bgmac: don't update slot on skb alloc/dma mapping error

Don't update the slot in "bgmac_dma_rx_skb_for_slot" unless both the
skb alloc and dma mapping are successful; and free the newly allocated
skb if a dma mapping error occurs.  This relieves the caller of the need
to deduce/execute the appropriate cleanup action required when an error
occurs.

Signed-off-by: Nathan Hintz <nlhintz@hotmail.com>
Acked-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 6 deletions

diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c
index 249468f95365..9e8a3e024e01 100644
--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -244,25 +244,33 @@ static int bgmac_dma_rx_skb_for_slot(struct bgmac *bgmac,
                                      struct bgmac_slot_info *slot)
 {
         struct device *dma_dev = bgmac->core->dma_dev;
+        struct sk_buff *skb;
+        dma_addr_t dma_addr;
         struct bgmac_rx_header *rx;
 
         /* Alloc skb */
-        slot->skb = netdev_alloc_skb(bgmac->net_dev, BGMAC_RX_BUF_SIZE);
-        if (!slot->skb)
+        skb = netdev_alloc_skb(bgmac->net_dev, BGMAC_RX_BUF_SIZE);
+        if (!skb)
                 return -ENOMEM;
 
         /* Poison - if everything goes fine, hardware will overwrite it */
-        rx = (struct bgmac_rx_header *)slot->skb->data;
+        rx = (struct bgmac_rx_header *)skb->data;
         rx->len = cpu_to_le16(0xdead);
         rx->flags = cpu_to_le16(0xbeef);
 
         /* Map skb for the DMA */
-        slot->dma_addr = dma_map_single(dma_dev, slot->skb->data,
-                                        BGMAC_RX_BUF_SIZE, DMA_FROM_DEVICE);
-        if (dma_mapping_error(dma_dev, slot->dma_addr)) {
+        dma_addr = dma_map_single(dma_dev, skb->data,
+                                  BGMAC_RX_BUF_SIZE, DMA_FROM_DEVICE);
+        if (dma_mapping_error(dma_dev, dma_addr)) {
                 bgmac_err(bgmac, "DMA mapping error\n");
+                dev_kfree_skb(skb);
                 return -ENOMEM;
         }
+
+        /* Update the slot */
+        slot->skb = skb;
+        slot->dma_addr = dma_addr;
+
         if (slot->dma_addr & 0xC0000000)
                 bgmac_warn(bgmac, "DMA address using 0xC0000000 bit(s), it may need translation trick\n");