[PATCH v8 2/7] powerpc/smp: add generic_set_cpu_up() to set cpu_state as CPU_UP_PREPARE

From: Zhao Chenhui
Date: Fri Jul 20 2012 - 08:41:17 EST


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@xxxxxxxxxxxxx>
---
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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