[SRU][R][PATCH 2/3] UBUNTU: SAUCE: Reapply "serial: 8250: Revert "drop lockdep annotation from serial8250_clear_IER()""

[Kevin Becker]

From: Sebastian Andrzej Siewior <bigeasy at linutronix.de>

BugLink: https://bugs.launchpad.net/bugs/2161757

This reverts commit 244eb5c6ec62ccab59ecac1f4815bb33130c423a.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy at linutronix.de>
Signed-off-by: Kevin Becker <kevin.becker at canonical.com>
---
 drivers/tty/serial/8250/8250_port.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 2139e7bed41b..6547915c8c1a 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -723,6 +723,9 @@ static void __serial8250_clear_IER(struct uart_8250_port *up)
 
 static inline void serial8250_clear_IER(struct uart_8250_port *up)
 {
+	/* Port locked to synchronize UART_IER access against the console */
+	lockdep_assert_held_once(&up->port.lock);
+
 	__serial8250_clear_IER(up);
 }
 
-- 
2.43.0