From 5b057c6b1a25d57edf2b4d1e956e50936480a9ff Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Fri, 23 Jun 2006 02:06:41 -0700
Subject: [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>
---
drivers/net/lance.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
(limited to 'drivers/net/lance.c')
diff --git a/drivers/net/lance.c b/drivers/net/lance.c
index bb5ad479210..c1c3452c90c 100644
--- a/drivers/net/lance.c
+++ b/drivers/net/lance.c
@@ -968,8 +968,7 @@ static int lance_start_xmit(struct sk_buff *skb, struct net_device *dev)
/* The old LANCE chips doesn't automatically pad buffers to min. size. */
if (chip_table[lp->chip_version].flags & LANCE_MUST_PAD) {
if (skb->len < ETH_ZLEN) {
- skb = skb_padto(skb, ETH_ZLEN);
- if (skb == NULL)
+ if (skb_padto(skb, ETH_ZLEN))
goto out;
lp->tx_ring[entry].length = -ETH_ZLEN;
}
--
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