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percpu_counter: make percpu_counters_lock irq-safe

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percpu_counter is scheduled to grow @gfp support to allow atomic
initialization.  This patch makes percpu_counters_lock irq-safe so
that it can be safely used from atomic contexts.

Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tejun Heo 2014-09-08 09:51:29 +09:00
parent 1a4d76076c
commit ebd8fef304
1 changed files with 10 additions and 6 deletions
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16
lib/percpu_counter.c
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@ -115,6 +115,8 @@ EXPORT_SYMBOL(__percpu_counter_sum);
int __percpu_counter_init(struct percpu_counter *fbc, s64 amount, int __percpu_counter_init(struct percpu_counter *fbc, s64 amount,
struct lock_class_key *key) struct lock_class_key *key)
{ {
unsigned long flags __maybe_unused;
raw_spin_lock_init(&fbc->lock); raw_spin_lock_init(&fbc->lock);
lockdep_set_class(&fbc->lock, key); lockdep_set_class(&fbc->lock, key);
fbc->count = amount; fbc->count = amount;
@ -126,9 +128,9 @@ int __percpu_counter_init(struct percpu_counter *fbc, s64 amount,
#ifdef CONFIG_HOTPLUG_CPU #ifdef CONFIG_HOTPLUG_CPU
INIT_LIST_HEAD(&fbc->list); INIT_LIST_HEAD(&fbc->list);
spin_lock(&percpu_counters_lock); spin_lock_irqsave(&percpu_counters_lock, flags);
list_add(&fbc->list, &percpu_counters); list_add(&fbc->list, &percpu_counters);
spin_unlock(&percpu_counters_lock); spin_unlock_irqrestore(&percpu_counters_lock, flags);
#endif #endif
return 0; return 0;
} }
@ -136,15 +138,17 @@ EXPORT_SYMBOL(__percpu_counter_init);
void percpu_counter_destroy(struct percpu_counter *fbc) void percpu_counter_destroy(struct percpu_counter *fbc)
{ {
unsigned long flags __maybe_unused;
if (!fbc->counters) if (!fbc->counters)
return; return;
debug_percpu_counter_deactivate(fbc); debug_percpu_counter_deactivate(fbc);
#ifdef CONFIG_HOTPLUG_CPU #ifdef CONFIG_HOTPLUG_CPU
spin_lock(&percpu_counters_lock); spin_lock_irqsave(&percpu_counters_lock, flags);
list_del(&fbc->list); list_del(&fbc->list);
spin_unlock(&percpu_counters_lock); spin_unlock_irqrestore(&percpu_counters_lock, flags);
#endif #endif
free_percpu(fbc->counters); free_percpu(fbc->counters);
fbc->counters = NULL; fbc->counters = NULL;
@ -173,7 +177,7 @@ static int percpu_counter_hotcpu_callback(struct notifier_block *nb,
return NOTIFY_OK; return NOTIFY_OK;
cpu = (unsigned long)hcpu; cpu = (unsigned long)hcpu;
spin_lock(&percpu_counters_lock); spin_lock_irq(&percpu_counters_lock);
list_for_each_entry(fbc, &percpu_counters, list) { list_for_each_entry(fbc, &percpu_counters, list) {
s32 *pcount; s32 *pcount;
unsigned long flags; unsigned long flags;
@ -184,7 +188,7 @@ static int percpu_counter_hotcpu_callback(struct notifier_block *nb,
*pcount = 0; *pcount = 0;
raw_spin_unlock_irqrestore(&fbc->lock, flags); raw_spin_unlock_irqrestore(&fbc->lock, flags);
} }
spin_unlock(&percpu_counters_lock); spin_unlock_irq(&percpu_counters_lock);
#endif #endif
return NOTIFY_OK; return NOTIFY_OK;
} }