Thread (8 messages) flat view 8 messages, 3 authors, 2016-05-14
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[PATCH v2 4/5] drivers: net: xgene: fix statistics counters race condition

From: Iyappan Subramanian <hidden>
Date: 2016-05-13 23:53:00
Also in: linux-arm-kernel
Subsystem: applied micro (apm) x-gene soc ethernet driver, networking drivers, the rest · Maintainers: Iyappan Subramanian, Keyur Chudgar, Quan Nguyen, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

This patch fixes the race condition on updating the statistics
counters by moving the counters to the ring structure.

Signed-off-by: Iyappan Subramanian <redacted>
Tested-by: Toan Le <redacted>
---
 drivers/net/ethernet/apm/xgene/xgene_enet_hw.c   | 19 ++++++-----
 drivers/net/ethernet/apm/xgene/xgene_enet_hw.h   |  2 ++
 drivers/net/ethernet/apm/xgene/xgene_enet_main.c | 41 +++++++++++++++++-------
 drivers/net/ethernet/apm/xgene/xgene_enet_main.h | 10 ++++++
 4 files changed, 53 insertions(+), 19 deletions(-)
diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c b/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c
index 457f745..2f5638f 100644
--- a/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c
+++ b/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c
@@ -219,27 +219,30 @@ void xgene_enet_parse_error(struct xgene_enet_desc_ring *ring,
 			    struct xgene_enet_pdata *pdata,
 			    enum xgene_enet_err_code status)
 {
-	struct rtnl_link_stats64 *stats = &pdata->stats;
-
 	switch (status) {
 	case INGRESS_CRC:
-		stats->rx_crc_errors++;
+		ring->rx_crc_errors++;
+		ring->rx_dropped++;
 		break;
 	case INGRESS_CHECKSUM:
 	case INGRESS_CHECKSUM_COMPUTE:
-		stats->rx_errors++;
+		ring->rx_errors++;
+		ring->rx_dropped++;
 		break;
 	case INGRESS_TRUNC_FRAME:
-		stats->rx_frame_errors++;
+		ring->rx_frame_errors++;
+		ring->rx_dropped++;
 		break;
 	case INGRESS_PKT_LEN:
-		stats->rx_length_errors++;
+		ring->rx_length_errors++;
+		ring->rx_dropped++;
 		break;
 	case INGRESS_PKT_UNDER:
-		stats->rx_frame_errors++;
+		ring->rx_frame_errors++;
+		ring->rx_dropped++;
 		break;
 	case INGRESS_FIFO_OVERRUN:
-		stats->rx_fifo_errors++;
+		ring->rx_fifo_errors++;
 		break;
 	default:
 		break;
diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_hw.h b/drivers/net/ethernet/apm/xgene/xgene_enet_hw.h
index ba7da98..ecfeffe 100644
--- a/drivers/net/ethernet/apm/xgene/xgene_enet_hw.h
+++ b/drivers/net/ethernet/apm/xgene/xgene_enet_hw.h
@@ -201,6 +201,8 @@ enum xgene_enet_rm {
 #define USERINFO_LEN			32
 #define FPQNUM_POS			32
 #define FPQNUM_LEN			12
+#define ELERR_POS                       46
+#define ELERR_LEN                       2
 #define NV_POS				50
 #define NV_LEN				1
 #define LL_POS				51
diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
index e75d1a9..d208b17 100644
--- a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
+++ b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
@@ -443,8 +443,8 @@ static netdev_tx_t xgene_enet_start_xmit(struct sk_buff *skb,
 
 	skb_tx_timestamp(skb);
 
-	pdata->stats.tx_packets++;
-	pdata->stats.tx_bytes += skb->len;
+	tx_ring->tx_packets++;
+	tx_ring->tx_bytes += skb->len;
 
 	pdata->ring_ops->wr_cmd(tx_ring, count);
 	return NETDEV_TX_OK;
@@ -483,12 +483,12 @@ static int xgene_enet_rx_frame(struct xgene_enet_desc_ring *rx_ring,
 	skb = buf_pool->rx_skb[skb_index];
 
 	/* checking for error */
-	status = GET_VAL(LERR, le64_to_cpu(raw_desc->m0));
+	status = (GET_VAL(ELERR, le64_to_cpu(raw_desc->m0)) << LERR_LEN) ||
+		  GET_VAL(LERR, le64_to_cpu(raw_desc->m0));
 	if (unlikely(status > 2)) {
 		dev_kfree_skb_any(skb);
 		xgene_enet_parse_error(rx_ring, netdev_priv(rx_ring->ndev),
 				       status);
-		pdata->stats.rx_dropped++;
 		ret = -EIO;
 		goto out;
 	}
@@ -506,8 +506,8 @@ static int xgene_enet_rx_frame(struct xgene_enet_desc_ring *rx_ring,
 		xgene_enet_skip_csum(skb);
 	}
 
-	pdata->stats.rx_packets++;
-	pdata->stats.rx_bytes += datalen;
+	rx_ring->rx_packets++;
+	rx_ring->rx_bytes += datalen;
 	napi_gro_receive(&rx_ring->napi, skb);
 out:
 	if (--rx_ring->nbufpool == 0) {
@@ -1127,12 +1127,31 @@ static struct rtnl_link_stats64 *xgene_enet_get_stats64(
 {
 	struct xgene_enet_pdata *pdata = netdev_priv(ndev);
 	struct rtnl_link_stats64 *stats = &pdata->stats;
+	struct xgene_enet_desc_ring *ring;
+	int i;
+
+	memset(stats, 0, sizeof(struct rtnl_link_stats64));
+	for (i = 0; i < pdata->txq_cnt; i++) {
+		ring = pdata->tx_ring[i];
+		if (ring) {
+			stats->tx_packets += ring->tx_packets;
+			stats->tx_bytes += ring->tx_bytes;
+		}
+	}
 
-	stats->rx_errors += stats->rx_length_errors +
-			    stats->rx_crc_errors +
-			    stats->rx_frame_errors +
-			    stats->rx_fifo_errors;
-	memcpy(storage, &pdata->stats, sizeof(struct rtnl_link_stats64));
+	for (i = 0; i < pdata->rxq_cnt; i++) {
+		ring = pdata->rx_ring[i];
+		if (ring) {
+			stats->rx_packets += ring->rx_packets;
+			stats->rx_bytes += ring->rx_bytes;
+			stats->rx_errors += ring->rx_length_errors +
+				ring->rx_crc_errors +
+				ring->rx_frame_errors +
+				ring->rx_fifo_errors;
+			stats->rx_dropped += ring->rx_dropped;
+		}
+	}
+	memcpy(storage, stats, sizeof(struct rtnl_link_stats64));
 
 	return storage;
 }
diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_main.h b/drivers/net/ethernet/apm/xgene/xgene_enet_main.h
index cc40c30..092fbec 100644
--- a/drivers/net/ethernet/apm/xgene/xgene_enet_main.h
+++ b/drivers/net/ethernet/apm/xgene/xgene_enet_main.h
@@ -121,6 +121,16 @@ struct xgene_enet_desc_ring {
 		struct xgene_enet_raw_desc16 *raw_desc16;
 	};
 	__le64 *exp_bufs;
+	u64 tx_packets;
+	u64 tx_bytes;
+	u64 rx_packets;
+	u64 rx_bytes;
+	u64 rx_dropped;
+	u64 rx_errors;
+	u64 rx_length_errors;
+	u64 rx_crc_errors;
+	u64 rx_frame_errors;
+	u64 rx_fifo_errors;
 };
 
 struct xgene_mac_ops {
-- 
1.9.1
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