Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935129AbZLKXkb (ORCPT ); Fri, 11 Dec 2009 18:40:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933787AbZLKXgy (ORCPT ); Fri, 11 Dec 2009 18:36:54 -0500 Received: from kroah.org ([198.145.64.141]:50447 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933771AbZLKX25 (ORCPT ); Fri, 11 Dec 2009 18:28:57 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Alan Cox , Alan Stern , Oliver Neukum , Greg Kroah-Hartman Subject: [PATCH 13/58] tty_port: add "tty_port_open" helper Date: Fri, 11 Dec 2009 15:27:57 -0800 Message-Id: <1260574122-10676-13-git-send-email-gregkh@suse.de> X-Mailer: git-send-email 1.6.5.3 In-Reply-To: <20091211232805.GA10652@kroah.com> References: <20091211232805.GA10652@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6089 Lines: 180 From: Alan Cox For the moment this just moves the USB logic over and fixes the 'what if we open and hangup at the same time' race noticed by Oliver Neukum. Signed-off-by: Alan Cox Cc: Alan Stern Cc: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- drivers/char/tty_port.c | 36 +++++++++++++++++++++++++++- drivers/usb/serial/usb-serial.c | 49 ++++++++++++++++----------------------- include/linux/tty.h | 10 +++++++- 3 files changed, 64 insertions(+), 31 deletions(-) diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c index c63f3d3..b22a61a 100644 --- a/drivers/char/tty_port.c +++ b/drivers/char/tty_port.c @@ -99,10 +99,11 @@ EXPORT_SYMBOL(tty_port_tty_set); static void tty_port_shutdown(struct tty_port *port) { + mutex_lock(&port->mutex); if (port->ops->shutdown && test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags)) port->ops->shutdown(port); - + mutex_unlock(&port->mutex); } /** @@ -381,3 +382,36 @@ void tty_port_close(struct tty_port *port, struct tty_struct *tty, tty_port_tty_set(port, NULL); } EXPORT_SYMBOL(tty_port_close); + +int tty_port_open(struct tty_port *port, struct tty_struct *tty, + struct file *filp) +{ + spin_lock_irq(&port->lock); + if (!tty_hung_up_p(filp)) + ++port->count; + spin_unlock_irq(&port->lock); + tty_port_tty_set(port, tty); + + /* + * Do the device-specific open only if the hardware isn't + * already initialized. Serialize open and shutdown using the + * port mutex. + */ + + mutex_lock(&port->mutex); + + if (!test_bit(ASYNCB_INITIALIZED, &port->flags)) { + if (port->ops->activate) { + int retval = port->ops->activate(port, tty); + if (retval) { + mutex_unlock(&port->mutex); + return retval; + } + } + set_bit(ASYNCB_INITIALIZED, &port->flags); + } + mutex_unlock(&port->mutex); + return tty_port_block_til_ready(port, tty, filp); +} + +EXPORT_SYMBOL(tty_port_open); diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c index bd3fa7f..b0649d9 100644 --- a/drivers/usb/serial/usb-serial.c +++ b/drivers/usb/serial/usb-serial.c @@ -247,41 +247,31 @@ static int serial_install(struct tty_driver *driver, struct tty_struct *tty) return retval; } -static int serial_open(struct tty_struct *tty, struct file *filp) +static int serial_activate(struct tty_port *tport, struct tty_struct *tty) { - struct usb_serial_port *port = tty->driver_data; + struct usb_serial_port *port = + container_of(tport, struct usb_serial_port, port); struct usb_serial *serial = port->serial; int retval; - dbg("%s - port %d", __func__, port->number); - - spin_lock_irq(&port->port.lock); - if (!tty_hung_up_p(filp)) - ++port->port.count; - spin_unlock_irq(&port->port.lock); - tty_port_tty_set(&port->port, tty); + if (mutex_lock_interruptible(&port->mutex)) + return -ERESTARTSYS; + mutex_lock(&serial->disc_mutex); + if (serial->disconnected) + retval = -ENODEV; + else + retval = port->serial->type->open(tty, port); + mutex_unlock(&serial->disc_mutex); + mutex_unlock(&port->mutex); + return retval; +} - /* Do the device-specific open only if the hardware isn't - * already initialized. - */ - if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) { - if (mutex_lock_interruptible(&port->mutex)) - return -ERESTARTSYS; - mutex_lock(&serial->disc_mutex); - if (serial->disconnected) - retval = -ENODEV; - else - retval = port->serial->type->open(tty, port); - mutex_unlock(&serial->disc_mutex); - mutex_unlock(&port->mutex); - if (retval) - return retval; - set_bit(ASYNCB_INITIALIZED, &port->port.flags); - } +static int serial_open(struct tty_struct *tty, struct file *filp) +{ + struct usb_serial_port *port = tty->driver_data; - /* Now do the correct tty layer semantics */ - retval = tty_port_block_til_ready(&port->port, tty, filp); - return retval; + dbg("%s - port %d", __func__, port->number); + return tty_port_open(&port->port, tty, filp); } /** @@ -725,6 +715,7 @@ static void serial_dtr_rts(struct tty_port *port, int on) static const struct tty_port_operations serial_port_ops = { .carrier_raised = serial_carrier_raised, .dtr_rts = serial_dtr_rts, + .activate = serial_activate, }; int usb_serial_probe(struct usb_interface *interface, diff --git a/include/linux/tty.h b/include/linux/tty.h index f0f43d0..6352ac2 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -190,9 +190,15 @@ struct tty_port_operations { /* Control the DTR line */ void (*dtr_rts)(struct tty_port *port, int raise); /* Called when the last close completes or a hangup finishes - IFF the port was initialized. Do not use to free resources */ + IFF the port was initialized. Do not use to free resources. Called + under the port mutex to serialize against activate/shutdowns */ void (*shutdown)(struct tty_port *port); void (*drop)(struct tty_port *port); + /* Called under the port mutex from tty_port_open, serialized using + the port mutex */ + /* FIXME: long term getting the tty argument *out* of this would be + good for consoles */ + int (*activate)(struct tty_port *port, struct tty_struct *tty); }; struct tty_port { @@ -467,6 +473,8 @@ extern int tty_port_close_start(struct tty_port *port, extern void tty_port_close_end(struct tty_port *port, struct tty_struct *tty); extern void tty_port_close(struct tty_port *port, struct tty_struct *tty, struct file *filp); +extern int tty_port_open(struct tty_port *port, + struct tty_struct *tty, struct file *filp); extern inline int tty_port_users(struct tty_port *port) { return port->count + port->blocked_open; -- 1.6.5.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/