kref: fix CPU ordering with respect to krefs
some atomic operations are only atomic, not ordered. Thus a CPU is allowed to reorder memory references to an object to before the reference is obtained. This fixes it. Signed-off-by: Oliver Neukum <oneukum@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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@ -21,6 +21,7 @@
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void kref_init(struct kref *kref)
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{
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atomic_set(&kref->refcount,1);
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smp_mb();
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}
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/**
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@ -31,6 +32,7 @@ void kref_get(struct kref *kref)
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{
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WARN_ON(!atomic_read(&kref->refcount));
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atomic_inc(&kref->refcount);
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smp_mb__after_atomic_inc();
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}
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/**
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