korina: rework korina_rx() for use with napi

This function needs an early exit condition to function properly, or
else caller assumes napi workload wasn't enough to handle all received
packets and korina_rx is called again (and again and again and ...).
Signed-off-by: Phil Sutter <n0-1@freewrt.org>
Acked-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/korina.c

@@ -353,15 +353,20 @@ static int korina_rx(struct net_device *dev, int limit)
 	struct dma_desc *rd = &lp->rd_ring[lp->rx_next_done];
 	struct sk_buff *skb, *skb_new;
 	u8 *pkt_buf;
-	u32 devcs, pkt_len, dmas, rx_free_desc;
+	u32 devcs, pkt_len, dmas;
 	int count;
 
 	dma_cache_inv((u32)rd, sizeof(*rd));
 
 	for (count = 0; count < limit; count++) {
+		skb = lp->rx_skb[lp->rx_next_done];
+		skb_new = NULL;
 
 		devcs = rd->devcs;
 
+		if ((KORINA_RBSIZE - (u32)DMA_COUNT(rd->control)) == 0)
+			break;
+
 		/* Update statistics counters */
 		if (devcs & ETH_RX_CRC)
 			dev->stats.rx_crc_errors++;
@@ -384,16 +389,9 @@ static int korina_rx(struct net_device *dev, int limit)
 			 * in Rc32434 (errata ref #077) */
 			dev->stats.rx_errors++;
 			dev->stats.rx_dropped++;
-		}
-
-		while ((rx_free_desc = KORINA_RBSIZE - (u32)DMA_COUNT(rd->control)) != 0) {
-			/* init the var. used for the later
-			 * operations within the while loop */
-			skb_new = NULL;
+		} else if ((devcs & ETH_RX_ROK)) {
 			pkt_len = RCVPKT_LENGTH(devcs);
-			skb = lp->rx_skb[lp->rx_next_done];
 
-			if ((devcs & ETH_RX_ROK)) {
 			/* must be the (first and) last
 			 * descriptor then */
 			pkt_buf = (u8 *)lp->rx_skb[lp->rx_next_done]->data;
@@ -441,7 +439,6 @@ static int korina_rx(struct net_device *dev, int limit)
 		rd = &lp->rd_ring[lp->rx_next_done];
 		writel(~DMA_STAT_DONE, &lp->rx_dma_regs->dmas);
 	}
-	}
 
 	dmas = readl(&lp->rx_dma_regs->dmas);