Commit-ID: e0454311903d3fd0f12a86c9e65d7b271c2bb05d Gitweb: http://git.kernel.org/tip/e0454311903d3fd0f12a86c9e65d7b271c2bb05d Author: Thomas Gleixner <[email protected]> AuthorDate: Tue, 7 Jul 2015 14:07:27 +0200 Committer: Thomas Gleixner <[email protected]> CommitDate: Tue, 7 Jul 2015 18:46:47 +0200
tick/broadcast: Sanity check the shutdown of the local clock_event The broadcast code shuts down the local clock event unconditionally even if no broadcast device is installed or if the broadcast device is hrtimer based. Add proper sanity checks. [ Split out from a larger combo patch ] Reported-and-tested-by: Sudeep Holla <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Cc: Suzuki Poulose <[email protected]> Cc: Lorenzo Pieralisi <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Rafael J. Wysocki <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Preeti U Murthy <[email protected]> Cc: Ingo Molnar <[email protected]> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos --- kernel/time/tick-broadcast.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index a762040..9877d0b 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -159,7 +159,7 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) { struct clock_event_device *bc = tick_broadcast_device.evtdev; unsigned long flags; - int ret; + int ret = 0; raw_spin_lock_irqsave(&tick_broadcast_lock, flags); @@ -221,13 +221,14 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) * If we kept the cpu in the broadcast mask, * tell the caller to leave the per cpu device * in shutdown state. The periodic interrupt - * is delivered by the broadcast device. + * is delivered by the broadcast device, if + * the broadcast device exists and is not + * hrtimer based. */ - ret = cpumask_test_cpu(cpu, tick_broadcast_mask); + if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER)) + ret = cpumask_test_cpu(cpu, tick_broadcast_mask); break; default: - /* Nothing to do */ - ret = 0; break; } } @@ -373,8 +374,16 @@ void tick_broadcast_control(enum tick_broadcast_mode mode) case TICK_BROADCAST_ON: cpumask_set_cpu(cpu, tick_broadcast_on); if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_mask)) { - if (tick_broadcast_device.mode == - TICKDEV_MODE_PERIODIC) + /* + * Only shutdown the cpu local device, if: + * + * - the broadcast device exists + * - the broadcast device is not a hrtimer based one + * - the broadcast device is in periodic mode to + * avoid a hickup during switch to oneshot mode + */ + if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER) && + tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) clockevents_shutdown(dev); } break; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
