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Date: Wed, 29 Aug 2018 15:20:46 -0700
From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: mingo@...nel.org, jiangshanlai@...il.com, dipankar@...ibm.com,
akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
fweisbec@...il.com, oleg@...hat.com, joel@...lfernandes.org,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 18/19] rcu: Remove rcu_state_p pointer to default rcu_state structure
The rcu_state_p pointer references the default rcu_state structure,
that is, the one that call_rcu() uses, as opposed to call_rcu_bh()
and sometimes call_rcu_sched(). But there is now only one rcu_state
structure, so that one structure is by definition the default, which
means that the rcu_state_p pointer no longer serves any useful purpose.
This commit therefore removes it.
Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
---
kernel/rcu/tree.c | 27 ++++++++++++---------------
kernel/rcu/tree_exp.h | 2 +-
kernel/rcu/tree_plugin.h | 16 ++++++++--------
3 files changed, 21 insertions(+), 24 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 1dd8086ee90d..a3bcf08ad596 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -85,7 +85,6 @@ struct rcu_state rcu_state = {
.ofl_lock = __SPIN_LOCK_UNLOCKED(rcu_state.ofl_lock),
};
-static struct rcu_state *const rcu_state_p = &rcu_state;
static struct rcu_data __percpu *const rcu_data_p = &rcu_data;
LIST_HEAD(rcu_struct_flavors);
@@ -491,7 +490,7 @@ static int rcu_pending(void);
*/
unsigned long rcu_get_gp_seq(void)
{
- return READ_ONCE(rcu_state_p->gp_seq);
+ return READ_ONCE(rcu_state.gp_seq);
}
EXPORT_SYMBOL_GPL(rcu_get_gp_seq);
@@ -510,7 +509,7 @@ EXPORT_SYMBOL_GPL(rcu_sched_get_gp_seq);
*/
unsigned long rcu_bh_get_gp_seq(void)
{
- return READ_ONCE(rcu_state_p->gp_seq);
+ return READ_ONCE(rcu_state.gp_seq);
}
EXPORT_SYMBOL_GPL(rcu_bh_get_gp_seq);
@@ -522,7 +521,7 @@ EXPORT_SYMBOL_GPL(rcu_bh_get_gp_seq);
*/
unsigned long rcu_exp_batches_completed(void)
{
- return rcu_state_p->expedited_sequence;
+ return rcu_state.expedited_sequence;
}
EXPORT_SYMBOL_GPL(rcu_exp_batches_completed);
@@ -541,7 +540,7 @@ EXPORT_SYMBOL_GPL(rcu_exp_batches_completed_sched);
*/
void rcu_force_quiescent_state(void)
{
- force_quiescent_state(rcu_state_p);
+ force_quiescent_state(&rcu_state);
}
EXPORT_SYMBOL_GPL(rcu_force_quiescent_state);
@@ -550,7 +549,7 @@ EXPORT_SYMBOL_GPL(rcu_force_quiescent_state);
*/
void rcu_bh_force_quiescent_state(void)
{
- force_quiescent_state(rcu_state_p);
+ force_quiescent_state(&rcu_state);
}
EXPORT_SYMBOL_GPL(rcu_bh_force_quiescent_state);
@@ -611,7 +610,7 @@ void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
case RCU_FLAVOR:
case RCU_BH_FLAVOR:
case RCU_SCHED_FLAVOR:
- rsp = rcu_state_p;
+ rsp = &rcu_state;
break;
default:
break;
@@ -2291,7 +2290,6 @@ rcu_report_unblock_qs_rnp(struct rcu_state *rsp,
raw_lockdep_assert_held_rcu_node(rnp);
if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT)) ||
- WARN_ON_ONCE(rsp != rcu_state_p) ||
WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)) ||
rnp->qsmask != 0) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
@@ -2603,7 +2601,6 @@ static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *rsp))
raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (rnp->qsmask == 0) {
if (!IS_ENABLED(CONFIG_PREEMPT) ||
- rsp != rcu_state_p ||
rcu_preempt_blocked_readers_cgp(rnp)) {
/*
* No point in scanning bits because they
@@ -2972,7 +2969,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func,
*/
void call_rcu(struct rcu_head *head, rcu_callback_t func)
{
- __call_rcu(head, func, rcu_state_p, -1, 0);
+ __call_rcu(head, func, &rcu_state, -1, 0);
}
EXPORT_SYMBOL_GPL(call_rcu);
@@ -2999,7 +2996,7 @@ EXPORT_SYMBOL_GPL(call_rcu_sched);
void kfree_call_rcu(struct rcu_head *head,
rcu_callback_t func)
{
- __call_rcu(head, func, rcu_state_p, -1, 1);
+ __call_rcu(head, func, &rcu_state, -1, 1);
}
EXPORT_SYMBOL_GPL(kfree_call_rcu);
@@ -3028,7 +3025,7 @@ unsigned long get_state_synchronize_rcu(void)
* before the load from ->gp_seq.
*/
smp_mb(); /* ^^^ */
- return rcu_seq_snap(&rcu_state_p->gp_seq);
+ return rcu_seq_snap(&rcu_state.gp_seq);
}
EXPORT_SYMBOL_GPL(get_state_synchronize_rcu);
@@ -3048,7 +3045,7 @@ EXPORT_SYMBOL_GPL(get_state_synchronize_rcu);
*/
void cond_synchronize_rcu(unsigned long oldstate)
{
- if (!rcu_seq_done(&rcu_state_p->gp_seq, oldstate))
+ if (!rcu_seq_done(&rcu_state.gp_seq, oldstate))
synchronize_rcu();
else
smp_mb(); /* Ensure GP ends before subsequent accesses. */
@@ -3307,7 +3304,7 @@ static void _rcu_barrier(struct rcu_state *rsp)
*/
void rcu_barrier_bh(void)
{
- _rcu_barrier(rcu_state_p);
+ _rcu_barrier(&rcu_state);
}
EXPORT_SYMBOL_GPL(rcu_barrier_bh);
@@ -3321,7 +3318,7 @@ EXPORT_SYMBOL_GPL(rcu_barrier_bh);
*/
void rcu_barrier(void)
{
- _rcu_barrier(rcu_state_p);
+ _rcu_barrier(&rcu_state);
}
EXPORT_SYMBOL_GPL(rcu_barrier);
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index 3a8a582d9958..298a6904bbcd 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -756,7 +756,7 @@ static void sync_sched_exp_online_cleanup(int cpu)
*/
void synchronize_rcu_expedited(void)
{
- struct rcu_state *rsp = rcu_state_p;
+ struct rcu_state *rsp = &rcu_state;
RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
lock_is_held(&rcu_lock_map) ||
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index b7a99a6e64b6..329d5802d899 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -381,7 +381,7 @@ void rcu_note_context_switch(bool preempt)
*/
rcu_qs();
if (rdp->deferred_qs)
- rcu_report_exp_rdp(rcu_state_p, rdp);
+ rcu_report_exp_rdp(&rcu_state, rdp);
trace_rcu_utilization(TPS("End context switch"));
barrier(); /* Avoid RCU read-side critical sections leaking up. */
}
@@ -509,7 +509,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
* blocked-tasks list below.
*/
if (rdp->deferred_qs) {
- rcu_report_exp_rdp(rcu_state_p, rdp);
+ rcu_report_exp_rdp(&rcu_state, rdp);
if (!t->rcu_read_unlock_special.s) {
local_irq_restore(flags);
return;
@@ -566,7 +566,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
rnp->grplo,
rnp->grphi,
!!rnp->gp_tasks);
- rcu_report_unblock_qs_rnp(rcu_state_p, rnp, flags);
+ rcu_report_unblock_qs_rnp(&rcu_state, rnp, flags);
} else {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
@@ -580,7 +580,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
* then we need to report up the rcu_node hierarchy.
*/
if (!empty_exp && empty_exp_now)
- rcu_report_exp_rnp(rcu_state_p, rnp, true);
+ rcu_report_exp_rnp(&rcu_state, rnp, true);
} else {
local_irq_restore(flags);
}
@@ -1300,7 +1300,7 @@ static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
struct sched_param sp;
struct task_struct *t;
- if (rcu_state_p != rsp)
+ if (&rcu_state != rsp)
return 0;
if (!rcu_scheduler_fully_active || rcu_rnp_online_cpus(rnp) == 0)
@@ -1431,8 +1431,8 @@ static void __init rcu_spawn_boost_kthreads(void)
for_each_possible_cpu(cpu)
per_cpu(rcu_cpu_has_work, cpu) = 0;
BUG_ON(smpboot_register_percpu_thread(&rcu_cpu_thread_spec));
- rcu_for_each_leaf_node(rcu_state_p, rnp)
- (void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp);
+ rcu_for_each_leaf_node(&rcu_state, rnp)
+ (void)rcu_spawn_one_boost_kthread(&rcu_state, rnp);
}
static void rcu_prepare_kthreads(int cpu)
@@ -1442,7 +1442,7 @@ static void rcu_prepare_kthreads(int cpu)
/* Fire up the incoming CPU's kthread and leaf rcu_node kthread. */
if (rcu_scheduler_fully_active)
- (void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp);
+ (void)rcu_spawn_one_boost_kthread(&rcu_state, rnp);
}
#else /* #ifdef CONFIG_RCU_BOOST */
--
2.17.1
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