From 192251352f912bccfb942ea35801d2357f11f592 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Tue, 1 Jun 2010 22:52:51 +0200 Subject: [PATCH] tty: serial - fix various misuses/mishandlings of port->tty 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 Cc: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman --- drivers/serial/serial_core.c | 109 +++++++++++++++++++---------------- 1 file changed, 60 insertions(+), 49 deletions(-) diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c index 7f2830709512..12ee7e0f99ce 100644 --- a/drivers/serial/serial_core.c +++ b/drivers/serial/serial_core.c @@ -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); @@ -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; @@ -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; @@ -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)) @@ -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 @@ -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; @@ -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; @@ -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; @@ -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; @@ -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) { @@ -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); @@ -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); @@ -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; @@ -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, @@ -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; @@ -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 */ @@ -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: { @@ -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)) @@ -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); @@ -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); @@ -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) { @@ -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. @@ -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. @@ -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: @@ -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); @@ -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); @@ -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); } } -- GitLab