On Tue, Jan 31, 2017 at 02:17:10PM -0800, Linus Torvalds wrote: > Because there definitely have been users of the bitop routines that > assign the result to an "int", and I have some dim memory of us also > having had things like drivers that made their own "bool" variables > and use "char" for them. > > But I'm not seeing it. The generic bitop pattern seems to be > > static inline int test_and_change_bit(int nr, volatile unsigned long > *addr) > ... > return (old & mask) != 0; > > which is fine. > > Just exactly what code did you look at?
My bad. I misread the generic test_bit() code and was reading the inner helper of ppc, DEFINE_TESTOP macro, which returns the masked value. We used to have this problem, right? I seem to have a memory of hitting this issue. Is there a reason we don't make these functions explicitly return bool? To avoid unnecessary boolean conversion by the compiler? If so, there gotta be a way to avoid that. Thanks. -- tejun
