USB: ftdi_sio: fix chars_in_buffer overhead
Use the new generic usb-serial wait_until_sent implementation to wait
for hardware buffers to drain.
This removes the need to check the hardware buffers in chars_in_buffer
and thus removes the overhead introduced by commit 6f602912
("usb:
serial: ftdi_sio: Add missing chars_in_buffer function") without
breaking tty_wait_until_sent (used by, for example, tcdrain, tcsendbreak
and close).
Reported-by: Stas Sergeev <stsp@list.ru>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
c4133648bb
commit
a37025b5c7
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@ -924,7 +924,7 @@ static int ftdi_tiocmset(struct tty_struct *tty,
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static int ftdi_ioctl(struct tty_struct *tty,
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unsigned int cmd, unsigned long arg);
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static void ftdi_break_ctl(struct tty_struct *tty, int break_state);
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static int ftdi_chars_in_buffer(struct tty_struct *tty);
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static bool ftdi_tx_empty(struct usb_serial_port *port);
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static int ftdi_get_modem_status(struct usb_serial_port *port,
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unsigned char status[2]);
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@ -961,7 +961,7 @@ static struct usb_serial_driver ftdi_sio_device = {
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.ioctl = ftdi_ioctl,
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.set_termios = ftdi_set_termios,
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.break_ctl = ftdi_break_ctl,
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.chars_in_buffer = ftdi_chars_in_buffer,
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.tx_empty = ftdi_tx_empty,
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};
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static struct usb_serial_driver * const serial_drivers[] = {
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@ -2056,27 +2056,18 @@ static void ftdi_break_ctl(struct tty_struct *tty, int break_state)
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}
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static int ftdi_chars_in_buffer(struct tty_struct *tty)
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static bool ftdi_tx_empty(struct usb_serial_port *port)
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{
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struct usb_serial_port *port = tty->driver_data;
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int chars;
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unsigned char buf[2];
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int ret;
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chars = usb_serial_generic_chars_in_buffer(tty);
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if (chars)
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goto out;
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/* Check if hardware buffer is empty. */
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ret = ftdi_get_modem_status(port, buf);
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if (ret == 2) {
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if (!(buf[1] & FTDI_RS_TEMT))
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chars = 1;
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return false;
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}
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out:
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dev_dbg(&port->dev, "%s - %d\n", __func__, chars);
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return chars;
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return true;
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}
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/* old_termios contains the original termios settings and tty->termios contains
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