From 61cd8a21d8a9fb4b11111270cf2d3aa919c20624 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Tue, 1 Jun 2010 22:52:57 +0200 Subject: serial: Change the wait for carrier locking We want to push the lock/unlock into the helper functions so that we can prepare to move to using the tty_port helper. The expansion initially comes out a bit ugly but its worth the temporary expansion IMHO just so we can produce a nice testable series of changes. Signed-off-by: Alan Cox Cc: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c index 570dca2..424b1c7 100644 --- a/drivers/serial/serial_core.c +++ b/drivers/serial/serial_core.c @@ -1272,6 +1272,7 @@ static void uart_close(struct tty_struct *tty, struct file *filp) struct uart_state *state = tty->driver_data; struct tty_port *port; struct uart_port *uport; + unsigned long flags; BUG_ON(!kernel_locked()); @@ -1284,9 +1285,12 @@ static void uart_close(struct tty_struct *tty, struct file *filp) pr_debug("uart_close(%d) called\n", uport->line); mutex_lock(&port->mutex); + spin_lock_irqsave(&port->lock, flags); - if (tty_hung_up_p(filp)) + if (tty_hung_up_p(filp)) { + spin_unlock_irqrestore(&port->lock, flags); goto done; + } if ((tty->count == 1) && (port->count != 1)) { /* @@ -1305,8 +1309,10 @@ static void uart_close(struct tty_struct *tty, struct file *filp) tty->name, port->count); port->count = 0; } - if (port->count) + if (port->count) { + spin_unlock_irqrestore(&port->lock, flags); goto done; + } /* * Now we wait for the transmit buffer to clear; and we notify @@ -1314,6 +1320,7 @@ static void uart_close(struct tty_struct *tty, struct file *filp) * setting tty->closing. */ tty->closing = 1; + spin_unlock_irqrestore(&port->lock, flags); if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE) tty_wait_until_sent(tty, msecs_to_jiffies(port->closing_wait)); @@ -1340,20 +1347,26 @@ static void uart_close(struct tty_struct *tty, struct file *filp) tty_ldisc_flush(tty); - tty->closing = 0; tty_port_tty_set(port, NULL); + spin_lock_irqsave(&port->lock, flags); + tty->closing = 0; if (port->blocked_open) { + spin_unlock_irqrestore(&port->lock, flags); if (port->close_delay) msleep_interruptible(port->close_delay); + spin_lock_irqsave(&port->lock, flags); } else if (!uart_console(uport)) { + spin_unlock_irqrestore(&port->lock, flags); uart_change_pm(state, 3); + spin_lock_irqsave(&port->lock, flags); } /* * Wake up anyone trying to open this port. */ clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags); + spin_unlock_irqrestore(&port->lock, flags); wake_up_interruptible(&port->open_wait); done: @@ -1429,6 +1442,7 @@ static void uart_hangup(struct tty_struct *tty) { struct uart_state *state = tty->driver_data; struct tty_port *port = &state->port; + unsigned long flags; BUG_ON(!kernel_locked()); pr_debug("uart_hangup(%d)\n", state->uart_port->line); @@ -1437,8 +1451,10 @@ static void uart_hangup(struct tty_struct *tty) if (port->flags & ASYNC_NORMAL_ACTIVE) { 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_tty_set(port, NULL); wake_up_interruptible(&port->open_wait); wake_up_interruptible(&port->delta_msr_wait); @@ -1496,9 +1512,13 @@ uart_block_til_ready(struct file *filp, struct uart_state *state) struct uart_port *uport = state->uart_port; struct tty_port *port = &state->port; unsigned int mctrl; + unsigned long flags; + spin_lock_irqsave(&port->lock, flags); + if (!tty_hung_up_p(filp)) + port->count--; port->blocked_open++; - port->count--; + spin_unlock_irqrestore(&port->lock, flags); add_wait_queue(&port->open_wait, &wait); while (1) { @@ -1535,23 +1555,26 @@ uart_block_til_ready(struct file *filp, struct uart_state *state) * not set RTS here - we want to make sure we catch * the data from the modem. */ - if (port->tty->termios->c_cflag & CBAUD) + if (port->tty->termios->c_cflag & CBAUD) { + mutex_lock(&port->mutex); uart_set_mctrl(uport, TIOCM_DTR); + mutex_unlock(&port->mutex); + } /* * and wait for the carrier to indicate that the * modem is ready for us. */ + mutex_lock(&port->mutex); spin_lock_irq(&uport->lock); uport->ops->enable_ms(uport); mctrl = uport->ops->get_mctrl(uport); spin_unlock_irq(&uport->lock); + mutex_unlock(&port->mutex); if (mctrl & TIOCM_CAR) break; - mutex_unlock(&port->mutex); schedule(); - mutex_lock(&port->mutex); if (signal_pending(current)) break; @@ -1559,8 +1582,11 @@ uart_block_til_ready(struct file *filp, struct uart_state *state) set_current_state(TASK_RUNNING); remove_wait_queue(&port->open_wait, &wait); - port->count++; + spin_lock_irqsave(&port->lock, flags); + if (!tty_hung_up_p(filp)) + port->count++; port->blocked_open--; + spin_unlock_irqrestore(&port->lock, flags); if (signal_pending(current)) return -ERESTARTSYS; @@ -1677,9 +1703,9 @@ static int uart_open(struct tty_struct *tty, struct file *filp) /* * If we succeeded, wait until the port is ready. */ + mutex_unlock(&port->mutex); if (retval == 0) retval = uart_block_til_ready(filp, state); - mutex_unlock(&port->mutex); /* * If this is the first open to succeed, adjust things to suit. -- cgit v0.10.2