diff options
| author | John Ogness <john.ogness@linutronix.de> | 2022-11-16 19:21:45 +0300 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2022-12-02 13:25:02 +0300 |
| commit | 7c2af0f634f1bc761ca827310dc7e8e586af502f (patch) | |
| tree | 02cf4fbe0f84214aa148c8acc27ef47ac49de535 /drivers/tty | |
| parent | 6f8836756f3cbb02bfd1f0e033516585250318a9 (diff) | |
| download | linux-7c2af0f634f1bc761ca827310dc7e8e586af502f.tar.xz | |
tty: tty_io: use console_list_lock for list synchronization
show_cons_active() uses the console_lock to gather information
on registered consoles. It requires that no consoles are unregistered
until it is finished. The console_list_lock should be used because
list synchronization responsibility will be removed from the
console_lock in a later change.
Note, the console_lock is still needed to serialize the device()
callback with other console operations.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-34-john.ogness@linutronix.de
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/tty_io.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index ee4da2fec328..cafdff575716 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -3527,16 +3527,13 @@ static ssize_t show_cons_active(struct device *dev, ssize_t count = 0; /* - * Hold the console_lock to guarantee that no consoles are + * Hold the console_list_lock to guarantee that no consoles are * unregistered until all console processing is complete. * This also allows safe traversal of the console list and * race-free reading of @flags. - * - * Take console_lock to serialize device() callback with - * other console operations. For example, fg_console is - * modified under console_lock when switching vt. */ - console_lock(); + console_list_lock(); + for_each_console(c) { if (!c->device) continue; @@ -3548,6 +3545,13 @@ static ssize_t show_cons_active(struct device *dev, if (i >= ARRAY_SIZE(cs)) break; } + + /* + * Take console_lock to serialize device() callback with + * other console operations. For example, fg_console is + * modified under console_lock when switching vt. + */ + console_lock(); while (i--) { int index = cs[i]->index; struct tty_driver *drv = cs[i]->device(cs[i], &index); @@ -3563,6 +3567,8 @@ static ssize_t show_cons_active(struct device *dev, } console_unlock(); + console_list_unlock(); + return count; } static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL); |