2020-12-15 05:11:17

by Tiezhu Yang

Subject: [PATCH] MIPS: No need to check CPU 0 in cps_cpu_disable()

After commit 9cce844abf07 ("MIPS: CPU#0 is not hotpluggable"),
c->hotpluggable is 0 for CPU 0 and it will not generate a control
file in sysfs for this CPU:

[root@linux loongson]# cat /sys/devices/system/cpu/cpu0/online
cat: /sys/devices/system/cpu/cpu0/online: No such file or directory
[root@linux loongson]# echo 0 > /sys/devices/system/cpu/cpu0/online
bash: /sys/devices/system/cpu/cpu0/online: Permission denied

So no need to check CPU 0 in cps_cpu_disable(), just remove it.

Reported-by: liwei (GF) <[email protected]>
Signed-off-by: Tiezhu Yang <[email protected]>
---

cps_cpu_disable() is not done in the early similar patch,
sorry for that.

arch/mips/kernel/smp-cps.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/mips/kernel/smp-cps.c b/arch/mips/kernel/smp-cps.c
index 8b027c7..bcd6a94 100644
--- a/arch/mips/kernel/smp-cps.c
+++ b/arch/mips/kernel/smp-cps.c
@@ -451,9 +451,6 @@ static int cps_cpu_disable(void)
unsigned cpu = smp_processor_id();
struct core_boot_config *core_cfg;

- if (!cpu)
- return -EBUSY;
-
if (!cps_pm_support_state(CPS_PM_POWER_GATED))
return -EINVAL;

--
2.1.0

2020-12-29 01:31:00

by Thomas Bogendoerfer

Subject: Re: [PATCH] MIPS: No need to check CPU 0 in cps_cpu_disable()

On Tue, Dec 15, 2020 at 01:07:26PM +0800, Tiezhu Yang wrote:
> After commit 9cce844abf07 ("MIPS: CPU#0 is not hotpluggable"),
> c->hotpluggable is 0 for CPU 0 and it will not generate a control
> file in sysfs for this CPU:
>
> [root@linux loongson]# cat /sys/devices/system/cpu/cpu0/online
> cat: /sys/devices/system/cpu/cpu0/online: No such file or directory
> [root@linux loongson]# echo 0 > /sys/devices/system/cpu/cpu0/online
> bash: /sys/devices/system/cpu/cpu0/online: Permission denied
>
> So no need to check CPU 0 in cps_cpu_disable(), just remove it.
>
> Reported-by: liwei (GF) <[email protected]>
> Signed-off-by: Tiezhu Yang <[email protected]>
> ---
>
> cps_cpu_disable() is not done in the early similar patch,
> sorry for that.
>
> arch/mips/kernel/smp-cps.c | 3 ---
> 1 file changed, 3 deletions(-)

applied to mips-next.

Thomas.

--
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good idea. [ RFC1925, 2.3 ]