net: ethernet: mtk_eth_soc: rework NAPI callbacks

Use napi_complete_done to communicate total TX and RX work done to NAPI.
Count total RX work up instead of remaining work down for clarity.
Remove unneeded local variables for clarity. Use do {} while instead of
goto for clarity.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -1496,7 +1496,6 @@ static void mtk_handle_status_irq(struct mtk_eth *eth)
 static int mtk_napi_tx(struct napi_struct *napi, int budget)
 {
 	struct mtk_eth *eth = container_of(napi, struct mtk_eth, tx_napi);
-	u32 status, mask;
 	int tx_done = 0;
 
 	if (MTK_HAS_CAPS(eth->soc->caps, MTK_QDMA))
@@ -1505,21 +1504,19 @@ static int mtk_napi_tx(struct napi_struct *napi, int budget)
 	tx_done = mtk_poll_tx(eth, budget);
 
 	if (unlikely(netif_msg_intr(eth))) {
-		status = mtk_r32(eth, eth->tx_int_status_reg);
-		mask = mtk_r32(eth, eth->tx_int_mask_reg);
 		dev_info(eth->dev,
-			 "done tx %d, intr 0x%08x/0x%x\n",
-			 tx_done, status, mask);
+			 "done tx %d, intr 0x%08x/0x%x\n", tx_done,
+			 mtk_r32(eth, eth->tx_int_status_reg),
+			 mtk_r32(eth, eth->tx_int_mask_reg));
 	}
 
 	if (tx_done == budget)
 		return budget;
 
-	status = mtk_r32(eth, eth->tx_int_status_reg);
-	if (status & MTK_TX_DONE_INT)
+	if (mtk_r32(eth, eth->tx_int_status_reg) & MTK_TX_DONE_INT)
 		return budget;
 
-	if (napi_complete(napi))
+	if (napi_complete_done(napi, tx_done))
 		mtk_tx_irq_enable(eth, MTK_TX_DONE_INT);
 
 	return tx_done;
@@ -1528,36 +1525,33 @@ static int mtk_napi_tx(struct napi_struct *napi, int budget)
 static int mtk_napi_rx(struct napi_struct *napi, int budget)
 {
 	struct mtk_eth *eth = container_of(napi, struct mtk_eth, rx_napi);
-	u32 status, mask;
-	int rx_done = 0;
-	int remain_budget = budget;
+	int rx_done_total = 0;
 
 	mtk_handle_status_irq(eth);
 
-poll_again:
-	mtk_w32(eth, MTK_RX_DONE_INT, MTK_PDMA_INT_STATUS);
-	rx_done = mtk_poll_rx(napi, remain_budget, eth);
+	do {
+		int rx_done;
 
-	if (unlikely(netif_msg_intr(eth))) {
-		status = mtk_r32(eth, MTK_PDMA_INT_STATUS);
-		mask = mtk_r32(eth, MTK_PDMA_INT_MASK);
-		dev_info(eth->dev,
-			 "done rx %d, intr 0x%08x/0x%x\n",
-			 rx_done, status, mask);
-	}
-	if (rx_done == remain_budget)
-		return budget;
+		mtk_w32(eth, MTK_RX_DONE_INT, MTK_PDMA_INT_STATUS);
+		rx_done = mtk_poll_rx(napi, budget - rx_done_total, eth);
+		rx_done_total += rx_done;
 
-	status = mtk_r32(eth, MTK_PDMA_INT_STATUS);
-	if (status & MTK_RX_DONE_INT) {
-		remain_budget -= rx_done;
-		goto poll_again;
-	}
+		if (unlikely(netif_msg_intr(eth))) {
+			dev_info(eth->dev,
+				 "done rx %d, intr 0x%08x/0x%x\n", rx_done,
+				 mtk_r32(eth, MTK_PDMA_INT_STATUS),
+				 mtk_r32(eth, MTK_PDMA_INT_MASK));
+		}
+
+		if (rx_done_total == budget)
+			return budget;
+
+	} while (mtk_r32(eth, MTK_PDMA_INT_STATUS) & MTK_RX_DONE_INT);
 
-	if (napi_complete(napi))
+	if (napi_complete_done(napi, rx_done_total))
 		mtk_rx_irq_enable(eth, MTK_RX_DONE_INT);
 
-	return rx_done + budget - remain_budget;
+	return rx_done_total;
 }
 
 static int mtk_tx_alloc(struct mtk_eth *eth)