[PATCH net-next v4 2/2] net: ethernet: mediatek: enhance RX path by aggregating more SKBs into NAPI

[sean.wang at mediatek.com]

From: Sean Wang <sean.wang at mediatek.com>

The patch adds support for aggregating more SKBs feed into NAPI in
order to get more benefits from generic receive offload (GRO) by
peeking at the RX ring status and moving more packets right before
returning from NAPI RX polling handler if NAPI budgets are still
available and some packets already present in hardware.

Signed-off-by: Sean Wang <sean.wang at mediatek.com>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 33bb10f..44cab1b 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -960,9 +960,6 @@ release_desc:
 	wmb();
 	mtk_w32(eth, ring->calc_idx, MTK_PRX_CRX_IDX0);
 
-	if (done < budget)
-		mtk_w32(eth, MTK_RX_DONE_INT, MTK_PDMA_INT_STATUS);
-
 	return done;
 }
 
@@ -1081,10 +1078,13 @@ 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;
 
 	mtk_handle_status_irq(eth);
+
+poll_again:
 	mtk_w32(eth, MTK_RX_DONE_INT, MTK_PDMA_INT_STATUS);
-	rx_done = mtk_poll_rx(napi, budget, eth);
+	rx_done = mtk_poll_rx(napi, remain_budget, eth);
 
 	if (unlikely(netif_msg_intr(eth))) {
 		status = mtk_r32(eth, MTK_PDMA_INT_STATUS);
@@ -1093,14 +1093,14 @@ static int mtk_napi_rx(struct napi_struct *napi, int budget)
 			 "done rx %d, intr 0x%08x/0x%x\n",
 			 rx_done, status, mask);
 	}
-
-	if (rx_done == budget)
+	if (rx_done == remain_budget)
 		return budget;
 
 	status = mtk_r32(eth, MTK_PDMA_INT_STATUS);
-	if (status & MTK_RX_DONE_INT)
-		return budget;
-
+	if (status & MTK_RX_DONE_INT) {
+		remain_budget -= rx_done;
+		goto poll_again;
+	}
 	napi_complete(napi);
 	mtk_irq_enable(eth, MTK_PDMA_INT_MASK, MTK_RX_DONE_INT);
 
-- 
1.9.1