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serial: 8250: Prevent concurrent updates to shadow registers 

The port shadow registers, ->fcr and ->mcr, must be protected from
concurrent updates. Relocate the shadow register updates in
serial8250_do_set_termios() to the port lock critical section.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley 2015-01-22 12:24:31 -05:00 committed by Greg Kroah-Hartman
parent 4516d50aab
commit e9cef8625e
1 changed files with 9 additions and 9 deletions
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18
drivers/tty/serial/8250/8250_core.c
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@ -2549,6 +2549,15 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
port->uartclk / 16);
quot = serial8250_get_divisor(up, baud, &frac);
/*
* Ok, we're now changing the port state. Do it with
* interrupts disabled.
*/
serial8250_rpm_get(up);
spin_lock_irqsave(&port->lock, flags);
up->lcr = cval; /* Save computed LCR */
if (up->capabilities & UART_CAP_FIFO && port->fifosize > 1) {
/* NOTE: If fifo_bug is not set, a user can set RX_trigger. */
if ((baud < 2400 && !up->dma) || up->fifo_bug) {
@ -2571,15 +2580,6 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
up->mcr |= UART_MCR_AFE;
}
/*
* Ok, we're now changing the port state. Do it with
* interrupts disabled.
*/
serial8250_rpm_get(up);
spin_lock_irqsave(&port->lock, flags);
up->lcr = cval; /* Save computed LCR */
/*
* Update the per-port timeout.
*/