Commit d792db6f authored by John Ogness's avatar John Ogness Committed by Petr Mladek
Browse files

printk: console_unblank: use srcu console list iterator 



Use srcu console list iteration for console list traversal.

Document why the console_lock is still necessary. Note that this
is a preparatory change for when console_lock no longer provides
synchronization for the console list.

Signed-off-by: default avatarJohn Ogness <john.ogness@linutronix.de>
Reviewed-by: default avatarPetr Mladek <pmladek@suse.com>
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-19-john.ogness@linutronix.de
parent 12f1da5f

kernel/printk/printk.c

+13 −4
Original line number Diff line number Diff line
@@ -3000,10 +3000,14 @@ EXPORT_SYMBOL(console_conditional_schedule); 
void console_unblank(void)

{

	struct console *c;

	int cookie;



	/*

	 * console_unblank can no longer be called in interrupt context unless

	 * oops_in_progress is set to 1..

	 * Stop console printing because the unblank() callback may

	 * assume the console is not within its write() callback.

	 *

	 * If @oops_in_progress is set, this may be an atomic context.

	 * In that case, attempt a trylock as best-effort.

	 */

	if (oops_in_progress) {

		if (down_trylock_console_sem() != 0)
@@ -3013,9 +3017,14 @@ void console_unblank(void) 


	console_locked = 1;

	console_may_schedule = 0;

	for_each_console(c)

		if ((c->flags & CON_ENABLED) && c->unblank)



	cookie = console_srcu_read_lock();

	for_each_console_srcu(c) {

		if ((console_srcu_read_flags(c) & CON_ENABLED) && c->unblank)

			c->unblank();

	}

	console_srcu_read_unlock(cookie);



	console_unlock();



	if (!oops_in_progress)