Commit 04e4cd4f authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

mptcp: cleanup mptcp_subflow_discard_data() 



There is no need to use the tcp_read_sock(), we can
simply drop the skb. Additionally try to look at the
next buffer for in order data.

This both simplifies the code and avoid unneeded indirect
calls.

Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Reviewed-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ab174ad8

net/mptcp/protocol.h

+0 −1
Original line number Diff line number Diff line
@@ -355,7 +355,6 @@ int mptcp_is_enabled(struct net *net); 
void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,

				     struct mptcp_options_received *mp_opt);

bool mptcp_subflow_data_available(struct sock *sk);

int mptcp_subflow_discard_data(struct sock *sk, unsigned int limit);

void __init mptcp_subflow_init(void);



/* called with sk socket lock held */

net/mptcp/subflow.c

+14 −44
Original line number Diff line number Diff line
@@ -805,51 +805,23 @@ validate_seq: 
	return MAPPING_OK;

}



static int subflow_read_actor(read_descriptor_t *desc,

			      struct sk_buff *skb,

			      unsigned int offset, size_t len)

{

	size_t copy_len = min(desc->count, len);



	desc->count -= copy_len;



	pr_debug("flushed %zu bytes, %zu left", copy_len, desc->count);

	return copy_len;

}



int mptcp_subflow_discard_data(struct sock *ssk, unsigned int limit)

static void mptcp_subflow_discard_data(struct sock *ssk, struct sk_buff *skb,

				       unsigned int limit)

{

	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);

	u32 map_remaining;

	size_t delta;

	bool fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;

	u32 incr;



	map_remaining = subflow->map_data_len -

			mptcp_subflow_get_map_offset(subflow);

	delta = min_t(size_t, limit, map_remaining);



	/* discard mapped data */

	pr_debug("discarding %zu bytes, current map len=%d", delta,

		 map_remaining);

	if (delta) {

		read_descriptor_t desc = {

			.count = delta,

		};

		int ret;

	incr = limit >= skb->len ? skb->len + fin : limit;



		ret = tcp_read_sock(ssk, &desc, subflow_read_actor);

		if (ret < 0) {

			ssk->sk_err = -ret;

			return ret;

		}

		if (ret < delta)

			return 0;

		if (delta == map_remaining) {

			subflow->data_avail = 0;

	pr_debug("discarding=%d len=%d seq=%d", incr, skb->len,

		 subflow->map_subflow_seq);

	tcp_sk(ssk)->copied_seq += incr;

	if (!before(tcp_sk(ssk)->copied_seq, TCP_SKB_CB(skb)->end_seq))

		sk_eat_skb(ssk, skb);

	if (mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len)

		subflow->map_valid = 0;

}

	}

	return 0;

}



static bool subflow_check_data_avail(struct sock *ssk)

{
@@ -923,9 +895,7 @@ static bool subflow_check_data_avail(struct sock *ssk) 
		/* only accept in-sequence mapping. Old values are spurious

		 * retransmission

		 */

		if (mptcp_subflow_discard_data(ssk, old_ack - ack_seq))

			goto fatal;

		return false;

		mptcp_subflow_discard_data(ssk, skb, old_ack - ack_seq);

	}

	return true;

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