Re: [PATCH v2] printk: Set console_set_on_cmdline=1 when __add_preferred_console() is called with user_specified == true

Petr Mladek
2022-02-15T17:58:19Z

On Tue 2022-02-15 12:15:58, Sergey Senozhatsky wrote:
> On (22/02/14 14:21), Andre Kalb wrote:
> > +static void set_user_specified(struct console_cmdline *c, bool user_specified)
> > +{
> > + if (!user_specified)
> > + return;
> > +
> > + c->user_specified = true;
> > + console_set_on_cmdline = 1;
> > +}
>
> In original code we always set c->user_specified. Is it guaranteed that
> ->user_specified is properly initialized to 0? Maybe can do something like:

It is guaranteed. console_cmdline is a static array initialized with
zeroes. The 2nd set_user_specified() call is done for a not-yet-used
slot in the array, so it must be zero.

> static void set_user_specified(struct console_cmdline *c, bool user_specified)
> {
> c->user_specified = user_specified;

This will change the behavior for the 1st set_user_specified() call.
It happens when the same console is added more times by device tree,
SPCR, and/or command line. c->user_specified must stay "true" when
at least one __add_preferred_console() call added it from the command line.

> if (!user_specified)
> return;
>
> console_set_on_cmdline = 1;
> }

I agree that it is not obvious. It would make sense to add a comment
into the code. I am going to propose something in a reply to the
original post.

Best Regards,
Petr