On Thu, Mar 21, 2013 at 09:35:34AM -0700, Kent Overstreet wrote: > Analagous to wait_event_timeout() and friends, this adds > wait_event_hrtimeout() and wait_event_interruptible_hrtimeout(). > > Note that unlike the versions that use regular timers, these don't return > the amount of time remaining when they return - instead, they return 0 or > -ETIME if they timed out. because I was uncomfortable with the semantics > of doing it the other way (that I could get it right, anyways). > > If the timer expires, there's no real guarantee that expire_time - > current_time would be <= 0 - due to timer slack certainly, and I'm not > sure I want to know the implications of the different clock bases in > hrtimers. > > If the timer does expire and the code calculates that the time remaining > is nonnegative, that could be even worse if the calling code then reuses > that timeout. Probably safer to just return 0 then, but I could imagine > weird bugs or at least unintended behaviour arising from that too. > > I came to the conclusion that if other users end up actually needing the > amount of time remaining, the sanest thing to do would be to create a > version that uses absolute timeouts instead of relative.
Reviewed-by: "Theodore Ts'o" <ty...@mit.edu> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
