[PATCH 2/3] xhci: dbgtty: Fix unregister on tty_alloc_driver() failure

[Lucas De Marchi]

Make sure to set dbc_tty_driver to NULL to match the check in
dbc_tty_exit(). For that, make detached error handling path common to the
other branch in the same function.

Fixes: 4521f1613940 ("xhci: dbctty: split dbc tty driver registration and unregistration functions.")
Cc: stable@xxxxxxxxxxxxxxx # v5.10
Cc: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Lucas De Marchi <ldemarchi@xxxxxxxxxx>
---
 drivers/usb/host/xhci-dbgtty.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c
index 01decd46f313..7e44e62d6ea9 100644
--- a/drivers/usb/host/xhci-dbgtty.c
+++ b/drivers/usb/host/xhci-dbgtty.c
@@ -628,8 +628,8 @@ int dbc_tty_init(void)
 	dbc_tty_driver = tty_alloc_driver(64, TTY_DRIVER_REAL_RAW |
 					  TTY_DRIVER_DYNAMIC_DEV);
 	if (IS_ERR(dbc_tty_driver)) {
-		idr_destroy(&dbc_tty_minors);
-		return PTR_ERR(dbc_tty_driver);
+		ret = PTR_ERR(dbc_tty_driver);
+		goto fail;
 	}
 
 	dbc_tty_driver->driver_name = "dbc_serial";
@@ -649,11 +649,17 @@ int dbc_tty_init(void)
 	ret = tty_register_driver(dbc_tty_driver);
 	if (ret) {
 		pr_err("Can't register dbc tty driver\n");
-		tty_driver_kref_put(dbc_tty_driver);
-		idr_destroy(&dbc_tty_minors);
-		dbc_tty_driver = NULL;
+		goto fail_put;
 	}
 
+	return ret;
+
+fail_put:
+	tty_driver_kref_put(dbc_tty_driver);
+fail:
+	idr_destroy(&dbc_tty_minors);
+	dbc_tty_driver = NULL;
+
 	return ret;
 }
 
-- 
2.54.0