Commit 9023ca08 authored by John Ogness's avatar John Ogness Committed by Petr Mladek
Browse files

printk: do not wait for consoles when suspended 



The console_stop() and console_start() functions call pr_flush().
When suspending, these functions are called by the serial subsystem
while the serial port is suspended. In this scenario, if there are
any pending messages, a call to pr_flush() will always result in a
timeout because the serial port cannot make forward progress. This
causes longer suspend and resume times.

Add a check in pr_flush() so that it will immediately timeout if
the consoles are suspended.

Fixes: 3b604ca8 ("printk: add pr_flush()")
Reported-by: default avatarTodd Brandt <todd.e.brandt@linux.intel.com>
Signed-off-by: default avatarJohn Ogness <john.ogness@linutronix.de>
Tested-by: default avatarTodd Brandt <todd.e.brandt@linux.intel.com>
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220715061042.373640-2-john.ogness@linutronix.de
parent 07a22b61

kernel/printk/printk.c

+11 −2
Original line number Diff line number Diff line
@@ -3380,6 +3380,7 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre 
		diff = 0;



		console_lock();



		for_each_console(c) {

			if (con && con != c)

				continue;
@@ -3389,11 +3390,19 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre 
			if (printk_seq < seq)

				diff += seq - printk_seq;

		}

		console_unlock();



		if (diff != last_diff && reset_on_progress)

		/*

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

		 * make forward progress, so timeout immediately. @diff is

		 * still used to return a valid flush status.

		 */

		if (console_suspended)

			remaining = 0;

		else if (diff != last_diff && reset_on_progress)

			remaining = timeout_ms;



		console_unlock();



		if (diff == 0 || remaining == 0)

			break;