On 06/16/2014 09:17 AM, Peter Hurley wrote:
The tty_ldisc_flush() after port hardware shutdown is unnecessary; the ldisc flush was just performed before the hardware shutdown in tty_port_close_start() and the ldisc will be released when uart_close() returns (because the last port close implies the last tty close). Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/serial_core.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 212ee07..15212d7 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1351,9 +1351,6 @@ static void uart_close(struct tty_struct *tty, struct file *filp) mutex_lock(&port->mutex); uart_shutdown(tty, state); - - tty_ldisc_flush(tty); -
This isn't exactly correct. There is a small window of time between the ldisc flush being performed in tty_port_close_start() and the subsequent stop_rx() in uart_close(). This might allow for data to be received, and a racing tty reopen to receive that stale data. Unlikely, but possible.
tty_port_tty_set(port, NULL); tty->closing = 0; spin_lock_irqsave(&port->lock, flags);
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