[PATCH] tty: ehv_bytechan: clean up init error handling

From: Johan Hovold
Date: Wed Apr 26 2017 - 06:30:45 EST


Straighten out the initcall error handling to avoid deregistering a
never-registered tty driver (something which would lead to a
NULL-pointer dereference) in the most unlikely event that driver
registration fails (e.g. we've run out of major numbers).

Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/tty/ehv_bytechan.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/tty/ehv_bytechan.c b/drivers/tty/ehv_bytechan.c
index 7ac9bcdf1e61..61fe8d6fd24e 100644
--- a/drivers/tty/ehv_bytechan.c
+++ b/drivers/tty/ehv_bytechan.c
@@ -764,7 +764,7 @@ static int __init ehv_bc_init(void)
ehv_bc_driver = alloc_tty_driver(count);
if (!ehv_bc_driver) {
ret = -ENOMEM;
- goto error;
+ goto err_free_bcs;
}

ehv_bc_driver->driver_name = "ehv-bc";
@@ -778,24 +778,23 @@ static int __init ehv_bc_init(void)
ret = tty_register_driver(ehv_bc_driver);
if (ret) {
pr_err("ehv-bc: could not register tty driver (ret=%i)\n", ret);
- goto error;
+ goto err_put_tty_driver;
}

ret = platform_driver_register(&ehv_bc_tty_driver);
if (ret) {
pr_err("ehv-bc: could not register platform driver (ret=%i)\n",
ret);
- goto error;
+ goto err_deregister_tty_driver;
}

return 0;

-error:
- if (ehv_bc_driver) {
- tty_unregister_driver(ehv_bc_driver);
- put_tty_driver(ehv_bc_driver);
- }
-
+err_deregister_tty_driver:
+ tty_unregister_driver(ehv_bc_driver);
+err_put_tty_driver:
+ put_tty_driver(ehv_bc_driver);
+err_free_bcs:
kfree(bcs);

return ret;
--
2.12.2