diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 743016baa048..f33c9dddaa12 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -642,7 +642,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss * eventually). The difference is that pulled data not copied, but * immediately discarded. */ -static unsigned char *__pskb_trim_head(struct sk_buff *skb, int len) +static void __pskb_trim_head(struct sk_buff *skb, int len) { int i, k, eat; @@ -667,7 +667,6 @@ static unsigned char *__pskb_trim_head(struct sk_buff *skb, int len) skb->tail = skb->data; skb->data_len -= len; skb->len = skb->data_len; - return skb->tail; } int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len) @@ -676,12 +675,11 @@ int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len) pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) return -ENOMEM; - if (len <= skb_headlen(skb)) { + /* If len == headlen, we avoid __skb_pull to preserve alignment. */ + if (unlikely(len < skb_headlen(skb))) __skb_pull(skb, len); - } else { - if (__pskb_trim_head(skb, len-skb_headlen(skb)) == NULL) - return -ENOMEM; - } + else + __pskb_trim_head(skb, len - skb_headlen(skb)); TCP_SKB_CB(skb)->seq += len; skb->ip_summed = CHECKSUM_HW;