skb = alloc_skb(size + hdr_len, gfp);
skb = alloc_skb_fclone(size + hdr_len, gfp);
static inline struct sk_buff *sk_stream_alloc_pskb(struct sock *sk,						   int size, int mem,						   unsigned int __nocast gfp){	struct sk_buff *skb;	int hdr_len;	hdr_len = SKB_DATA_ALIGN(sk->sk_prot->max_header);	skb = alloc_skb(size + hdr_len, gfp);	if (skb) {		skb->truesize += mem;		if (sk->sk_forward_alloc >= (int)skb->truesize ||		    sk_stream_mem_schedule(sk, skb->truesize, 0)) {			skb_reserve(skb, hdr_len);			return skb;		}		__kfree_skb(skb);	} else {		sk->sk_prot->enter_memory_pressure();		sk_stream_moderate_sndbuf(sk);	}	return NULL;}