After commit b3b57646186400d4f ("tty: serial_core: convert uart_open
to use tty_port_open") and 761ed4a94582ab291a ("tty: serial_core:
convert uart_close to use tty_port_close"), TTY_IO_ERROR is set by
tty_port_close() unconditionally, but cleared by tty_port_open() only
when tty_port_initialized() return 0.
This is a bug: If we use "console=ttyS*" in kernel parameters, the
corresponding serial port's port->console will be true. When somebody
close the serial port, tty_port_close() will return without calling
tty_port_set_initialized(port, 0). Then, when it is opened again,
tty_port_open() will not clear TTY_IO_ERROR, and serial port becomes
unavailable at last.
So, this patch clear TTY_IO_ERROR in uart_open() if tty_port_open()
return 0.
Signed-off-by: Ce Sun <sunc@xxxxxxxxxx>
Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx>
---
drivers/tty/serial/serial_core.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index f2303f3..58be3ef 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1690,6 +1690,8 @@ static int uart_open(struct tty_struct *tty, struct file *filp)
tty->driver_data = state;
retval = tty_port_open(&state->port, tty, filp);
+ if (!retval)
+ clear_bit(TTY_IO_ERROR, &tty->flags);
if (retval > 0)
retval = 0;
--
2.7.0
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