Messages in this thread Patch in this message | | | From | Peter Hurley <> | Subject | [PATCH 7/7] serial: 8250: Prevent concurrent updates to shadow registers | Date | Thu, 22 Jan 2015 12:24:31 -0500 |
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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> --- drivers/tty/serial/8250/8250_core.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 8fd4b57..ed15341 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -2526,6 +2526,15 @@ 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) { @@ -2549,15 +2558,6 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, } /* - * 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. */ uart_update_timeout(port, termios->c_cflag, baud); -- 2.2.2
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