stop_machine: make stop_machine safe and efficient to call early

Make stop_machine() safe to call early in boot, before SMP has been set
up, by simply calling the callback function directly if there's only one
CPU online.

[ Fixes from AKPM:
   - add comment
   - local_irq_flags, not save_flags
   - also call hard_irq_disable() for systems which need it

  Tejun suggested using an explicit flag rather than just looking at
  the online cpu count. ]

Cc: Tejun Heo <[email protected]>
Acked-by: Rusty Russell <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Steven Rostedt <[email protected]>
Acked-by: Tejun Heo <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Signed-off-by: Jeremy Fitzhardinge <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions