lkml.org 
[lkml]   [2010]   [Aug]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 30/67] serial: Change the wait for carrier locking
    Date
    From: Alan Cox <alan@linux.intel.com>

    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 <alan@linux.intel.com>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
    ---
    drivers/serial/serial_core.c | 44 +++++++++++++++++++++++++++++++++--------
    1 files changed, 35 insertions(+), 9 deletions(-)

    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.
    --
    1.7.2


    \
     
     \ /
      Last update: 2010-08-06 00:45    [W:0.029 / U:0.040 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site