net: smsc911x: fix skb handling in receive path
The SMSC911x driver resets the ->head, ->data and ->tail pointers in the
skb on the reset path in order to avoid buffer overflow due to packet
padding performed by the hardware.
This patch fixes the receive path so that the skb pointers are fixed up
after the data has been read from the device, The error path is also
fixed to use number of words consistently and prevent erroneous FIFO
fastforwarding when skipping over bad data.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/smsc/smsc911x.c b/drivers/net/ethernet/smsc/smsc911x.c
index 4a69710..5aa2dbe 100644
--- a/drivers/net/ethernet/smsc/smsc911x.c
+++ b/drivers/net/ethernet/smsc/smsc911x.c
@@ -1166,10 +1166,8 @@
/* Quickly dumps bad packets */
static void
-smsc911x_rx_fastforward(struct smsc911x_data *pdata, unsigned int pktbytes)
+smsc911x_rx_fastforward(struct smsc911x_data *pdata, unsigned int pktwords)
{
- unsigned int pktwords = (pktbytes + NET_IP_ALIGN + 3) >> 2;
-
if (likely(pktwords >= 4)) {
unsigned int timeout = 500;
unsigned int val;
@@ -1233,7 +1231,7 @@
continue;
}
- skb = netdev_alloc_skb(dev, pktlength + NET_IP_ALIGN);
+ skb = netdev_alloc_skb(dev, pktwords << 2);
if (unlikely(!skb)) {
SMSC_WARN(pdata, rx_err,
"Unable to allocate skb for rx packet");
@@ -1243,14 +1241,12 @@
break;
}
- skb->data = skb->head;
- skb_reset_tail_pointer(skb);
+ pdata->ops->rx_readfifo(pdata,
+ (unsigned int *)skb->data, pktwords);
/* Align IP on 16B boundary */
skb_reserve(skb, NET_IP_ALIGN);
skb_put(skb, pktlength - 4);
- pdata->ops->rx_readfifo(pdata,
- (unsigned int *)skb->head, pktwords);
skb->protocol = eth_type_trans(skb, dev);
skb_checksum_none_assert(skb);
netif_receive_skb(skb);
@@ -1565,7 +1561,7 @@
smsc911x_reg_write(pdata, FIFO_INT, temp);
/* set RX Data offset to 2 bytes for alignment */
- smsc911x_reg_write(pdata, RX_CFG, (2 << 8));
+ smsc911x_reg_write(pdata, RX_CFG, (NET_IP_ALIGN << 8));
/* enable NAPI polling before enabling RX interrupts */
napi_enable(&pdata->napi);