linux-kernel - [tip:smp/hotplug] SPARC: SMP: Remove call to ipi_call_lock_irq()/ ipi_call_unlock

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Message-ID: <tip-bc6833009583bd5b096ef7aa2bb006854a5a2dce@git.kernel.org>
Date:	Tue, 5 Jun 2012 08:49:42 -0700
From:	tip-bot for Yong Zhang <yong.zhang0@...il.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
	peterz@...radead.org, srivatsa.bhat@...ux.vnet.ibm.com,
	yong.zhang0@...il.com, tglx@...utronix.de, davem@...emloft.net
Subject: [tip:smp/hotplug] SPARC: SMP: Remove call to ipi_call_lock_irq()/
 ipi_call_unlock_irq()

Commit-ID:  bc6833009583bd5b096ef7aa2bb006854a5a2dce
Gitweb:     http://git.kernel.org/tip/bc6833009583bd5b096ef7aa2bb006854a5a2dce
Author:     Yong Zhang <yong.zhang0@...il.com>
AuthorDate: Tue, 29 May 2012 16:27:33 +0800
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Tue, 5 Jun 2012 17:27:13 +0200

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

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@...il.com>
Cc: ralf@...ux-mips.org
Cc: sshtylyov@...sta.com
Cc: david.daney@...ium.com
Cc: nikunj@...ux.vnet.ibm.com
Cc: paulmck@...ux.vnet.ibm.com
Cc: axboe@...nel.dk
Cc: peterz@...radead.org
Cc: sparclinux@...r.kernel.org
Link: http://lkml.kernel.org/r/20120529082732.GA4250@zhy
Acked-by: "David S. Miller" <davem@...emloft.net>
Acked-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@...radead.org>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/sparc/kernel/smp_64.c |    7 +------
 1 files changed, 1 insertions(+), 6 deletions(-)

diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index f591598..781bcb1 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -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();
 
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