On Wed, Jul 21, 2021 at 9:09 PM Johan Hovold johan@kernel.org wrote:
On Wed, Jul 21, 2021 at 08:53:47PM +0800, Dongliang Mu wrote:
On Wed, Jul 21, 2021 at 8:01 PM Johan Hovold johan@kernel.org wrote:
On Wed, Jul 21, 2021 at 07:33:04PM +0800, Dongliang Mu wrote:
The pairwise api invocation of tty_port_register_device should be tty_port_unregister_device, other than tty_unregister_device.
Are you sure about that? Please explain why you think this to be the case and why this change is needed.
I am sure about this.
I'm afraid you are mistaken. There is a bit of inconsistency in the API, but it is *not* a requirement to use the port helper for deregistration here.
- From the implementation, tty_port_register_device -> tty_port_register_device_attr ->
tty_port_link_device; tty_register_device_attr tty_register_device -> tty_register_device_attr
tty_port_unregister_device -> serdev_tty_port_unregister;tty_unregister_device tty_unregister_device
As to the functionability, tty_port_register_device pairs withtty_port_unregister_device; meanwhile, the same to tty_register_device and tty_unregister_device.
Again, this is not an explanation. Why do think it is needed? What could possibly go wrong if you don't change the code like you propose?
From the function naming style,
tty_port_register_device - tty_port_unregister_device;
tty_register_device - tty_unregister_device
Yes, the naming suggests you should be using the port helper and it is ok to do so, but again, it is not a requirement (unless you're using the serdev variant).
OK, I see. Thanks for your information.
Next time I will double-check the underlying details of each function to verify if they are in pairs.
Fixes: a6afd9f3e819 ("tty: move a number of tty drivers from drivers/char/ to drivers/tty/")
Please try a little harder, that's clearly not the commit that changed to the port registration helper.
Cc: stable@vger.kernel.org
Why do you think this is stable material? (hint: it is not)
From the documentation, this label could make the patch automatically go to stable tree. And stable tree is also using the incorrect api.
No, it is not using an "incorrect api". There is nothing wrong with current code. And it certainly does not need to be changed in stable.
Johan