net/mlx4_en: Fix handling of dma_map failure

Result of skb_frag_dma_map() and dma_map_single() wasn't checked.
Added a check and proper handling in case of failure.
Moved the mapping to the beginning of mlx4_en_xmit(), before updating
the ring data structure to make error handling easier.

Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 0d691e3644d6108a541b4f756c9c989a3517fb46..c28868bde40535001320c251b456c037731e3ab0 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -588,6 +588,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 {
        struct mlx4_en_priv *priv = netdev_priv(dev);
        struct mlx4_en_dev *mdev = priv->mdev;
+       struct device *ddev = priv->ddev;
        struct mlx4_en_tx_ring *ring;
        struct mlx4_en_tx_desc *tx_desc;
        struct mlx4_wqe_data_seg *data;
@@ -674,6 +675,56 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
        tx_info->skb = skb;
        tx_info->nr_txbb = nr_txbb;
 
+       if (lso_header_size)
+               data = ((void *)&tx_desc->lso + ALIGN(lso_header_size + 4,
+                                                     DS_SIZE));
+       else
+               data = &tx_desc->data;
+
+       /* valid only for none inline segments */
+       tx_info->data_offset = (void *)data - (void *)tx_desc;
+
+       tx_info->linear = (lso_header_size < skb_headlen(skb) &&
+                          !is_inline(skb, NULL)) ? 1 : 0;
+
+       data += skb_shinfo(skb)->nr_frags + tx_info->linear - 1;
+
+       if (is_inline(skb, &fragptr)) {
+               tx_info->inl = 1;
+       } else {
+               /* Map fragments */
+               for (i = skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) {
+                       frag = &skb_shinfo(skb)->frags[i];
+                       dma = skb_frag_dma_map(ddev, frag,
+                                              0, skb_frag_size(frag),
+                                              DMA_TO_DEVICE);
+                       if (dma_mapping_error(ddev, dma))
+                               goto tx_drop_unmap;
+
+                       data->addr = cpu_to_be64(dma);
+                       data->lkey = cpu_to_be32(mdev->mr.key);
+                       wmb();
+                       data->byte_count = cpu_to_be32(skb_frag_size(frag));
+                       --data;
+               }
+
+               /* Map linear part */
+               if (tx_info->linear) {
+                       u32 byte_count = skb_headlen(skb) - lso_header_size;
+                       dma = dma_map_single(ddev, skb->data +
+                                            lso_header_size, byte_count,
+                                            PCI_DMA_TODEVICE);
+                       if (dma_mapping_error(ddev, dma))
+                               goto tx_drop_unmap;
+
+                       data->addr = cpu_to_be64(dma);
+                       data->lkey = cpu_to_be32(mdev->mr.key);
+                       wmb();
+                       data->byte_count = cpu_to_be32(byte_count);
+               }
+               tx_info->inl = 0;
+       }
+
        /*
         * For timestamping add flag to skb_shinfo and
         * set flag for further reference
@@ -720,8 +771,6 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
                /* Copy headers;
                 * note that we already verified that it is linear */
                memcpy(tx_desc->lso.header, skb->data, lso_header_size);
-               data = ((void *) &tx_desc->lso +
-                       ALIGN(lso_header_size + 4, DS_SIZE));
 
                priv->port_stats.tso_packets++;
                i = ((skb->len - lso_header_size) / skb_shinfo(skb)->gso_size) +
@@ -733,7 +782,6 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
                op_own = cpu_to_be32(MLX4_OPCODE_SEND) |
                        ((ring->prod & ring->size) ?
                         cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0);
-               data = &tx_desc->data;
                tx_info->nr_bytes = max_t(unsigned int, skb->len, ETH_ZLEN);
                ring->packets++;
 
@@ -742,38 +790,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
        netdev_tx_sent_queue(ring->tx_queue, tx_info->nr_bytes);
        AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, skb->len);
 
-
-       /* valid only for none inline segments */
-       tx_info->data_offset = (void *) data - (void *) tx_desc;
-
-       tx_info->linear = (lso_header_size < skb_headlen(skb) && !is_inline(skb, NULL)) ? 1 : 0;
-       data += skb_shinfo(skb)->nr_frags + tx_info->linear - 1;
-
-       if (!is_inline(skb, &fragptr)) {
-               /* Map fragments */
-               for (i = skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) {
-                       frag = &skb_shinfo(skb)->frags[i];
-                       dma = skb_frag_dma_map(priv->ddev, frag,
-                                              0, skb_frag_size(frag),
-                                              DMA_TO_DEVICE);
-                       data->addr = cpu_to_be64(dma);
-                       data->lkey = cpu_to_be32(mdev->mr.key);
-                       wmb();
-                       data->byte_count = cpu_to_be32(skb_frag_size(frag));
-                       --data;
-               }
-
-               /* Map linear part */
-               if (tx_info->linear) {
-                       dma = dma_map_single(priv->ddev, skb->data + lso_header_size,
-                                            skb_headlen(skb) - lso_header_size, PCI_DMA_TODEVICE);
-                       data->addr = cpu_to_be64(dma);
-                       data->lkey = cpu_to_be32(mdev->mr.key);
-                       wmb();
-                       data->byte_count = cpu_to_be32(skb_headlen(skb) - lso_header_size);
-               }
-               tx_info->inl = 0;
-       } else {
+       if (tx_info->inl) {
                build_inline_wqe(tx_desc, skb, real_size, &vlan_tag, tx_ind, fragptr);
                tx_info->inl = 1;
        }
@@ -813,6 +830,16 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 
        return NETDEV_TX_OK;
 
+tx_drop_unmap:
+       en_err(priv, "DMA mapping error\n");
+
+       for (i++; i < skb_shinfo(skb)->nr_frags; i++) {
+               data++;
+               dma_unmap_page(ddev, (dma_addr_t) be64_to_cpu(data->addr),
+                              be32_to_cpu(data->byte_count),
+                              PCI_DMA_TODEVICE);
+       }
+
 tx_drop:
        dev_kfree_skb_any(skb);
        priv->stats.tx_dropped++;