Commit a6f0459a authored by Paolo Abeni's avatar Paolo Abeni Committed by Jakub Kicinski
Browse files

mptcp: fix subflow rcvbuf adjust 



The mptcp PM can add subflow to the conn_list before tcp_init_transfer().
Calling tcp_rcvbuf_grow() on such subflow is not correct as later
init will overwrite the update.

Fix the issue calling tcp_rcvbuf_grow() only after init buffer
initialization.

Fixes: e118cdc3 ("mptcp: rcvbuf auto-tuning improvement")
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251028-net-tcp-recv-autotune-v3-1-74b43ba4c84c@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent f99c5792

net/mptcp/protocol.c

+6 −2
Original line number Diff line number Diff line
@@ -2051,6 +2051,7 @@ static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied) 


	msk->rcvq_space.space = msk->rcvq_space.copied;

	if (mptcp_rcvbuf_grow(sk)) {

		int copied = msk->rcvq_space.copied;



		/* Make subflows follow along.  If we do not do this, we

		 * get drops at subflow level if skbs can't be moved to
@@ -2063,8 +2064,11 @@ static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied) 


			ssk = mptcp_subflow_tcp_sock(subflow);

			slow = lock_sock_fast(ssk);

			tcp_sk(ssk)->rcvq_space.space = msk->rcvq_space.copied;

			/* subflows can be added before tcp_init_transfer() */

			if (tcp_sk(ssk)->rcvq_space.space) {

				tcp_sk(ssk)->rcvq_space.space = copied;

				tcp_rcvbuf_grow(ssk);

			}

			unlock_sock_fast(ssk, slow);

		}

	}