Commit 5b057c6b authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
Browse files

[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: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5fa21d82

drivers/net/3c527.c

+1 −2
Original line number Diff line number Diff line
@@ -1031,8 +1031,7 @@ static int mc32_send_packet(struct sk_buff *skb, struct net_device *dev) 
		return 1;

	}



	skb = skb_padto(skb, ETH_ZLEN);

	if (skb == NULL) {

	if (skb_padto(skb, ETH_ZLEN)) {

		netif_wake_queue(dev);

		return 0;

	}

drivers/net/82596.c

+1 −2
Original line number Diff line number Diff line
@@ -1070,8 +1070,7 @@ static int i596_start_xmit(struct sk_buff *skb, struct net_device *dev) 
				skb->len, (unsigned int)skb->data));



	if (skb->len < ETH_ZLEN) {

		skb = skb_padto(skb, ETH_ZLEN);

		if (skb == NULL)

		if (skb_padto(skb, ETH_ZLEN))

			return 0;

		length = ETH_ZLEN;

	}

drivers/net/a2065.c

+1 −2
Original line number Diff line number Diff line
@@ -573,8 +573,7 @@ static int lance_start_xmit (struct sk_buff *skb, struct net_device *dev) 
	

	if (len < ETH_ZLEN) {

		len = ETH_ZLEN;

		skb = skb_padto(skb, ETH_ZLEN);

		if (skb == NULL)

		if (skb_padto(skb, ETH_ZLEN))

			return 0;

	}

drivers/net/ariadne.c

+1 −2
Original line number Diff line number Diff line
@@ -607,8 +607,7 @@ static int ariadne_start_xmit(struct sk_buff *skb, struct net_device *dev) 
    /* FIXME: is the 79C960 new enough to do its own padding right ? */

    if (skb->len < ETH_ZLEN)

    {

    	skb = skb_padto(skb, ETH_ZLEN);

    	if (skb == NULL)

    	if (skb_padto(skb, ETH_ZLEN))

    	    return 0;

    	len = ETH_ZLEN;

    }

drivers/net/arm/ether1.c

+1 −2
Original line number Diff line number Diff line
@@ -700,8 +700,7 @@ ether1_sendpacket (struct sk_buff *skb, struct net_device *dev) 
	}



	if (skb->len < ETH_ZLEN) {

		skb = skb_padto(skb, ETH_ZLEN);

		if (skb == NULL)

		if (skb_padto(skb, ETH_ZLEN))

			goto out;

	}

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