linux-kernel - Re: [PATCH v1 1/2] ata: libahci_platform: Get rid of dup message when IRQ can't be retrieved

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Message-ID: <YbfDCNIMNy4PdBwL@smile.fi.intel.com>
Date:   Tue, 14 Dec 2021 00:02:48 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Damien Le Moal <damien.lemoal@...nsource.wdc.com>
Cc:     Sergey Shtylyov <s.shtylyov@....ru>, linux-ide@...r.kernel.org,
        linux-kernel@...r.kernel.org, Hans de Goede <hdegoede@...hat.com>,
        Jens Axboe <axboe@...nel.dk>
Subject: Re: [PATCH v1 1/2] ata: libahci_platform: Get rid of dup message
 when IRQ can't be retrieved

On Tue, Dec 14, 2021 at 06:36:00AM +0900, Damien Le Moal wrote:
> On 2021/12/13 20:52, Andy Shevchenko wrote:
> > On Mon, Dec 13, 2021 at 07:39:31AM +0900, Damien Le Moal wrote:
> >> On 2021/12/11 19:25, Sergey Shtylyov wrote:

...

> >> The problem I see is that the current behavior is unclear: what does
> >> platform_get_irq_optional() returning 0 mean ? IRQ == 0 ? or "no IRQ" ? I think
> >> it should be the latter rather than the former. Note that the function could
> >> return ENOENT (or similar) for the "no IRQ" case. With that, case (2) goes away,
> >> but then I do not see any difference between platform_get_irq_optional() and
> >> platform_get_irq().
> >>
> >> If the preferred API semantic is to allow returning IRQ 0 with a warning, then
> >> the kdoc comments of platform_get_irq_optional() and platform_get_irq() are
> >> totally broken, and the code for many drivers is probably wrong too.
> > 
> > Yeah, what we need to do is that (roughly a roadmap):
> >  - revisit callers of platform_get_irq_optional() to be prepared for
> >    new behaviour
> >  - rewrite platform_get_irq() to return -ENOENT
> >  - rewrite platform_get_irq_optional() to return 0 on -ENOENT
> > 
> > This is how other similar (i.e. _optional) APIs do.
> 
> Sounds like a good plan to me. In the mean time though, your patch 1/2 should
> keep the "if (!irq)" test and return an error for that case. No ?

No problem. I can send a v2.

-- 
With Best Regards,
Andy Shevchenko