net/macb: fix race with RX interrupt while doing NAPI

When interrupts are disabled, an RX condition can occur but
it is not reported when enabling interrupts again. We need to check
RSR and use napi_reschedule() if condition is met.
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/cadence/macb.c

@@ -693,6 +693,11 @@ static int macb_poll(struct napi_struct *napi, int budget)
 		 * get notified when new packets arrive.
 		 */
 		macb_writel(bp, IER, MACB_RX_INT_FLAGS);
+
+		/* Packets received while interrupts were disabled */
+		status = macb_readl(bp, RSR);
+		if (unlikely(status))
+			napi_reschedule(napi);
 	}
 
 	/* TODO: Handle errors */