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Commit d8a5a8d7 authored by Russell King's avatar Russell King Committed by Russell King
Browse files

[SERIAL] 8250: add locking to console write function 



x86 SMP breaks as a result of the previous change, we have no real
option other than to add locking to the 8250 console write function.
If an oops is in progress, try to acquire the lock.  If we fail to
do so, continue anyway.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent a88d75b2

drivers/serial/8250.c

+10 −0
Original line number Diff line number Diff line
@@ -2235,10 +2235,17 @@ static void 
serial8250_console_write(struct console *co, const char *s, unsigned int count)

{

	struct uart_8250_port *up = &serial8250_ports[co->index];

	unsigned long flags;

	unsigned int ier;

	int locked = 1;



	touch_nmi_watchdog();



	if (oops_in_progress) {

		locked = spin_trylock_irqsave(&up->port.lock, flags);

	} else

		spin_lock_irqsave(&up->port.lock, flags);



	/*

	 *	First save the IER then disable the interrupts

	 */
@@ -2257,6 +2264,9 @@ serial8250_console_write(struct console *co, const char *s, unsigned int count) 
	 */

	wait_for_xmitr(up, BOTH_EMPTY);

	serial_out(up, UART_IER, ier);



	if (locked)

		spin_unlock_irqrestore(&up->port.lock, flags);

}



static int serial8250_console_setup(struct console *co, char *options)