realtek: eth: add rteth_free_skb() helper

Add a helper to simplify SKB freeing and rx counter handling. If SKB
is given, it is freed and the pointer is set to zero. The return value
is the number of freed SKBs (0/1). With this the existing cleanup and
error handling can be simplified like

dev->stats.tx_errors += rteth_free_skb(&packet->skb);

Link: https://github.com/openwrt/openwrt/pull/24245
Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>

diff --git a/target/linux/realtek/files-6.18/drivers/net/ethernet/rtl838x_eth.c b/target/linux/realtek/files-6.18/drivers/net/ethernet/rtl838x_eth.c
index 0dfd36a82f4089ad670cc0df11b7770f928afcc0..c8591541e319a2fbc5d2eca60f32aa7e2f1dab52 100644 (file)
--- a/target/linux/realtek/files-6.18/drivers/net/ethernet/rtl838x_eth.c
+++ b/target/linux/realtek/files-6.18/drivers/net/ethernet/rtl838x_eth.c
@@ -174,6 +174,17 @@ static void rteth_93xx_create_tx_header(struct rteth_packet *h, unsigned int por
        h->cpu_tag[7] = BIT_ULL(port) & 0xffff;
 }
 
+static int rteth_free_skb(struct sk_buff **skb)
+{
+       if (*skb) {
+               dev_kfree_skb_any(*skb);
+               *skb = NULL;
+               return 1;
+       }
+
+       return 0;
+}
+
 static inline void rteth_reenable_irq(struct rteth_ctrl *ctrl, int ring)
 {
        u32 shift = ctrl->r->rx_rings % 32;
@@ -623,8 +634,7 @@ static void rteth_free_tx_buffers(struct rteth_ctrl *ctrl)
 
                        dma_unmap_single(&ctrl->pdev->dev, packet->dma,
                                         packet->skb->len, DMA_TO_DEVICE);
-                       dev_kfree_skb_any(packet->skb);
-                       packet->skb = NULL;
+                       rteth_free_skb(&packet->skb);
                }
        }
 }
@@ -1056,21 +1066,18 @@ static int rteth_start_xmit(struct sk_buff *skb, struct net_device *dev)
                dev_consume_skb_any(packet->skb);
        }
 
+       packet->len = len;
+       packet->skb = skb;
        packet->dma = dma_map_single(&ctrl->pdev->dev, skb->data, len, DMA_TO_DEVICE);
        if (unlikely(dma_mapping_error(&ctrl->pdev->dev, packet->dma))) {
-               dev_kfree_skb_any(skb);
-               packet->skb = NULL;
-               dev->stats.tx_errors++;
-
+               dev->stats.tx_errors += rteth_free_skb(&packet->skb);
                return NETDEV_TX_OK;
        }
 
        if (port >= 0)
                ctrl->r->create_tx_header(packet, port, 0); // TODO ok to set prio to 0?
 
-       /* Transfer data and hand packet over to switch */
-       packet->len = len;
-       packet->skb = skb;
+       /* Hand packet over to switch */
        dma_wmb();
        ctrl->tx_data[ring].ring[slot] = packet_dma | RING_OWN_HW;
        ctrl->tx_data[ring].slot = (slot + 1) % RTETH_TX_RING_SIZE;