sched/completions: Fix complete_all() semantics

Documentation/scheduler/completion.txt says this about complete_all():

  "calls complete_all() to signal all current and future waiters."

Which doesn't strictly match the current semantics. Currently
complete_all() is equivalent to UINT_MAX/2 complete() invocations,
which is distinctly less than 'all current and future waiters'
(enumerable vs innumerable), although it has worked in practice.

However, Dmitry had a weird case where it might matter, so change
completions to use saturation semantics for complete()/complete_all().
Once done hits UINT_MAX (and complete_all() sets it there) it will
never again be decremented.

Requested-by: Dmitry Torokhov <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions