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Subject[RFC PATCH 07/10] ia64: smp: remove call to ipi_call_lock_irq()/ipi_call_unlock_irq()
Date
From: Yong Zhang <yong.zhang@windriver.com>

1) call_function.lock used in smp_call_function_many() is just to protect
call_function.queue and &data->refs, cpu_online_mask is outside of the
lock. And it's not necessary to protect cpu_online_mask,
because data->cpumask is pre-calculate and even if a cpu is brougt up
when calling arch_send_call_function_ipi_mask(), it's harmless because
validation test in generic_smp_call_function_interrupt() will take care
of it.

2) For cpu down issue, stop_machine() will guarantee that no concurrent
smp_call_fuction() is processing.

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-ia64@vger.kernel.org
---
arch/ia64/kernel/smpboot.c | 2 --
1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index 1113b8a..963d2db 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -382,7 +382,6 @@ smp_callin (void)
set_numa_node(cpu_to_node_map[cpuid]);
set_numa_mem(local_memory_node(cpu_to_node_map[cpuid]));

- ipi_call_lock_irq();
spin_lock(&vector_lock);
/* Setup the per cpu irq handling data structures */
__setup_vector_irq(cpuid);
@@ -390,7 +389,6 @@ smp_callin (void)
set_cpu_online(cpuid, true);
per_cpu(cpu_state, cpuid) = CPU_ONLINE;
spin_unlock(&vector_lock);
- ipi_call_unlock_irq();

smp_setup_percpu_timer();

--
1.7.5.4


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