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rcu: Remove rcu_state_p pointer to default rcu_state structure

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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@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2018-07-03 15:54:39 -07:00
parent da1df50d16
commit 16fc9c600b
3 changed files with 21 additions and 24 deletions
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27
kernel/rcu/tree.c
View file

@ -85,7 +85,6 @@ struct rcu_state rcu_state = {
.ofl_lock = __SPIN_LOCK_UNLOCKED(rcu_state.ofl_lock), .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; static struct rcu_data __percpu *const rcu_data_p = &rcu_data;
LIST_HEAD(rcu_struct_flavors); LIST_HEAD(rcu_struct_flavors);
@ -491,7 +490,7 @@ static int rcu_pending(void);
*/ */
unsigned long rcu_get_gp_seq(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); 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) 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); 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) 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); 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) void rcu_force_quiescent_state(void)
{ {
force_quiescent_state(rcu_state_p); force_quiescent_state(&rcu_state);
} }
EXPORT_SYMBOL_GPL(rcu_force_quiescent_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) 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); 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_FLAVOR:
case RCU_BH_FLAVOR: case RCU_BH_FLAVOR:
case RCU_SCHED_FLAVOR: case RCU_SCHED_FLAVOR:
rsp = rcu_state_p; rsp = &rcu_state;
break; break;
default: default:
break; break;
@ -2292,7 +2291,6 @@ rcu_report_unblock_qs_rnp(struct rcu_state *rsp,
raw_lockdep_assert_held_rcu_node(rnp); raw_lockdep_assert_held_rcu_node(rnp);
if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT)) || if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT)) ||
WARN_ON_ONCE(rsp != rcu_state_p) ||
WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)) || WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)) ||
rnp->qsmask != 0) { rnp->qsmask != 0) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
@ -2604,7 +2602,6 @@ static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *rsp))
raw_spin_lock_irqsave_rcu_node(rnp, flags); raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (rnp->qsmask == 0) { if (rnp->qsmask == 0) {
if (!IS_ENABLED(CONFIG_PREEMPT) || if (!IS_ENABLED(CONFIG_PREEMPT) ||
rsp != rcu_state_p ||
rcu_preempt_blocked_readers_cgp(rnp)) { rcu_preempt_blocked_readers_cgp(rnp)) {
/* /*
* No point in scanning bits because they * No point in scanning bits because they
@ -2973,7 +2970,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func,
*/ */
void 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); EXPORT_SYMBOL_GPL(call_rcu);
@ -3000,7 +2997,7 @@ EXPORT_SYMBOL_GPL(call_rcu_sched);
void kfree_call_rcu(struct rcu_head *head, void kfree_call_rcu(struct rcu_head *head,
rcu_callback_t func) 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); EXPORT_SYMBOL_GPL(kfree_call_rcu);
@ -3029,7 +3026,7 @@ unsigned long get_state_synchronize_rcu(void)
* before the load from ->gp_seq. * before the load from ->gp_seq.
*/ */
smp_mb(); /* ^^^ */ 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); EXPORT_SYMBOL_GPL(get_state_synchronize_rcu);
@ -3049,7 +3046,7 @@ EXPORT_SYMBOL_GPL(get_state_synchronize_rcu);
*/ */
void cond_synchronize_rcu(unsigned long oldstate) 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(); synchronize_rcu();
else else
smp_mb(); /* Ensure GP ends before subsequent accesses. */ smp_mb(); /* Ensure GP ends before subsequent accesses. */
@ -3308,7 +3305,7 @@ static void _rcu_barrier(struct rcu_state *rsp)
*/ */
void rcu_barrier_bh(void) void rcu_barrier_bh(void)
{ {
_rcu_barrier(rcu_state_p); _rcu_barrier(&rcu_state);
} }
EXPORT_SYMBOL_GPL(rcu_barrier_bh); EXPORT_SYMBOL_GPL(rcu_barrier_bh);
@ -3322,7 +3319,7 @@ EXPORT_SYMBOL_GPL(rcu_barrier_bh);
*/ */
void rcu_barrier(void) void rcu_barrier(void)
{ {
_rcu_barrier(rcu_state_p); _rcu_barrier(&rcu_state);
} }
EXPORT_SYMBOL_GPL(rcu_barrier); EXPORT_SYMBOL_GPL(rcu_barrier);

2
kernel/rcu/tree_exp.h
View file

@ -756,7 +756,7 @@ static void sync_sched_exp_online_cleanup(int cpu)
*/ */
void synchronize_rcu_expedited(void) 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) || RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
lock_is_held(&rcu_lock_map) || lock_is_held(&rcu_lock_map) ||

16
kernel/rcu/tree_plugin.h
View file

@ -381,7 +381,7 @@ void rcu_note_context_switch(bool preempt)
*/ */
rcu_qs(); rcu_qs();
if (rdp->deferred_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")); trace_rcu_utilization(TPS("End context switch"));
barrier(); /* Avoid RCU read-side critical sections leaking up. */ 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. * blocked-tasks list below.
*/ */
if (rdp->deferred_qs) { 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) { if (!t->rcu_read_unlock_special.s) {
local_irq_restore(flags); local_irq_restore(flags);
return; return;
@ -566,7 +566,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
rnp->grplo, rnp->grplo,
rnp->grphi, rnp->grphi,
!!rnp->gp_tasks); !!rnp->gp_tasks);
rcu_report_unblock_qs_rnp(rcu_state_p, rnp, flags); rcu_report_unblock_qs_rnp(&rcu_state, rnp, flags);
} else { } else {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); 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. * then we need to report up the rcu_node hierarchy.
*/ */
if (!empty_exp && empty_exp_now) if (!empty_exp && empty_exp_now)
rcu_report_exp_rnp(rcu_state_p, rnp, true); rcu_report_exp_rnp(&rcu_state, rnp, true);
} else { } else {
local_irq_restore(flags); local_irq_restore(flags);
} }
@ -1300,7 +1300,7 @@ static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
struct sched_param sp; struct sched_param sp;
struct task_struct *t; struct task_struct *t;
if (rcu_state_p != rsp) if (&rcu_state != rsp)
return 0; return 0;
if (!rcu_scheduler_fully_active || rcu_rnp_online_cpus(rnp) == 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) for_each_possible_cpu(cpu)
per_cpu(rcu_cpu_has_work, cpu) = 0; per_cpu(rcu_cpu_has_work, cpu) = 0;
BUG_ON(smpboot_register_percpu_thread(&rcu_cpu_thread_spec)); BUG_ON(smpboot_register_percpu_thread(&rcu_cpu_thread_spec));
rcu_for_each_leaf_node(rcu_state_p, rnp) rcu_for_each_leaf_node(&rcu_state, rnp)
(void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp); (void)rcu_spawn_one_boost_kthread(&rcu_state, rnp);
} }
static void rcu_prepare_kthreads(int cpu) 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. */ /* Fire up the incoming CPU's kthread and leaf rcu_node kthread. */
if (rcu_scheduler_fully_active) 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 */ #else /* #ifdef CONFIG_RCU_BOOST */