[PATCH 02/15] sched/cputime: Remove superfluous and error prone kcpustat_field() parameter

[Frederic Weisbecker <frederic@kernel.org>]

The first parameter to kcpustat_field() is a pointer to the cpu kcpustat
to be fetched from. This parameter is error prone because a copy to a
kcpustat could be passed by accident instead of the original one. Also
the kcpustat structure can already be retrieved with the help of the
mandatory CPU argument.

Remove the needless paramater.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 drivers/cpufreq/cpufreq_governor.c | 6 +++---
 drivers/macintosh/rack-meter.c     | 2 +-
 include/linux/kernel_stat.h        | 8 +++-----
 kernel/rcu/tree.c                  | 9 +++------
 kernel/rcu/tree_stall.h            | 7 +++----
 kernel/sched/cputime.c             | 5 ++---
 6 files changed, 15 insertions(+), 22 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index 1a7fcaf39cc9..b6683628091d 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -105,7 +105,7 @@ void gov_update_cpu_data(struct dbs_data *dbs_data)
 			j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time,
 								  dbs_data->io_is_busy);
 			if (dbs_data->ignore_nice_load)
-				j_cdbs->prev_cpu_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
+				j_cdbs->prev_cpu_nice = kcpustat_field(CPUTIME_NICE, j);
 		}
 	}
 }
@@ -165,7 +165,7 @@ unsigned int dbs_update(struct cpufreq_policy *policy)
 		j_cdbs->prev_cpu_idle = cur_idle_time;
 
 		if (ignore_nice) {
-			u64 cur_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
+			u64 cur_nice = kcpustat_field(CPUTIME_NICE, j);
 
 			idle_time += div_u64(cur_nice - j_cdbs->prev_cpu_nice, NSEC_PER_USEC);
 			j_cdbs->prev_cpu_nice = cur_nice;
@@ -539,7 +539,7 @@ int cpufreq_dbs_governor_start(struct cpufreq_policy *policy)
 		j_cdbs->prev_load = 0;
 
 		if (ignore_nice)
-			j_cdbs->prev_cpu_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
+			j_cdbs->prev_cpu_nice = kcpustat_field(CPUTIME_NICE, j);
 	}
 
 	gov->start(policy);
diff --git a/drivers/macintosh/rack-meter.c b/drivers/macintosh/rack-meter.c
index 896a43bd819f..20b2ecd32340 100644
--- a/drivers/macintosh/rack-meter.c
+++ b/drivers/macintosh/rack-meter.c
@@ -87,7 +87,7 @@ static inline u64 get_cpu_idle_time(unsigned int cpu)
 		 kcpustat->cpustat[CPUTIME_IOWAIT];
 
 	if (rackmeter_ignore_nice)
-		retval += kcpustat_field(kcpustat, CPUTIME_NICE, cpu);
+		retval += kcpustat_field(CPUTIME_NICE, cpu);
 
 	return retval;
 }
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index b97ce2df376f..dd020ecaf67b 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -100,14 +100,12 @@ static inline unsigned long kstat_cpu_irqs_sum(unsigned int cpu)
 }
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
-extern u64 kcpustat_field(struct kernel_cpustat *kcpustat,
-			  enum cpu_usage_stat usage, int cpu);
+extern u64 kcpustat_field(enum cpu_usage_stat usage, int cpu);
 extern void kcpustat_cpu_fetch(struct kernel_cpustat *dst, int cpu);
 #else
-static inline u64 kcpustat_field(struct kernel_cpustat *kcpustat,
-				 enum cpu_usage_stat usage, int cpu)
+static inline u64 kcpustat_field(enum cpu_usage_stat usage, int cpu)
 {
-	return kcpustat->cpustat[usage];
+	return kcpustat_cpu(cpu).cpustat[usage];
 }
 
 static inline void kcpustat_cpu_fetch(struct kernel_cpustat *dst, int cpu)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 293bbd9ac3f4..ceea4b2f755b 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -968,14 +968,11 @@ static int rcu_watching_snap_recheck(struct rcu_data *rdp)
 		if (rcu_cpu_stall_cputime && rdp->snap_record.gp_seq != rdp->gp_seq) {
 			int cpu = rdp->cpu;
 			struct rcu_snap_record *rsrp;
-			struct kernel_cpustat *kcsp;
-
-			kcsp = &kcpustat_cpu(cpu);
 
 			rsrp = &rdp->snap_record;
-			rsrp->cputime_irq     = kcpustat_field(kcsp, CPUTIME_IRQ, cpu);
-			rsrp->cputime_softirq = kcpustat_field(kcsp, CPUTIME_SOFTIRQ, cpu);
-			rsrp->cputime_system  = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu);
+			rsrp->cputime_irq     = kcpustat_field(CPUTIME_IRQ, cpu);
+			rsrp->cputime_softirq = kcpustat_field(CPUTIME_SOFTIRQ, cpu);
+			rsrp->cputime_system  = kcpustat_field(CPUTIME_SYSTEM, cpu);
 			rsrp->nr_hardirqs = kstat_cpu_irqs_sum(cpu) + arch_irq_stat_cpu(cpu);
 			rsrp->nr_softirqs = kstat_cpu_softirqs_sum(cpu);
 			rsrp->nr_csw = nr_context_switches_cpu(cpu);
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index b67532cb8770..cf7ae51cba40 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -479,7 +479,6 @@ static void print_cpu_stat_info(int cpu)
 {
 	struct rcu_snap_record rsr, *rsrp;
 	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
-	struct kernel_cpustat *kcsp = &kcpustat_cpu(cpu);
 
 	if (!rcu_cpu_stall_cputime)
 		return;
@@ -488,9 +487,9 @@ static void print_cpu_stat_info(int cpu)
 	if (rsrp->gp_seq != rdp->gp_seq)
 		return;
 
-	rsr.cputime_irq     = kcpustat_field(kcsp, CPUTIME_IRQ, cpu);
-	rsr.cputime_softirq = kcpustat_field(kcsp, CPUTIME_SOFTIRQ, cpu);
-	rsr.cputime_system  = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu);
+	rsr.cputime_irq     = kcpustat_field(CPUTIME_IRQ, cpu);
+	rsr.cputime_softirq = kcpustat_field(CPUTIME_SOFTIRQ, cpu);
+	rsr.cputime_system  = kcpustat_field(CPUTIME_SYSTEM, cpu);
 
 	pr_err("\t         hardirqs   softirqs   csw/system\n");
 	pr_err("\t number: %8lld %10d %12lld\n",
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 4f97896887ec..5dcb0f2e01bc 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -961,10 +961,9 @@ static int kcpustat_field_vtime(u64 *cpustat,
 	return 0;
 }
 
-u64 kcpustat_field(struct kernel_cpustat *kcpustat,
-		   enum cpu_usage_stat usage, int cpu)
+u64 kcpustat_field(enum cpu_usage_stat usage, int cpu)
 {
-	u64 *cpustat = kcpustat->cpustat;
+	u64 *cpustat = kcpustat_cpu(cpu).cpustat;
 	u64 val = cpustat[usage];
 	struct rq *rq;
 	int err;
-- 
2.51.1