GRETH: fixed skb buffer memory leak on frame errors

A new SKB buffer should not be allocated when the old SKB is reused.

Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 4 deletions

diff --git a/drivers/net/greth.c b/drivers/net/greth.c
index 869e38d6f41..9386bce9dea 100644
--- a/drivers/net/greth.c
+++ b/drivers/net/greth.c
@@ -870,10 +870,9 @@ static int greth_rx_gbit(struct net_device *dev, int limit)
                         }
                 }
 
-                /* Allocate new skb to replace current */
-                newskb = netdev_alloc_skb(dev, MAX_FRAME_SIZE + NET_IP_ALIGN);
-
-                if (!bad && newskb) {
+                /* Allocate new skb to replace current, not needed if the
+                 * current skb can be reused */
+                if (!bad && (newskb=netdev_alloc_skb(dev, MAX_FRAME_SIZE + NET_IP_ALIGN))) {
                         skb_reserve(newskb, NET_IP_ALIGN);
 
                         dma_addr = dma_map_single(greth->dev,
@@ -910,11 +909,22 @@ static int greth_rx_gbit(struct net_device *dev, int limit)
                                 if (net_ratelimit())
                                         dev_warn(greth->dev, "Could not create DMA mapping, dropping packet\n");
                                 dev_kfree_skb(newskb);
+                                /* reusing current skb, so it is a drop */
                                 dev->stats.rx_dropped++;
                         }
+                } else if (bad) {
+                        /* Bad Frame transfer, the skb is reused */
+                        dev->stats.rx_dropped++;
                 } else {
+                        /* Failed Allocating a new skb. This is rather stupid
+                         * but the current "filled" skb is reused, as if
+                         * transfer failure. One could argue that RX descriptor
+                         * table handling should be divided into cleaning and
+                         * filling as the TX part of the driver
+                         */
                         if (net_ratelimit())
                                 dev_warn(greth->dev, "Could not allocate SKB, dropping packet\n");
+                        /* reusing current skb, so it is a drop */
                         dev->stats.rx_dropped++;
                 }