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Message-ID: <20130218124333.26245.70033.stgit@srivatsabhat.in.ibm.com>
Date:	Mon, 18 Feb 2013 18:13:33 +0530
From:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
To:	tglx@...utronix.de, peterz@...radead.org, tj@...nel.org,
	oleg@...hat.com, paulmck@...ux.vnet.ibm.com, rusty@...tcorp.com.au,
	mingo@...nel.org, akpm@...ux-foundation.org, namhyung@...nel.org
Cc:	rostedt@...dmis.org, wangyun@...ux.vnet.ibm.com,
	xiaoguangrong@...ux.vnet.ibm.com, rjw@...k.pl, sbw@....edu,
	fweisbec@...il.com, linux@....linux.org.uk,
	nikunj@...ux.vnet.ibm.com, srivatsa.bhat@...ux.vnet.ibm.com,
	linux-pm@...r.kernel.org, linux-arch@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linuxppc-dev@...ts.ozlabs.org, netdev@...r.kernel.org,
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
	walken@...gle.com, vincent.guittot@...aro.org
Subject: [PATCH v6 38/46] mn10300: Use get/put_online_cpus_atomic() to prevent
 CPU offline

Once stop_machine() is gone from the CPU offline path, we won't be able to
depend on preempt_disable() or local_irq_disable() to prevent CPUs from
going offline from under us.

Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going offline,
while invoking from atomic context.

Cc: David Howells <dhowells@...hat.com>
Cc: Koichi Yasutake <yasutake.koichi@...panasonic.com>
Cc: linux-am33-list@...hat.com
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com>
---

 arch/mn10300/kernel/smp.c   |    2 ++
 arch/mn10300/mm/cache-smp.c |    5 +++++
 arch/mn10300/mm/tlb-smp.c   |   15 +++++++++------
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/arch/mn10300/kernel/smp.c b/arch/mn10300/kernel/smp.c
index 5d7e152..9dfa172 100644
--- a/arch/mn10300/kernel/smp.c
+++ b/arch/mn10300/kernel/smp.c
@@ -349,9 +349,11 @@ void send_IPI_allbutself(int irq)
 {
 	cpumask_t cpumask;
 
+	get_online_cpus_atomic();
 	cpumask_copy(&cpumask, cpu_online_mask);
 	cpumask_clear_cpu(smp_processor_id(), &cpumask);
 	send_IPI_mask(&cpumask, irq);
+	put_online_cpus_atomic();
 }
 
 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
diff --git a/arch/mn10300/mm/cache-smp.c b/arch/mn10300/mm/cache-smp.c
index 2d23b9e..47ca1c9 100644
--- a/arch/mn10300/mm/cache-smp.c
+++ b/arch/mn10300/mm/cache-smp.c
@@ -13,6 +13,7 @@
 #include <linux/mman.h>
 #include <linux/threads.h>
 #include <linux/interrupt.h>
+#include <linux/cpu.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
 #include <asm/processor.h>
@@ -94,6 +95,8 @@ void smp_cache_call(unsigned long opr_mask,
 	smp_cache_mask = opr_mask;
 	smp_cache_start = start;
 	smp_cache_end = end;
+
+	get_online_cpus_atomic();
 	cpumask_copy(&smp_cache_ipi_map, cpu_online_mask);
 	cpumask_clear_cpu(smp_processor_id(), &smp_cache_ipi_map);
 
@@ -102,4 +105,6 @@ void smp_cache_call(unsigned long opr_mask,
 	while (!cpumask_empty(&smp_cache_ipi_map))
 		/* nothing. lockup detection does not belong here */
 		mb();
+
+	put_online_cpus_atomic();
 }
diff --git a/arch/mn10300/mm/tlb-smp.c b/arch/mn10300/mm/tlb-smp.c
index 3e57faf..d47304d 100644
--- a/arch/mn10300/mm/tlb-smp.c
+++ b/arch/mn10300/mm/tlb-smp.c
@@ -23,6 +23,7 @@
 #include <linux/sched.h>
 #include <linux/profile.h>
 #include <linux/smp.h>
+#include <linux/cpu.h>
 #include <asm/tlbflush.h>
 #include <asm/bitops.h>
 #include <asm/processor.h>
@@ -105,6 +106,7 @@ static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
 	BUG_ON(cpumask_empty(&cpumask));
 	BUG_ON(cpumask_test_cpu(smp_processor_id(), &cpumask));
 
+	get_online_cpus_atomic();
 	cpumask_and(&tmp, &cpumask, cpu_online_mask);
 	BUG_ON(!cpumask_equal(&cpumask, &tmp));
 
@@ -134,6 +136,7 @@ static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
 	flush_mm = NULL;
 	flush_va = 0;
 	spin_unlock(&tlbstate_lock);
+	put_online_cpus_atomic();
 }
 
 /**
@@ -144,7 +147,7 @@ void flush_tlb_mm(struct mm_struct *mm)
 {
 	cpumask_t cpu_mask;
 
-	preempt_disable();
+	get_online_cpus_atomic();
 	cpumask_copy(&cpu_mask, mm_cpumask(mm));
 	cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
 
@@ -152,7 +155,7 @@ void flush_tlb_mm(struct mm_struct *mm)
 	if (!cpumask_empty(&cpu_mask))
 		flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
 
-	preempt_enable();
+	put_online_cpus_atomic();
 }
 
 /**
@@ -163,7 +166,7 @@ void flush_tlb_current_task(void)
 	struct mm_struct *mm = current->mm;
 	cpumask_t cpu_mask;
 
-	preempt_disable();
+	get_online_cpus_atomic();
 	cpumask_copy(&cpu_mask, mm_cpumask(mm));
 	cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
 
@@ -171,7 +174,7 @@ void flush_tlb_current_task(void)
 	if (!cpumask_empty(&cpu_mask))
 		flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
 
-	preempt_enable();
+	put_online_cpus_atomic();
 }
 
 /**
@@ -184,7 +187,7 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long va)
 	struct mm_struct *mm = vma->vm_mm;
 	cpumask_t cpu_mask;
 
-	preempt_disable();
+	get_online_cpus_atomic();
 	cpumask_copy(&cpu_mask, mm_cpumask(mm));
 	cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
 
@@ -192,7 +195,7 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long va)
 	if (!cpumask_empty(&cpu_mask))
 		flush_tlb_others(cpu_mask, mm, va);
 
-	preempt_enable();
+	put_online_cpus_atomic();
 }
 
 /**

--
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