proc: Add nbcon support for /proc/consoles

Update /proc/consoles output to show 'W' if an nbcon console is
registered. Since the write_thread() callback is mandatory, it
enough just to check if it is an nbcon console.

Also update /proc/consoles output to show 'N' if it is an
nbcon console.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240904120536.115780-14-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>

diff --git a/fs/proc/consoles.c b/fs/proc/consoles.c
index 7036fdf..b7cab1a 100644 (file)
--- a/fs/proc/consoles.c
+++ b/fs/proc/consoles.c
@@ -21,6 +21,7 @@ static int show_console_dev(struct seq_file *m, void *v)
                { CON_ENABLED,          'E' },
                { CON_CONSDEV,          'C' },
                { CON_BOOT,             'B' },
+               { CON_NBCON,            'N' },
                { CON_PRINTBUFFER,      'p' },
                { CON_BRL,              'b' },
                { CON_ANYTIME,          'a' },
@@ -58,8 +59,8 @@ static int show_console_dev(struct seq_file *m, void *v)
        seq_printf(m, "%s%d", con->name, con->index);
        seq_pad(m, ' ');
        seq_printf(m, "%c%c%c (%s)", con->read ? 'R' : '-',
-                       con->write ? 'W' : '-', con->unblank ? 'U' : '-',
-                       flags);
+                  ((con->flags & CON_NBCON) || con->write) ? 'W' : '-',
+                  con->unblank ? 'U' : '-', flags);
        if (dev)
                seq_printf(m, " %4d:%d", MAJOR(dev), MINOR(dev));