Re: [PATCH v3 3/3] printk: fix double printing with earlycon

Sergey Senozhatsky
2017-03-06T15:06:52Z

On (03/03/17 18:49), Aleksey Makarov wrote:
[..]
> +static enum { CONSOLE_MATCH, CONSOLE_MATCH_RETURN, CONSOLE_MATCH_NEXT }
> +match_console(struct console *newcon, struct console_cmdline *c)

that enum in function return is interesting :)
can we make it less hackish?

> + if (!newcon->match ||
> + newcon->match(newcon, c->name, c->index, c->options) != 0) {
> + /* default matching */
> + BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name));
> + if (strcmp(c->name, newcon->name) != 0)
> + return CONSOLE_MATCH_NEXT;
> + if (newcon->index >= 0 && newcon->index != c->index)
> + return CONSOLE_MATCH_NEXT;

who is checking CONSOLE_MATCH_NEXT?

> + if (newcon->index < 0)
> + newcon->index = c->index;
> +
> + if (_braille_register_console(newcon, c))
> + return CONSOLE_MATCH_RETURN;
> +
> + if (newcon->setup &&
> + newcon->setup(newcon, c->options) != 0)
> + return CONSOLE_MATCH;
> + }
> +
> + newcon->flags |= CON_ENABLED;
> + return CONSOLE_MATCH;
> +}
> +
> /*
> * The console driver calls this routine during kernel initialization
> * to register the console printing procedure with printk() and to
> @@ -2454,40 +2480,50 @@ void register_console(struct console *newcon)
> }
>
> /*
> + * Check if this console was set as preferred by command line parameters
> + * or by call to add_preferred_console(). There may be several entries
> + * in the console_cmdline array matching with the same console so we
> + * can not just use the first match. Instead check the entry pointed
> + * by preferred_console and then all other entries.
> + */
> + if (preferred_console >= 0) {
> + switch (match_console(newcon,
> + console_cmdline + preferred_console)) {
> + case CONSOLE_MATCH:
> + if (newcon->flags | CON_ENABLED) {

newcon->flags & CON_ENABLED ?

> + newcon->flags |= CON_CONSDEV;
> + has_preferred = true;
> + }
> + goto match;
> + case CONSOLE_MATCH_RETURN:
> + return;
> + default:
> + break;
> + }
> + }
> +
> + /*
> * See if this console matches one we selected on
> * the command line.
> */
> for (i = 0, c = console_cmdline;
> i < MAX_CMDLINECONSOLES && c->name[0];
> i++, c++) {
> - if (!newcon->match ||
> - newcon->match(newcon, c->name, c->index, c->options) != 0) {
> - /* default matching */
> - BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name));
> - if (strcmp(c->name, newcon->name) != 0)
> - continue;
> - if (newcon->index >= 0 &&
> - newcon->index != c->index)
> - continue;
> - if (newcon->index < 0)
> - newcon->index = c->index;
> -
> - if (_braille_register_console(newcon, c))
> - return;
>
> - if (newcon->setup &&
> - newcon->setup(newcon, c->options) != 0)
> - break;
> - }
> + if (preferred_console == i)
> + continue;
>
> - newcon->flags |= CON_ENABLED;
> - if (i == preferred_console) {
> - newcon->flags |= CON_CONSDEV;
> - has_preferred = true;
> + switch (match_console(newcon, c)) {
> + case CONSOLE_MATCH:
> + goto match;
> + case CONSOLE_MATCH_RETURN:
> + return;
> + default:
> + break;

sorry, it was a rather long for me today. need to look more at this.
for what is now CONSOLE_MATCH_NEXT we used to have continue, and now
we break out of the loop?

-ss