From 0f1a7b3fac0583083ca19d4de47403511ced3521 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 2 Oct 2019 16:16:07 -0700 Subject: [PATCH] timer-of: don't use conditional expression with mixed 'void' types Randy Dunlap reports on the sparse list that sparse warns about this expression: of_irq->percpu ? free_percpu_irq(of_irq->irq, clkevt) : free_irq(of_irq->irq, clkevt); and honestly, sparse is correct to warn. The return type of free_percpu_irq() is 'void', while free_irq() returns a 'const void *' that is the devname argument passed in to the request_irq(). You can't mix a void type with a non-void types in a conditional expression according to the C standard. It so happens that gcc seems to accept it - and the resulting type of the expression is void - but there's really no reason for the kernel to have this kind of non-standard expression with no real upside. The natural way to write that expression is with an if-statement: if (of_irq->percpu) free_percpu_irq(of_irq->irq, clkevt); else free_irq(of_irq->irq, clkevt); which is more legible anyway. I'm not sure why that timer-of code seems to have this odd pattern. It does the same at allocation time, but at least there the types match, and it makes sense as an expression. Reported-by: Randy Dunlap Signed-off-by: Linus Torvalds --- drivers/clocksource/timer-of.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/clocksource/timer-of.c b/drivers/clocksource/timer-of.c index d8c2bd4391d0..11ff701ff4bb 100644 --- a/drivers/clocksource/timer-of.c +++ b/drivers/clocksource/timer-of.c @@ -25,7 +25,9 @@ static __init void timer_of_irq_exit(struct of_timer_irq *of_irq) struct clock_event_device *clkevt = &to->clkevt; - of_irq->percpu ? free_percpu_irq(of_irq->irq, clkevt) : + if (of_irq->percpu) + free_percpu_irq(of_irq->irq, clkevt); + else free_irq(of_irq->irq, clkevt); }