Merge: CNB97: saner replacement for debugfs_rename()

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/6762

JIRA: https://issues.redhat.com/browse/RHEL-87378

saner replacement for debugfs_rename()

Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>

Approved-by: Ivan Vecera <ivecera@redhat.com>
Approved-by: Desnes Nunes <desnesn@redhat.com>
Approved-by: Rafael Aquini <raquini@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Augusto Caringi <acaringi@redhat.com>

Author: caringi

Documentation/filesystems/debugfs.rst

@@ -211,18 +211,16 @@ seq_file content.
 
 There are a couple of other directory-oriented helper functions::
 
-    struct dentry *debugfs_rename(struct dentry *old_dir,
-    				  struct dentry *old_dentry,
-		                  struct dentry *new_dir,
-				  const char *new_name);
+    struct dentry *debugfs_change_name(struct dentry *dentry,
+					  const char *fmt, ...);
 
     struct dentry *debugfs_create_symlink(const char *name,
                                           struct dentry *parent,
 				      	  const char *target);
 
-A call to debugfs_rename() will give a new name to an existing debugfs
-file, possibly in a different directory.  The new_name must not exist prior
-to the call; the return value is old_dentry with updated information.
+A call to debugfs_change_name() will give a new name to an existing debugfs
+file, always in the same directory.  The new_name must not exist prior
+to the call; the return value is 0 on success and -E... on failuer.
 Symbolic links can be created with debugfs_create_symlink().
 
 There is one important thing that all debugfs users must take into account:

drivers/net/bonding/bond_debugfs.c

@@ -49,9 +49,6 @@ DEFINE_SHOW_ATTRIBUTE(bond_debug_rlb_hash);
 
 void bond_debug_register(struct bonding *bond)
 {
-	if (!bonding_debug_root)
-		return;
-
 	bond->debug_dir =
 		debugfs_create_dir(bond->dev->name, bonding_debug_root);
 
@@ -61,24 +58,13 @@ void bond_debug_register(struct bonding *bond)
 
 void bond_debug_unregister(struct bonding *bond)
 {
-	if (!bonding_debug_root)
-		return;
-
 	debugfs_remove_recursive(bond->debug_dir);
 }
 
 void bond_debug_reregister(struct bonding *bond)
 {
-	struct dentry *d;
-
-	if (!bonding_debug_root)
-		return;
-
-	d = debugfs_rename(bonding_debug_root, bond->debug_dir,
-			   bonding_debug_root, bond->dev->name);
-	if (d) {
-		bond->debug_dir = d;
-	} else {
+	int err = debugfs_change_name(bond->debug_dir, "%s", bond->dev->name);
+	if (err) {
 		netdev_warn(bond->dev, "failed to reregister, so just unregister old one\n");
 		bond_debug_unregister(bond);
 	}
@@ -88,7 +74,7 @@ void __init bond_create_debugfs(void)
 {
 	bonding_debug_root = debugfs_create_dir("bonding", NULL);
 
-	if (!bonding_debug_root)
+	if (IS_ERR(bonding_debug_root))
 		pr_warn("Warning: Cannot create bonding directory in debugfs\n");
 }
 

drivers/net/bonding/bond_main.c

@@ -6638,16 +6638,16 @@ static int __init bonding_init(void)
 	if (res)
 		goto out;
 
+	bond_create_debugfs();
+
 	res = register_pernet_subsys(&bond_net_ops);
 	if (res)
-		goto out;
+		goto err_net_ops;
 
 	res = bond_netlink_init();
 	if (res)
 		goto err_link;
 
-	bond_create_debugfs();
-
 	for (i = 0; i < max_bonds; i++) {
 		res = bond_create(&init_net, NULL);
 		if (res)
@@ -6662,10 +6662,11 @@ static int __init bonding_init(void)
 out:
 	return res;
 err:
-	bond_destroy_debugfs();
 	bond_netlink_fini();
 err_link:
 	unregister_pernet_subsys(&bond_net_ops);
+err_net_ops:
+	bond_destroy_debugfs();
 	goto out;
 
 }
@@ -6674,11 +6675,11 @@ static void __exit bonding_exit(void)
 {
 	unregister_netdevice_notifier(&bond_netdev_notifier);
 
-	bond_destroy_debugfs();
-
 	bond_netlink_fini();
 	unregister_pernet_subsys(&bond_net_ops);
 
+	bond_destroy_debugfs();
+
 #ifdef CONFIG_NET_POLL_CONTROLLER
 	/* Make sure we don't have an imbalance on our netpoll blocking */
 	WARN_ON(atomic_read(&netpoll_block_tx));

drivers/net/ethernet/amd/xgbe/xgbe-debugfs.c

@@ -505,21 +505,6 @@ void xgbe_debugfs_exit(struct xgbe_prv_data *pdata)
 
 void xgbe_debugfs_rename(struct xgbe_prv_data *pdata)
 {
-	char *buf;
-
-	if (!pdata->xgbe_debugfs)
-		return;
-
-	buf = kasprintf(GFP_KERNEL, "amd-xgbe-%s", pdata->netdev->name);
-	if (!buf)
-		return;
-
-	if (!strcmp(pdata->xgbe_debugfs->d_name.name, buf))
-		goto out;
-
-	debugfs_rename(pdata->xgbe_debugfs->d_parent, pdata->xgbe_debugfs,
-		       pdata->xgbe_debugfs->d_parent, buf);
-
-out:
-	kfree(buf);
+	debugfs_change_name(pdata->xgbe_debugfs,
+			    "amd-xgbe-%s", pdata->netdev->name);
 }

drivers/net/ethernet/marvell/skge.c

@@ -3742,10 +3742,7 @@ static int skge_device_event(struct notifier_block *unused,
 	skge = netdev_priv(dev);
 	switch (event) {
 	case NETDEV_CHANGENAME:
-		if (skge->debugfs)
-			skge->debugfs = debugfs_rename(skge_debug,
-						       skge->debugfs,
-						       skge_debug, dev->name);
+		debugfs_change_name(skge->debugfs, "%s", dev->name);
 		break;
 
 	case NETDEV_GOING_DOWN:

drivers/net/ethernet/marvell/sky2.c

@@ -4635,10 +4635,7 @@ static int sky2_device_event(struct notifier_block *unused,
 
 	switch (event) {
 	case NETDEV_CHANGENAME:
-		if (sky2->debugfs) {
-			sky2->debugfs = debugfs_rename(sky2_debug, sky2->debugfs,
-						       sky2_debug, dev->name);
-		}
+		debugfs_change_name(sky2->debugfs, "%s", dev->name);
 		break;
 
 	case NETDEV_GOING_DOWN:

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -6564,11 +6564,7 @@ static int stmmac_device_event(struct notifier_block *unused,
 
 	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);
+		debugfs_change_name(priv->dbgfs_dir, "%s", dev->name);
 		break;
 	}
 done:

drivers/opp/debugfs.c

@@ -215,7 +215,7 @@ static void opp_migrate_dentry(struct opp_device *opp_dev,
 {
 	struct opp_device *new_dev = NULL, *iter;
 	const struct device *dev;
-	struct dentry *dentry;
+	int err;
 
 	/* Look for next opp-dev */
 	list_for_each_entry(iter, &opp_table->dev_list, node)
@@ -232,16 +232,14 @@ static void opp_migrate_dentry(struct opp_device *opp_dev,
 
 	opp_set_dev_name(dev, opp_table->dentry_name);
 
-	dentry = debugfs_rename(rootdir, opp_dev->dentry, rootdir,
-				opp_table->dentry_name);
-	if (!dentry) {
+	err = debugfs_change_name(opp_dev->dentry, "%s", opp_table->dentry_name);
+	if (err) {
 		dev_err(dev, "%s: Failed to rename link from: %s to %s\n",
 			__func__, dev_name(opp_dev->dev), dev_name(dev));
 		return;
 	}
 
-	new_dev->dentry = dentry;
-	opp_table->dentry = dentry;
+	new_dev->dentry = opp_table->dentry = opp_dev->dentry;
 }
 
 /**