net: sh_eth: fix up the buffer pointers

After freeing the buffer, the driver should change the value of
the pointer to NULL.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index 43e76d2..2dd2ff5 100644 (file)
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -788,6 +788,7 @@ static void sh_eth_ring_free(struct net_device *ndev)
                }
        }
        kfree(mdp->rx_skbuff);
+       mdp->rx_skbuff = NULL;
 
        /* Free Tx skb ringbuffer */
        if (mdp->tx_skbuff) {
@@ -797,6 +798,7 @@ static void sh_eth_ring_free(struct net_device *ndev)
                }
        }
        kfree(mdp->tx_skbuff);
+       mdp->tx_skbuff = NULL;
 }
 
 /* format skb and descriptor buffer */
@@ -933,10 +935,31 @@ desc_ring_free:
 skb_ring_free:
        /* Free Rx and Tx skb ring buffer */
        sh_eth_ring_free(ndev);
+       mdp->tx_ring = NULL;
+       mdp->rx_ring = NULL;
 
        return ret;
 }
 
+static void sh_eth_free_dma_buffer(struct sh_eth_private *mdp)
+{
+       int ringsize;
+
+       if (mdp->rx_ring) {
+               ringsize = sizeof(struct sh_eth_rxdesc) * RX_RING_SIZE;
+               dma_free_coherent(NULL, ringsize, mdp->rx_ring,
+                                 mdp->rx_desc_dma);
+               mdp->rx_ring = NULL;
+       }
+
+       if (mdp->tx_ring) {
+               ringsize = sizeof(struct sh_eth_txdesc) * TX_RING_SIZE;
+               dma_free_coherent(NULL, ringsize, mdp->tx_ring,
+                                 mdp->tx_desc_dma);
+               mdp->tx_ring = NULL;
+       }
+}
+
 static int sh_eth_dev_init(struct net_device *ndev)
 {
        int ret = 0;
@@ -1677,7 +1700,6 @@ static int sh_eth_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 static int sh_eth_close(struct net_device *ndev)
 {
        struct sh_eth_private *mdp = netdev_priv(ndev);
-       int ringsize;
 
        netif_stop_queue(ndev);
 
@@ -1700,12 +1722,7 @@ static int sh_eth_close(struct net_device *ndev)
        sh_eth_ring_free(ndev);
 
        /* free DMA buffer */
-       ringsize = sizeof(struct sh_eth_rxdesc) * RX_RING_SIZE;
-       dma_free_coherent(NULL, ringsize, mdp->rx_ring, mdp->rx_desc_dma);
-
-       /* free DMA buffer */
-       ringsize = sizeof(struct sh_eth_txdesc) * TX_RING_SIZE;
-       dma_free_coherent(NULL, ringsize, mdp->tx_ring, mdp->tx_desc_dma);
+       sh_eth_free_dma_buffer(mdp);
 
        pm_runtime_put_sync(&mdp->pdev->dev);