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Subject[MPTCP][PATCH net-next 07/16] mptcp: add accept_subflow re-check
Date
The re-check of pm->accept_subflow with pm->lock held was missing, this
patch fixed it.

Suggested-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
---
net/mptcp/pm.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 39a76620d0a5..be4157279e15 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -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);
- ret = pm->subflows < pm->subflows_max;
- if (ret && ++pm->subflows == pm->subflows_max)
- WRITE_ONCE(pm->accept_subflow, false);
+ 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;
--
2.17.1
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