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authorPeter Hurley <peter@hurleysoftware.com>2014-09-10 15:06:26 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-09-23 21:19:35 -0700
commitd01f4d181c92877ecc678adce248a30cb7077ff1 (patch)
treef4b9a5723be98e63e2b238f8290fd418179a238a /drivers/tty
parent317c1360200059a7a8a832294a58409c73b784bf (diff)
serial: core: Privatize tty->hw_stopped
tty->hw_stopped is not used by the tty core and is thread-unsafe; hw_stopped is a member of a bitfield whose fields are updated non-atomically and no lock is suitable for serializing updates. Replace serial core usage of tty->hw_stopped with uport->hw_stopped. Use int storage which works around Alpha EV4/5 non-atomic byte storage, since uart_port uses different locks to protect certain fields within the structure. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/bfin_uart.c14
-rw-r--r--drivers/tty/serial/serial_core.c28
2 files changed, 20 insertions, 22 deletions
diff --git a/drivers/tty/serial/bfin_uart.c b/drivers/tty/serial/bfin_uart.c
index dec0fd725d80..fc9fbf3f24a7 100644
--- a/drivers/tty/serial/bfin_uart.c
+++ b/drivers/tty/serial/bfin_uart.c
@@ -108,22 +108,22 @@ static void bfin_serial_set_mctrl(struct uart_port *port, unsigned int mctrl)
static irqreturn_t bfin_serial_mctrl_cts_int(int irq, void *dev_id)
{
struct bfin_serial_port *uart = dev_id;
- unsigned int status = bfin_serial_get_mctrl(&uart->port);
+ struct uart_port *uport = &uart->port;
+ unsigned int status = bfin_serial_get_mctrl(uport);
#ifdef CONFIG_SERIAL_BFIN_HARD_CTSRTS
- struct tty_struct *tty = uart->port.state->port.tty;
UART_CLEAR_SCTS(uart);
- if (tty->hw_stopped) {
+ if (uport->hw_stopped) {
if (status) {
- tty->hw_stopped = 0;
- uart_write_wakeup(&uart->port);
+ uport->hw_stopped = 0;
+ uart_write_wakeup(uport);
}
} else {
if (!status)
- tty->hw_stopped = 1;
+ uport->hw_stopped = 1;
}
#endif
- uart_handle_cts_change(&uart->port, status & TIOCM_CTS);
+ uart_handle_cts_change(uport, status & TIOCM_CTS);
return IRQ_HANDLED;
}
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index dd21ed900635..7d51e26627fb 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -95,7 +95,7 @@ static void __uart_start(struct tty_struct *tty)
struct uart_state *state = tty->driver_data;
struct uart_port *port = state->uart_port;
- if (!tty->stopped && !tty->hw_stopped)
+ if (!uart_tx_stopped(port))
port->ops->start_tx(port);
}
@@ -181,10 +181,11 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
}
spin_lock_irq(&uport->lock);
- if (uart_cts_enabled(uport)) {
- if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS))
- tty->hw_stopped = 1;
- }
+ if (uart_cts_enabled(uport) &&
+ !(uport->ops->get_mctrl(uport) & TIOCM_CTS))
+ uport->hw_stopped = 1;
+ else
+ uport->hw_stopped = 0;
spin_unlock_irq(&uport->lock);
}
@@ -949,7 +950,7 @@ static int uart_get_lsr_info(struct tty_struct *tty,
*/
if (uport->x_char ||
((uart_circ_chars_pending(&state->xmit) > 0) &&
- !tty->stopped && !tty->hw_stopped))
+ !uart_tx_stopped(uport)))
result &= ~TIOCSER_TEMT;
return put_user(result, value);
@@ -1295,7 +1296,7 @@ static void uart_set_termios(struct tty_struct *tty,
/*
* If the port is doing h/w assisted flow control, do nothing.
- * We assume that tty->hw_stopped has never been set.
+ * We assume that port->hw_stopped has never been set.
*/
if (uport->flags & UPF_HARD_FLOW)
return;
@@ -1303,7 +1304,7 @@ static void uart_set_termios(struct tty_struct *tty,
/* Handle turning off CRTSCTS */
if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {
spin_lock_irqsave(&uport->lock, flags);
- tty->hw_stopped = 0;
+ uport->hw_stopped = 0;
__uart_start(tty);
spin_unlock_irqrestore(&uport->lock, flags);
}
@@ -1311,7 +1312,7 @@ static void uart_set_termios(struct tty_struct *tty,
else if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {
spin_lock_irqsave(&uport->lock, flags);
if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS)) {
- tty->hw_stopped = 1;
+ uport->hw_stopped = 1;
uport->ops->stop_tx(uport);
}
spin_unlock_irqrestore(&uport->lock, flags);
@@ -2788,23 +2789,20 @@ EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
*/
void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
{
- struct tty_port *port = &uport->state->port;
- struct tty_struct *tty = port->tty;
-
lockdep_assert_held_once(&uport->lock);
uport->icount.cts++;
if (uart_cts_enabled(uport)) {
- if (tty->hw_stopped) {
+ if (uport->hw_stopped) {
if (status) {
- tty->hw_stopped = 0;
+ uport->hw_stopped = 0;
uport->ops->start_tx(uport);
uart_write_wakeup(uport);
}
} else {
if (!status) {
- tty->hw_stopped = 1;
+ uport->hw_stopped = 1;
uport->ops->stop_tx(uport);
}
}