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printk: Track nbcon consoles

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Add a global flag @have_nbcon_console to identify if any nbcon
consoles are registered. This will be used in follow-up commits
to preserve legacy behavior when no nbcon consoles are registered.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240820063001.36405-29-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
This commit is contained in:
John Ogness 2024-08-20 08:35:54 +02:06 committed by Petr Mladek
parent 60013065fd
commit bebd87ae27
1 changed files with 13 additions and 1 deletions
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14
kernel/printk/printk.c
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@ -470,6 +470,11 @@ static DEFINE_MUTEX(syslog_lock);
*/
static bool have_legacy_console;
/*
* Specifies if an nbcon console is registered.
*/
static bool have_nbcon_console;
/*
* Specifies if a boot console is registered. If boot consoles are present,
* nbcon consoles cannot print simultaneously and must be synchronized by
@ -3638,6 +3643,7 @@ void register_console(struct console *newcon)
init_seq = get_init_console_seq(newcon, bootcon_registered);
if (newcon->flags & CON_NBCON) {
have_nbcon_console = true;
nbcon_seq_force(newcon, init_seq);
} else {
have_legacy_console = true;
@ -3718,6 +3724,7 @@ static int unregister_console_locked(struct console *console)
{
bool use_device_lock = (console->flags & CON_NBCON) && console->write_atomic;
bool found_legacy_con = false;
bool found_nbcon_con = false;
bool found_boot_con = false;
unsigned long flags;
struct console *c;
@ -3785,13 +3792,18 @@ static int unregister_console_locked(struct console *console)
for_each_console(c) {
if (c->flags & CON_BOOT)
found_boot_con = true;
if (!(c->flags & CON_NBCON))
if (c->flags & CON_NBCON)
found_nbcon_con = true;
else
found_legacy_con = true;
}
if (!found_boot_con)
have_boot_console = found_boot_con;
if (!found_legacy_con)
have_legacy_console = found_legacy_con;
if (!found_nbcon_con)
have_nbcon_console = found_nbcon_con;
return res;
}