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Commit 7be7f0be authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Paul E. McKenney
Browse files

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: default avatarPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 7db74df8

kernel/rcutree.c

+3 −6
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ static struct lock_class_key rcu_node_class[RCU_NUM_LVLS]; 
	.onofflock = __RAW_SPIN_LOCK_UNLOCKED(&sname##_state.onofflock), \

	.orphan_nxttail = &sname##_state.orphan_nxtlist, \

	.orphan_donetail = &sname##_state.orphan_donelist, \

	.barrier_mutex = __MUTEX_INITIALIZER(sname##_state.barrier_mutex), \

	.fqslock = __RAW_SPIN_LOCK_UNLOCKED(&sname##_state.fqslock), \

	.n_force_qs = 0, \

	.n_force_qs_ngp = 0, \
@@ -155,10 +156,6 @@ static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp); 
unsigned long rcutorture_testseq;

unsigned long rcutorture_vernum;



/* State information for rcu_barrier() and friends. */



static DEFINE_MUTEX(rcu_barrier_mutex);



/*

 * Return true if an RCU grace period is in progress.  The ACCESS_ONCE()s

 * permit this function to be invoked without holding the root rcu_node
@@ -2303,7 +2300,7 @@ static void _rcu_barrier(struct rcu_state *rsp) 
	init_rcu_head_on_stack(&rd.barrier_head);



	/* Take mutex to serialize concurrent rcu_barrier() requests. */

	mutex_lock(&rcu_barrier_mutex);

	mutex_lock(&rsp->barrier_mutex);



	smp_mb();  /* Prevent any prior operations from leaking in. */
@@ -2380,7 +2377,7 @@ static void _rcu_barrier(struct rcu_state *rsp) 
	wait_for_completion(&rsp->barrier_completion);



	/* Other rcu_barrier() invocations can now safely proceed. */

	mutex_unlock(&rcu_barrier_mutex);

	mutex_unlock(&rsp->barrier_mutex);



	destroy_rcu_head_on_stack(&rd.barrier_head);

}

kernel/rcutree.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */