Re: [PATCH] serial: core: Add support for dev_name:0.0 naming for kernel console

Jiri Slaby
2023-07-19T05:36:43Z

On 19. 07. 23, 7:32, Tony Lindgren wrote:
> * Jiri Slaby <jirislaby@kernel.org> [230719 05:29]:
>> On 19. 07. 23, 7:28, Tony Lindgren wrote:
>>> * Jiri Slaby <jirislaby@kernel.org> [230719 05:25]:
>>>> On 19. 07. 23, 7:15, Tony Lindgren wrote:
>>>>> +/*
>>>>> + * Add preferred console if configured on kernel command line with naming
>>>>> + * "console=dev_name:0.0".
>>>>> + */
>>>>> +static int serial_core_add_preferred_console(struct uart_driver *drv,
>>>>> + struct uart_port *port)
>>>>> +{
>>>>> + char *port_match, *opt, *name;
>>>>> + int len, ret = 0;
>>>>> +
>>>>> + port_match = kasprintf(GFP_KERNEL, "console=%s:%i.%i",
>>>>> + dev_name(port->dev), port->ctrl_id,
>>>>> + port->port_id);
>>>>> + if (!port_match)
>>>>> + return -ENOMEM;
>>>>> +
>>>>> + opt = strstr(saved_command_line, port_match);
>>>>> + if (!opt)
>>>>> + goto free_port_match;
>>>>> +
>>>>> + len = strlen(port_match);
>>>>> +
>>>>> + if (strlen(opt) > len + 1 && opt[len] == ',')
>>>>> + opt += len + 1;
>>>>> + else
>>>>> + opt = NULL;
>>>>> +
>>>>> + name = kstrdup(drv->dev_name, GFP_KERNEL);
>>>>
>>>> Why do you dup the name here?
>>>
>>> I was getting ignoring const warning, but maybe the right solution is
>>> to just use const char *name here.. Let me check.
>>
>> So fix add_preferred_console() instead ;).
>
> Let's see what kind of trouble changing it to use const char *name
> might be.

I don't see any, the string is copied internally. So it should be
straightforward. Actually all three parameters of
__add_preferred_console() should be const, IMO. But that involves
changing struct console_cmdline. But that should be straightforward too.

Aside from that, why do you parse saved_command_line on your own?
Instead of using setup() or other commonly used mechanisms for command
line handling?

thanks,
--
js
suse labs