• Linus Torvalds's avatar
    timer-of: don't use conditional expression with mixed 'void' types · 0f1a7b3f
    Linus Torvalds authored
    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: default avatarRandy Dunlap <rdunlap@infradead.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    0f1a7b3f
timer-of.c 5.23 KB