The BAM-DMUX data path does not update the network device packet and byte counters. As a result, userspace sees zero traffic even while packets are being transferred. Use the standard per-CPU software statistics helpers. Account transmitted packets after their DMA completion and received packets after removing the BAM-DMUX header and padding. Fixes: 21a0ffd9b38c ("net: wwan: Add Qualcomm BAM-DMUX WWAN network driver") Signed-off-by: Dmitry Sinyavin Reviewed-by: Loic Poulain --- v3: - Count packets discarded by the transmit error path. v2: - Read the TX payload length after unmapping the DMA buffer and combine the network-device checks. v2: https://lore.kernel.org/netdev/20260831181006.1382372-1-sinyavin@gmail.com/ v1: https://lore.kernel.org/netdev/20260830085400.2542956-1-sinyavin@gmail.com/ Build-tested for ARM with Clang and W=1 using allmodconfig and allyesconfig. Hardware-tested on an MDM9607-based device: three 32-byte ICMP probes completed without loss, and the RX and TX counters each advanced by three packets and 180 bytes. drivers/net/wwan/qcom_bam_dmux.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/net/wwan/qcom_bam_dmux.c b/drivers/net/wwan/qcom_bam_dmux.c index cc6ace8d6437..ef3356200b3e 100644 --- a/drivers/net/wwan/qcom_bam_dmux.c +++ b/drivers/net/wwan/qcom_bam_dmux.c @@ -177,8 +177,12 @@ static void bam_dmux_tx_callback(void *data) { struct bam_dmux_skb_dma *skb_dma = data; struct sk_buff *skb = skb_dma->skb; + struct net_device *netdev = skb->dev; bam_dmux_tx_done(skb_dma); + if (netdev) + dev_sw_netstats_tx_add(netdev, 1, + ((struct bam_dmux_hdr *)skb->data)->len); dev_consume_skb_any(skb); } @@ -368,6 +372,7 @@ static netdev_tx_t bam_dmux_netdev_start_xmit(struct sk_buff *skb, drop: bam_dmux_tx_done(skb_dma); + dev_core_stats_tx_dropped_inc(netdev); dev_kfree_skb_any(skb); return NETDEV_TX_OK; } @@ -402,6 +407,7 @@ static const struct net_device_ops bam_dmux_ops = { .ndo_open = bam_dmux_netdev_open, .ndo_stop = bam_dmux_netdev_stop, .ndo_start_xmit = bam_dmux_netdev_start_xmit, + .ndo_get_stats64 = dev_get_tstats64, }; static const struct device_type wwan_type = { @@ -421,6 +427,7 @@ static void bam_dmux_netdev_setup(struct net_device *dev) dev->needed_headroom = sizeof(struct bam_dmux_hdr); dev->needed_tailroom = sizeof(u32); /* word-aligned */ dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN; + dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS; /* This perm addr will be used as interface identifier by IPv6 */ dev->addr_assign_type = NET_ADDR_RANDOM; @@ -533,6 +540,7 @@ static void bam_dmux_cmd_data(struct bam_dmux_skb_dma *skb_dma) break; } + dev_sw_netstats_rx_add(netdev, skb->len); netif_receive_skb(skb); } base-commit: 2188569e7e1b0bc3f3b557dc97ab7a02befc11c8 -- 2.53.0