diff options
Diffstat (limited to 'drivers/tty/serial/serial_core.c')
| -rw-r--r-- | drivers/tty/serial/serial_core.c | 430 |
1 files changed, 288 insertions, 142 deletions
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index a126a603b..a333c59cb 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -64,6 +64,41 @@ static int uart_dcd_enabled(struct uart_port *uport) return !!(uport->status & UPSTAT_DCD_ENABLE); } +static inline struct uart_port *uart_port_ref(struct uart_state *state) +{ + if (atomic_add_unless(&state->refcount, 1, 0)) + return state->uart_port; + return NULL; +} + +static inline void uart_port_deref(struct uart_port *uport) +{ + if (uport && atomic_dec_and_test(&uport->state->refcount)) + wake_up(&uport->state->remove_wait); +} + +#define uart_port_lock(state, flags) \ + ({ \ + struct uart_port *__uport = uart_port_ref(state); \ + if (__uport) \ + spin_lock_irqsave(&__uport->lock, flags); \ + __uport; \ + }) + +#define uart_port_unlock(uport, flags) \ + ({ \ + struct uart_port *__uport = uport; \ + if (__uport) \ + spin_unlock_irqrestore(&__uport->lock, flags); \ + uart_port_deref(__uport); \ + }) + +static inline struct uart_port *uart_port_check(struct uart_state *state) +{ + lockdep_assert_held(&state->port.mutex); + return state->uart_port; +} + /* * This routine is used by the interrupt handler to schedule processing in * the software interrupt portion of the driver. @@ -82,12 +117,13 @@ void uart_write_wakeup(struct uart_port *port) static void uart_stop(struct tty_struct *tty) { struct uart_state *state = tty->driver_data; - struct uart_port *port = state->uart_port; + struct uart_port *port; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); - port->ops->stop_tx(port); - spin_unlock_irqrestore(&port->lock, flags); + port = uart_port_lock(state, flags); + if (port) + port->ops->stop_tx(port); + uart_port_unlock(port, flags); } static void __uart_start(struct tty_struct *tty) @@ -95,19 +131,19 @@ static void __uart_start(struct tty_struct *tty) struct uart_state *state = tty->driver_data; struct uart_port *port = state->uart_port; - if (!uart_tx_stopped(port)) + if (port && !uart_tx_stopped(port)) port->ops->start_tx(port); } static void uart_start(struct tty_struct *tty) { struct uart_state *state = tty->driver_data; - struct uart_port *port = state->uart_port; + struct uart_port *port; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + port = uart_port_lock(state, flags); __uart_start(tty); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock(port, flags); } static void @@ -134,7 +170,7 @@ uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear) static int uart_port_startup(struct tty_struct *tty, struct uart_state *state, int init_hw) { - struct uart_port *uport = state->uart_port; + struct uart_port *uport = uart_port_check(state); unsigned long page; int retval = 0; @@ -196,7 +232,7 @@ static int uart_startup(struct tty_struct *tty, struct uart_state *state, struct tty_port *port = &state->port; int retval; - if (port->flags & ASYNC_INITIALIZED) + if (tty_port_initialized(port)) return 0; /* @@ -207,7 +243,7 @@ static int uart_startup(struct tty_struct *tty, struct uart_state *state, retval = uart_port_startup(tty, state, init_hw); if (!retval) { - set_bit(ASYNCB_INITIALIZED, &port->flags); + tty_port_set_initialized(port, 1); clear_bit(TTY_IO_ERROR, &tty->flags); } else if (retval > 0) retval = 0; @@ -219,10 +255,12 @@ static int uart_startup(struct tty_struct *tty, struct uart_state *state, * This routine will shutdown a serial port; interrupts are disabled, and * DTR is dropped if the hangup on close termio flag is on. Calls to * uart_shutdown are serialised by the per-port semaphore. + * + * uport == NULL if uart_port has already been removed */ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state) { - struct uart_port *uport = state->uart_port; + struct uart_port *uport = uart_port_check(state); struct tty_port *port = &state->port; /* @@ -231,11 +269,13 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state) if (tty) set_bit(TTY_IO_ERROR, &tty->flags); - if (test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags)) { + if (tty_port_initialized(port)) { + tty_port_set_initialized(port, 0); + /* * Turn off DTR and RTS early. */ - if (uart_console(uport) && tty) + if (uport && uart_console(uport) && tty) uport->cons->cflag = tty->termios.c_cflag; if (!tty || C_HUPCL(tty)) @@ -249,7 +289,7 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state) * a DCD drop (hangup) at just the right time. Clear suspended bit so * we don't try to resume a port that has been shutdown. */ - clear_bit(ASYNCB_SUSPENDED, &port->flags); + tty_port_set_suspended(port, 0); /* * Free the transmit buffer page. @@ -441,7 +481,7 @@ EXPORT_SYMBOL(uart_get_divisor); static void uart_change_speed(struct tty_struct *tty, struct uart_state *state, struct ktermios *old_termios) { - struct uart_port *uport = state->uart_port; + struct uart_port *uport = uart_port_check(state); struct ktermios *termios; int hw_stopped; @@ -486,7 +526,7 @@ static void uart_change_speed(struct tty_struct *tty, struct uart_state *state, static int uart_put_char(struct tty_struct *tty, unsigned char c) { struct uart_state *state = tty->driver_data; - struct uart_port *port = state->uart_port; + struct uart_port *port; struct circ_buf *circ; unsigned long flags; int ret = 0; @@ -495,13 +535,13 @@ static int uart_put_char(struct tty_struct *tty, unsigned char c) if (!circ->buf) return 0; - spin_lock_irqsave(&port->lock, flags); - if (uart_circ_chars_free(circ) != 0) { + port = uart_port_lock(state, flags); + if (port && uart_circ_chars_free(circ) != 0) { circ->buf[circ->head] = c; circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1); ret = 1; } - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock(port, flags); return ret; } @@ -528,14 +568,12 @@ static int uart_write(struct tty_struct *tty, return -EL3HLT; } - port = state->uart_port; circ = &state->xmit; - if (!circ->buf) return 0; - spin_lock_irqsave(&port->lock, flags); - while (1) { + port = uart_port_lock(state, flags); + while (port) { c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE); if (count < c) c = count; @@ -549,32 +587,33 @@ static int uart_write(struct tty_struct *tty, } __uart_start(tty); - spin_unlock_irqrestore(&port->lock, flags); - + uart_port_unlock(port, flags); return ret; } static int uart_write_room(struct tty_struct *tty) { struct uart_state *state = tty->driver_data; + struct uart_port *port; unsigned long flags; int ret; - spin_lock_irqsave(&state->uart_port->lock, flags); + port = uart_port_lock(state, flags); ret = uart_circ_chars_free(&state->xmit); - spin_unlock_irqrestore(&state->uart_port->lock, flags); + uart_port_unlock(port, flags); return ret; } static int uart_chars_in_buffer(struct tty_struct *tty) { struct uart_state *state = tty->driver_data; + struct uart_port *port; unsigned long flags; int ret; - spin_lock_irqsave(&state->uart_port->lock, flags); + port = uart_port_lock(state, flags); ret = uart_circ_chars_pending(&state->xmit); - spin_unlock_irqrestore(&state->uart_port->lock, flags); + uart_port_unlock(port, flags); return ret; } @@ -593,14 +632,15 @@ static void uart_flush_buffer(struct tty_struct *tty) return; } - port = state->uart_port; pr_debug("uart_flush_buffer(%d) called\n", tty->index); - spin_lock_irqsave(&port->lock, flags); + port = uart_port_lock(state, flags); + if (!port) + return; uart_circ_clear(&state->xmit); if (port->ops->flush_buffer) port->ops->flush_buffer(port); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock(port, flags); tty_wakeup(tty); } @@ -611,9 +651,13 @@ static void uart_flush_buffer(struct tty_struct *tty) static void uart_send_xchar(struct tty_struct *tty, char ch) { struct uart_state *state = tty->driver_data; - struct uart_port *port = state->uart_port; + struct uart_port *port; unsigned long flags; + port = uart_port_ref(state); + if (!port) + return; + if (port->ops->send_xchar) port->ops->send_xchar(port, ch); else { @@ -623,14 +667,19 @@ static void uart_send_xchar(struct tty_struct *tty, char ch) port->ops->start_tx(port); spin_unlock_irqrestore(&port->lock, flags); } + uart_port_deref(port); } static void uart_throttle(struct tty_struct *tty) { struct uart_state *state = tty->driver_data; - struct uart_port *port = state->uart_port; + struct uart_port *port; upstat_t mask = 0; + port = uart_port_ref(state); + if (!port) + return; + if (I_IXOFF(tty)) mask |= UPSTAT_AUTOXOFF; if (C_CRTSCTS(tty)) @@ -646,14 +695,20 @@ static void uart_throttle(struct tty_struct *tty) if (mask & UPSTAT_AUTOXOFF) uart_send_xchar(tty, STOP_CHAR(tty)); + + uart_port_deref(port); } static void uart_unthrottle(struct tty_struct *tty) { struct uart_state *state = tty->driver_data; - struct uart_port *port = state->uart_port; + struct uart_port *port; upstat_t mask = 0; + port = uart_port_ref(state); + if (!port) + return; + if (I_IXOFF(tty)) mask |= UPSTAT_AUTOXOFF; if (C_CRTSCTS(tty)) @@ -669,12 +724,15 @@ static void uart_unthrottle(struct tty_struct *tty) if (mask & UPSTAT_AUTOXOFF) uart_send_xchar(tty, START_CHAR(tty)); + + uart_port_deref(port); } -static void uart_get_info(struct tty_port *port, struct serial_struct *retinfo) +static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo) { struct uart_state *state = container_of(port, struct uart_state, port); - struct uart_port *uport = state->uart_port; + struct uart_port *uport; + int ret = -ENODEV; memset(retinfo, 0, sizeof(*retinfo)); @@ -683,6 +741,10 @@ static void uart_get_info(struct tty_port *port, struct serial_struct *retinfo) * occur as we go */ mutex_lock(&port->mutex); + uport = uart_port_check(state); + if (!uport) + goto out; + retinfo->type = uport->type; retinfo->line = uport->line; retinfo->port = uport->iobase; @@ -701,7 +763,11 @@ static void uart_get_info(struct tty_port *port, struct serial_struct *retinfo) retinfo->io_type = uport->iotype; retinfo->iomem_reg_shift = uport->regshift; retinfo->iomem_base = (void *)(unsigned long)uport->mapbase; + + ret = 0; +out: mutex_unlock(&port->mutex); + return ret; } static int uart_get_info_user(struct tty_port *port, @@ -709,7 +775,8 @@ static int uart_get_info_user(struct tty_port *port, { struct serial_struct tmp; - uart_get_info(port, &tmp); + if (uart_get_info(port, &tmp) < 0) + return -EIO; if (copy_to_user(retinfo, &tmp, sizeof(*retinfo))) return -EFAULT; @@ -720,13 +787,16 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port, struct uart_state *state, struct serial_struct *new_info) { - struct uart_port *uport = state->uart_port; + struct uart_port *uport = uart_port_check(state); unsigned long new_port; unsigned int change_irq, change_port, closing_wait; unsigned int old_custom_divisor, close_delay; upf_t old_flags, new_flags; int retval = 0; + if (!uport) + return -EIO; + new_port = new_info->port; if (HIGH_BITS_OFFSET) new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET; @@ -886,7 +956,7 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port, retval = 0; if (uport->type == PORT_UNKNOWN) goto exit; - if (port->flags & ASYNC_INITIALIZED) { + if (tty_port_initialized(port)) { if (((old_flags ^ uport->flags) & UPF_SPD_MASK) || old_custom_divisor != uport->custom_divisor) { /* @@ -936,13 +1006,11 @@ static int uart_set_info_user(struct tty_struct *tty, struct uart_state *state, * @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 tty_struct *tty, struct uart_state *state, unsigned int __user *value) { - struct uart_port *uport = state->uart_port; + struct uart_port *uport = uart_port_check(state); unsigned int result; result = uport->ops->tx_empty(uport); @@ -965,18 +1033,22 @@ static int uart_tiocmget(struct tty_struct *tty) { struct uart_state *state = tty->driver_data; struct tty_port *port = &state->port; - struct uart_port *uport = state->uart_port; + struct uart_port *uport; int result = -EIO; mutex_lock(&port->mutex); - if (!(tty->flags & (1 << TTY_IO_ERROR))) { + uport = uart_port_check(state); + if (!uport) + goto out; + + if (!tty_io_error(tty)) { result = uport->mctrl; spin_lock_irq(&uport->lock); result |= uport->ops->get_mctrl(uport); spin_unlock_irq(&uport->lock); } +out: mutex_unlock(&port->mutex); - return result; } @@ -984,15 +1056,20 @@ static int uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear) { struct uart_state *state = tty->driver_data; - struct uart_port *uport = state->uart_port; struct tty_port *port = &state->port; + struct uart_port *uport; int ret = -EIO; mutex_lock(&port->mutex); - if (!(tty->flags & (1 << TTY_IO_ERROR))) { + uport = uart_port_check(state); + if (!uport) + goto out; + + if (!tty_io_error(tty)) { uart_update_mctrl(uport, set, clear); ret = 0; } +out: mutex_unlock(&port->mutex); return ret; } @@ -1001,21 +1078,26 @@ static int uart_break_ctl(struct tty_struct *tty, int break_state) { struct uart_state *state = tty->driver_data; struct tty_port *port = &state->port; - struct uart_port *uport = state->uart_port; + struct uart_port *uport; + int ret = -EIO; mutex_lock(&port->mutex); + uport = uart_port_check(state); + if (!uport) + goto out; if (uport->type != PORT_UNKNOWN) uport->ops->break_ctl(uport, break_state); - + ret = 0; +out: mutex_unlock(&port->mutex); - return 0; + return ret; } 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; + struct uart_port *uport; int flags, ret; if (!capable(CAP_SYS_ADMIN)) @@ -1029,6 +1111,12 @@ static int uart_do_autoconfig(struct tty_struct *tty,struct uart_state *state) if (mutex_lock_interruptible(&port->mutex)) return -ERESTARTSYS; + uport = uart_port_check(state); + if (!uport) { + ret = -EIO; + goto out; + } + ret = -EBUSY; if (tty_port_users(port) == 1) { uart_shutdown(tty, state); @@ -1052,6 +1140,7 @@ static int uart_do_autoconfig(struct tty_struct *tty,struct uart_state *state) ret = uart_startup(tty, state, 1); } +out: mutex_unlock(&port->mutex); return ret; } @@ -1074,10 +1163,9 @@ static void uart_enable_ms(struct uart_port *uport) * FIXME: This wants extracting into a common all driver implementation * of TIOCMWAIT using tty_port. */ -static int -uart_wait_modem_status(struct uart_state *state, unsigned long arg) +static int uart_wait_modem_status(struct uart_state *state, unsigned long arg) { - struct uart_port *uport = state->uart_port; + struct uart_port *uport; struct tty_port *port = &state->port; DECLARE_WAITQUEUE(wait, current); struct uart_icount cprev, cnow; @@ -1086,6 +1174,9 @@ uart_wait_modem_status(struct uart_state *state, unsigned long arg) /* * note the counters on entry */ + uport = uart_port_ref(state); + if (!uport) + return -EIO; spin_lock_irq(&uport->lock); memcpy(&cprev, &uport->icount, sizeof(struct uart_icount)); uart_enable_ms(uport); @@ -1119,6 +1210,7 @@ uart_wait_modem_status(struct uart_state *state, unsigned long arg) } __set_current_state(TASK_RUNNING); remove_wait_queue(&port->delta_msr_wait, &wait); + uart_port_deref(uport); return ret; } @@ -1134,11 +1226,15 @@ static int uart_get_icount(struct tty_struct *tty, { struct uart_state *state = tty->driver_data; struct uart_icount cnow; - struct uart_port *uport = state->uart_port; + struct uart_port *uport; + uport = uart_port_ref(state); + if (!uport) + return -EIO; spin_lock_irq(&uport->lock); memcpy(&cnow, &uport->icount, sizeof(struct uart_icount)); spin_unlock_irq(&uport->lock); + uart_port_deref(uport); icount->cts = cnow.cts; icount->dsr = cnow.dsr; @@ -1200,11 +1296,11 @@ static int uart_set_rs485_config(struct uart_port *port, * Called via sys_ioctl. We can use spin_lock_irq() here. */ static int -uart_ioctl(struct tty_struct *tty, unsigned int cmd, - unsigned long arg) +uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg) { struct uart_state *state = tty->driver_data; struct tty_port *port = &state->port; + struct uart_port *uport; void __user *uarg = (void __user *)arg; int ret = -ENOIOCTLCMD; @@ -1238,7 +1334,7 @@ uart_ioctl(struct tty_struct *tty, unsigned int cmd, if (ret != -ENOIOCTLCMD) goto out; - if (tty->flags & (1 << TTY_IO_ERROR)) { + if (tty_io_error(tty)) { ret = -EIO; goto out; } @@ -1256,8 +1352,9 @@ uart_ioctl(struct tty_struct *tty, unsigned int cmd, goto out; mutex_lock(&port->mutex); + uport = uart_port_check(state); - if (tty->flags & (1 << TTY_IO_ERROR)) { + if (!uport || tty_io_error(tty)) { ret = -EIO; goto out_up; } @@ -1273,19 +1370,17 @@ uart_ioctl(struct tty_struct *tty, unsigned int cmd, break; case TIOCGRS485: - ret = uart_get_rs485_config(state->uart_port, uarg); + ret = uart_get_rs485_config(uport, uarg); break; case TIOCSRS485: - ret = uart_set_rs485_config(state->uart_port, uarg); + ret = uart_set_rs485_config(uport, uarg); break; - default: { - struct uart_port *uport = state->uart_port; + default: if (uport->ops->ioctl) ret = uport->ops->ioctl(uport, cmd, arg); break; } - } out_up: mutex_unlock(&port->mutex); out: @@ -1295,24 +1390,29 @@ out: static void uart_set_ldisc(struct tty_struct *tty) { struct uart_state *state = tty->driver_data; - struct uart_port *uport = state->uart_port; + struct uart_port *uport; - if (uport->ops->set_ldisc) { - mutex_lock(&state->port.mutex); + mutex_lock(&state->port.mutex); + uport = uart_port_check(state); + if (uport && uport->ops->set_ldisc) uport->ops->set_ldisc(uport, &tty->termios); - mutex_unlock(&state->port.mutex); - } + mutex_unlock(&state->port.mutex); } static void uart_set_termios(struct tty_struct *tty, struct ktermios *old_termios) { struct uart_state *state = tty->driver_data; - struct uart_port *uport = state->uart_port; + struct uart_port *uport; unsigned int cflag = tty->termios.c_cflag; unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK; bool sw_changed = false; + mutex_lock(&state->port.mutex); + uport = uart_port_check(state); + if (!uport) + goto out; + /* * Drivers doing software flow control also need to know * about changes to these input settings. @@ -1335,12 +1435,10 @@ static void uart_set_termios(struct tty_struct *tty, tty->termios.c_ispeed == old_termios->c_ispeed && ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 && !sw_changed) { - return; + goto out; } - mutex_lock(&state->port.mutex); uart_change_speed(tty, state, old_termios); - mutex_unlock(&state->port.mutex); /* reload cflag from termios; port driver may have overriden flags */ cflag = tty->termios.c_cflag; @@ -1350,17 +1448,18 @@ static void uart_set_termios(struct tty_struct *tty, /* Handle transition away from B0 status */ else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) { unsigned int mask = TIOCM_DTR; - if (!(cflag & CRTSCTS) || !test_bit(TTY_THROTTLED, &tty->flags)) + if (!(cflag & CRTSCTS) || !tty_throttled(tty)) mask |= TIOCM_RTS; uart_set_mctrl(uport, mask); } +out: + mutex_unlock(&state->port.mutex); } /* * Calls to uart_close() are serialised via the tty_lock in * drivers/tty/tty_io.c:tty_release() * drivers/tty/tty_io.c:do_tty_hangup() - * This runs from a workqueue and can sleep for a _short_ time only. */ static void uart_close(struct tty_struct *tty, struct file *filp) { @@ -1379,18 +1478,21 @@ static void uart_close(struct tty_struct *tty, struct file *filp) return; } - uport = state->uart_port; port = &state->port; pr_debug("uart_close(%d) called\n", tty->index); - if (!port->count || tty_port_close_start(port, tty, filp) == 0) + if (tty_port_close_start(port, tty, filp) == 0) return; + mutex_lock(&port->mutex); + uport = uart_port_check(state); + /* * At this point, we stop accepting input. To do this, we * disable the receive line status interrupts. */ - if (port->flags & ASYNC_INITIALIZED) { + if (tty_port_initialized(port) && + !WARN(!uport, "detached port still initialized!\n")) { spin_lock_irq(&uport->lock); uport->ops->stop_rx(uport); spin_unlock_irq(&uport->lock); @@ -1402,7 +1504,6 @@ static void uart_close(struct tty_struct *tty, struct file *filp) uart_wait_until_sent(tty, uport->timeout); } - mutex_lock(&port->mutex); uart_shutdown(tty, state); tty_port_tty_set(port, NULL); @@ -1413,17 +1514,17 @@ static void uart_close(struct tty_struct *tty, struct file *filp) if (port->close_delay) msleep_interruptible(jiffies_to_msecs(port->close_delay)); spin_lock_irq(&port->lock); - } else if (!uart_console(uport)) { + } else if (uport && !uart_console(uport)) { spin_unlock_irq(&port->lock); uart_change_pm(state, UART_PM_STATE_OFF); spin_lock_irq(&port->lock); } + spin_unlock_irq(&port->lock); + tty_port_set_active(port, 0); /* * Wake up anyone trying to open this port. */ - clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags); - spin_unlock_irq(&port->lock); wake_up_interruptible(&port->open_wait); mutex_unlock(&port->mutex); @@ -1435,11 +1536,14 @@ static void uart_close(struct tty_struct *tty, struct file *filp) static void uart_wait_until_sent(struct tty_struct *tty, int timeout) { struct uart_state *state = tty->driver_data; - struct uart_port *port = state->uart_port; + struct uart_port *port; unsigned long char_time, expire; - if (port->type == PORT_UNKNOWN || port->fifosize == 0) + port = uart_port_ref(state); + if (!port || port->type == PORT_UNKNOWN || port->fifosize == 0) { + uart_port_deref(port); return; + } /* * Set the check interval to be 1/5 of the estimated time to @@ -1485,6 +1589,7 @@ static void uart_wait_until_sent(struct tty_struct *tty, int timeout) if (time_after(jiffies, expire)) break; } + uart_port_deref(port); } /* @@ -1496,20 +1601,24 @@ static void uart_hangup(struct tty_struct *tty) { struct uart_state *state = tty->driver_data; struct tty_port *port = &state->port; + struct uart_port *uport; unsigned long flags; pr_debug("uart_hangup(%d)\n", tty->index); mutex_lock(&port->mutex); - if (port->flags & ASYNC_NORMAL_ACTIVE) { + uport = uart_port_check(state); + WARN(!uport, "hangup of detached port!\n"); + + if (tty_port_active(port)) { uart_flush_buffer(tty); uart_shutdown(tty, state); spin_lock_irqsave(&port->lock, flags); port->count = 0; - clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags); spin_unlock_irqrestore(&port->lock, flags); + tty_port_set_active(port, 0); tty_port_tty_set(port, NULL); - if (!uart_console(state->uart_port)) + if (uport && !uart_console(uport)) uart_change_pm(state, UART_PM_STATE_OFF); wake_up_interruptible(&port->open_wait); wake_up_interruptible(&port->delta_msr_wait); @@ -1517,10 +1626,11 @@ static void uart_hangup(struct tty_struct *tty) mutex_unlock(&port->mutex); } +/* uport == NULL if uart_port has already been removed */ static void uart_port_shutdown(struct tty_port *port) { struct uart_state *state = container_of(port, struct uart_state, port); - struct uart_port *uport = state->uart_port; + struct uart_port *uport = uart_port_check(state); /* * clear delta_msr_wait queue to avoid mem leaks: we may free @@ -1534,23 +1644,36 @@ static void uart_port_shutdown(struct tty_port *port) /* * Free the IRQ and disable the port. */ - uport->ops->shutdown(uport); + if (uport) + uport->ops->shutdown(uport); /* * Ensure that the IRQ handler isn't running on another CPU. */ - synchronize_irq(uport->irq); + if (uport) + synchronize_irq(uport->irq); } static int uart_carrier_raised(struct tty_port *port) { struct uart_state *state = container_of(port, struct uart_state, port); - struct uart_port *uport = state->uart_port; + struct uart_port *uport; int mctrl; + + uport = uart_port_ref(state); + /* + * Should never observe uport == NULL since checks for hangup should + * abort the tty_port_block_til_ready() loop before checking for carrier + * raised -- but report carrier raised if it does anyway so open will + * continue and not sleep + */ + if (WARN_ON(!uport)) + return 1; spin_lock_irq(&uport->lock); uart_enable_ms(uport); mctrl = uport->ops->get_mctrl(uport); spin_unlock_irq(&uport->lock); + uart_port_deref(uport); if (mctrl & TIOCM_CAR) return 1; return 0; @@ -1559,12 +1682,18 @@ static int uart_carrier_raised(struct tty_port *port) static void uart_dtr_rts(struct tty_port *port, int onoff) { struct uart_state *state = container_of(port, struct uart_state, port); - struct uart_port *uport = state->uart_port; + struct uart_port *uport; + + uport = uart_port_ref(state); + if (!uport) + return; if (onoff) uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS); else uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS); + + uart_port_deref(uport); } /* @@ -1583,6 +1712,7 @@ static int uart_open(struct tty_struct *tty, struct file *filp) int retval, line = tty->index; struct uart_state *state = drv->state + line; struct tty_port *port = &state->port; + struct uart_port *uport; pr_debug("uart_open(%d) called\n", line); @@ -1602,15 +1732,15 @@ static int uart_open(struct tty_struct *tty, struct file *filp) goto end; } - if (!state->uart_port || state->uart_port->flags & UPF_DEAD) { + uport = uart_port_check(state); + if (!uport || uport->flags & UPF_DEAD) { retval = -ENXIO; goto err_unlock; } tty->driver_data = state; - state->uart_port->state = state; - state->port.low_latency = - (state->uart_port->flags & UPF_LOW_LATENCY) ? 1 : 0; + uport->state = state; + port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0; tty_port_tty_set(port, tty); /* @@ -1649,13 +1779,15 @@ static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i) struct uart_state *state = drv->state + i; struct tty_port *port = &state->port; enum uart_pm_state pm_state; - struct uart_port *uport = state->uart_port; + struct uart_port *uport; char stat_buf[32]; unsigned int status; int mmio; + mutex_lock(&port->mutex); + uport = uart_port_check(state); if (!uport) - return; + goto out; mmio = uport->iotype >= UPIO_MEM; seq_printf(m, "%d: uart:%s %s%08llX irq:%d", @@ -1667,11 +1799,10 @@ static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i) if (uport->type == PORT_UNKNOWN) { seq_putc(m, '\n'); - return; + goto out; } if (capable(CAP_SYS_ADMIN)) { - mutex_lock(&port->mutex); pm_state = state->pm_state; if (pm_state != UART_PM_STATE_ON) uart_change_pm(state, UART_PM_STATE_ON); @@ -1680,7 +1811,6 @@ static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i) spin_unlock_irq(&uport->lock); if (pm_state != UART_PM_STATE_ON) uart_change_pm(state, pm_state); - mutex_unlock(&port->mutex); seq_printf(m, " tx:%d rx:%d", uport->icount.tx, uport->icount.rx); @@ -1718,6 +1848,8 @@ static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i) seq_putc(m, '\n'); #undef STATBIT #undef INFOBIT +out: + mutex_unlock(&port->mutex); } static int uart_proc_show(struct seq_file *m, void *v) @@ -1954,10 +2086,10 @@ EXPORT_SYMBOL_GPL(uart_set_options); static void uart_change_pm(struct uart_state *state, enum uart_pm_state pm_state) { - struct uart_port *port = state->uart_port; + struct uart_port *port = uart_port_check(state); if (state->pm_state != pm_state) { - if (port->ops->pm) + if (port && port->ops->pm) port->ops->pm(port, pm_state, state->pm_state); state->pm_state = pm_state; } @@ -2003,12 +2135,12 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport) uport->suspended = 1; - if (port->flags & ASYNC_INITIALIZED) { + if (tty_port_initialized(port)) { const struct uart_ops *ops = uport->ops; int tries; - set_bit(ASYNCB_SUSPENDED, &port->flags); - clear_bit(ASYNCB_INITIALIZED, &port->flags); + tty_port_set_suspended(port, 1); + tty_port_set_initialized(port, 0); spin_lock_irq(&uport->lock); ops->stop_tx(uport); @@ -2088,7 +2220,7 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport) console_start(uport->cons); } - if (port->flags & ASYNC_SUSPENDED) { + if (tty_port_suspended(port)) { const struct uart_ops *ops = uport->ops; int ret; @@ -2107,7 +2239,7 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport) ops->set_mctrl(uport, uport->mctrl); ops->start_tx(uport); spin_unlock_irq(&uport->lock); - set_bit(ASYNCB_INITIALIZED, &port->flags); + tty_port_set_initialized(port, 1); } else { /* * Failed to resume - maybe hardware went away? @@ -2118,7 +2250,7 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport) } } - clear_bit(ASYNCB_SUSPENDED, &port->flags); + tty_port_set_suspended(port, 0); } mutex_unlock(&port->mutex); @@ -2228,42 +2360,42 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options) { struct uart_driver *drv = driver->driver_state; struct uart_state *state = drv->state + line; + struct tty_port *tport; struct uart_port *port; int baud = 9600; int bits = 8; int parity = 'n'; int flow = 'n'; - int ret; + int ret = 0; - if (!state || !state->uart_port) + if (!state) return -1; - port = state->uart_port; - if (!(port->ops->poll_get_char && port->ops->poll_put_char)) - return -1; + tport = &state->port; + mutex_lock(&tport->mutex); - if (port->ops->poll_init) { - struct tty_port *tport = &state->port; + port = uart_port_check(state); + if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) { + ret = -1; + goto out; + } - ret = 0; - mutex_lock(&tport->mutex); + if (port->ops->poll_init) { /* - * We don't set ASYNCB_INITIALIZED as we only initialized the - * hw, e.g. state->xmit is still uninitialized. + * We don't set initialized as we only initialized the hw, + * e.g. state->xmit is still uninitialized. */ - if (!test_bit(ASYNCB_INITIALIZED, &tport->flags)) + if (!tty_port_initialized(tport)) ret = port->ops->poll_init(port); - mutex_unlock(&tport->mutex); - if (ret) - return ret; } - if (options) { + if (!ret && options) { uart_parse_options(options, &baud, &parity, &bits, &flow); - return uart_set_options(port, NULL, baud, parity, bits, flow); + ret = uart_set_options(port, NULL, baud, parity, bits, flow); } - - return 0; +out: + mutex_unlock(&tport->mutex); + return ret; } static int uart_poll_get_char(struct tty_driver *driver, int line) @@ -2271,12 +2403,15 @@ static int uart_poll_get_char(struct tty_driver *driver, int line) struct uart_driver *drv = driver->driver_state; struct uart_state *state = drv->state + line; struct uart_port *port; + int ret = -1; - if (!state || !state->uart_port) - return -1; - - port = state->uart_port; - return port->ops->poll_get_char(port); + if (state) { + port = uart_port_ref(state); + if (port) + ret = port->ops->poll_get_char(port); + uart_port_deref(port); + } + return ret; } static void uart_poll_put_char(struct tty_driver *driver, int line, char ch) @@ -2285,14 +2420,17 @@ static void uart_poll_put_char(struct tty_driver *driver, int line, char ch) struct uart_state *state = drv->state + line; struct uart_port *port; - if (!state || !state->uart_port) + if (!state) return; - port = state->uart_port; + port = uart_port_ref(state); + if (!port) + return; if (ch == '\n') port->ops->poll_put_char(port, '\r'); port->ops->poll_put_char(port, ch); + uart_port_deref(port); } #endif @@ -2639,6 +2777,8 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport) } /* Link the port to the driver state table and vice versa */ + atomic_set(&state->refcount, 1); + init_waitqueue_head(&state->remove_wait); state->uart_port = uport; uport->state = state; @@ -2711,15 +2851,12 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport) { struct uart_state *state = drv->state + uport->line; struct tty_port *port = &state->port; + struct uart_port *uart_port; struct tty_struct *tty; int ret = 0; BUG_ON(in_interrupt()); - if (state->uart_port != uport) - dev_alert(uport->dev, "Removing wrong port: %p != %p\n", - state->uart_port, uport); - mutex_lock(&port_mutex); /* @@ -2727,7 +2864,12 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport) * succeeding while we shut down the port. */ mutex_lock(&port->mutex); - if (!state->uart_port) { + uart_port = uart_port_check(state); + if (uart_port != uport) + dev_alert(uport->dev, "Removing wrong port: %p != %p\n", + uart_port, uport); + + if (!uart_port) { mutex_unlock(&port->mutex); ret = -EINVAL; goto out; @@ -2764,7 +2906,11 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport) */ uport->type = PORT_UNKNOWN; + mutex_lock(&port->mutex); + WARN_ON(atomic_dec_return(&state->refcount) < 0); + wait_event(state->remove_wait, !atomic_read(&state->refcount)); state->uart_port = NULL; + mutex_unlock(&port->mutex); out: mutex_unlock(&port_mutex); |