rcu: Move rcu_barrier_mutex to rcu_state structure

In order to allow each RCU flavor to concurrently execute its
rcu_barrier() function, it is necessary to move the relevant
state to the rcu_state structure.  This commit therefore moves the
rcu_barrier_mutex global variable to a new ->barrier_mutex field
in the rcu_state structure.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index d1ca4424122b..7641aec3e59c 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -400,6 +400,7 @@ struct rcu_state {
         struct task_struct *rcu_barrier_in_progress;
                                                 /* Task doing rcu_barrier(), */
                                                 /*  or NULL if no barrier. */
+        struct mutex barrier_mutex;             /* Guards barrier fields. */
         atomic_t barrier_cpu_count;             /* # CPUs waiting on. */
         struct completion barrier_completion;   /* Wake at barrier end. */
         raw_spinlock_t fqslock;                 /* Only one task forcing */