tree 88633b53318c1adb8f648eaf5edcabac8f81b01b
parent c1ae6e9b4db00023b9caed72af49a93abad46452
author Tejun Heo <tj@kernel.org> 1371094986 -0700
committer Tejun Heo <tj@kernel.org> 1371094986 -0700

percpu-refcount: consistently use plain (non-sched) RCU

percpu_ref_get/put() are using preempt_disable/enable() while
percpu_ref_kill() is using plain call_rcu() instead of
call_rcu_sched().  This is buggy as grace periods of the two may not
match.  Fix it by using plain RCU in percpu_ref_get/put().

(I suggested using sched RCU in the first place but there's no actual
 benefit in doing so unless we're gonna introduce different variants
 of get/put to be called while preemption is alredy disabled, which we
 definitely shouldn't.)

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Kent Overstreet <koverstreet@google.com>