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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>
This commit is contained in:
Alan Cox 2010-06-01 22:52:51 +02:00 • committed by Greg Kroah-Hartman
parent a360fae67b
commit 192251352f
1 changed files with 60 additions and 49 deletions
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109
drivers/serial/serial_core.c
View file

@ -58,7 +58,7 @@ static struct lock_class_key port_lock_key;
#define uart_console(port) (0) #define uart_console(port) (0)
#endif #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); struct ktermios *old_termios);
static void uart_wait_until_sent(struct tty_struct *tty, int timeout); static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
static void uart_change_pm(struct uart_state *state, int pm_state); static void uart_change_pm(struct uart_state *state, int pm_state);
@ -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 * Startup the port. This will be called once per open. All calls
* will be serialised by the per-port mutex. * 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 uart_port *uport = state->uart_port;
struct tty_port *port = &state->port; struct tty_port *port = &state->port;
@ -152,7 +152,7 @@ static int uart_startup(struct uart_state *state, int init_hw)
* once we have successfully opened the port. Also set * once we have successfully opened the port. Also set
* up the tty->alt_speed kludge * 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) if (uport->type == PORT_UNKNOWN)
return 0; return 0;
@ -177,26 +177,26 @@ static int uart_startup(struct uart_state *state, int init_hw)
/* /*
* Initialise the hardware port settings. * Initialise the hardware port settings.
*/ */
uart_change_speed(state, NULL); uart_change_speed(tty, state, NULL);
/* /*
* Setup the RTS and DTR signals once the * Setup the RTS and DTR signals once the
* port is open and ready to respond. * 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); uart_set_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
} }
if (port->flags & ASYNC_CTS_FLOW) { if (port->flags & ASYNC_CTS_FLOW) {
spin_lock_irq(&uport->lock); spin_lock_irq(&uport->lock);
if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS)) if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS))
port->tty->hw_stopped = 1; tty->hw_stopped = 1;
spin_unlock_irq(&uport->lock); spin_unlock_irq(&uport->lock);
} }
set_bit(ASYNCB_INITIALIZED, &port->flags); 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)) if (retval && capable(CAP_SYS_ADMIN))
@ -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 * DTR is dropped if the hangup on close termio flag is on. Calls to
* uart_shutdown are serialised by the per-port semaphore. * 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 uart_port *uport = state->uart_port;
struct tty_port *port = &state->port; struct tty_port *port = &state->port;
struct tty_struct *tty = port->tty;
/* /*
* Set the TTY IO error marker * Set the TTY IO error marker
@ -430,11 +429,10 @@ uart_get_divisor(struct uart_port *port, unsigned int baud)
EXPORT_SYMBOL(uart_get_divisor); EXPORT_SYMBOL(uart_get_divisor);
/* FIXME: Consistent locking policy */ /* FIXME: Consistent locking policy */
static void static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
uart_change_speed(struct uart_state *state, struct ktermios *old_termios) struct ktermios *old_termios)
{ {
struct tty_port *port = &state->port; struct tty_port *port = &state->port;
struct tty_struct *tty = port->tty;
struct uart_port *uport = state->uart_port; struct uart_port *uport = state->uart_port;
struct ktermios *termios; struct ktermios *termios;
@ -463,8 +461,8 @@ uart_change_speed(struct uart_state *state, struct ktermios *old_termios)
uport->ops->set_termios(uport, termios, old_termios); uport->ops->set_termios(uport, termios, old_termios);
} }
static inline int static inline int __uart_put_char(struct uart_port *port,
__uart_put_char(struct uart_port *port, struct circ_buf *circ, unsigned char c) struct circ_buf *circ, unsigned char c)
{ {
unsigned long flags; unsigned long flags;
int ret = 0; int ret = 0;
@ -494,8 +492,8 @@ static void uart_flush_chars(struct tty_struct *tty)
uart_start(tty); uart_start(tty);
} }
static int static int uart_write(struct tty_struct *tty,
uart_write(struct tty_struct *tty, const unsigned char *buf, int count) const unsigned char *buf, int count)
{ {
struct uart_state *state = tty->driver_data; struct uart_state *state = tty->driver_data;
struct uart_port *port; struct uart_port *port;
@ -675,7 +673,7 @@ static int uart_get_info(struct uart_state *state,
return 0; 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 __user *newinfo)
{ {
struct serial_struct new_serial; struct serial_struct new_serial;
@ -770,7 +768,7 @@ static int uart_set_info(struct uart_state *state,
* We need to shutdown the serial port at the old * We need to shutdown the serial port at the old
* port/type/irq combination. * port/type/irq combination.
*/ */
uart_shutdown(state); uart_shutdown(tty, state);
} }
if (change_port) { if (change_port) {
@ -869,25 +867,27 @@ static int uart_set_info(struct uart_state *state,
"is deprecated.\n", current->comm, "is deprecated.\n", current->comm,
tty_name(port->tty, buf)); tty_name(port->tty, buf));
} }
uart_change_speed(state, NULL); uart_change_speed(tty, state, NULL);
} }
} else } else
retval = uart_startup(state, 1); retval = uart_startup(tty, state, 1);
exit: exit:
mutex_unlock(&port->mutex); mutex_unlock(&port->mutex);
return retval; return retval;
} }
/**
/* * uart_get_lsr_info - get line status register info
* uart_get_lsr_info - get line status register info. * @tty: tty associated with the UART
* Note: uart_ioctl protects us against hangups. * @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, static int uart_get_lsr_info(struct tty_struct *tty,
unsigned int __user *value) struct uart_state *state, unsigned int __user *value)
{ {
struct uart_port *uport = state->uart_port; struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
unsigned int result; unsigned int result;
result = uport->ops->tx_empty(uport); result = uport->ops->tx_empty(uport);
@ -900,7 +900,7 @@ static int uart_get_lsr_info(struct uart_state *state,
*/ */
if (uport->x_char || if (uport->x_char ||
((uart_circ_chars_pending(&state->xmit) > 0) && ((uart_circ_chars_pending(&state->xmit) > 0) &&
!port->tty->stopped && !port->tty->hw_stopped)) !tty->stopped && !tty->hw_stopped))
result &= ~TIOCSER_TEMT; result &= ~TIOCSER_TEMT;
return put_user(result, value); return put_user(result, value);
@ -961,7 +961,7 @@ static int uart_break_ctl(struct tty_struct *tty, int break_state)
return 0; 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 uart_port *uport = state->uart_port;
struct tty_port *port = &state->port; struct tty_port *port = &state->port;
@ -980,7 +980,7 @@ static int uart_do_autoconfig(struct uart_state *state)
ret = -EBUSY; ret = -EBUSY;
if (tty_port_users(port) == 1) { if (tty_port_users(port) == 1) {
uart_shutdown(state); uart_shutdown(tty, state);
/* /*
* If we already have a port type configured, * If we already have a port type configured,
@ -999,7 +999,7 @@ static int uart_do_autoconfig(struct uart_state *state)
*/ */
uport->ops->config_port(uport, flags); uport->ops->config_port(uport, flags);
ret = uart_startup(state, 1); ret = uart_startup(tty, state, 1);
} }
mutex_unlock(&port->mutex); mutex_unlock(&port->mutex);
return ret; return ret;
@ -1122,11 +1122,11 @@ uart_ioctl(struct tty_struct *tty, struct file *filp, unsigned int cmd,
break; break;
case TIOCSSERIAL: case TIOCSSERIAL:
ret = uart_set_info(state, uarg); ret = uart_set_info(tty, state, uarg);
break; break;
case TIOCSERCONFIG: case TIOCSERCONFIG:
ret = uart_do_autoconfig(state); ret = uart_do_autoconfig(tty, state);
break; break;
case TIOCSERGWILD: /* obsolete */ case TIOCSERGWILD: /* obsolete */
@ -1172,7 +1172,7 @@ uart_ioctl(struct tty_struct *tty, struct file *filp, unsigned int cmd,
*/ */
switch (cmd) { switch (cmd) {
case TIOCSERGETLSR: /* Get line status register */ case TIOCSERGETLSR: /* Get line status register */
ret = uart_get_lsr_info(state, uarg); ret = uart_get_lsr_info(tty, state, uarg);
break; break;
default: { default: {
@ -1219,7 +1219,7 @@ static void uart_set_termios(struct tty_struct *tty,
return; return;
} }
uart_change_speed(state, old_termios); uart_change_speed(tty, state, old_termios);
/* Handle transition to B0 status */ /* Handle transition to B0 status */
if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD)) if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
@ -1335,7 +1335,7 @@ static void uart_close(struct tty_struct *tty, struct file *filp)
uart_wait_until_sent(tty, uport->timeout); uart_wait_until_sent(tty, uport->timeout);
} }
uart_shutdown(state); uart_shutdown(tty, state);
uart_flush_buffer(tty); uart_flush_buffer(tty);
tty_ldisc_flush(tty); tty_ldisc_flush(tty);
@ -1436,7 +1436,7 @@ static void uart_hangup(struct tty_struct *tty)
mutex_lock(&port->mutex); mutex_lock(&port->mutex);
if (port->flags & ASYNC_NORMAL_ACTIVE) { if (port->flags & ASYNC_NORMAL_ACTIVE) {
uart_flush_buffer(tty); uart_flush_buffer(tty);
uart_shutdown(state); uart_shutdown(tty, state);
port->count = 0; port->count = 0;
clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags); clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
tty_port_tty_set(port, NULL); tty_port_tty_set(port, NULL);
@ -1446,15 +1446,19 @@ static void uart_hangup(struct tty_struct *tty)
mutex_unlock(&port->mutex); mutex_unlock(&port->mutex);
} }
/* /**
* Copy across the serial console cflag setting into the termios settings * uart_update_termios - update the terminal hw settings
* for the initial open of the port. This allows continuity between the * @tty: tty associated with UART
* kernel settings, and the settings init adopts when it opens the port * @state: UART to update
* for the first time. *
* 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; struct uart_port *port = state->uart_port;
if (uart_console(port) && port->cons->cflag) { if (uart_console(port) && port->cons->cflag) {
@ -1471,7 +1475,7 @@ static void uart_update_termios(struct uart_state *state)
/* /*
* Make termios settings take effect. * Make termios settings take effect.
*/ */
uart_change_speed(state, NULL); uart_change_speed(tty, state, NULL);
/* /*
* And finally enable the RTS and DTR signals. * And finally enable the RTS and DTR signals.
@ -1668,7 +1672,7 @@ static int uart_open(struct tty_struct *tty, struct file *filp)
/* /*
* Start up the serial port. * 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. * If we succeeded, wait until the port is ready.
@ -1683,7 +1687,7 @@ static int uart_open(struct tty_struct *tty, struct file *filp)
if (retval == 0 && !(port->flags & ASYNC_NORMAL_ACTIVE)) { if (retval == 0 && !(port->flags & ASYNC_NORMAL_ACTIVE)) {
set_bit(ASYNCB_NORMAL_ACTIVE, &port->flags); set_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
uart_update_termios(state); uart_update_termios(tty, state);
} }
fail: fail:
@ -2010,9 +2014,13 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
struct tty_port *port = &state->port; struct tty_port *port = &state->port;
struct device *tty_dev; struct device *tty_dev;
struct uart_match match = {uport, drv}; struct uart_match match = {uport, drv};
struct tty_struct *tty;
mutex_lock(&port->mutex); 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); tty_dev = device_find_child(uport->dev, &match, serial_match_port);
if (device_may_wakeup(tty_dev)) { if (device_may_wakeup(tty_dev)) {
enable_irq_wake(uport->irq); enable_irq_wake(uport->irq);
@ -2105,9 +2113,12 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
ops->set_mctrl(uport, 0); ops->set_mctrl(uport, 0);
spin_unlock_irq(&uport->lock); spin_unlock_irq(&uport->lock);
if (console_suspend_enabled || !uart_console(uport)) { if (console_suspend_enabled || !uart_console(uport)) {
/* Protected by port mutex for now */
struct tty_struct *tty = port->tty;
ret = ops->startup(uport); ret = ops->startup(uport);
if (ret == 0) { if (ret == 0) {
uart_change_speed(state, NULL); if (tty)
uart_change_speed(tty, state, NULL);
spin_lock_irq(&uport->lock); spin_lock_irq(&uport->lock);
ops->set_mctrl(uport, uport->mctrl); ops->set_mctrl(uport, uport->mctrl);
ops->start_tx(uport); ops->start_tx(uport);
@ -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 * Clear the "initialized" flag so we won't try
* to call the low level drivers shutdown method. * to call the low level drivers shutdown method.
*/ */
uart_shutdown(state); uart_shutdown(tty, state);
} }
} }