net: axienet: Switch to 64-bit RX/TX statistics

The RX and TX byte/packet statistics in this driver could be overflowed
relatively quickly on a 32-bit platform. Switch these stats to use the
u64_stats infrastructure to avoid this.

Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Link: https://lore.kernel.org/r/20220829233901.3429419-1-robert.hancock@calian.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet.h b/drivers/net/ethernet/xilinx/xilinx_axienet.h
index f2e2261..8ff4333 100644 (file)
--- a/drivers/net/ethernet/xilinx/xilinx_axienet.h
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet.h
@@ -402,6 +402,9 @@ struct axidma_bd {
  * @rx_bd_num: Size of RX buffer descriptor ring
  * @rx_bd_ci:  Stores the index of the Rx buffer descriptor in the ring being
  *             accessed currently.
+ * @rx_packets: RX packet count for statistics
+ * @rx_bytes:  RX byte count for statistics
+ * @rx_stat_sync: Synchronization object for RX stats
  * @napi_tx:   NAPI TX control structure
  * @tx_dma_cr:  Nominal content of TX DMA control register
  * @tx_bd_v:   Virtual address of the TX buffer descriptor ring
@@ -411,6 +414,9 @@ struct axidma_bd {
  *             complete. Only updated at runtime by TX NAPI poll.
  * @tx_bd_tail:        Stores the index of the next Tx buffer descriptor in the ring
  *              to be populated.
+ * @tx_packets: TX packet count for statistics
+ * @tx_bytes:  TX byte count for statistics
+ * @tx_stat_sync: Synchronization object for TX stats
  * @dma_err_task: Work structure to process Axi DMA errors
  * @tx_irq:    Axidma TX IRQ number
  * @rx_irq:    Axidma RX IRQ number
@@ -458,6 +464,9 @@ struct axienet_local {
        dma_addr_t rx_bd_p;
        u32 rx_bd_num;
        u32 rx_bd_ci;
+       u64_stats_t rx_packets;
+       u64_stats_t rx_bytes;
+       struct u64_stats_sync rx_stat_sync;
 
        struct napi_struct napi_tx;
        u32 tx_dma_cr;
@@ -466,6 +475,9 @@ struct axienet_local {
        u32 tx_bd_num;
        u32 tx_bd_ci;
        u32 tx_bd_tail;
+       u64_stats_t tx_packets;
+       u64_stats_t tx_bytes;
+       struct u64_stats_sync tx_stat_sync;
 
        struct work_struct dma_err_task;
 

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 52e0589..9fde594 100644 (file)
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -752,8 +752,10 @@ static int axienet_tx_poll(struct napi_struct *napi, int budget)
                if (lp->tx_bd_ci >= lp->tx_bd_num)
                        lp->tx_bd_ci %= lp->tx_bd_num;
 
-               ndev->stats.tx_packets += packets;
-               ndev->stats.tx_bytes += size;
+               u64_stats_update_begin(&lp->tx_stat_sync);
+               u64_stats_add(&lp->tx_packets, packets);
+               u64_stats_add(&lp->tx_bytes, size);
+               u64_stats_update_end(&lp->tx_stat_sync);
 
                /* Matches barrier in axienet_start_xmit */
                smp_mb();
@@ -984,8 +986,10 @@ static int axienet_rx_poll(struct napi_struct *napi, int budget)
                cur_p = &lp->rx_bd_v[lp->rx_bd_ci];
        }
 
-       lp->ndev->stats.rx_packets += packets;
-       lp->ndev->stats.rx_bytes += size;
+       u64_stats_update_begin(&lp->rx_stat_sync);
+       u64_stats_add(&lp->rx_packets, packets);
+       u64_stats_add(&lp->rx_bytes, size);
+       u64_stats_update_end(&lp->rx_stat_sync);
 
        if (tail_p)
                axienet_dma_out_addr(lp, XAXIDMA_RX_TDESC_OFFSET, tail_p);
@@ -1292,10 +1296,32 @@ static int axienet_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
        return phylink_mii_ioctl(lp->phylink, rq, cmd);
 }
 
+static void
+axienet_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
+{
+       struct axienet_local *lp = netdev_priv(dev);
+       unsigned int start;
+
+       netdev_stats_to_stats64(stats, &dev->stats);
+
+       do {
+               start = u64_stats_fetch_begin_irq(&lp->rx_stat_sync);
+               stats->rx_packets = u64_stats_read(&lp->rx_packets);
+               stats->rx_bytes = u64_stats_read(&lp->rx_bytes);
+       } while (u64_stats_fetch_retry_irq(&lp->rx_stat_sync, start));
+
+       do {
+               start = u64_stats_fetch_begin_irq(&lp->tx_stat_sync);
+               stats->tx_packets = u64_stats_read(&lp->tx_packets);
+               stats->tx_bytes = u64_stats_read(&lp->tx_bytes);
+       } while (u64_stats_fetch_retry_irq(&lp->tx_stat_sync, start));
+}
+
 static const struct net_device_ops axienet_netdev_ops = {
        .ndo_open = axienet_open,
        .ndo_stop = axienet_stop,
        .ndo_start_xmit = axienet_start_xmit,
+       .ndo_get_stats64 = axienet_get_stats64,
        .ndo_change_mtu = axienet_change_mtu,
        .ndo_set_mac_address = netdev_set_mac_address,
        .ndo_validate_addr = eth_validate_addr,
@@ -1850,6 +1876,9 @@ static int axienet_probe(struct platform_device *pdev)
        lp->rx_bd_num = RX_BD_NUM_DEFAULT;
        lp->tx_bd_num = TX_BD_NUM_DEFAULT;
 
+       u64_stats_init(&lp->rx_stat_sync);
+       u64_stats_init(&lp->tx_stat_sync);
+
        netif_napi_add(ndev, &lp->napi_rx, axienet_rx_poll, NAPI_POLL_WEIGHT);
        netif_napi_add(ndev, &lp->napi_tx, axienet_tx_poll, NAPI_POLL_WEIGHT);