Re: [RFC v2] mac80211: assign needed_headroom/tailroom for netdevs

Johannes Berg
2008-05-05T23:36:31Z

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On Mon, 2008-05-05 at 16:03 -0700, David Miller wrote:

> @@ -255,11 +255,12 @@ struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
> unsigned int length, gfp_t gfp_mask)
> {
> int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1;
> + unsigned int extra = dev->rx_alloc_extra + NET_SKB_PAD;
> struct sk_buff *skb;
>
> - skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, node);
> + skb = __alloc_skb(length + extra, gfp_mask, 0, node);
> if (likely(skb)) {
> - skb_reserve(skb, NET_SKB_PAD);
> + skb_reserve(skb, extra);

Come to think of it, if you want to bridge two wireless AP-mode devices
with different headroom .... Nah.

four-byte multiple isn't quite right though, but I'm not sure what would
be, probably multiple of NET_SKB_PAD?

johannes

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