Commit f58f065a authored by Geliang Tang's avatar Geliang Tang Committed by David S. Miller
Browse files

mptcp: add accept_subflow re-check 



The re-check of pm->accept_subflow with pm->lock held was missing, this
patch fixed it.

Suggested-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Reviewed-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarGeliang Tang <geliangtang@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent be613160

net/mptcp/pm.c

+6 −4
Original line number Diff line number Diff line
@@ -48,7 +48,7 @@ void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side) 
bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)

{

	struct mptcp_pm_data *pm = &msk->pm;

	int ret;

	int ret = 0;



	pr_debug("msk=%p subflows=%d max=%d allow=%d", msk, pm->subflows,

		 pm->subflows_max, READ_ONCE(pm->accept_subflow));
@@ -58,9 +58,11 @@ bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk) 
		return false;



	spin_lock_bh(&pm->lock);

	if (READ_ONCE(pm->accept_subflow)) {

		ret = pm->subflows < pm->subflows_max;

		if (ret && ++pm->subflows == pm->subflows_max)

			WRITE_ONCE(pm->accept_subflow, false);

	}

	spin_unlock_bh(&pm->lock);



	return ret;