Re: [PATCH net] net: ethernet: nixge: Add missing check after DMA map

[Eric Dumazet]

On Fri, Jul 25, 2025 at 8:10 AM Jakub Kicinski <kuba@xxxxxxxxxx> wrote:
>
> On Fri, 25 Jul 2025 06:53:16 -0700 Eric Dumazet wrote:
> > Not sure if this driver is actively used...
>
> Like most of the drivers that are missing dma_mappnig_error() :(

Well, a failure in __netdev_alloc_skb_ip_align() is more probable.

Maybe the following would help (and fix
ndev->stats.rx_packets/ndev->stats.rx_bytes) as well.

diff --git a/drivers/net/ethernet/ni/nixge.c b/drivers/net/ethernet/ni/nixge.c
index 230d5ff99dd7e1e9fabe21a6617d72d663cc1a7c..835463c301e11dca9f824137e75dd0eacf130419
100644
--- a/drivers/net/ethernet/ni/nixge.c
+++ b/drivers/net/ethernet/ni/nixge.c
@@ -606,9 +606,6 @@ static int nixge_recv(struct net_device *ndev, int budget)

        while ((cur_p->status & XAXIDMA_BD_STS_COMPLETE_MASK &&
                budget > packets)) {
-               tail_p = priv->rx_bd_p + sizeof(*priv->rx_bd_v) *
-                        priv->rx_bd_ci;
-
                skb = (struct sk_buff *)(uintptr_t)
                        nixge_hw_dma_bd_get_addr(cur_p, sw_id_offset);

@@ -639,7 +636,7 @@ static int nixge_recv(struct net_device *ndev, int budget)
                new_skb = netdev_alloc_skb_ip_align(ndev,
                                                    NIXGE_MAX_JUMBO_FRAME_SIZE);
                if (!new_skb)
-                       return packets;
+                       goto end;

                cur_phys = dma_map_single(ndev->dev.parent, new_skb->data,
                                          NIXGE_MAX_JUMBO_FRAME_SIZE,
@@ -653,11 +650,15 @@ static int nixge_recv(struct net_device *ndev, int budget)
                cur_p->status = 0;
                nixge_hw_dma_bd_set_offset(cur_p, (uintptr_t)new_skb);

+               tail_p = priv->rx_bd_p + sizeof(*priv->rx_bd_v) *
+                        priv->rx_bd_ci;
+
                ++priv->rx_bd_ci;
                priv->rx_bd_ci %= RX_BD_NUM;
                cur_p = &priv->rx_bd_v[priv->rx_bd_ci];
        }

+end:
        ndev->stats.rx_packets += packets;
        ndev->stats.rx_bytes += size;