> @@ -36,10 +37,26 @@ int res_counter_charge(struct res_counter *counter, unsigned long val)
> {
> int ret;
> unsigned long flags;
> + struct res_counter *c, *unroll_c;
> +
> + local_irq_save(flags);
> + for (c = counter; c != NULL; c = c->parent) {
> + spin_lock(&c->lock);
> + ret = res_counter_charge_locked(c, val);
> + spin_unlock(&c->lock);
> + if (ret < 0)
> + goto unroll;
> + }
> + local_irq_restore(flags);
> + return 0;
>
> - spin_lock_irqsave(&counter->lock, flags);
> - ret = res_counter_charge_locked(counter, val);
> - spin_unlock_irqrestore(&counter->lock, flags);
> +unroll:
> + for (unroll_c = counter; unroll_c != c; unroll_c = unroll_c->parent) {
> + spin_lock(&unroll_c->lock);
> + res_counter_uncharge_locked(unroll_c, val);
> + spin_unlock(&unroll_c->lock);
> + }
> + local_irq_restore(flags);
> return ret;
> }
what prevents the topology (in particular, ->parent pointers) from
changing behind us?
YAMAMOTO Takashi
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