3.16.80-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> commit b8a62f1ff0ccb18fdc25c6150d1cd394610f4753 upstream. The assignment of bc_moved in the conditional construct relies on the fact that in the case of hrtimer_start() invocation the return value is always 0. It took me a while to understand it. We want to get rid of the hrtimer_start() return value. Open code the logic which makes it readable as well. Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Reviewed-by: Preeti U Murthy <preeti@xxxxxxxxxxxxxxxxxx> Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx> Cc: Marcelo Tosatti <mtosatti@xxxxxxxxxx> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx> Link: http://lkml.kernel.org/r/20150414203503.404751457@xxxxxxxxxxxxx Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> [bwh: Backported to 3.16 to ease backporting commit b9023b91dd02 "tick: broadcast-hrtimer: Fix a race in bc_set_next"] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- kernel/time/tick-broadcast-hrtimer.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/kernel/time/tick-broadcast-hrtimer.c +++ b/kernel/time/tick-broadcast-hrtimer.c @@ -66,9 +66,11 @@ static int bc_set_next(ktime_t expires, * hrtimer_{start/cancel} functions call into tracing, * calls to these functions must be bound within RCU_NONIDLE. */ - RCU_NONIDLE(bc_moved = (hrtimer_try_to_cancel(&bctimer) >= 0) ? - !hrtimer_start(&bctimer, expires, HRTIMER_MODE_ABS_PINNED) : - 0); + RCU_NONIDLE({ + bc_moved = hrtimer_try_to_cancel(&bctimer) >= 0; + if (bc_moved) + hrtimer_start(&bctimer, expires, + HRTIMER_MODE_ABS_PINNED);}); if (bc_moved) { /* Bind the "device" to the cpu */ bc->bound_on = smp_processor_id();
