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| author | Peter Hurley | 2014-09-02 23:39:14 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2014-09-09 01:22:42 +0200 |
| commit | fba594a848f6f35417a358565086d22c533c19c8 (patch) | |
| tree | bbab00d9c8d6e0bb52e053dedf873ae4ac5c4482 /drivers/tty/serial | |
| parent | serial: core: Fix x_char race (diff) | |
| download | kernel-qcow2-linux-fba594a848f6f35417a358565086d22c533c19c8.tar.gz kernel-qcow2-linux-fba594a848f6f35417a358565086d22c533c19c8.tar.xz kernel-qcow2-linux-fba594a848f6f35417a358565086d22c533c19c8.zip | |
serial: core: Remove unsafe x_char optimization
uart_unthrottle() attempts to avoid sending START and the previous
x_char if the previous x_char has not yet been sent. However, this
optimization could leave the sender in a throttled state; for example,
if the sender is throttled and this unthrottle coincides with a manual
tcflow(TCION) from user-space, then neither START would be sent.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial')
| -rw-r--r-- | drivers/tty/serial/serial_core.c | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index bd20cf51e912..bdc543caf069 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -647,12 +647,8 @@ static void uart_unthrottle(struct tty_struct *tty) mask &= ~port->flags; } - if (mask & UPF_SOFT_FLOW) { - if (port->x_char) - port->x_char = 0; - else - uart_send_xchar(tty, START_CHAR(tty)); - } + if (mask & UPF_SOFT_FLOW) + uart_send_xchar(tty, START_CHAR(tty)); if (mask & UPF_HARD_FLOW) uart_set_mctrl(port, TIOCM_RTS); |