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Subject[PATCH tip/core/rcu 22/52] rcu: Remove rsp parameter from rcu_gp_kthread() and friends
Date
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>
---
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 751c28ddf5b1..b2d79570c70f 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1831,13 +1831,14 @@ 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);
@@ -1962,12 +1963,12 @@ 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;

@@ -1981,9 +1982,10 @@ 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++;
@@ -2006,13 +2008,14 @@ 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);
@@ -2089,13 +2092,13 @@ 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();
@@ -2111,7 +2114,7 @@ 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);
@@ -2136,7 +2139,7 @@ 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. */
@@ -2149,7 +2152,7 @@ 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),
@@ -2177,7 +2180,7 @@ 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;
}
}
@@ -3743,7 +3746,7 @@ 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);
--
2.17.1
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