Patch "net: stmmac: Move debugfs init/exit to ->probe()/->remove()" has been added to the 4.14-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    net: stmmac: Move debugfs init/exit to ->probe()/->remove()

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-stmmac-move-debugfs-init-exit-to-probe-remove.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 959fa621be56021462f161720a958461e54df524
Author: Thierry Reding <treding@xxxxxxxxxx>
Date:   Tue Nov 27 14:21:43 2018 +0100

    net: stmmac: Move debugfs init/exit to ->probe()/->remove()
    
    [ Upstream commit 5f2b8b62786853341a20d4cd4948f9cbca3db002 ]
    
    Setting up and tearing down debugfs is current unbalanced, as seen by
    this error during resume from suspend:
    
        [  752.134067] dwc-eth-dwmac 2490000.ethernet eth0: ERROR failed to create debugfs directory
        [  752.134347] dwc-eth-dwmac 2490000.ethernet eth0: stmmac_hw_setup: failed debugFS registration
    
    The imbalance happens because the driver creates the debugfs hierarchy
    when the device is opened and tears it down when the device is closed.
    There's little gain in that, and it could be argued that it is even
    surprising because it's not usually done for other devices. Fix the
    imbalance by moving the debugfs creation and teardown to the driver's
    ->probe() and ->remove() implementations instead.
    
    Note that the ring descriptors cannot be read while the interface is
    down, so make sure to return an empty file when the descriptors_status
    debugfs file is read.
    
    Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
    Acked-by: Jose Abreu <joabreu@xxxxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 0f85e540001ff..f4df9ab0aed5f 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2530,12 +2530,6 @@ static int stmmac_hw_setup(struct net_device *dev, bool init_ptp)
 			netdev_warn(priv->dev, "PTP init failed\n");
 	}
 
-#ifdef CONFIG_DEBUG_FS
-	ret = stmmac_init_fs(dev);
-	if (ret < 0)
-		netdev_warn(priv->dev, "%s: failed debugFS registration\n",
-			    __func__);
-#endif
 	priv->tx_lpi_timer = STMMAC_DEFAULT_TWT_LS;
 
 	if ((priv->use_riwt) && (priv->hw->dma->rx_watchdog)) {
@@ -2729,10 +2723,6 @@ static int stmmac_release(struct net_device *dev)
 
 	netif_carrier_off(dev);
 
-#ifdef CONFIG_DEBUG_FS
-	stmmac_exit_fs(dev);
-#endif
-
 	stmmac_release_ptp(priv);
 
 	return 0;
@@ -3839,6 +3829,9 @@ static int stmmac_sysfs_ring_read(struct seq_file *seq, void *v)
 	u32 tx_count = priv->plat->tx_queues_to_use;
 	u32 queue;
 
+	if ((dev->flags & IFF_UP) == 0)
+		return 0;
+
 	for (queue = 0; queue < rx_count; queue++) {
 		struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
 
@@ -4310,6 +4303,13 @@ int stmmac_dvr_probe(struct device *device,
 		goto error_netdev_register;
 	}
 
+#ifdef CONFIG_DEBUG_FS
+	ret = stmmac_init_fs(ndev);
+	if (ret < 0)
+		netdev_warn(priv->dev, "%s: failed debugFS registration\n",
+			    __func__);
+#endif
+
 	return ret;
 
 error_netdev_register:
@@ -4343,6 +4343,9 @@ int stmmac_dvr_remove(struct device *dev)
 
 	netdev_info(priv->dev, "%s: removing driver", __func__);
 
+#ifdef CONFIG_DEBUG_FS
+	stmmac_exit_fs(ndev);
+#endif
 	stmmac_stop_all_dma(priv);
 
 	priv->hw->mac->set_mac(priv->ioaddr, false);