Merge branch 'fsl-fman-fix-refcount-handling-of-fman-related-devices'

Aleksandr Mishin says:

====================
fsl/fman: Fix refcount handling of fman-related devices

The series is intended to fix refcount handling for fman-related "struct
device" objects - the devices are not released upon driver removal or in
the error paths during probe. This leads to device reference leaks.

The device pointers are now saved to struct mac_device and properly handled
in the driver's probe and removal functions.

Originally reported by Simon Horman <horms@kernel.org>
(https://lore.kernel.org/all/20240702133651.GK598357@kernel.org/)

Compile tested only.
====================

Link: https://patch.msgid.link/20241015060122.25709-1-amishin@t-argos.ru
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: Paolo Abeni

drivers/net/ethernet/freescale/fman/mac.c

@@ -197,55 +197,67 @@ static int mac_probe(struct platform_device *_of_dev)
 		err = -EINVAL;
 		goto _return_of_node_put;
 	}
+	mac_dev->fman_dev = &of_dev->dev;
 
 	/* Get the FMan cell-index */
 	err = of_property_read_u32(dev_node, "cell-index", &val);
 	if (err) {
 		dev_err(dev, "failed to read cell-index for %pOF\n", dev_node);
 		err = -EINVAL;
-		goto _return_of_node_put;
+		goto _return_dev_put;
 	}
 	/* cell-index 0 => FMan id 1 */
 	fman_id = (u8)(val + 1);
 
-	priv->fman = fman_bind(&of_dev->dev);
+	priv->fman = fman_bind(mac_dev->fman_dev);
 	if (!priv->fman) {
 		dev_err(dev, "fman_bind(%pOF) failed\n", dev_node);
 		err = -ENODEV;
-		goto _return_of_node_put;
+		goto _return_dev_put;
 	}
 
+	/* Two references have been taken in of_find_device_by_node()
+	 * and fman_bind(). Release one of them here. The second one
+	 * will be released in mac_remove().
+	 */
+	put_device(mac_dev->fman_dev);
 	of_node_put(dev_node);
+	dev_node = NULL;
 
 	/* Get the address of the memory mapped registers */
 	mac_dev->res = platform_get_mem_or_io(_of_dev, 0);
 	if (!mac_dev->res) {
 		dev_err(dev, "could not get registers\n");
-		return -EINVAL;
+		err = -EINVAL;
+		goto _return_dev_put;
 	}
 
 	err = devm_request_resource(dev, fman_get_mem_region(priv->fman),
 				    mac_dev->res);
 	if (err) {
 		dev_err_probe(dev, err, "could not request resource\n");
-		return err;
+		goto _return_dev_put;
 	}
 
 	mac_dev->vaddr = devm_ioremap(dev, mac_dev->res->start,
 				      resource_size(mac_dev->res));
 	if (!mac_dev->vaddr) {
 		dev_err(dev, "devm_ioremap() failed\n");
-		return -EIO;
+		err = -EIO;
+		goto _return_dev_put;
 	}
 
-	if (!of_device_is_available(mac_node))
-		return -ENODEV;
+	if (!of_device_is_available(mac_node)) {
+		err = -ENODEV;
+		goto _return_dev_put;
+	}
 
 	/* Get the cell-index */
 	err = of_property_read_u32(mac_node, "cell-index", &val);
 	if (err) {
 		dev_err(dev, "failed to read cell-index for %pOF\n", mac_node);
-		return -EINVAL;
+		err = -EINVAL;
+		goto _return_dev_put;
 	}
 	priv->cell_index = (u8)val;
 
@@ -259,40 +271,51 @@ static int mac_probe(struct platform_device *_of_dev)
 	if (unlikely(nph < 0)) {
 		dev_err(dev, "of_count_phandle_with_args(%pOF, fsl,fman-ports) failed\n",
 			mac_node);
-		return nph;
+		err = nph;
+		goto _return_dev_put;
 	}
 
 	if (nph != ARRAY_SIZE(mac_dev->port)) {
 		dev_err(dev, "Not supported number of fman-ports handles of mac node %pOF from device tree\n",
 			mac_node);
-		return -EINVAL;
+		err = -EINVAL;
+		goto _return_dev_put;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(mac_dev->port); i++) {
+	/* PORT_NUM determines the size of the port array */
+	for (i = 0; i < PORT_NUM; i++) {
 		/* Find the port node */
 		dev_node = of_parse_phandle(mac_node, "fsl,fman-ports", i);
 		if (!dev_node) {
 			dev_err(dev, "of_parse_phandle(%pOF, fsl,fman-ports) failed\n",
 				mac_node);
-			return -EINVAL;
+			err = -EINVAL;
+			goto _return_dev_arr_put;
 		}
 
 		of_dev = of_find_device_by_node(dev_node);
 		if (!of_dev) {
 			dev_err(dev, "of_find_device_by_node(%pOF) failed\n",
 				dev_node);
 			err = -EINVAL;
-			goto _return_of_node_put;
+			goto _return_dev_arr_put;
 		}
+		mac_dev->fman_port_devs[i] = &of_dev->dev;
 
-		mac_dev->port[i] = fman_port_bind(&of_dev->dev);
+		mac_dev->port[i] = fman_port_bind(mac_dev->fman_port_devs[i]);
 		if (!mac_dev->port[i]) {
 			dev_err(dev, "dev_get_drvdata(%pOF) failed\n",
 				dev_node);
 			err = -EINVAL;
-			goto _return_of_node_put;
+			goto _return_dev_arr_put;
 		}
+		/* Two references have been taken in of_find_device_by_node()
+		 * and fman_port_bind(). Release one of them here. The second
+		 * one will be released in mac_remove().
+		 */
+		put_device(mac_dev->fman_port_devs[i]);
 		of_node_put(dev_node);
+		dev_node = NULL;
 	}
 
 	/* Get the PHY connection type */
@@ -312,7 +335,7 @@ static int mac_probe(struct platform_device *_of_dev)
 
 	err = init(mac_dev, mac_node, &params);
 	if (err < 0)
-		return err;
+		goto _return_dev_arr_put;
 
 	if (!is_zero_ether_addr(mac_dev->addr))
 		dev_info(dev, "FMan MAC address: %pM\n", mac_dev->addr);
@@ -327,6 +350,12 @@ static int mac_probe(struct platform_device *_of_dev)
 
 	return err;
 
+_return_dev_arr_put:
+	/* mac_dev is kzalloc'ed */
+	for (i = 0; i < PORT_NUM; i++)
+		put_device(mac_dev->fman_port_devs[i]);
+_return_dev_put:
+	put_device(mac_dev->fman_dev);
 _return_of_node_put:
 	of_node_put(dev_node);
 	return err;
@@ -335,6 +364,11 @@ static int mac_probe(struct platform_device *_of_dev)
 static void mac_remove(struct platform_device *pdev)
 {
 	struct mac_device *mac_dev = platform_get_drvdata(pdev);
+	int		   i;
+
+	for (i = 0; i < PORT_NUM; i++)
+		put_device(mac_dev->fman_port_devs[i]);
+	put_device(mac_dev->fman_dev);
 
 	platform_device_unregister(mac_dev->priv->eth_dev);
 }

drivers/net/ethernet/freescale/fman/mac.h

@@ -19,12 +19,13 @@
 struct fman_mac;
 struct mac_priv_s;
 
+#define PORT_NUM 2
 struct mac_device {
 	void __iomem		*vaddr;
 	struct device		*dev;
 	struct resource		*res;
 	u8			 addr[ETH_ALEN];
-	struct fman_port	*port[2];
+	struct fman_port	*port[PORT_NUM];
 	struct phylink		*phylink;
 	struct phylink_config	phylink_config;
 	phy_interface_t		phy_if;
@@ -52,6 +53,9 @@ struct mac_device {
 
 	struct fman_mac		*fman_mac;
 	struct mac_priv_s	*priv;
+
+	struct device		*fman_dev;
+	struct device		*fman_port_devs[PORT_NUM];
 };
 
 static inline struct mac_device