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SPARC: SMP: Remove call to ipi_call_lock_irq()/ipi_call_unlock_irq()

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ipi_call_lock/unlock() lock resp. unlock call_function.lock. This lock
protects only the call_function data structure itself, but it's
completely unrelated to cpu_online_mask. The mask to which the IPIs
are sent is calculated before call_function.lock is taken in
smp_call_function_many(), so the locking around set_cpu_online() is
pointless and can be removed.

Delay irq enable to after set_cpu_online().

[ tglx: Massaged changelog ]

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: ralf@linux-mips.org
Cc: sshtylyov@mvista.com
Cc: david.daney@cavium.com
Cc: nikunj@linux.vnet.ibm.com
Cc: paulmck@linux.vnet.ibm.com
Cc: axboe@kernel.dk
Cc: peterz@infradead.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/20120529082732.GA4250@zhy
Acked-by: "David S. Miller" <davem@davemloft.net>
Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Yong Zhang 2012-05-29 16:27:33 +08:00 committed by Thomas Gleixner
parent 459165e250
commit bc68330095
1 changed files with 1 additions and 6 deletions
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7
arch/sparc/kernel/smp_64.c
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@ -103,8 +103,6 @@ void __cpuinit smp_callin(void)
if (cheetah_pcache_forced_on)
cheetah_enable_pcache();
local_irq_enable();
callin_flag = 1;
__asm__ __volatile__("membar #Sync\n\t"
"flush %%g6" : : : "memory");
@ -124,9 +122,8 @@ void __cpuinit smp_callin(void)
while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
rmb();
ipi_call_lock_irq();
set_cpu_online(cpuid, true);
ipi_call_unlock_irq();
local_irq_enable();
/* idle thread is expected to have preempt disabled */
preempt_disable();
@ -1308,9 +1305,7 @@ int __cpu_disable(void)
mdelay(1);
local_irq_disable();
ipi_call_lock();
set_cpu_online(cpu, false);
ipi_call_unlock();
cpu_map_rebuild();