Commit e3859603 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

mptcp: better msk receive window updates 



Move mptcp_cleanup_rbuf() related checks inside the mentioned
helper and extend them to mirror TCP checks more closely.

Additionally drop the 'rmem_pending' hack, since commit 87952603
("mptcp: protect the rx path with the msk socket spinlock") we
can use instead 'rmem_released'.

Fixes: ea4ca586 ("mptcp: refine MPTCP-level ack scheduling")
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d8b59efa

net/mptcp/options.c

+4 −3
Original line number Diff line number Diff line
@@ -498,8 +498,8 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, 
{

	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);

	struct mptcp_sock *msk = mptcp_sk(subflow->conn);

	u64 snd_data_fin_enable, ack_seq;

	unsigned int dss_size = 0;

	u64 snd_data_fin_enable;

	struct mptcp_ext *mpext;

	unsigned int ack_size;

	bool ret = false;
@@ -531,13 +531,14 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, 
		return ret;

	}



	ack_seq = READ_ONCE(msk->ack_seq);

	if (READ_ONCE(msk->use_64bit_ack)) {

		ack_size = TCPOLEN_MPTCP_DSS_ACK64;

		opts->ext_copy.data_ack = READ_ONCE(msk->ack_seq);

		opts->ext_copy.data_ack = ack_seq;

		opts->ext_copy.ack64 = 1;

	} else {

		ack_size = TCPOLEN_MPTCP_DSS_ACK32;

		opts->ext_copy.data_ack32 = (uint32_t)READ_ONCE(msk->ack_seq);

		opts->ext_copy.data_ack32 = (uint32_t)ack_seq;

		opts->ext_copy.ack64 = 0;

	}

	opts->ext_copy.use_ack = 1;

net/mptcp/protocol.c

+22 −16
Original line number Diff line number Diff line
@@ -457,7 +457,18 @@ static bool mptcp_subflow_cleanup_rbuf(struct sock *ssk) 
static void mptcp_cleanup_rbuf(struct mptcp_sock *msk)

{

	struct sock *ack_hint = READ_ONCE(msk->ack_hint);

	int old_space = READ_ONCE(msk->old_wspace);

	struct mptcp_subflow_context *subflow;

	struct sock *sk = (struct sock *)msk;

	bool cleanup;



	/* this is a simple superset of what tcp_cleanup_rbuf() implements

	 * so that we don't have to acquire the ssk socket lock most of the time

	 * to do actually nothing

	 */

	cleanup = __mptcp_space(sk) - old_space >= max(0, old_space);

	if (!cleanup)

		return;



	/* if the hinted ssk is still active, try to use it */

	if (likely(ack_hint)) {
@@ -1865,7 +1876,7 @@ static void __mptcp_splice_receive_queue(struct sock *sk) 
	skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue);

}



static bool __mptcp_move_skbs(struct mptcp_sock *msk, unsigned int rcv)

static bool __mptcp_move_skbs(struct mptcp_sock *msk)

{

	struct sock *sk = (struct sock *)msk;

	unsigned int moved = 0;
@@ -1885,13 +1896,10 @@ static bool __mptcp_move_skbs(struct mptcp_sock *msk, unsigned int rcv) 


		slowpath = lock_sock_fast(ssk);

		mptcp_data_lock(sk);

		__mptcp_update_rmem(sk);

		done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);

		mptcp_data_unlock(sk);

		if (moved && rcv) {

			WRITE_ONCE(msk->rmem_pending, min(rcv, moved));

			tcp_cleanup_rbuf(ssk, 1);

			WRITE_ONCE(msk->rmem_pending, 0);

		}

		tcp_cleanup_rbuf(ssk, moved);

		unlock_sock_fast(ssk, slowpath);

	} while (!done);
@@ -1904,6 +1912,7 @@ static bool __mptcp_move_skbs(struct mptcp_sock *msk, unsigned int rcv) 
		ret |= __mptcp_ofo_queue(msk);

		__mptcp_splice_receive_queue(sk);

		mptcp_data_unlock(sk);

		mptcp_cleanup_rbuf(msk);

	}

	if (ret)

		mptcp_check_data_fin((struct sock *)msk);
@@ -1933,7 +1942,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 
	target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);



	while (copied < len) {

		int bytes_read, old_space;

		int bytes_read;



		bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied);

		if (unlikely(bytes_read < 0)) {
@@ -1944,15 +1953,12 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 


		copied += bytes_read;



		if (skb_queue_empty(&msk->receive_queue) &&

		    __mptcp_move_skbs(msk, len - copied))

			continue;



		/* be sure to advertise window change */

		old_space = READ_ONCE(msk->old_wspace);

		if ((tcp_space(sk) - old_space) >= old_space)

		mptcp_cleanup_rbuf(msk);



		if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk))

			continue;



		/* only the master socket status is relevant here. The exit

		 * conditions mirror closely tcp_recvmsg()

		 */
@@ -1979,7 +1985,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 
				/* race breaker: the shutdown could be after the

				 * previous receive queue check

				 */

				if (__mptcp_move_skbs(msk, len - copied))

				if (__mptcp_move_skbs(msk))

					continue;

				break;

			}
@@ -2012,7 +2018,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 
		/* .. race-breaker: ssk might have gotten new data

		 * after last __mptcp_move_skbs() returned false.

		 */

		if (unlikely(__mptcp_move_skbs(msk, 0)))

		if (unlikely(__mptcp_move_skbs(msk)))

			set_bit(MPTCP_DATA_READY, &msk->flags);

	} else if (unlikely(!test_bit(MPTCP_DATA_READY, &msk->flags))) {

		/* data to read but mptcp_wait_data() cleared DATA_READY */

net/mptcp/protocol.h

+1 −2
Original line number Diff line number Diff line
@@ -234,7 +234,6 @@ struct mptcp_sock { 
	u64		wnd_end;

	unsigned long	timer_ival;

	u32		token;

	int		rmem_pending;

	int		rmem_released;

	unsigned long	flags;

	bool		can_ack;
@@ -293,7 +292,7 @@ static inline struct mptcp_sock *mptcp_sk(const struct sock *sk) 


static inline int __mptcp_space(const struct sock *sk)

{

	return tcp_space(sk) + READ_ONCE(mptcp_sk(sk)->rmem_pending);

	return tcp_space(sk) + READ_ONCE(mptcp_sk(sk)->rmem_released);

}



static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)