tsnep: Fix NAPI scheduling

According to the NAPI documentation networking/napi.rst, drivers which
have to mask interrupts explicitly should use the napi_schedule_prep()
and __napi_schedule() calls.

No problem seen so far with current implementation. Nevertheless, let's
align the implementation with documentation.
Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/engleder/tsnep_main.c

@@ -87,8 +87,11 @@ static irqreturn_t tsnep_irq(int irq, void *arg)
 
 	/* handle TX/RX queue 0 interrupt */
 	if ((active & adapter->queue[0].irq_mask) != 0) {
-		tsnep_disable_irq(adapter, adapter->queue[0].irq_mask);
-		napi_schedule(&adapter->queue[0].napi);
+		if (napi_schedule_prep(&adapter->queue[0].napi)) {
+			tsnep_disable_irq(adapter, adapter->queue[0].irq_mask);
+			/* schedule after masking to avoid races */
+			__napi_schedule(&adapter->queue[0].napi);
+		}
 	}
 
 	return IRQ_HANDLED;
@@ -99,8 +102,11 @@ static irqreturn_t tsnep_irq_txrx(int irq, void *arg)
 	struct tsnep_queue *queue = arg;
 
 	/* handle TX/RX queue interrupt */
-	tsnep_disable_irq(queue->adapter, queue->irq_mask);
-	napi_schedule(&queue->napi);
+	if (napi_schedule_prep(&queue->napi)) {
+		tsnep_disable_irq(queue->adapter, queue->irq_mask);
+		/* schedule after masking to avoid races */
+		__napi_schedule(&queue->napi);
+	}
 
 	return IRQ_HANDLED;
 }