On Fri, Dec 10, 2021 at 07:38:40PM +0300, Sergey Shtylyov wrote: > On 12/10/21 11:47 AM, 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; > > -ENXIO seems to me more fitting indeed (than -EINVAL that I used). > > > > > No, this is wrong for the same reasons I explained to Sergey. > > I fail to understand you, sorry. We're going in circles, it seems... :-/ platform_get_irq_optional() is supposed to return 0 when there is no IRQ found, but everything else went alright. I'm tired to waste my time to go circles. Again, the problem is that platform_get_irq_optional() has wrong set of output values. And your patch doesn't fix that. And it has nothing to do with my code here. > > The problem is that this is _optional API and it has been misdesigned. > > Replacing things like above will increase the mess. > > What's wrong with replacing IRQ0 with -ENXIO now? platform_get_irq_optional() > (as in your patch) could then happily return 0 ISO -ENXIO. Contrarywise, if we don't > replace IRQ0 with -ENXIO, platform_get_irq_optional() will return 0 for both IRQ0 > and missing IRQ! Am I clear enough? If you don't understand me now, I don't know what > to say... :-/ See above. Read my messages again, please. I'm really tired to explain again and again the same. TL;DR: You simply try to "fix" in a correct place but in a wrong way. > >> return ret; > >> > >> Otherwise, I do not think that removing the "if (!irq)" hunk is safe. no ? > > > > No. This is not a business of the caller to workaround implementation > > details (bugs) of the core APIs. > > If something goes wrong, then it's platform_get_irq() to blame, and > > not the libahci_platform. > > I'm repeating myself already: we don't work around the bug in platform_get_irq(), Yes, you do. > we're working around the driver subsystems that treat 0 specially (and so don't > support IRQ0); libata treats 0 as an indication of the polling mode (moreover, > it will curse if you pass to it both IRQ == 0 and a pointer to an interrupt handler! > Am I clear enough this time? :-) Yes, and it doesn't contradict to what my patch does. Read comment against platform_get_irq(). If it returns 0, it's not a business of the callers to work around it. Am I clear enough this time? :-) -- With Best Regards, Andy Shevchenko
