[PATCH 3/7] x86/irq: arch_irq_stat_cpu() returns unsigned int

Alexei Lozovsky
2021-09-11T03:48:42Z

Like with PowerPC's version, on x86 the interrupt counters that are
added here are all unsigned int too (see irq_cpustat_t for x86)
as well as mce_exception_count and mce_poll_count.

Summing up unsigned int values into u64 does not "handle" overflows,
but if any of the individual counters overflows then the computed
sum is inaccurate.

Signed-off-by: Alexei Lozovsky <me@ilammy.net>
---
arch/x86/include/asm/hardirq.h | 2 +-
arch/x86/kernel/irq.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/hardirq.h b/arch/x86/include/asm/hardirq.h
index 275e7fd20310..461536b45391 100644
--- a/arch/x86/include/asm/hardirq.h
+++ b/arch/x86/include/asm/hardirq.h
@@ -54,7 +54,7 @@ DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);

extern void ack_bad_irq(unsigned int irq);

-extern u64 arch_irq_stat_cpu(unsigned int cpu);
+extern unsigned int arch_irq_stat_cpu(unsigned int cpu);
#define arch_irq_stat_cpu arch_irq_stat_cpu

extern u64 arch_irq_stat(void);
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index e28f6a5d14f1..cefe1bc9f42c 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -188,9 +188,9 @@ int arch_show_interrupts(struct seq_file *p, int prec)
/*
* /proc/stat helpers
*/
-u64 arch_irq_stat_cpu(unsigned int cpu)
+unsigned int arch_irq_stat_cpu(unsigned int cpu)
{
- u64 sum = irq_stats(cpu)->__nmi_count;
+ unsigned int sum = irq_stats(cpu)->__nmi_count;

#ifdef CONFIG_X86_LOCAL_APIC
sum += irq_stats(cpu)->apic_timer_irqs;
--
2.25.1