[PATCH AUTOSEL for 4.9 154/156] IB/ipoib: Grab rtnl lock on heavy flush when calling ndo_open/stop

[alexander . levin]

From: Alex Vesker <va...@mellanox.com>

[ Upstream commit b4b678b06f6eef18bff44a338c01870234db0bc9 ]

When ndo_open and ndo_stop are called RTNL lock should be held.
In this specific case ipoib_ib_dev_open calls the offloaded ndo_open
which re-sets the number of TX queue assuming RTNL lock is held.
Since RTNL lock is not held, RTNL assert will fail.

Signed-off-by: Alex Vesker <va...@mellanox.com>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
---
 drivers/infiniband/ulp/ipoib/ipoib_ib.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c 
b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
index 830fecb6934c..335bd2c9e16e 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
@@ -1177,10 +1177,15 @@ static void __ipoib_ib_dev_flush(struct ipoib_dev_priv 
*priv,
                ipoib_ib_dev_down(dev);
 
        if (level == IPOIB_FLUSH_HEAVY) {
+               rtnl_lock();
                if (test_bit(IPOIB_FLAG_INITIALIZED, &priv->flags))
                        ipoib_ib_dev_stop(dev);
-               if (ipoib_ib_dev_open(dev) != 0)
+
+               result = ipoib_ib_dev_open(dev);
+               rtnl_unlock();
+               if (result)
                        return;
+
                if (netif_queue_stopped(dev))
                        netif_start_queue(dev);
        }
-- 
2.11.0