[PATCHv4 2/2] cpu/hotplug: Remove the input parameter primary_cpu of smp_shutdown_nonboot_cpus()

Pingfan Liu
2022-05-12T03:06:19Z

For all call sites of smp_shutdown_nonboot_cpus(),

$git grep smp_shutdown_nonboot_cpus -- arch | grep -v \*
arch/arm/kernel/reboot.c:94: smp_shutdown_nonboot_cpus(reboot_cpu);
arch/arm64/kernel/process.c:89: smp_shutdown_nonboot_cpus(reboot_cpu);
arch/ia64/kernel/process.c:578: smp_shutdown_nonboot_cpus(reboot_cpu);
arch/riscv/kernel/machine_kexec.c:135: smp_shutdown_nonboot_cpus(smp_processor_id());

As it shows, the input parameter seems a little arbitrary.

Since kernel_kexec()->migrate_to_reboot_cpu() has already pinned the
rebooting thread on the selected CPU and the CPU hotplug keeps disabled
before smp_shutdown_nonboot_cpus(). Let smp_shutdown_nonboot_cpus()
deduce the rebooting CPU by smp_processor_id(), instead of passing the
parameter primary_cpu to it.

As a result, all call sites look consistent.

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
To: linux-ia64@vger.kernel.org
Cc: Russell King <linux@armlinux.org.uk>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
arch/arm/kernel/reboot.c | 2 +-
arch/arm64/kernel/process.c | 2 +-
arch/ia64/kernel/process.c | 2 +-
arch/riscv/kernel/machine_kexec.c | 2 +-
include/linux/cpu.h | 4 ++--
kernel/cpu.c | 4 ++--
6 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
index 3044fcb8d073..98c961f0b377 100644
--- a/arch/arm/kernel/reboot.c
+++ b/arch/arm/kernel/reboot.c
@@ -91,7 +91,7 @@ void soft_restart(unsigned long addr)
*/
void machine_shutdown(void)
{
- smp_shutdown_nonboot_cpus(reboot_cpu);
+ smp_shutdown_nonboot_cpus();
}

/*
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 7fa97df55e3a..1f6498d44740 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -86,7 +86,7 @@ void arch_cpu_idle_dead(void)
*/
void machine_shutdown(void)
{
- smp_shutdown_nonboot_cpus(reboot_cpu);
+ smp_shutdown_nonboot_cpus();
}

/*
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index d7a256bd9d6b..9af53ff43983 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -575,7 +575,7 @@ cpu_halt (void)

void machine_shutdown(void)
{
- smp_shutdown_nonboot_cpus(reboot_cpu);
+ smp_shutdown_nonboot_cpus();

#ifdef CONFIG_KEXEC
kexec_disable_iosapic();
diff --git a/arch/riscv/kernel/machine_kexec.c b/arch/riscv/kernel/machine_kexec.c
index cbef0fc73afa..a30c545714cc 100644
--- a/arch/riscv/kernel/machine_kexec.c
+++ b/arch/riscv/kernel/machine_kexec.c
@@ -132,7 +132,7 @@ void machine_shutdown(void)
local_irq_disable();

#if defined(CONFIG_HOTPLUG_CPU)
- smp_shutdown_nonboot_cpus(smp_processor_id());
+ smp_shutdown_nonboot_cpus();
#endif
}

diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 54dc2f9a2d56..0506ba3ac85e 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -127,7 +127,7 @@ extern void cpu_hotplug_enable(void);
void clear_tasks_mm_cpumask(int cpu);
int remove_cpu(unsigned int cpu);
int cpu_device_down(struct device *dev);
-extern void smp_shutdown_nonboot_cpus(unsigned int primary_cpu);
+extern void smp_shutdown_nonboot_cpus(void);

#else /* CONFIG_HOTPLUG_CPU */

@@ -140,7 +140,7 @@ static inline void lockdep_assert_cpus_held(void) { }
static inline void cpu_hotplug_disable(void) { }
static inline void cpu_hotplug_enable(void) { }
static inline int remove_cpu(unsigned int cpu) { return -EPERM; }
-static inline void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) { }
+static inline void smp_shutdown_nonboot_cpus(void) { }
#endif /* !CONFIG_HOTPLUG_CPU */

#ifdef CONFIG_PM_SLEEP_SMP
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 4415370f0e91..66b8af6b8a3e 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1228,7 +1228,7 @@ int remove_cpu(unsigned int cpu)
}
EXPORT_SYMBOL_GPL(remove_cpu);

-void smp_shutdown_nonboot_cpus(unsigned int primary_cpu)
+void smp_shutdown_nonboot_cpus(void)
{
unsigned int cpu;
int error;
@@ -1244,7 +1244,7 @@ void smp_shutdown_nonboot_cpus(unsigned int primary_cpu)
__cpu_hotplug_enable();

for_each_online_cpu(cpu) {
- if (cpu = primary_cpu)
+ if (cpu = smp_processor_id())
continue;

error = cpu_down_maps_locked(cpu, CPUHP_OFFLINE);
--
2.31.1