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From:   Wong Vee Khee <vee.khee.wong@intel.com>
To:     Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        Jose Abreu <joabreu@synopsys.com>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc:     netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Ong Boon Leong <boon.leong.ong@intel.com>,
        Voon Wei Feng <weifeng.voon@intel.com>,
        Tan Tee Min <tee.min.tan@intel.com>,
        Wong Vee Khee <vee.khee.wong@intel.com>,
        Vijaya Balan Sadhishkhanna 
        <sadhishkhanna.vijaya.balan@intel.com>,
        Seow Chen Yong <chen.yong.seow@intel.com>
Subject: [PATCH net-next] net: stmmac: introduce rtnl_lock|unlock() on configuring real_num_rx|tx_queues
Date:   Thu, 17 Sep 2020 13:02:15 +0800
Message-Id: <20200917050215.8725-1-vee.khee.wong@intel.com>
Precedence: bulk

From: "Tan, Tee Min" <tee.min.tan@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.tan@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