[NET]: Avoid allocating skb in skb_pad
First of all it is unnecessary to allocate a new skb in skb_pad since
the existing one is not shared. More importantly, our hard_start_xmit
interface does not allow a new skb to be allocated since that breaks
requeueing.
This patch uses pskb_expand_head to expand the existing skb and linearize
it if needed. Actually, someone should sift through every instance of
skb_pad on a non-linear skb as they do not fit the reasons why this was
originally created.
Incidentally, this fixes a minor bug when the skb is cloned (tcpdump,
TCP, etc.). As it is skb_pad will simply write over a cloned skb. Because
of the position of the write it is unlikely to cause problems but still
it's best if we don't do it.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/yellowfin.c b/drivers/net/yellowfin.c
index fd0f43b..ecec8e5 100644
--- a/drivers/net/yellowfin.c
+++ b/drivers/net/yellowfin.c
@@ -862,13 +862,11 @@
/* Fix GX chipset errata. */
if (cacheline_end > 24 || cacheline_end == 0) {
len = skb->len + 32 - cacheline_end + 1;
- if (len != skb->len)
- skb = skb_padto(skb, len);
- }
- if (skb == NULL) {
- yp->tx_skbuff[entry] = NULL;
- netif_wake_queue(dev);
- return 0;
+ if (skb_padto(skb, len)) {
+ yp->tx_skbuff[entry] = NULL;
+ netif_wake_queue(dev);
+ return 0;
+ }
}
}
yp->tx_skbuff[entry] = skb;
