| Date | Thu, 20 Oct 2022 09:43:18 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH printk v2 23/38] tty: tty_io: document console_lock usage |
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On Wed, Oct 19, 2022 at 05:01:45PM +0206, John Ogness wrote: > show_cons_active() uses the console_lock to gather information > on registered consoles. Since the console_lock is being used for > multiple reasons, explicitly document these reasons. This will > be useful when the console_lock is split into fine-grained > locking. > > Signed-off-by: John Ogness <john.ogness@linutronix.de> > --- > drivers/tty/tty_io.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c > index 2050e63963bb..333579bfa335 100644 > --- a/drivers/tty/tty_io.c > +++ b/drivers/tty/tty_io.c > @@ -3526,6 +3526,14 @@ static ssize_t show_cons_active(struct device *dev, > struct console *c; > ssize_t count = 0; > > + /* > + * Hold the console_lock to guarantee that no consoles are > + * unregistered until all console processing is complete. > + * This also allows safe traversal of the console list. > + * > + * Stop console printing because the device() callback may > + * assume the console is not within its write() callback. > + */ > console_lock(); > for_each_console(c) { > if (!c->device) > -- > 2.30.2 >
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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