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Commit 34a802a5 authored by Alexander Duyck's avatar Alexander Duyck Committed by David S. Miller
Browse files

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: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 57b55a7e

net/ipv4/tcp_input.c

+29 −26
Original line number Diff line number Diff line
@@ -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 @@ static bool tcp_try_coalesce(struct sock *sk, 
		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 @@ static bool tcp_try_coalesce(struct sock *sk, 


		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))

	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);

		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;



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)