Commit eb7f1ed2 authored by John Ogness's avatar John Ogness Committed by Petr Mladek
Browse files

printk: __pr_flush: 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/20221116162152.193147-17-john.ogness@linutronix.de
parent fc956ae0

kernel/printk/printk.c

+9 −1
Original line number Diff line number Diff line
@@ -3561,6 +3561,7 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre 
	struct console *c;

	u64 last_diff = 0;

	u64 printk_seq;

	int cookie;

	u64 diff;

	u64 seq;
@@ -3571,9 +3572,15 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre 
	for (;;) {

		diff = 0;



		/*

		 * Hold the console_lock to guarantee safe access to

		 * console->seq and to prevent changes to @console_suspended

		 * until all consoles have been processed.

		 */

		console_lock();



		for_each_console(c) {

		cookie = console_srcu_read_lock();

		for_each_console_srcu(c) {

			if (con && con != c)

				continue;

			if (!console_is_usable(c))
@@ -3582,6 +3589,7 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre 
			if (printk_seq < seq)

				diff += seq - printk_seq;

		}

		console_srcu_read_unlock(cookie);



		/*

		 * If consoles are suspended, it cannot be expected that they