One more doc correction while we are at it...
preempt_enable() decrement the preempt counter
preempt_disable() increment the preempt counter
preempt_enable_no_resched() decrement, but do not immediately preempt
-preempt_get_count() return the preempt counter
+preempt_check_resched() if needed, reschedule
+preempt_count() return the preempt counter
The functions are nestable. In other words, you can call preempt_disable
n-times in a code path, and preemption will not be reenabled until the n-th