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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jiping Ma <jiping.ma2@windriver.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 072/110] stmmac: debugfs entry name is not be changed when udev rename device name.
Date:   Thu, 30 Jan 2020 19:38:48 +0100
Message-Id: <20200130183622.973401988@linuxfoundation.org>
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From: Jiping Ma <jiping.ma2@windriver.com>

[ Upstream commit 481a7d154cbbd5ca355cc01cc8969876b240eded ]

Add one notifier for udev changes net device name.
Fixes: b6601323ef9e ("net: stmmac: debugfs entry name is not be changed when udev rename")

Signed-off-by: Jiping Ma <jiping.ma2@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 1b3520d0e59ef..06dd65c419c49 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -105,6 +105,7 @@ MODULE_PARM_DESC(chain_mode, "To use chain instead of ring mode");
 static irqreturn_t stmmac_interrupt(int irq, void *dev_id);
 
 #ifdef CONFIG_DEBUG_FS
+static const struct net_device_ops stmmac_netdev_ops;
 static void stmmac_init_fs(struct net_device *dev);
 static void stmmac_exit_fs(struct net_device *dev);
 #endif
@@ -4175,6 +4176,34 @@ static int stmmac_dma_cap_show(struct seq_file *seq, void *v)
 }
 DEFINE_SHOW_ATTRIBUTE(stmmac_dma_cap);
 
+/* Use network device events to rename debugfs file entries.
+ */
+static int stmmac_device_event(struct notifier_block *unused,
+			       unsigned long event, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct stmmac_priv *priv = netdev_priv(dev);
+
+	if (dev->netdev_ops != &stmmac_netdev_ops)
+		goto done;
+
+	switch (event) {
+	case NETDEV_CHANGENAME:
+		if (priv->dbgfs_dir)
+			priv->dbgfs_dir = debugfs_rename(stmmac_fs_dir,
+							 priv->dbgfs_dir,
+							 stmmac_fs_dir,
+							 dev->name);
+		break;
+	}
+done:
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block stmmac_notifier = {
+	.notifier_call = stmmac_device_event,
+};
+
 static void stmmac_init_fs(struct net_device *dev)
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
@@ -4189,12 +4218,15 @@ static void stmmac_init_fs(struct net_device *dev)
 	/* Entry to report the DMA HW features */
 	debugfs_create_file("dma_cap", 0444, priv->dbgfs_dir, dev,
 			    &stmmac_dma_cap_fops);
+
+	register_netdevice_notifier(&stmmac_notifier);
 }
 
 static void stmmac_exit_fs(struct net_device *dev)
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
 
+	unregister_netdevice_notifier(&stmmac_notifier);
 	debugfs_remove_recursive(priv->dbgfs_dir);
 }
 #endif /* CONFIG_DEBUG_FS */
-- 
2.20.1