Commit 0854a05c authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Remove rsp parameter from rcu_gp_kthread() and friends 



There now is only one rcu_state structure in a given build of the
Linux kernel, so there is no need to pass it as a parameter to RCU's
functions.  This commit therefore removes the rsp parameter from
rcu_gp_init(), rcu_gp_fqs_check_wake(), rcu_gp_fqs(), rcu_gp_cleanup(),
and rcu_gp_kthread().

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 22212332

kernel/rcu/tree.c

+15 −12
Original line number Diff line number Diff line
@@ -1832,13 +1832,14 @@ static void rcu_gp_slow(int delay) 
/*

 * Initialize a new grace period.  Return false if no grace period required.

 */

static bool rcu_gp_init(struct rcu_state *rsp)

static bool rcu_gp_init(void)

{

	unsigned long flags;

	unsigned long oldmask;

	unsigned long mask;

	struct rcu_data *rdp;

	struct rcu_node *rnp = rcu_get_root();

	struct rcu_state *rsp = &rcu_state;



	WRITE_ONCE(rsp->gp_activity, jiffies);

	raw_spin_lock_irq_rcu_node(rnp);
@@ -1963,12 +1964,12 @@ static bool rcu_gp_init(struct rcu_state *rsp) 
 * Helper function for swait_event_idle_exclusive() wakeup at force-quiescent-state

 * time.

 */

static bool rcu_gp_fqs_check_wake(struct rcu_state *rsp, int *gfp)

static bool rcu_gp_fqs_check_wake(int *gfp)

{

	struct rcu_node *rnp = rcu_get_root();



	/* Someone like call_rcu() requested a force-quiescent-state scan. */

	*gfp = READ_ONCE(rsp->gp_flags);

	*gfp = READ_ONCE(rcu_state.gp_flags);

	if (*gfp & RCU_GP_FLAG_FQS)

		return true;
@@ -1982,9 +1983,10 @@ static bool rcu_gp_fqs_check_wake(struct rcu_state *rsp, int *gfp) 
/*

 * Do one round of quiescent-state forcing.

 */

static void rcu_gp_fqs(struct rcu_state *rsp, bool first_time)

static void rcu_gp_fqs(bool first_time)

{

	struct rcu_node *rnp = rcu_get_root();

	struct rcu_state *rsp = &rcu_state;



	WRITE_ONCE(rsp->gp_activity, jiffies);

	rsp->n_force_qs++;
@@ -2007,13 +2009,14 @@ static void rcu_gp_fqs(struct rcu_state *rsp, bool first_time) 
/*

 * Clean up after the old grace period.

 */

static void rcu_gp_cleanup(struct rcu_state *rsp)

static void rcu_gp_cleanup(void)

{

	unsigned long gp_duration;

	bool needgp = false;

	unsigned long new_gp_seq;

	struct rcu_data *rdp;

	struct rcu_node *rnp = rcu_get_root();

	struct rcu_state *rsp = &rcu_state;

	struct swait_queue_head *sq;



	WRITE_ONCE(rsp->gp_activity, jiffies);
@@ -2090,13 +2093,13 @@ static void rcu_gp_cleanup(struct rcu_state *rsp) 
/*

 * Body of kthread that handles grace periods.

 */

static int __noreturn rcu_gp_kthread(void *arg)

static int __noreturn rcu_gp_kthread(void *unused)

{

	bool first_gp_fqs;

	int gf;

	unsigned long j;

	int ret;

	struct rcu_state *rsp = arg;

	struct rcu_state *rsp = &rcu_state;

	struct rcu_node *rnp = rcu_get_root();



	rcu_bind_gp_kthread();
@@ -2112,7 +2115,7 @@ static int __noreturn rcu_gp_kthread(void *arg) 
						     RCU_GP_FLAG_INIT);

			rsp->gp_state = RCU_GP_DONE_GPS;

			/* Locking provides needed memory barrier. */

			if (rcu_gp_init(rsp))

			if (rcu_gp_init())

				break;

			cond_resched_tasks_rcu_qs();

			WRITE_ONCE(rsp->gp_activity, jiffies);
@@ -2137,7 +2140,7 @@ static int __noreturn rcu_gp_kthread(void *arg) 
					       TPS("fqswait"));

			rsp->gp_state = RCU_GP_WAIT_FQS;

			ret = swait_event_idle_timeout_exclusive(rsp->gp_wq,

					rcu_gp_fqs_check_wake(rsp, &gf), j);

					rcu_gp_fqs_check_wake(&gf), j);

			rsp->gp_state = RCU_GP_DOING_FQS;

			/* Locking provides needed memory barriers. */

			/* If grace period done, leave loop. */
@@ -2150,7 +2153,7 @@ static int __noreturn rcu_gp_kthread(void *arg) 
				trace_rcu_grace_period(rsp->name,

						       READ_ONCE(rsp->gp_seq),

						       TPS("fqsstart"));

				rcu_gp_fqs(rsp, first_gp_fqs);

				rcu_gp_fqs(first_gp_fqs);

				first_gp_fqs = false;

				trace_rcu_grace_period(rsp->name,

						       READ_ONCE(rsp->gp_seq),
@@ -2178,7 +2181,7 @@ static int __noreturn rcu_gp_kthread(void *arg) 


		/* Handle grace-period end. */

		rsp->gp_state = RCU_GP_CLEANUP;

		rcu_gp_cleanup(rsp);

		rcu_gp_cleanup();

		rsp->gp_state = RCU_GP_CLEANED;

	}

}
@@ -3744,7 +3747,7 @@ static int __init rcu_spawn_gp_kthread(void) 


	rcu_scheduler_fully_active = 1;

	for_each_rcu_flavor(rsp) {

		t = kthread_create(rcu_gp_kthread, rsp, "%s", rsp->name);

		t = kthread_create(rcu_gp_kthread, NULL, "%s", rsp->name);

		BUG_ON(IS_ERR(t));

		rnp = rcu_get_root();

		raw_spin_lock_irqsave_rcu_node(rnp, flags);