tty: Incorrect use tty_ldisc_flush() in TTY drivers.

PATCH New Ilya Zykov 1 participant 1 message Nov 23, 2012 TTY layer and serial drivers

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Ilya Zykov

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2012-11-23 18:43 UTC #0 lore raw

PATCH 1/1 tty: Incorrect use tty_ldisc_flush() in TTY drivers.

This patch correct tty serial drivers.

Unfortunately, many drivers indirectly call ldisc's flush_buffer() function in own callback function close(). Рarticularly, by the use of tty_ldisc_flush(), before TTY LAYER calls ldisc's flush_buffer() in the right moment.

1. It disturb the logic of work ldisc's layer.
2. It is simple overhead because we call ldisc's flush_buffer() at least two times.

Signed-off-by Ilya Zykov <[email protected]>

---

drivers/tty/serial/serial_core.c +1 -1

index a21dc8e..c4a0a6d 100644
@@ -1288,7 +1288,7 @@ static void uart_close(struct tty_struct *tty, struct file *filp)
        uart_shutdown(tty, state);
        uart_flush_buffer(tty);
 
-       tty_ldisc_flush(tty);
+       tty_buffer_flush(tty);
 
        tty_port_tty_set(port, NULL);
        spin_lock_irqsave(&port->lock, flags);

drivers/tty/tty_port.c +2 -2

index bf6e238..c23dd30 100644
@@ -364,8 +364,8 @@ int tty_port_close_start(struct tty_port *port,
                        timeout = 2 * HZ;
                schedule_timeout_interruptible(timeout);
        }
-       /* Flush the ldisc buffering */
-       tty_ldisc_flush(tty);
+       /* Flush the driver buffering */
+       tty_buffer_flush(tty);
 
        /* Drop DTR/RTS if HUPCL is set. This causes any attached modem to
           hang up the line */