From 34a802a5b9c4c4efb61828781230805be6dd0f8e Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Wed, 2 May 2012 21:19:09 +0000 Subject: [PATCH] tcp: move stats merge to the end of tcp_try_coalesce This change cleans up the last bits of tcp_try_coalesce so that we only need one goto which jumps to the end of the function. The idea is to make the code more readable by putting things in a linear order so that we start execution at the top of the function, and end it at the bottom. I also made a slight tweak to the code for handling frags when we are a clone. Instead of making it an if (clone) loop else nr_frags = 0 I changed the logic so that if (!clone) we just set the number of frags to 0 which disables the for loop anyway. Signed-off-by: Alexander Duyck Cc: Eric Dumazet Cc: Jeff Kirsher Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 55 +++++++++++++++++++++++++++------------------------- 1 file changed, 29 insertions(+), 26 deletions(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 41fa5df..84e69e0 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4548,15 +4548,13 @@ static bool tcp_try_coalesce(struct sock *sk, int i, delta, len = from->len; *fragstolen = false; + if (tcp_hdr(from)->fin || skb_cloned(to)) return false; + if (len <= skb_tailroom(to)) { BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len)); -merge: - NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPRCVCOALESCE); - TCP_SKB_CB(to)->end_seq = TCP_SKB_CB(from)->end_seq; - TCP_SKB_CB(to)->ack_seq = TCP_SKB_CB(from)->ack_seq; - return true; + goto merge; } if (skb_has_frag_list(to) || skb_has_frag_list(from)) @@ -4581,7 +4579,6 @@ merge: skb_fill_page_desc(to, skb_shinfo(to)->nr_frags, page, offset, skb_headlen(from)); *fragstolen = true; - goto copyfrags; } else { if (skb_shinfo(to)->nr_frags + skb_shinfo(from)->nr_frags > MAX_SKB_FRAGS) @@ -4589,27 +4586,33 @@ merge: delta = from->truesize - SKB_TRUESIZE(skb_end_pointer(from) - from->head); -copyfrags: - WARN_ON_ONCE(delta < len); - memcpy(skb_shinfo(to)->frags + skb_shinfo(to)->nr_frags, - skb_shinfo(from)->frags, - skb_shinfo(from)->nr_frags * sizeof(skb_frag_t)); - skb_shinfo(to)->nr_frags += skb_shinfo(from)->nr_frags; - - if (skb_cloned(from)) - for (i = 0; i < skb_shinfo(from)->nr_frags; i++) - skb_frag_ref(from, i); - else - skb_shinfo(from)->nr_frags = 0; - - to->truesize += delta; - atomic_add(delta, &sk->sk_rmem_alloc); - sk_mem_charge(sk, delta); - to->len += len; - to->data_len += len; - goto merge; } - return false; + + WARN_ON_ONCE(delta < len); + + memcpy(skb_shinfo(to)->frags + skb_shinfo(to)->nr_frags, + skb_shinfo(from)->frags, + skb_shinfo(from)->nr_frags * sizeof(skb_frag_t)); + skb_shinfo(to)->nr_frags += skb_shinfo(from)->nr_frags; + + if (!skb_cloned(from)) + skb_shinfo(from)->nr_frags = 0; + + /* if the skb is cloned this does nothing since we set nr_frags to 0 */ + for (i = 0; i < skb_shinfo(from)->nr_frags; i++) + skb_frag_ref(from, i); + + to->truesize += delta; + atomic_add(delta, &sk->sk_rmem_alloc); + sk_mem_charge(sk, delta); + to->len += len; + to->data_len += len; + +merge: + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPRCVCOALESCE); + TCP_SKB_CB(to)->end_seq = TCP_SKB_CB(from)->end_seq; + TCP_SKB_CB(to)->ack_seq = TCP_SKB_CB(from)->ack_seq; + return true; } static void kfree_skb_partial(struct sk_buff *skb, bool head_stolen) -- 2.7.4