tree 71b90af82e70ea33e05455bf1e6d93cec77ea79e
parent 8fa7845df539105a8962c3173c866483da74ff6d
author Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1414014709 -0700
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1415071261 -0800

cpu: Avoid puts_pending overflow

A long string of get_online_cpus() with each followed by a
put_online_cpu() that fails to acquire cpu_hotplug.lock can result in
overflow of the cpu_hotplug.puts_pending counter.  Although this is
perhaps improbably, a system with absolutely no CPU-hotplug operations
will have an arbitrarily long time in which this overflow could occur.
This commit therefore adds overflow checks to get_online_cpus() and
try_get_online_cpus().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>