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    Subject[PATCH 2/3] usb console,usb-serial: fix regression use of serial->console
    Date
    During the 2.6.32 development usb serial tty interface was changed.
    This change caused the usb serial driver to crash when used as a
    system console.

    The open and close of the raw hardware has to be protected by the
    serial->console variable so either the console code does the open and
    close or the higher level tty based driver executes the open and
    close.

    * In serial_open() the raw open must be protected by serial->console
    * In serial_down() the test_and_clear_bit must be executed before
    leaving the function if the device is a serial console
    * serial_release() should no longer protect for the console condition
    due to the 2.6.32 interface changes. The actual low level close
    protection is accounted for in serial_down()

    Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
    Cc: Greg KH <gregkh@suse.de>
    Cc: Alan Stern <stern@rowland.harvard.edu>

    ---
    drivers/usb/serial/usb-serial.c | 28 +++++++++++++---------------
    1 files changed, 13 insertions(+), 15 deletions(-)

    diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
    index ff75a35..3d35ed2 100644
    --- a/drivers/usb/serial/usb-serial.c
    +++ b/drivers/usb/serial/usb-serial.c
    @@ -267,10 +267,14 @@ static int serial_open(struct tty_struct *tty, struct file *filp)
    if (mutex_lock_interruptible(&port->mutex))
    return -ERESTARTSYS;
    mutex_lock(&serial->disc_mutex);
    - if (serial->disconnected)
    + if (serial->disconnected) {
    retval = -ENODEV;
    - else
    - retval = port->serial->type->open(tty, port);
    + } else {
    + if (port->console)
    + retval = 0;
    + else
    + retval = port->serial->type->open(tty, port);
    + }
    mutex_unlock(&serial->disc_mutex);
    mutex_unlock(&port->mutex);
    if (retval)
    @@ -294,6 +298,12 @@ static void serial_down(struct usb_serial_port *port)
    {
    struct usb_serial_driver *drv = port->serial->type;

    + /* Don't call the close method if the hardware hasn't been
    + * initialized.
    + */
    + if (!test_and_clear_bit(ASYNCB_INITIALIZED, &port->port.flags))
    + return;
    +
    /*
    * The console is magical. Do not hang up the console hardware
    * or there will be tears.
    @@ -301,12 +311,6 @@ static void serial_down(struct usb_serial_port *port)
    if (port->console)
    return;

    - /* Don't call the close method if the hardware hasn't been
    - * initialized.
    - */
    - if (!test_and_clear_bit(ASYNCB_INITIALIZED, &port->port.flags))
    - return;
    -
    mutex_lock(&port->mutex);
    if (drv->close)
    drv->close(port);
    @@ -353,12 +357,6 @@ static void serial_release(struct tty_struct *tty)
    struct usb_serial *serial;
    struct module *owner;

    - /* The console is magical. Do not hang up the console hardware
    - * or there will be tears.
    - */
    - if (port->console)
    - return;
    -
    dbg("%s - port %d", __func__, port->number);

    /* Standard shutdown processing */
    --
    1.6.4.rc1


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