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net: dsa: trailer: don't allocate additional memory for padding/tagging

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The caller (dsa_slave_xmit) guarantees that the frame length is at least
ETH_ZLEN and that enough memory for tail tagging is available.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Christian Eggers 2020-11-01 21:16:11 +02:00 committed by Jakub Kicinski
parent 88fda8eefd
commit ef3f72fee2
1 changed files with 2 additions and 29 deletions
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31
net/dsa/tag_trailer.c
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@ -13,42 +13,15 @@
static struct sk_buff *trailer_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct dsa_port *dp = dsa_slave_to_port(dev);
struct sk_buff *nskb;
int padlen;
u8 *trailer;
/*
* We have to make sure that the trailer ends up as the very
* last 4 bytes of the packet. This means that we have to pad
* the packet to the minimum ethernet frame size, if necessary,
* before adding the trailer.
*/
padlen = 0;
if (skb->len < 60)
padlen = 60 - skb->len;
nskb = alloc_skb(NET_IP_ALIGN + skb->len + padlen + 4, GFP_ATOMIC);
if (!nskb)
return NULL;
skb_reserve(nskb, NET_IP_ALIGN);
skb_reset_mac_header(nskb);
skb_set_network_header(nskb, skb_network_header(skb) - skb->head);
skb_set_transport_header(nskb, skb_transport_header(skb) - skb->head);
skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len));
consume_skb(skb);
if (padlen) {
skb_put_zero(nskb, padlen);
}
trailer = skb_put(nskb, 4);
trailer = skb_put(skb, 4);
trailer[0] = 0x80;
trailer[1] = 1 << dp->index;
trailer[2] = 0x10;
trailer[3] = 0x00;
return nskb;
return skb;
}
static struct sk_buff *trailer_rcv(struct sk_buff *skb, struct net_device *dev,