[PATCH net] net: cavium: liquidio: Avoid dma_unmap_single on uninitialized ndata

[Florian Fainelli]

The label lio_xmit_failed is used 3 times through liquidio_xmit() but it
always makes a call to dma_unmap_single() using potentially
uninitialized variables from "ndata" variable. Out of the 3 gotos, 2 run
after ndata has been initialized, and had a prior dma_map_single() call.

Fix this by adding a new error label: lio_xmit_dma_failed which does
this dma_unmap_single() and then processed with the lio_xmit_failed
fallthrough.

Fixes: f21fb3ed364bb ("Add support of Cavium Liquidio ethernet adapters")
Reported-by: coverity (CID 1309740)
Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
---
 drivers/net/ethernet/cavium/liquidio/lio_main.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/cavium/liquidio/lio_main.c 
b/drivers/net/ethernet/cavium/liquidio/lio_main.c
index 8de79ae63231..0e7e7da8d201 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_main.c
@@ -2821,7 +2821,7 @@ static int liquidio_xmit(struct sk_buff *skb, struct 
net_device *netdev)
                if (!g) {
                        netif_info(lio, tx_err, lio->netdev,
                                   "Transmit scatter gather: glist null!\n");
-                       goto lio_xmit_failed;
+                       goto lio_xmit_dma_failed;
                }
 
                cmdsetup.s.gather = 1;
@@ -2892,7 +2892,7 @@ static int liquidio_xmit(struct sk_buff *skb, struct 
net_device *netdev)
        else
                status = octnet_send_nic_data_pkt(oct, &ndata, xmit_more);
        if (status == IQ_SEND_FAILED)
-               goto lio_xmit_failed;
+               goto lio_xmit_dma_failed;
 
        netif_info(lio, tx_queued, lio->netdev, "Transmit queued 
successfully\n");
 
@@ -2906,12 +2906,13 @@ static int liquidio_xmit(struct sk_buff *skb, struct 
net_device *netdev)
 
        return NETDEV_TX_OK;
 
+lio_xmit_dma_failed:
+       dma_unmap_single(&oct->pci_dev->dev, ndata.cmd.dptr,
+                        ndata.datasize, DMA_TO_DEVICE);
 lio_xmit_failed:
        stats->tx_dropped++;
        netif_info(lio, tx_err, lio->netdev, "IQ%d Transmit dropped:%llu\n",
                   iq_no, stats->tx_dropped);
-       dma_unmap_single(&oct->pci_dev->dev, ndata.cmd.dptr,
-                        ndata.datasize, DMA_TO_DEVICE);
        recv_buffer_free(skb);
        return NETDEV_TX_OK;
 }
-- 
2.7.4