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rcu: Remove unused "cpu" parameter from rcu_report_qs_rdp()

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The "cpu" parameter to rcu_report_qs_rdp() is not used, with rdp->cpu
being used instead.  Furtheremore, every call to rcu_report_qs_rdp()
invokes it on rdp->cpu.  This commit therefore removes this unused "cpu"
parameter and converts a check of rdp->cpu against smp_processor_id()
to a WARN_ON_ONCE().

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Paul E. McKenney
2020-08-20 11:26:14 -07:00
parent aa40c138cc
commit cfeac3977a
2 changed files with 6 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
kernel/rcu/tree.c
View File

@@ -2240,7 +2240,7 @@ rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags)
* structure. This must be called from the specified CPU. * structure. This must be called from the specified CPU.
*/ */
static void static void
rcu_report_qs_rdp(int cpu, struct rcu_data *rdp) rcu_report_qs_rdp(struct rcu_data *rdp)
{ {
unsigned long flags; unsigned long flags;
unsigned long mask; unsigned long mask;
@@ -2249,6 +2249,7 @@ rcu_report_qs_rdp(int cpu, struct rcu_data *rdp)
rcu_segcblist_is_offloaded(&rdp->cblist); rcu_segcblist_is_offloaded(&rdp->cblist);
struct rcu_node *rnp; struct rcu_node *rnp;
WARN_ON_ONCE(rdp->cpu != smp_processor_id());
rnp = rdp->mynode; rnp = rdp->mynode;
raw_spin_lock_irqsave_rcu_node(rnp, flags); raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (rdp->cpu_no_qs.b.norm || rdp->gp_seq != rnp->gp_seq || if (rdp->cpu_no_qs.b.norm || rdp->gp_seq != rnp->gp_seq ||
@@ -2265,8 +2266,7 @@ rcu_report_qs_rdp(int cpu, struct rcu_data *rdp)
return; return;
} }
mask = rdp->grpmask; mask = rdp->grpmask;
if (rdp->cpu == smp_processor_id()) rdp->core_needs_qs = false;
rdp->core_needs_qs = false;
if ((rnp->qsmask & mask) == 0) { if ((rnp->qsmask & mask) == 0) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
} else { } else {
@@ -2315,7 +2315,7 @@ rcu_check_quiescent_state(struct rcu_data *rdp)
* Tell RCU we are done (but rcu_report_qs_rdp() will be the * Tell RCU we are done (but rcu_report_qs_rdp() will be the
* judge of that). * judge of that).
*/ */
rcu_report_qs_rdp(rdp->cpu, rdp); rcu_report_qs_rdp(rdp);
} }
/* /*

4
kernel/rcu/tree_plugin.h
View File

@@ -461,7 +461,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
t->rcu_read_unlock_special.s = 0; t->rcu_read_unlock_special.s = 0;
if (special.b.need_qs) { if (special.b.need_qs) {
if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD)) { if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD)) {
rcu_report_qs_rdp(rdp->cpu, rdp); rcu_report_qs_rdp(rdp);
udelay(rcu_unlock_delay); udelay(rcu_unlock_delay);
} else { } else {
rcu_qs(); rcu_qs();
@@ -791,7 +791,7 @@ void rcu_read_unlock_strict(void)
irqs_disabled() || preempt_count() || !rcu_state.gp_kthread) irqs_disabled() || preempt_count() || !rcu_state.gp_kthread)
return; return;
rdp = this_cpu_ptr(&rcu_data); rdp = this_cpu_ptr(&rcu_data);
rcu_report_qs_rdp(rdp->cpu, rdp); rcu_report_qs_rdp(rdp);
udelay(rcu_unlock_delay); udelay(rcu_unlock_delay);
} }
EXPORT_SYMBOL_GPL(rcu_read_unlock_strict); EXPORT_SYMBOL_GPL(rcu_read_unlock_strict);