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Subject[PATCH tip/core/rcu 06/52] rcu: Remove rsp parameter from rcu_get_root()
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_get_root().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcu/tree.c | 38 +++++++++++++++++++-------------------
kernel/rcu/tree_exp.h | 6 +++---
kernel/rcu/tree_plugin.h | 2 +-
3 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 605e1c990619..9a40692f980d 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -623,9 +623,9 @@ EXPORT_SYMBOL_GPL(rcutorture_get_gp_data);
/*
* Return the root node of the specified rcu_state structure.
*/
-static struct rcu_node *rcu_get_root(struct rcu_state *rsp)
+static struct rcu_node *rcu_get_root(void)
{
- return &rsp->node[0];
+ return &rcu_state.node[0];
}

/*
@@ -1317,7 +1317,7 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gp_seq)
unsigned long gpa;
unsigned long j;
int ndetected = 0;
- struct rcu_node *rnp = rcu_get_root(rsp);
+ struct rcu_node *rnp = rcu_get_root();
long totqlen = 0;

/* Kick and suppress, if so configured. */
@@ -1366,7 +1366,7 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gp_seq)
pr_err("All QSes seen, last %s kthread activity %ld (%ld-%ld), jiffies_till_next_fqs=%ld, root ->qsmask %#lx\n",
rsp->name, j - gpa, j, gpa,
jiffies_till_next_fqs,
- rcu_get_root(rsp)->qsmask);
+ rcu_get_root()->qsmask);
/* In this case, the current CPU might be at fault. */
sched_show_task(current);
}
@@ -1388,7 +1388,7 @@ static void print_cpu_stall(struct rcu_state *rsp)
int cpu;
unsigned long flags;
struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
- struct rcu_node *rnp = rcu_get_root(rsp);
+ struct rcu_node *rnp = rcu_get_root();
long totqlen = 0;

/* Kick and suppress, if so configured. */
@@ -1834,7 +1834,7 @@ static bool rcu_gp_init(struct rcu_state *rsp)
unsigned long oldmask;
unsigned long mask;
struct rcu_data *rdp;
- struct rcu_node *rnp = rcu_get_root(rsp);
+ struct rcu_node *rnp = rcu_get_root();

WRITE_ONCE(rsp->gp_activity, jiffies);
raw_spin_lock_irq_rcu_node(rnp);
@@ -1961,7 +1961,7 @@ static bool rcu_gp_init(struct rcu_state *rsp)
*/
static bool rcu_gp_fqs_check_wake(struct rcu_state *rsp, int *gfp)
{
- struct rcu_node *rnp = rcu_get_root(rsp);
+ struct rcu_node *rnp = rcu_get_root();

/* Someone like call_rcu() requested a force-quiescent-state scan. */
*gfp = READ_ONCE(rsp->gp_flags);
@@ -1980,7 +1980,7 @@ static bool rcu_gp_fqs_check_wake(struct rcu_state *rsp, int *gfp)
*/
static void rcu_gp_fqs(struct rcu_state *rsp, bool first_time)
{
- struct rcu_node *rnp = rcu_get_root(rsp);
+ struct rcu_node *rnp = rcu_get_root();

WRITE_ONCE(rsp->gp_activity, jiffies);
rsp->n_force_qs++;
@@ -2009,7 +2009,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
bool needgp = false;
unsigned long new_gp_seq;
struct rcu_data *rdp;
- struct rcu_node *rnp = rcu_get_root(rsp);
+ struct rcu_node *rnp = rcu_get_root();
struct swait_queue_head *sq;

WRITE_ONCE(rsp->gp_activity, jiffies);
@@ -2057,7 +2057,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
WRITE_ONCE(rsp->gp_activity, jiffies);
rcu_gp_slow(rsp, gp_cleanup_delay);
}
- rnp = rcu_get_root(rsp);
+ rnp = rcu_get_root();
raw_spin_lock_irq_rcu_node(rnp); /* GP before rsp->gp_seq update. */

/* Declare grace period done. */
@@ -2093,7 +2093,7 @@ static int __noreturn rcu_gp_kthread(void *arg)
unsigned long j;
int ret;
struct rcu_state *rsp = arg;
- struct rcu_node *rnp = rcu_get_root(rsp);
+ struct rcu_node *rnp = rcu_get_root();

rcu_bind_gp_kthread();
for (;;) {
@@ -2189,14 +2189,14 @@ static int __noreturn rcu_gp_kthread(void *arg)
* which is released before return.
*/
static void rcu_report_qs_rsp(unsigned long flags)
- __releases(rcu_get_root(rsp)->lock)
+ __releases(rcu_get_root()->lock)
{
struct rcu_state *rsp = &rcu_state;

- raw_lockdep_assert_held_rcu_node(rcu_get_root(rsp));
+ raw_lockdep_assert_held_rcu_node(rcu_get_root());
WARN_ON_ONCE(!rcu_gp_in_progress());
WRITE_ONCE(rsp->gp_flags, READ_ONCE(rsp->gp_flags) | RCU_GP_FLAG_FQS);
- raw_spin_unlock_irqrestore_rcu_node(rcu_get_root(rsp), flags);
+ raw_spin_unlock_irqrestore_rcu_node(rcu_get_root(), flags);
rcu_gp_kthread_wake(rsp);
}

@@ -2653,7 +2653,7 @@ static void force_quiescent_state(struct rcu_state *rsp)
return;
rnp_old = rnp;
}
- /* rnp_old == rcu_get_root(rsp), rnp == NULL. */
+ /* rnp_old == rcu_get_root(), rnp == NULL. */

/* Reached the root of the rcu_node tree, acquire lock. */
raw_spin_lock_irqsave_rcu_node(rnp_old, flags);
@@ -2678,7 +2678,7 @@ rcu_check_gp_start_stall(struct rcu_state *rsp, struct rcu_node *rnp,
const unsigned long gpssdelay = rcu_jiffies_till_stall_check() * HZ;
unsigned long flags;
unsigned long j;
- struct rcu_node *rnp_root = rcu_get_root(rsp);
+ struct rcu_node *rnp_root = rcu_get_root();
static atomic_t warned = ATOMIC_INIT(0);

if (!IS_ENABLED(CONFIG_PROVE_RCU) || rcu_gp_in_progress() ||
@@ -3396,7 +3396,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
{
unsigned long flags;
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
- struct rcu_node *rnp = rcu_get_root(rsp);
+ struct rcu_node *rnp = rcu_get_root();

/* Set up local state, ensuring consistent view of global state. */
raw_spin_lock_irqsave_rcu_node(rnp, flags);
@@ -3645,7 +3645,7 @@ static void rcu_migrate_callbacks(int cpu, struct rcu_state *rsp)
unsigned long flags;
struct rcu_data *my_rdp;
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
- struct rcu_node *rnp_root = rcu_get_root(rdp->rsp);
+ struct rcu_node *rnp_root = rcu_get_root();
bool needwake;

if (rcu_is_nocb_cpu(cpu) || rcu_segcblist_empty(&rdp->cblist))
@@ -3743,7 +3743,7 @@ static int __init rcu_spawn_gp_kthread(void)
for_each_rcu_flavor(rsp) {
t = kthread_create(rcu_gp_kthread, rsp, "%s", rsp->name);
BUG_ON(IS_ERR(t));
- rnp = rcu_get_root(rsp);
+ rnp = rcu_get_root();
raw_spin_lock_irqsave_rcu_node(rnp, flags);
rsp->gp_kthread = t;
if (kthread_prio) {
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index 298a6904bbcd..0bcbb03c9702 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -288,7 +288,7 @@ static bool exp_funnel_lock(struct rcu_state *rsp, unsigned long s)
{
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, raw_smp_processor_id());
struct rcu_node *rnp = rdp->mynode;
- struct rcu_node *rnp_root = rcu_get_root(rsp);
+ struct rcu_node *rnp_root = rcu_get_root();

/* Low-contention fastpath. */
if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s) &&
@@ -479,7 +479,7 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp)
unsigned long mask;
int ndetected;
struct rcu_node *rnp;
- struct rcu_node *rnp_root = rcu_get_root(rsp);
+ struct rcu_node *rnp_root = rcu_get_root();
int ret;

trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("startwait"));
@@ -643,7 +643,7 @@ static void _synchronize_rcu_expedited(struct rcu_state *rsp,

/* Wait for expedited grace period to complete. */
rdp = per_cpu_ptr(&rcu_data, raw_smp_processor_id());
- rnp = rcu_get_root(rsp);
+ rnp = rcu_get_root();
wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3],
sync_exp_work_done(rsp, s));
smp_mb(); /* Workqueue actions happen before return. */
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 99f517035a6e..545e4ac9422a 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -685,7 +685,7 @@ static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp)
*/
static void rcu_print_detail_task_stall(struct rcu_state *rsp)
{
- struct rcu_node *rnp = rcu_get_root(rsp);
+ struct rcu_node *rnp = rcu_get_root();

rcu_print_detail_task_stall_rnp(rnp);
rcu_for_each_leaf_node(rsp, rnp)
--
2.17.1
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