[SERIAL] Fix oops when removing suspended serial port

A serial card might have been removed when the system is resumed.
This results in a suspended port being shut down, which results in
the ports shutdown method being called twice in a row.  This causes
BUGs.  Avoid this by tracking the suspended state separately from
the initialised state.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index d814bb1dcb05..397147a7054f 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1940,6 +1940,9 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
 	if (state->info && state->info->flags & UIF_INITIALIZED) {
 		const struct uart_ops *ops = port->ops;
 
+		state->info->flags = (state->info->flags & ~UIF_INITIALIZED)
+				     | UIF_SUSPENDED;
+
 		spin_lock_irq(&port->lock);
 		ops->stop_tx(port);
 		ops->set_mctrl(port, 0);
@@ -2006,7 +2009,7 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
 		console_start(port->cons);
 	}
 
-	if (state->info && state->info->flags & UIF_INITIALIZED) {
+	if (state->info && state->info->flags & UIF_SUSPENDED) {
 		const struct uart_ops *ops = port->ops;
 		int ret;
 
@@ -2018,15 +2021,17 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
 			ops->set_mctrl(port, port->mctrl);
 			ops->start_tx(port);
 			spin_unlock_irq(&port->lock);
+			state->info->flags |= UIF_INITIALIZED;
 		} else {
 			/*
 			 * Failed to resume - maybe hardware went away?
 			 * Clear the "initialized" flag so we won't try
 			 * to call the low level drivers shutdown method.
 			 */
-			state->info->flags &= ~UIF_INITIALIZED;
 			uart_shutdown(state);
 		}
+
+		state->info->flags &= ~UIF_SUSPENDED;
 	}
 
 	mutex_unlock(&state->mutex);