think, maybe Andrew
Morton or Linus himself?

> Is that arch even still alive?

Well, considering J-core should be still alive (there's #jcore channel on,
where you can find Rich Felker as dalias), arch/sh/ must be still alive too...
It probably needs the better maintainers though... :-)

> thanks,
> greg k-h

MBR, Sergey