net: spacemit: Fix error handling in emac_tx_mem_map()

The DMA mappings were leaked on mapping error. Free them with the
existing emac_free_tx_buf() function.

Fixes: bfec6d7 ("net: spacemit: Add K1 Ethernet MAC")
Signed-off-by: Vivian Wang <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: dramforever

drivers/net/ethernet/spacemit/k1_emac.c

@@ -733,7 +733,7 @@ static void emac_tx_mem_map(struct emac_priv *priv, struct sk_buff *skb)
 	struct emac_desc tx_desc, *tx_desc_addr;
 	struct device *dev = &priv->pdev->dev;
 	struct emac_tx_desc_buffer *tx_buf;
-	u32 head, old_head, frag_num, f;
+	u32 head, old_head, frag_num, f, i;
 	bool buf_idx;
 
 	frag_num = skb_shinfo(skb)->nr_frags;
@@ -801,6 +801,15 @@ static void emac_tx_mem_map(struct emac_priv *priv, struct sk_buff *skb)
 
 err_free_skb:
 	dev_dstats_tx_dropped(priv->ndev);
+
+	i = old_head;
+	while (i != head) {
+		emac_free_tx_buf(priv, i);
+
+		if (++i == tx_ring->total_cnt)
+			i = 0;
+	}
+
 	dev_kfree_skb_any(skb);
 }