linux-kernel - [PATCH v8 2/7] powerpc/smp: add generic_set_cpu_up() to set cpu_state as CPU_UP

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Date:	Fri, 20 Jul 2012 20:42:34 +0800
From:	Zhao Chenhui <chenhui.zhao@...escale.com>
To:	<linuxppc-dev@...ts.ozlabs.org>, <scottwood@...escale.com>,
	<galak@...nel.crashing.org>
CC:	<linux-kernel@...r.kernel.org>, <leoli@...escale.com>
Subject: [PATCH v8 2/7] powerpc/smp: add generic_set_cpu_up() to set cpu_state as CPU_UP_PREPARE

In the case of cpu hotplug, the cpu_state should be set to CPU_UP_PREPARE when kicking cpu.
Otherwise, the cpu_state is always CPU_DEAD after calling generic_set_cpu_dead(), which
makes the delay in generic_cpu_die() not happen.

Signed-off-by: Zhao Chenhui <chenhui.zhao@...escale.com>
---
 arch/powerpc/include/asm/smp.h |    1 +
 arch/powerpc/kernel/smp.c      |   12 +++++++++++-
 2 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index ebc24dc..ce8e2bd 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -65,6 +65,7 @@ int generic_cpu_disable(void);
 void generic_cpu_die(unsigned int cpu);
 void generic_mach_cpu_die(void);
 void generic_set_cpu_dead(unsigned int cpu);
+void generic_set_cpu_up(unsigned int cpu);
 int generic_check_cpu_restart(unsigned int cpu);
 #endif
 
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 0321007..fecb038 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -102,7 +102,7 @@ int __devinit smp_generic_kick_cpu(int nr)
 	 * Ok it's not there, so it might be soft-unplugged, let's
 	 * try to bring it back
 	 */
-	per_cpu(cpu_state, nr) = CPU_UP_PREPARE;
+	generic_set_cpu_up(nr);
 	smp_wmb();
 	smp_send_reschedule(nr);
 #endif /* CONFIG_HOTPLUG_CPU */
@@ -406,6 +406,16 @@ void generic_set_cpu_dead(unsigned int cpu)
 	per_cpu(cpu_state, cpu) = CPU_DEAD;
 }
 
+/*
+ * The cpu_state should be set to CPU_UP_PREPARE in kick_cpu(), otherwise
+ * the cpu_state is always CPU_DEAD after calling generic_set_cpu_dead(),
+ * which makes the delay in generic_cpu_die() not happen.
+ */
+void generic_set_cpu_up(unsigned int cpu)
+{
+	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
+}
+
 int generic_check_cpu_restart(unsigned int cpu)
 {
 	return per_cpu(cpu_state, cpu) == CPU_UP_PREPARE;
-- 
1.6.4.1


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