[PATCH net-next] net: stmmac: introduce rtnl_lock|unlock() on configuring real_num_rx|tx_queues

[Wong Vee Khee]

From: "Tan, Tee Min" <tee.min....@intel.com>

For driver open(), rtnl_lock is acquired by network stack but not in the
resume(). Therefore, we introduce lock_acquired boolean to control when
to use rtnl_lock|unlock() within stmmac_hw_setup().

Fixes: 686cff3d7022 ("net: stmmac: Fix incorrect location to set 
real_num_rx|tx_queues")

Signed-off-by: Tan, Tee Min <tee.min....@intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c 
b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index df2c74bbfcff..22e6a3defa78 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2607,7 +2607,8 @@ static void stmmac_safety_feat_configuration(struct 
stmmac_priv *priv)
  *  0 on success and an appropriate (-)ve integer as defined in errno.h
  *  file on failure.
  */
-static int stmmac_hw_setup(struct net_device *dev, bool init_ptp)
+static int stmmac_hw_setup(struct net_device *dev, bool init_ptp,
+                          bool lock_acquired)
 {
        struct stmmac_priv *priv = netdev_priv(dev);
        u32 rx_cnt = priv->plat->rx_queues_to_use;
@@ -2715,9 +2716,15 @@ static int stmmac_hw_setup(struct net_device *dev, bool 
init_ptp)
        }
 
        /* Configure real RX and TX queues */
+       if (!lock_acquired)
+               rtnl_lock();
+
        netif_set_real_num_rx_queues(dev, priv->plat->rx_queues_to_use);
        netif_set_real_num_tx_queues(dev, priv->plat->tx_queues_to_use);
 
+       if (!lock_acquired)
+               rtnl_unlock();
+
        /* Start the ball rolling... */
        stmmac_start_all_dma(priv);
 
@@ -2804,7 +2811,7 @@ static int stmmac_open(struct net_device *dev)
                goto init_error;
        }
 
-       ret = stmmac_hw_setup(dev, true);
+       ret = stmmac_hw_setup(dev, true, true);
        if (ret < 0) {
                netdev_err(priv->dev, "%s: Hw setup failed\n", __func__);
                goto init_error;
@@ -5238,7 +5245,7 @@ int stmmac_resume(struct device *dev)
 
        stmmac_clear_descriptors(priv);
 
-       stmmac_hw_setup(ndev, false);
+       stmmac_hw_setup(ndev, false, false);
        stmmac_init_coalesce(priv);
        stmmac_set_rx_mode(ndev);
 
-- 
2.17.0