atm: br2684: Make headroom and hard_header_len depend on the payload type

Routed payload requires less headroom than bridged payload.
So do not reallocate headroom if not needed.
Also, add worst case AAL5 overhead to netdev->hard_header_len.

Signed-off-by: Pascal Hambourg <pascal@plouf.fr.eu.org>
Signed-off-by: chas williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 2 deletions

diff --git a/net/atm/br2684.c b/net/atm/br2684.c
index 53b0aa14a1e6..ed72263d0dc7 100644
--- a/net/atm/br2684.c
+++ b/net/atm/br2684.c
@@ -202,7 +202,10 @@ static int br2684_xmit_vcc(struct sk_buff *skb, struct net_device *dev,
 {
         struct br2684_dev *brdev = BRPRIV(dev);
         struct atm_vcc *atmvcc;
-        int minheadroom = (brvcc->encaps == e_llc) ? 10 : 2;
+        int minheadroom = (brvcc->encaps == e_llc) ?
+                ((brdev->payload == p_bridged) ?
+                        sizeof(llc_oui_pid_pad) : sizeof(llc_oui_ipv4)) :
+                ((brdev->payload == p_bridged) ? BR2684_PAD_LEN : 0);
 
         if (skb_headroom(skb) < minheadroom) {
                 struct sk_buff *skb2 = skb_realloc_headroom(skb, minheadroom);
@@ -583,6 +586,7 @@ static void br2684_setup(struct net_device *netdev)
         struct br2684_dev *brdev = BRPRIV(netdev);
 
         ether_setup(netdev);
+        netdev->hard_header_len += sizeof(llc_oui_pid_pad); /* worst case */
         brdev->net_dev = netdev;
 
         netdev->netdev_ops = &br2684_netdev_ops;
@@ -595,7 +599,7 @@ static void br2684_setup_routed(struct net_device *netdev)
         struct br2684_dev *brdev = BRPRIV(netdev);
 
         brdev->net_dev = netdev;
-        netdev->hard_header_len = 0;
+        netdev->hard_header_len = sizeof(llc_oui_ipv4); /* worst case */
         netdev->netdev_ops = &br2684_netdev_ops_routed;
         netdev->addr_len = 0;
         netdev->mtu = 1500;