From 0854a05c9fa554930174f0fa7453c18f99108a4a Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 3 Jul 2018 17:22:34 -0700 Subject: [PATCH] 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 --- kernel/rcu/tree.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 29121629c004..af4aeaaee046 100644 --- 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);