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>

1 files changed, 24 insertions, 7 deletions

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index 43e76d21e57f..2dd2ff5ecb5a 100644
--- 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);