[tip:smp/hotplug] S390: Smp: remove call to ipi_call_lock()/ipi_call_unlock()

[tip-bot for Yong Zhang]

Commit-ID:  46ce7fbfdbe0be6aaf0e816331aac08a74a00e5a
Gitweb:     http://git.kernel.org/tip/46ce7fbfdbe0be6aaf0e816331aac08a74a00e5a
Author:     Yong Zhang <yong.zhang0@xxxxxxxxx>
AuthorDate: Tue, 29 May 2012 15:15:59 +0800
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 5 Jun 2012 17:27:12 +0200

S390: Smp: remove call to ipi_call_lock()/ipi_call_unlock()

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.

[ tglx: Massaged changelog ]

Signed-off-by: Yong Zhang <yong.zhang0@xxxxxxxxx>
Cc: ralf@xxxxxxxxxxxxxx
Cc: sshtylyov@xxxxxxxxxx
Cc: david.daney@xxxxxxxxxx
Cc: nikunj@xxxxxxxxxxxxxxxxxx
Cc: paulmck@xxxxxxxxxxxxxxxxxx
Cc: axboe@xxxxxxxxx
Cc: peterz@xxxxxxxxxxxxx
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: linux390@xxxxxxxxxx
Cc: linux-s390@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1338275765-3217-5-git-send-email-yong.zhang0@xxxxxxxxx
Acked-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
 arch/s390/kernel/smp.c |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 15cca26..8dca9c2 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -717,9 +717,7 @@ static void __cpuinit smp_start_secondary(void *cpuvoid)
 	init_cpu_vtimer();
 	pfault_init();
 	notify_cpu_starting(smp_processor_id());
-	ipi_call_lock();
 	set_cpu_online(smp_processor_id(), true);
-	ipi_call_unlock();
 	local_irq_enable();
 	/* cpu_idle will call schedule for us */
 	cpu_idle();
--
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