USB: ULPI: fix memory leak with using debugfs_lookup()

[ Upstream commit 8f4d25eba599c4bd4b5ea8ae8752cda480a9d563 ]

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20230202153235.2412790-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c
index d7c8461..3870378 100644 (file)
--- a/drivers/usb/common/ulpi.c
+++ b/drivers/usb/common/ulpi.c
@@ -271,7 +271,7 @@ static int ulpi_regs_show(struct seq_file *seq, void *data)
 }
 DEFINE_SHOW_ATTRIBUTE(ulpi_regs);
 
-#define ULPI_ROOT debugfs_lookup(KBUILD_MODNAME, NULL)
+static struct dentry *ulpi_root;
 
 static int ulpi_register(struct device *dev, struct ulpi *ulpi)
 {
@@ -301,7 +301,7 @@ static int ulpi_register(struct device *dev, struct ulpi *ulpi)
                return ret;
        }
 
-       root = debugfs_create_dir(dev_name(dev), ULPI_ROOT);
+       root = debugfs_create_dir(dev_name(dev), ulpi_root);
        debugfs_create_file("regs", 0444, root, ulpi, &ulpi_regs_fops);
 
        dev_dbg(&ulpi->dev, "registered ULPI PHY: vendor %04x, product %04x\n",
@@ -349,8 +349,7 @@ EXPORT_SYMBOL_GPL(ulpi_register_interface);
  */
 void ulpi_unregister_interface(struct ulpi *ulpi)
 {
-       debugfs_remove_recursive(debugfs_lookup(dev_name(&ulpi->dev),
-                                               ULPI_ROOT));
+       debugfs_lookup_and_remove(dev_name(&ulpi->dev), ulpi_root);
        device_unregister(&ulpi->dev);
 }
 EXPORT_SYMBOL_GPL(ulpi_unregister_interface);
@@ -360,12 +359,11 @@ EXPORT_SYMBOL_GPL(ulpi_unregister_interface);
 static int __init ulpi_init(void)
 {
        int ret;
-       struct dentry *root;
 
-       root = debugfs_create_dir(KBUILD_MODNAME, NULL);
+       ulpi_root = debugfs_create_dir(KBUILD_MODNAME, NULL);
        ret = bus_register(&ulpi_bus);
        if (ret)
-               debugfs_remove(root);
+               debugfs_remove(ulpi_root);
        return ret;
 }
 subsys_initcall(ulpi_init);
@@ -373,7 +371,7 @@ subsys_initcall(ulpi_init);
 static void __exit ulpi_exit(void)
 {
        bus_unregister(&ulpi_bus);
-       debugfs_remove_recursive(ULPI_ROOT);
+       debugfs_remove(ulpi_root);
 }
 module_exit(ulpi_exit);