[PATCH printk v5 24/30] printk: Track nbcon consoles

John Ogness
2024-05-02T21:38:54Z

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>
---
kernel/printk/printk.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 0cb6ae5fd7e3..31ed4450d9a6 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -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
@@ -3537,6 +3542,7 @@ 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_init(newcon, init_seq);
} else {
have_legacy_console = true;
@@ -3616,6 +3622,7 @@ EXPORT_SYMBOL(register_console);
static int unregister_console_locked(struct console *console)
{
bool found_legacy_con = false;
+ bool found_nbcon_con = false;
bool found_boot_con = false;
unsigned long flags;
struct console *c;
@@ -3683,13 +3690,18 @@ 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;
}
--
2.39.2