skb_tailroom_reserve - adjust reserved_tailroom
void skb_tailroom_reserve(struct sk_buff * skb, unsigned int mtu, unsigned int needed_tailroom);
Set reserved_tailroom so that headlen can be as large as possible but not larger than mtu and tailroom cannot be smaller than needed_tailroom. The required headroom should already have been reserved before using this function.
|January 2017||Kernel Hackers Manual 4.8.|