linux-kernel - [PATCH] MIPS: No need to check CPU 0 in {loongson3,bmips,octeon}_cpu

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Message-Id: <1606299090-14013-1-git-send-email-yangtiezhu@loongson.cn>
Date:   Wed, 25 Nov 2020 18:11:30 +0800
From:   Tiezhu Yang <yangtiezhu@...ngson.cn>
To:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Huacai Chen <chenhc@...ote.com>,
        Jiaxun Yang <jiaxun.yang@...goat.com>,
        Florian Fainelli <f.fainelli@...il.com>
Cc:     linux-mips@...r.kernel.org, bcm-kernel-feedback-list@...adcom.com,
        linux-kernel@...r.kernel.org, Xuefeng Li <lixuefeng@...ngson.cn>
Subject: [PATCH] MIPS: No need to check CPU 0 in {loongson3,bmips,octeon}_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@...ux loongson]# cat /sys/devices/system/cpu/cpu0/online
cat: /sys/devices/system/cpu/cpu0/online: No such file or directory
[root@...ux 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 {loongson3,bmips,octeon}_cpu_disable(),
just remove them.

Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
---
 arch/mips/cavium-octeon/smp.c | 3 ---
 arch/mips/kernel/smp-bmips.c  | 3 ---
 arch/mips/loongson64/smp.c    | 3 ---
 3 files changed, 9 deletions(-)

diff --git a/arch/mips/cavium-octeon/smp.c b/arch/mips/cavium-octeon/smp.c
index 076db9a..66ce552 100644
--- a/arch/mips/cavium-octeon/smp.c
+++ b/arch/mips/cavium-octeon/smp.c
@@ -290,9 +290,6 @@ static int octeon_cpu_disable(void)
 {
 	unsigned int cpu = smp_processor_id();
 
-	if (cpu == 0)
-		return -EBUSY;
-
 	if (!octeon_bootloader_entry_addr)
 		return -ENOTSUPP;
 
diff --git a/arch/mips/kernel/smp-bmips.c b/arch/mips/kernel/smp-bmips.c
index 1dbfb5a..359b176 100644
--- a/arch/mips/kernel/smp-bmips.c
+++ b/arch/mips/kernel/smp-bmips.c
@@ -362,9 +362,6 @@ static int bmips_cpu_disable(void)
 {
 	unsigned int cpu = smp_processor_id();
 
-	if (cpu == 0)
-		return -EBUSY;
-
 	pr_info("SMP: CPU%d is offline\n", cpu);
 
 	set_cpu_online(cpu, false);
diff --git a/arch/mips/loongson64/smp.c b/arch/mips/loongson64/smp.c
index aa0cd72..b8c1fc3 100644
--- a/arch/mips/loongson64/smp.c
+++ b/arch/mips/loongson64/smp.c
@@ -544,9 +544,6 @@ static int loongson3_cpu_disable(void)
 	unsigned long flags;
 	unsigned int cpu = smp_processor_id();
 
-	if (cpu == 0)
-		return -EBUSY;
-
 	set_cpu_online(cpu, false);
 	calculate_cpu_foreign_map();
 	local_irq_save(flags);
-- 
2.1.0