net: Allow netdevices to specify needed head/tailroom

This patch adds needed_headroom/needed_tailroom members to struct
net_device and updates many places that allocate sbks to use them. Not
all of them can be converted though, and I'm sure I missed some (I
mostly grepped for LL_RESERVED_SPACE)

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index 09cd9c0c2d80..3f964db908a7 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -25,11 +25,11 @@ static int xfrm_state_check_space(struct xfrm_state *x, struct sk_buff *skb)
         struct dst_entry *dst = skb->dst;
         int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
                 - skb_headroom(skb);
+        int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
 
-        if (nhead > 0)
-                return pskb_expand_head(skb, nhead, 0, GFP_ATOMIC);
+        if (nhead > 0 || ntail > 0)
+                return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
 
-        /* Check tail too... */
         return 0;
 }