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From: Aaro Koskinen <aaro.koskinen@iki.fi>
To: "David S. Miller" <davem@davemloft.net>,
	Jose Abreu <joabreu@synopsys.com>,
	Alexandre Torgue <alexandre.torgue@st.com>,
	Giuseppe Cavallaro <peppe.cavallaro@st.com>,
	netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Aaro Koskinen <aaro.koskinen@nokia.com>
Subject: [PATCH 3/6] net: stmmac: don't stop NAPI processing when dropping a packet
Date: Wed, 27 Mar 2019 22:35:37 +0200	[thread overview]
Message-ID: <20190327203540.1884-4-aaro.koskinen@iki.fi> (raw)
In-Reply-To: <20190327203540.1884-1-aaro.koskinen@iki.fi>

From: Aaro Koskinen <aaro.koskinen@nokia.com>

Currently, if we drop a packet, we exit from NAPI loop before the budget
is consumed. In some situations this will make the RX processing stall
e.g. when flood pinging the system with oversized packets, as the
errorneous packets are not dropped efficiently.

If we drop a packet, we should just continue to the next one as long as
the budget allows.

Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 392d94cede17..a26e36dbb5df 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3354,9 +3354,8 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
 {
 	struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
 	struct stmmac_channel *ch = &priv->channel[queue];
-	unsigned int entry = rx_q->cur_rx;
+	unsigned int next_entry = rx_q->cur_rx;
 	int coe = priv->hw->rx_csum;
-	unsigned int next_entry;
 	unsigned int count = 0;
 	bool xmac;
 
@@ -3374,10 +3373,12 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
 		stmmac_display_ring(priv, rx_head, DMA_RX_SIZE, true);
 	}
 	while (count < limit) {
-		int status;
+		int entry, status;
 		struct dma_desc *p;
 		struct dma_desc *np;
 
+		entry = next_entry;
+
 		if (priv->extend_desc)
 			p = (struct dma_desc *)(rx_q->dma_erx + entry);
 		else
@@ -3438,7 +3439,7 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
 						   "len %d larger than size (%d)\n",
 						   frame_len, priv->dma_buf_sz);
 				priv->dev->stats.rx_length_errors++;
-				break;
+				continue;
 			}
 
 			/* ACS is set; GMAC core strips PAD/FCS for IEEE 802.3
@@ -3473,7 +3474,7 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
 						dev_warn(priv->device,
 							 "packet dropped\n");
 					priv->dev->stats.rx_dropped++;
-					break;
+					continue;
 				}
 
 				dma_sync_single_for_cpu(priv->device,
@@ -3498,7 +3499,7 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
 							   "%s: Inconsistent Rx chain\n",
 							   priv->dev->name);
 					priv->dev->stats.rx_dropped++;
-					break;
+					continue;
 				}
 				prefetch(skb->data - NET_IP_ALIGN);
 				rx_q->rx_skbuff[entry] = NULL;
@@ -3533,7 +3534,6 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
 			priv->dev->stats.rx_packets++;
 			priv->dev->stats.rx_bytes += frame_len;
 		}
-		entry = next_entry;
 	}
 
 	stmmac_rx_refill(priv, queue);
-- 
2.17.0


  parent reply	other threads:[~2019-03-27 20:36 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-27 20:35 [PATCH 0/6] net: stmmac: fix handling of oversized frames Aaro Koskinen
2019-03-27 20:35 ` [PATCH 1/6] net: stmmac: use correct DMA buffer size in the RX descriptor Aaro Koskinen
2019-03-29 10:02   ` Jose Abreu
2019-03-29 10:48     ` Aaro Koskinen
2019-03-27 20:35 ` [PATCH 2/6] net: stmmac: ratelimit RX error logs Aaro Koskinen
2019-03-27 20:35 ` Aaro Koskinen [this message]
2019-03-27 20:35 ` [PATCH 4/6] net: stmmac: don't overwrite discard_frame status Aaro Koskinen
2019-03-27 20:35 ` [PATCH 5/6] net: stmmac: fix dropping of multi-descriptor RX frames Aaro Koskinen
2019-03-27 20:35 ` [PATCH 6/6] net: stmmac: don't log oversized frames Aaro Koskinen
2019-03-29  0:10 ` [PATCH 0/6] net: stmmac: fix handling of " David Miller
2019-03-31 21:01 ` David Miller

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