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: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 29121629c0046968e44e3e6532182a0271da0a6f..af4aeaaee04668e1d72069d9edb2627371bc2de6 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -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);