kthread_worker: fix return value when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync()

kthread_mod_delayed_work() might race with
kthread_cancel_delayed_work_sync() or another kthread_mod_delayed_work()
call.  The function lets the other operation win when it sees
work->canceling counter set.  And it returns @false.

But it should return @true as it is done by the related workqueue API, see
mod_delayed_work_on().

The reason is that the return value might be used for reference counting.
It has to distinguish the case when the number of queued works has changed
or stayed the same.

The change is safe.  kthread_mod_delayed_work() return value is not
checked anywhere at the moment.

Link: https://lore.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
Reported-by: Oleg Nesterov <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: <[email protected]>
Cc: Martin Liu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions