Le 06/10/2022 à 15:50, Alan Stern a écrit : > On Thu, Oct 06, 2022 at 07:15:44AM +0200, Christophe Leroy wrote: >> NO_IRQ is used to check the return of irq_of_parse_and_map(). >> >> On some architecture NO_IRQ is 0, on other architectures it is -1. >> >> irq_of_parse_and_map() returns 0 on error, independent of NO_IRQ. > > This isn't clear. Does absence of an irq count as an error? In other > words, will irq_of_parse_and_map() sometimes return 0 and other times > return NO_IRQ? What about architectures on which 0 is a valid irq > number? NO_IRQ doesn't exist anywhere in core functions. Only some drivers and some architectures have relics of it. irq_of_parse_and_map() will always return 0 on error. 0 can't be a valid logical IRQ number. It may only be a valid hwirq number but it will always be translated to a non-zero logical irq number. I'm trying to get rid of NO_IRQ completely in powerpc code, therefore trying to clean-up all drivers used by powerpc architecture. Long time ago Linus advocated for not using NO_IRQ, see https://lkml.org/lkml/2005/11/21/221 Thanks Christophe > >> So use 0 instead of using NO_IRQ. >> >> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> >> --- >> drivers/usb/host/ehci-grlib.c | 2 +- >> drivers/usb/host/ehci-ppc-of.c | 2 +- >> drivers/usb/host/fhci-hcd.c | 2 +- >> drivers/usb/host/ohci-ppc-of.c | 2 +- >> drivers/usb/host/uhci-grlib.c | 2 +- >> 5 files changed, 5 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/usb/host/ehci-grlib.c b/drivers/usb/host/ehci-grlib.c >> index a2c3b4ec8a8b..0717f2ccf49d 100644 >> --- a/drivers/usb/host/ehci-grlib.c >> +++ b/drivers/usb/host/ehci-grlib.c >> @@ -99,7 +99,7 @@ static int ehci_hcd_grlib_probe(struct platform_device *op) >> hcd->rsrc_len = resource_size(&res); >> >> irq = irq_of_parse_and_map(dn, 0); >> - if (irq == NO_IRQ) { >> + if (!irq) { >> dev_err(&op->dev, "%s: irq_of_parse_and_map failed\n", >> __FILE__); >> rv = -EBUSY; > > Since NO_IRQ is sometimes set to -1, shouldn't this test (and all the > other ones you changed) really be doing: > > if (!irq || irq == NO_IRQ) { ... > > ? > > Alan Stern
