net/mlx5e: TX, Use correct counter in dma_map error flow

In case of a dma_mapping_error, do not use wi->num_dma
as a parameter for dma unmap function because it's yet
to be set, and holds an out-of-date value.
Use actual value (local variable num_dma) instead.

Fixes: 34802a42 ("net/mlx5e: Do not modify the TX SKB")
Fixes: e586b3b0 ("net/mlx5: Ethernet Datapath files")
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en_tx.c

@@ -255,7 +255,7 @@ mlx5e_txwqe_build_dsegs(struct mlx5e_txqsq *sq, struct sk_buff *skb,
 		dma_addr = dma_map_single(sq->pdev, skb_data, headlen,
 					  DMA_TO_DEVICE);
 		if (unlikely(dma_mapping_error(sq->pdev, dma_addr)))
-			return -ENOMEM;
+			goto dma_unmap_wqe_err;
 
 		dseg->addr       = cpu_to_be64(dma_addr);
 		dseg->lkey       = sq->mkey_be;
@@ -273,7 +273,7 @@ mlx5e_txwqe_build_dsegs(struct mlx5e_txqsq *sq, struct sk_buff *skb,
 		dma_addr = skb_frag_dma_map(sq->pdev, frag, 0, fsz,
 					    DMA_TO_DEVICE);
 		if (unlikely(dma_mapping_error(sq->pdev, dma_addr)))
-			return -ENOMEM;
+			goto dma_unmap_wqe_err;
 
 		dseg->addr       = cpu_to_be64(dma_addr);
 		dseg->lkey       = sq->mkey_be;
@@ -285,6 +285,10 @@ mlx5e_txwqe_build_dsegs(struct mlx5e_txqsq *sq, struct sk_buff *skb,
 	}
 
 	return num_dma;
+
+dma_unmap_wqe_err:
+	mlx5e_dma_unmap_wqe_err(sq, num_dma);
+	return -ENOMEM;
 }
 
 static inline void
@@ -380,17 +384,15 @@ static netdev_tx_t mlx5e_sq_xmit(struct mlx5e_txqsq *sq, struct sk_buff *skb,
 	num_dma = mlx5e_txwqe_build_dsegs(sq, skb, skb_data, headlen,
 					  (struct mlx5_wqe_data_seg *)cseg + ds_cnt);
 	if (unlikely(num_dma < 0))
-		goto dma_unmap_wqe_err;
+		goto err_drop;
 
 	mlx5e_txwqe_complete(sq, skb, opcode, ds_cnt + num_dma,
 			     num_bytes, num_dma, wi, cseg);
 
 	return NETDEV_TX_OK;
 
-dma_unmap_wqe_err:
+err_drop:
 	sq->stats.dropped++;
-	mlx5e_dma_unmap_wqe_err(sq, wi->num_dma);
-
 	dev_kfree_skb_any(skb);
 
 	return NETDEV_TX_OK;
@@ -645,17 +647,15 @@ netdev_tx_t mlx5i_sq_xmit(struct mlx5e_txqsq *sq, struct sk_buff *skb,
 	num_dma = mlx5e_txwqe_build_dsegs(sq, skb, skb_data, headlen,
 					  (struct mlx5_wqe_data_seg *)cseg + ds_cnt);
 	if (unlikely(num_dma < 0))
-		goto dma_unmap_wqe_err;
+		goto err_drop;
 
 	mlx5e_txwqe_complete(sq, skb, opcode, ds_cnt + num_dma,
 			     num_bytes, num_dma, wi, cseg);
 
 	return NETDEV_TX_OK;
 
-dma_unmap_wqe_err:
+err_drop:
 	sq->stats.dropped++;
-	mlx5e_dma_unmap_wqe_err(sq, wi->num_dma);
-
 	dev_kfree_skb_any(skb);
 
 	return NETDEV_TX_OK;