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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 <alexander.h.duyck@intel.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexander Duyck 2012-05-02 21:19:09 +00:00 committed by David S. Miller
parent 57b55a7ec6
commit 34a802a5b9
1 changed files with 29 additions and 26 deletions
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55
net/ipv4/tcp_input.c
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@ -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)