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tty: serial - fix various misuses/mishandlings of port->tty
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Make it robust against hang up events. In most cases we can do this simply
by passing the right things in the first place.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Alan Cox authored and Greg Kroah-Hartman committed Aug 10, 2010
1 parent a360fae commit 1922513
Showing 1 changed file with 60 additions and 49 deletions.
109 changes: 60 additions & 49 deletions drivers/serial/serial_core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,7 @@ static struct lock_class_key port_lock_key;
#define uart_console(port) (0)
#endif

static void uart_change_speed(struct uart_state *state,
static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
struct ktermios *old_termios);
static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
static void uart_change_pm(struct uart_state *state, int pm_state);
Expand Down Expand Up @@ -137,7 +137,7 @@ uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
* Startup the port. This will be called once per open. All calls
* will be serialised by the per-port mutex.
*/
static int uart_startup(struct uart_state *state, int init_hw)
static int uart_startup(struct tty_struct *tty, struct uart_state *state, int init_hw)
{
struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
Expand All @@ -152,7 +152,7 @@ static int uart_startup(struct uart_state *state, int init_hw)
* once we have successfully opened the port. Also set
* up the tty->alt_speed kludge
*/
set_bit(TTY_IO_ERROR, &port->tty->flags);
set_bit(TTY_IO_ERROR, &tty->flags);

if (uport->type == PORT_UNKNOWN)
return 0;
Expand All @@ -177,26 +177,26 @@ static int uart_startup(struct uart_state *state, int init_hw)
/*
* Initialise the hardware port settings.
*/
uart_change_speed(state, NULL);
uart_change_speed(tty, state, NULL);

/*
* Setup the RTS and DTR signals once the
* port is open and ready to respond.
*/
if (port->tty->termios->c_cflag & CBAUD)
if (tty->termios->c_cflag & CBAUD)
uart_set_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
}

if (port->flags & ASYNC_CTS_FLOW) {
spin_lock_irq(&uport->lock);
if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS))
port->tty->hw_stopped = 1;
tty->hw_stopped = 1;
spin_unlock_irq(&uport->lock);
}

set_bit(ASYNCB_INITIALIZED, &port->flags);

clear_bit(TTY_IO_ERROR, &port->tty->flags);
clear_bit(TTY_IO_ERROR, &tty->flags);
}

if (retval && capable(CAP_SYS_ADMIN))
Expand All @@ -210,11 +210,10 @@ static int uart_startup(struct uart_state *state, int init_hw)
* DTR is dropped if the hangup on close termio flag is on. Calls to
* uart_shutdown are serialised by the per-port semaphore.
*/
static void uart_shutdown(struct uart_state *state)
static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
{
struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
struct tty_struct *tty = port->tty;

/*
* Set the TTY IO error marker
Expand Down Expand Up @@ -430,11 +429,10 @@ uart_get_divisor(struct uart_port *port, unsigned int baud)
EXPORT_SYMBOL(uart_get_divisor);

/* FIXME: Consistent locking policy */
static void
uart_change_speed(struct uart_state *state, struct ktermios *old_termios)
static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
struct ktermios *old_termios)
{
struct tty_port *port = &state->port;
struct tty_struct *tty = port->tty;
struct uart_port *uport = state->uart_port;
struct ktermios *termios;

Expand Down Expand Up @@ -463,8 +461,8 @@ uart_change_speed(struct uart_state *state, struct ktermios *old_termios)
uport->ops->set_termios(uport, termios, old_termios);
}

static inline int
__uart_put_char(struct uart_port *port, struct circ_buf *circ, unsigned char c)
static inline int __uart_put_char(struct uart_port *port,
struct circ_buf *circ, unsigned char c)
{
unsigned long flags;
int ret = 0;
Expand Down Expand Up @@ -494,8 +492,8 @@ static void uart_flush_chars(struct tty_struct *tty)
uart_start(tty);
}

static int
uart_write(struct tty_struct *tty, const unsigned char *buf, int count)
static int uart_write(struct tty_struct *tty,
const unsigned char *buf, int count)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port;
Expand Down Expand Up @@ -675,7 +673,7 @@ static int uart_get_info(struct uart_state *state,
return 0;
}

static int uart_set_info(struct uart_state *state,
static int uart_set_info(struct tty_struct *tty, struct uart_state *state,
struct serial_struct __user *newinfo)
{
struct serial_struct new_serial;
Expand Down Expand Up @@ -770,7 +768,7 @@ static int uart_set_info(struct uart_state *state,
* We need to shutdown the serial port at the old
* port/type/irq combination.
*/
uart_shutdown(state);
uart_shutdown(tty, state);
}

if (change_port) {
Expand Down Expand Up @@ -869,25 +867,27 @@ static int uart_set_info(struct uart_state *state,
"is deprecated.\n", current->comm,
tty_name(port->tty, buf));
}
uart_change_speed(state, NULL);
uart_change_speed(tty, state, NULL);
}
} else
retval = uart_startup(state, 1);
retval = uart_startup(tty, state, 1);
exit:
mutex_unlock(&port->mutex);
return retval;
}


/*
* uart_get_lsr_info - get line status register info.
* Note: uart_ioctl protects us against hangups.
/**
* uart_get_lsr_info - get line status register info
* @tty: tty associated with the UART
* @state: UART being queried
* @value: returned modem value
*
* Note: uart_ioctl protects us against hangups.
*/
static int uart_get_lsr_info(struct uart_state *state,
unsigned int __user *value)
static int uart_get_lsr_info(struct tty_struct *tty,
struct uart_state *state, unsigned int __user *value)
{
struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
unsigned int result;

result = uport->ops->tx_empty(uport);
Expand All @@ -900,7 +900,7 @@ static int uart_get_lsr_info(struct uart_state *state,
*/
if (uport->x_char ||
((uart_circ_chars_pending(&state->xmit) > 0) &&
!port->tty->stopped && !port->tty->hw_stopped))
!tty->stopped && !tty->hw_stopped))
result &= ~TIOCSER_TEMT;

return put_user(result, value);
Expand Down Expand Up @@ -961,7 +961,7 @@ static int uart_break_ctl(struct tty_struct *tty, int break_state)
return 0;
}

static int uart_do_autoconfig(struct uart_state *state)
static int uart_do_autoconfig(struct tty_struct *tty,struct uart_state *state)
{
struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
Expand All @@ -980,7 +980,7 @@ static int uart_do_autoconfig(struct uart_state *state)

ret = -EBUSY;
if (tty_port_users(port) == 1) {
uart_shutdown(state);
uart_shutdown(tty, state);

/*
* If we already have a port type configured,
Expand All @@ -999,7 +999,7 @@ static int uart_do_autoconfig(struct uart_state *state)
*/
uport->ops->config_port(uport, flags);

ret = uart_startup(state, 1);
ret = uart_startup(tty, state, 1);
}
mutex_unlock(&port->mutex);
return ret;
Expand Down Expand Up @@ -1122,11 +1122,11 @@ uart_ioctl(struct tty_struct *tty, struct file *filp, unsigned int cmd,
break;

case TIOCSSERIAL:
ret = uart_set_info(state, uarg);
ret = uart_set_info(tty, state, uarg);
break;

case TIOCSERCONFIG:
ret = uart_do_autoconfig(state);
ret = uart_do_autoconfig(tty, state);
break;

case TIOCSERGWILD: /* obsolete */
Expand Down Expand Up @@ -1172,7 +1172,7 @@ uart_ioctl(struct tty_struct *tty, struct file *filp, unsigned int cmd,
*/
switch (cmd) {
case TIOCSERGETLSR: /* Get line status register */
ret = uart_get_lsr_info(state, uarg);
ret = uart_get_lsr_info(tty, state, uarg);
break;

default: {
Expand Down Expand Up @@ -1219,7 +1219,7 @@ static void uart_set_termios(struct tty_struct *tty,
return;
}

uart_change_speed(state, old_termios);
uart_change_speed(tty, state, old_termios);

/* Handle transition to B0 status */
if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
Expand Down Expand Up @@ -1335,7 +1335,7 @@ static void uart_close(struct tty_struct *tty, struct file *filp)
uart_wait_until_sent(tty, uport->timeout);
}

uart_shutdown(state);
uart_shutdown(tty, state);
uart_flush_buffer(tty);

tty_ldisc_flush(tty);
Expand Down Expand Up @@ -1436,7 +1436,7 @@ static void uart_hangup(struct tty_struct *tty)
mutex_lock(&port->mutex);
if (port->flags & ASYNC_NORMAL_ACTIVE) {
uart_flush_buffer(tty);
uart_shutdown(state);
uart_shutdown(tty, state);
port->count = 0;
clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
tty_port_tty_set(port, NULL);
Expand All @@ -1446,15 +1446,19 @@ static void uart_hangup(struct tty_struct *tty)
mutex_unlock(&port->mutex);
}

/*
* Copy across the serial console cflag setting into the termios settings
* for the initial open of the port. This allows continuity between the
* kernel settings, and the settings init adopts when it opens the port
* for the first time.
/**
* uart_update_termios - update the terminal hw settings
* @tty: tty associated with UART
* @state: UART to update
*
* Copy across the serial console cflag setting into the termios settings
* for the initial open of the port. This allows continuity between the
* kernel settings, and the settings init adopts when it opens the port
* for the first time.
*/
static void uart_update_termios(struct uart_state *state)
static void uart_update_termios(struct tty_struct *tty,
struct uart_state *state)
{
struct tty_struct *tty = state->port.tty;
struct uart_port *port = state->uart_port;

if (uart_console(port) && port->cons->cflag) {
Expand All @@ -1471,7 +1475,7 @@ static void uart_update_termios(struct uart_state *state)
/*
* Make termios settings take effect.
*/
uart_change_speed(state, NULL);
uart_change_speed(tty, state, NULL);

/*
* And finally enable the RTS and DTR signals.
Expand Down Expand Up @@ -1668,7 +1672,7 @@ static int uart_open(struct tty_struct *tty, struct file *filp)
/*
* Start up the serial port.
*/
retval = uart_startup(state, 0);
retval = uart_startup(tty, state, 0);

/*
* If we succeeded, wait until the port is ready.
Expand All @@ -1683,7 +1687,7 @@ static int uart_open(struct tty_struct *tty, struct file *filp)
if (retval == 0 && !(port->flags & ASYNC_NORMAL_ACTIVE)) {
set_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);

uart_update_termios(state);
uart_update_termios(tty, state);
}

fail:
Expand Down Expand Up @@ -2010,9 +2014,13 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
struct tty_port *port = &state->port;
struct device *tty_dev;
struct uart_match match = {uport, drv};
struct tty_struct *tty;

mutex_lock(&port->mutex);

/* Must be inside the mutex lock until we convert to tty_port */
tty = port->tty;

tty_dev = device_find_child(uport->dev, &match, serial_match_port);
if (device_may_wakeup(tty_dev)) {
enable_irq_wake(uport->irq);
Expand Down Expand Up @@ -2105,9 +2113,12 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
ops->set_mctrl(uport, 0);
spin_unlock_irq(&uport->lock);
if (console_suspend_enabled || !uart_console(uport)) {
/* Protected by port mutex for now */
struct tty_struct *tty = port->tty;
ret = ops->startup(uport);
if (ret == 0) {
uart_change_speed(state, NULL);
if (tty)
uart_change_speed(tty, state, NULL);
spin_lock_irq(&uport->lock);
ops->set_mctrl(uport, uport->mctrl);
ops->start_tx(uport);
Expand All @@ -2119,7 +2130,7 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
* Clear the "initialized" flag so we won't try
* to call the low level drivers shutdown method.
*/
uart_shutdown(state);
uart_shutdown(tty, state);
}
}

Expand Down

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