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... :-/ > 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... :-/ > >> 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(), 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? :-) MBR, Sergey
