Messages in this thread | | | Date | Thu, 9 Dec 2021 22:06:19 +0200 | From | Andy Shevchenko <> | Subject | Re: [PATCH] platform: finally disallow IRQ0 in platform_get_irq() and its ilk |
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On Sat, Nov 06, 2021 at 11:26:47PM +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!
You are changing the return value of platform_get_irq_optional(). The problem here is the proposed change doesn't bring any value in such case. platform_get_irq_optional() should be able (at the end of the day) to return 3 types of values (as other APIs do): > 0: success == 0: IRQ not found < 0: an error that must be consumed by the caller
0 is unexpected result for non-optional APIs and there you may try to play tricks (like replacing it by error code).
There was a discussion around the topic: https://lore.kernel.org/lkml/20210331144526.19439-1-andriy.shevchenko@linux.intel.com/T/#u
Wanna help?
> Fixes: a85a6c86c25b ("driver core: platform: Clarify that IRQ 0 is invalid")
Not sure.
-- With Best Regards, Andy Shevchenko
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