write in 30M

hc

2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc

 kernel/drivers/uio/uio_dmem_genirq.c
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@@ -110,8 +110,10 @@
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 	 * remember the state so we can allow user space to enable it later.
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 	 */
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+	spin_lock(&priv->lock);
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 	if (!test_and_set_bit(0, &priv->flags))
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 		disable_irq_nosync(irq);
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+	spin_unlock(&priv->lock);
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 	return IRQ_HANDLED;
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 }
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@@ -125,20 +127,19 @@
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 	 * in the interrupt controller, but keep track of the
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 	 * state to prevent per-irq depth damage.
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 	 *
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-	 * Serialize this operation to support multiple tasks.
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+	 * Serialize this operation to support multiple tasks and concurrency
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+	 * with irq handler on SMP systems.
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 	 */
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 	spin_lock_irqsave(&priv->lock, flags);
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 	if (irq_on) {
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 		if (test_and_clear_bit(0, &priv->flags))
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 			enable_irq(dev_info->irq);
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-		spin_unlock_irqrestore(&priv->lock, flags);
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 	} else {
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-		if (!test_and_set_bit(0, &priv->flags)) {
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-			spin_unlock_irqrestore(&priv->lock, flags);
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-			disable_irq(dev_info->irq);
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-		}
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+		if (!test_and_set_bit(0, &priv->flags))
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+			disable_irq_nosync(dev_info->irq);
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 	}
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+	spin_unlock_irqrestore(&priv->lock, flags);
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 	return 0;
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 }