On Fri, Dec 10, 2021 at 08:15:43PM +0300, Sergei Shtylyov wrote: > On 12/10/21 2:36 PM, Andy Shevchenko wrote: > > >>>>>> platform_get_irq() will print a message when it fails. > >>>>>> No need to repeat this. > >>>>>> > >>>>>> While at it, drop redundant check for 0 as platform_get_irq() spills > >>>>>> out a big WARN() in such case. > >>>>> > >>>>> The reason you should be able to remove the "if (!irq)" test is that > >>>>> platform_get_irq() never returns 0. At least, that is what the function kdoc > >>>>> says. But looking at platform_get_irq_optional(), which is called by > >>>>> platform_get_irq(), the out label is: > >>>>> > >>>>> WARN(ret == 0, "0 is an invalid IRQ number\n"); > >>>>> return ret; > >>>>> > >>>>> So 0 will be returned as-is. That is rather weird. That should be fixed to > >>>>> return -ENXIO: > >>>>> > >>>>> if (WARN(ret == 0, "0 is an invalid IRQ number\n")) > >>>>> return -ENXIO; > >>>>> return ret; > >>>> > >>>> My unmerged patch (https://marc.info/?l=linux-kernel&m=163623041902285) does this > >>>> but returns -EINVAL instead. > >>>> > >>>>> Otherwise, I do not think that removing the "if (!irq)" hunk is safe. no ? > >>>> > >>>> Of course it isn't... > >>> > >>> It's unsubstantiated statement. The vIRQ 0 shouldn't be returned by any of > >>> those API calls. > >> > >> We do _not_ know what needs to be fixed, that's the problem, and that's why the WARN() > >> is there... > > > > So, have you seen this warning (being reported) related to libahci_platform? > > No (as if you need to really see this while it's obvious from the code review). > > > If no, what we are discussing about then? The workaround is redundant and > > I don't know. :-) Your arguments so far seem bogus (sorry! :-))... It seems you haven't got them at all. The problems of platform_get_irq() et al shouldn't be worked around in the callers. > > no need to have a dead code in the driver, really. > > "Jazz isn't dead, it just smells funny". :-) > > >>> If it is the case, go and fix them, no need to workaround > >>> in each of the callers. > >> > >> There's a need to work around as long as IRQ0 ican be returned, otherwise > >> we get partly functioning or non-functioning drivers... > > > > You get them unfunctioning anyways > > The drivers would be broken in not quite obvious ways. With IRQ0 check, they just > don't probe anymore. See the explanation of the IRQ0 check (in the drivers) in my > previous mail... > > > and you get the big WARN() even before this patch. > > As if that was enough... > The IRQ0 problem exists for at least 15 (if not 20) years... -- With Best Regards, Andy Shevchenko
