The invocation of do_softirq() in flush_smp_call_function_from_idle()
breaks on RT because RT does not provide do_softirq().

Aside of that flush_smp_call_function_from_idle() is a misnomer since the
function is invoked not only from idle, but also from the scheduler
migration thread.

The following series addresses this. Changes vs. V3, which can be found
here: https://lore.kernel.org/lkml/YgKgL6aPj8aBES6G@linutronix.de

  - Rename flush_smp_call_function_from_idle() and add comments

  - Confine the RT specifics in the softirq code

Thanks,

	tglx
---
 include/linux/interrupt.h |    9 +++++++++
 kernel/sched/core.c       |    2 +-
 kernel/sched/idle.c       |    2 +-
 kernel/sched/sched.h      |    4 ++--
 kernel/smp.c              |   32 ++++++++++++++++++++++++--------
 kernel/softirq.c          |   13 +++++++++++++
 6 files changed, 50 insertions(+), 12 deletions(-)