On Fri, Dec 04, 2020 at 12:21:15PM +0100, Uwe Kleine-König wrote: > Hello Lino, > > On Fri, Dec 04, 2020 at 12:42:15AM +0100, Lino Sanfilippo wrote: > > On 29.11.20 at 19:10, Uwe Kleine-König wrote: > > > You're storing an unsigned long long (i.e. 64 bits) in an u32. If > > > you are sure that this won't discard relevant bits, please explain > > > this in a comment for the cursory reader. > > > > What about an extra check then to make sure that the period has not been > > truncated, > > e.g: > > > > value = DIV_ROUND_CLOSEST_ULL(state->period, scaler); > > > > /* dont accept a period that is too small or has been truncated */ > > if ((value < PERIOD_MIN) || > > (value != DIV_ROUND_CLOSEST_ULL(state->period, scaler))) > > return -EINVAL; > > I'd make value an unsigned long long and check for > 0xffffffff instead > of repeating the (expensive) division. (Hmm, maybe the compiler is smart > enough to not actually repeat it, but still.)
I wonder where you got that idea from. Sean
