Commit 8b5dd400 authored by John Ogness's avatar John Ogness Committed by Petr Mladek
Browse files

proc: consoles: document console_lock usage 



The console_lock is held throughout the start/show/stop procedure
to print out device/driver information about all 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: 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/20221116162152.193147-11-john.ogness@linutronix.de
parent d25a2e74

fs/proc/consoles.c

+9 −0
Original line number Diff line number Diff line
@@ -63,6 +63,15 @@ static void *c_start(struct seq_file *m, loff_t *pos) 
	struct console *con;

	loff_t off = 0;



	/*

	 * Take console_lock to serialize device() callback with

	 * other console operations. For example, fg_console is

	 * modified under console_lock when switching vt.

	 *

	 * Hold the console_lock to guarantee safe traversal of the

	 * console list. SRCU cannot be used because there is no

	 * place to store the SRCU cookie.

	 */

	console_lock();

	for_each_console(con)

		if (off++ == *pos)