From 7b7fc97aa390dfe4770e1d19e215fa289d94b477 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 5 Dec 2013 22:31:30 -0800 Subject: [PATCH] tcp: optimize some skb_shinfo(skb) uses Compiler doesn't know skb_shinfo(skb) pointer is usually constant. By using a temporary variable, we help generating smaller code. For example, tcp_init_nondata_skb() is inlined after this patch. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_output.c | 36 +++++++++++++++++++++--------------- 1 file changed, 21 insertions(+), 15 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 7820f3a7dd70..993da005e087 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -363,15 +363,17 @@ static inline void TCP_ECN_send(struct sock *sk, struct sk_buff *skb, */ static void tcp_init_nondata_skb(struct sk_buff *skb, u32 seq, u8 flags) { + struct skb_shared_info *shinfo = skb_shinfo(skb); + skb->ip_summed = CHECKSUM_PARTIAL; skb->csum = 0; TCP_SKB_CB(skb)->tcp_flags = flags; TCP_SKB_CB(skb)->sacked = 0; - skb_shinfo(skb)->gso_segs = 1; - skb_shinfo(skb)->gso_size = 0; - skb_shinfo(skb)->gso_type = 0; + shinfo->gso_segs = 1; + shinfo->gso_size = 0; + shinfo->gso_type = 0; TCP_SKB_CB(skb)->seq = seq; if (flags & (TCPHDR_SYN | TCPHDR_FIN)) @@ -986,6 +988,8 @@ static void tcp_queue_skb(struct sock *sk, struct sk_buff *skb) static void tcp_set_skb_tso_segs(const struct sock *sk, struct sk_buff *skb, unsigned int mss_now) { + struct skb_shared_info *shinfo = skb_shinfo(skb); + /* Make sure we own this skb before messing gso_size/gso_segs */ WARN_ON_ONCE(skb_cloned(skb)); @@ -993,13 +997,13 @@ static void tcp_set_skb_tso_segs(const struct sock *sk, struct sk_buff *skb, /* Avoid the costly divide in the normal * non-TSO case. */ - skb_shinfo(skb)->gso_segs = 1; - skb_shinfo(skb)->gso_size = 0; - skb_shinfo(skb)->gso_type = 0; + shinfo->gso_segs = 1; + shinfo->gso_size = 0; + shinfo->gso_type = 0; } else { - skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss_now); - skb_shinfo(skb)->gso_size = mss_now; - skb_shinfo(skb)->gso_type = sk->sk_gso_type; + shinfo->gso_segs = DIV_ROUND_UP(skb->len, mss_now); + shinfo->gso_size = mss_now; + shinfo->gso_type = sk->sk_gso_type; } } @@ -1146,6 +1150,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, */ static void __pskb_trim_head(struct sk_buff *skb, int len) { + struct skb_shared_info *shinfo; int i, k, eat; eat = min_t(int, len, skb_headlen(skb)); @@ -1157,23 +1162,24 @@ static void __pskb_trim_head(struct sk_buff *skb, int len) } eat = len; k = 0; - for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { - int size = skb_frag_size(&skb_shinfo(skb)->frags[i]); + shinfo = skb_shinfo(skb); + for (i = 0; i < shinfo->nr_frags; i++) { + int size = skb_frag_size(&shinfo->frags[i]); if (size <= eat) { skb_frag_unref(skb, i); eat -= size; } else { - skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i]; + shinfo->frags[k] = shinfo->frags[i]; if (eat) { - skb_shinfo(skb)->frags[k].page_offset += eat; - skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat); + shinfo->frags[k].page_offset += eat; + skb_frag_size_sub(&shinfo->frags[k], eat); eat = 0; } k++; } } - skb_shinfo(skb)->nr_frags = k; + shinfo->nr_frags = k; skb_reset_tail_pointer(skb); skb->data_len -= len;