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[S390] smp: __smp_call_function_map vs cpu_online_map fix. 

Both smp_call_function() and __smp_call_function_map() access
cpu_online_map. Both functions run with preemption disabled which
protects for cpus going offline. However new cpus can be added and
therefore the cpu_online_map can change unexpectedly.
So use the call_lock to protect against changes to the cpu_online_map
in start_secondary() and all smp_call_* functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Heiko Carstens 2008-05-15 16:52:38 +02:00 committed by Martin Schwidefsky
parent f455adcff1
commit 85cb185dad
1 changed files with 8 additions and 8 deletions
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16
arch/s390/kernel/smp.c
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@ -139,7 +139,6 @@ static void __smp_call_function_map(void (*func) (void *info), void *info,
if (wait)
data.finished = CPU_MASK_NONE;
spin_lock(&call_lock);
call_data = &data;
for_each_cpu_mask(cpu, map)
@ -151,7 +150,6 @@ static void __smp_call_function_map(void (*func) (void *info), void *info,
if (wait)
while (!cpus_equal(map, data.finished))
cpu_relax();
spin_unlock(&call_lock);
out:
if (local) {
local_irq_disable();
@ -177,11 +175,11 @@ int smp_call_function(void (*func) (void *info), void *info, int nonatomic,
{
cpumask_t map;
preempt_disable();
spin_lock(&call_lock);
map = cpu_online_map;
cpu_clear(smp_processor_id(), map);
__smp_call_function_map(func, info, nonatomic, wait, map);
preempt_enable();
spin_unlock(&call_lock);
return 0;
}
EXPORT_SYMBOL(smp_call_function);
@ -202,10 +200,10 @@ EXPORT_SYMBOL(smp_call_function);
int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
int nonatomic, int wait)
{
preempt_disable();
spin_lock(&call_lock);
__smp_call_function_map(func, info, nonatomic, wait,
cpumask_of_cpu(cpu));
preempt_enable();
spin_unlock(&call_lock);
return 0;
}
EXPORT_SYMBOL(smp_call_function_single);
@ -228,10 +226,10 @@ EXPORT_SYMBOL(smp_call_function_single);
int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info,
int wait)
{
preempt_disable();
spin_lock(&call_lock);
cpu_clear(smp_processor_id(), mask);
__smp_call_function_map(func, info, 0, wait, mask);
preempt_enable();
spin_unlock(&call_lock);
return 0;
}
EXPORT_SYMBOL(smp_call_function_mask);
@ -592,7 +590,9 @@ int __cpuinit start_secondary(void *cpuvoid)
pfault_init();
/* Mark this cpu as online */
spin_lock(&call_lock);
cpu_set(smp_processor_id(), cpu_online_map);
spin_unlock(&call_lock);
/* Switch on interrupts */
local_irq_enable();
/* Print info about this processor */