[PATCH v2 1/2] can: bcm: registration process optimization in bcm_module_init()

From: Ziyang Xuan
Date: Wed Sep 14 2022 - 21:56:11 EST


Now, register_netdevice_notifier() and register_pernet_subsys() are both
after can_proto_register(). It can create CAN_BCM socket and process socket
once can_proto_register() successfully, so it is possible missing notifier
event or proc node creation because notifier or bcm proc directory is not
registered or created yet. Although this is a low probability scenario, it
is not impossible.

Move register_pernet_subsys() and register_netdevice_notifier() to the
front of can_proto_register(). In addition, register_pernet_subsys() and
register_netdevice_notifier() may fail, check their results are necessary.

Signed-off-by: Ziyang Xuan <william.xuanziyang@xxxxxxxxxx>
---
net/can/bcm.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/net/can/bcm.c b/net/can/bcm.c
index e60161bec850..e2783156bfd1 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -1744,15 +1744,27 @@ static int __init bcm_module_init(void)

pr_info("can: broadcast manager protocol\n");

+ err = register_pernet_subsys(&canbcm_pernet_ops);
+ if (err)
+ return err;
+
+ err = register_netdevice_notifier(&canbcm_notifier);
+ if (err)
+ goto register_notifier_failed;
+
err = can_proto_register(&bcm_can_proto);
if (err < 0) {
printk(KERN_ERR "can: registration of bcm protocol failed\n");
- return err;
+ goto register_proto_failed;
}

- register_pernet_subsys(&canbcm_pernet_ops);
- register_netdevice_notifier(&canbcm_notifier);
return 0;
+
+register_proto_failed:
+ unregister_netdevice_notifier(&canbcm_notifier);
+register_notifier_failed:
+ unregister_pernet_subsys(&canbcm_pernet_ops);
+ return err;
}

static void __exit bcm_module_exit(void)
--
2.25.1