From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261911AbVFUCvt (ORCPT ); Mon, 20 Jun 2005 22:51:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261679AbVFUCs7 (ORCPT ); Mon, 20 Jun 2005 22:48:59 -0400 Received: from mail.kroah.org ([69.55.234.183]:18404 "EHLO perch.kroah.org") by vger.kernel.org with ESMTP id S261677AbVFTW7l convert rfc822-to-8bit (ORCPT ); Mon, 20 Jun 2005 18:59:41 -0400 Cc: mochel@digitalimplant.org Subject: [PATCH] Add a semaphore to struct device to synchronize calls to its driver. In-Reply-To: <11193083641656@kroah.com> X-Mailer: gregkh_patchbomb Date: Mon, 20 Jun 2005 15:59:24 -0700 Message-Id: <1119308364310@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Reply-To: Greg K-H To: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 7BIT From: Greg KH Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org [PATCH] Add a semaphore to struct device to synchronize calls to its driver. This adds a per-device semaphore that is taken before every call from the core to a driver method. This prevents e.g. simultaneous calls to the ->suspend() or ->resume() and ->probe() or ->release(), potentially saving a whole lot of headaches. It also moves us a step closer to removing the bus rwsem, since it protects the fields in struct device that are modified by the core. Signed-off-by: Patrick Mochel Signed-off-by: Greg Kroah-Hartman --- commit af70316af182f4716cc5eec7e0d27fc731d164bd tree 22fa4732c8270db8fd3f681355cd83e4b8088847 parent eb51b65005737b777e0709683b061d5f82aefd97 author mochel@digitalimplant.org Mon, 21 Mar 2005 10:41:04 -0800 committer Greg Kroah-Hartman Mon, 20 Jun 2005 15:15:12 -0700 drivers/base/bus.c | 14 +++++++++++--- drivers/base/core.c | 1 + drivers/base/power/resume.c | 8 ++++++-- drivers/base/power/suspend.c | 3 ++- include/linux/device.h | 4 ++++ 5 files changed, 24 insertions(+), 6 deletions(-) diff --git a/drivers/base/bus.c b/drivers/base/bus.c --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -283,18 +283,22 @@ void device_bind_driver(struct device * */ int driver_probe_device(struct device_driver * drv, struct device * dev) { + int error = 0; + if (drv->bus->match && !drv->bus->match(dev, drv)) return -ENODEV; + down(&dev->sem); dev->driver = drv; if (drv->probe) { - int error = drv->probe(dev); + error = drv->probe(dev); if (error) { dev->driver = NULL; + up(&dev->sem); return error; } } - + up(&dev->sem); device_bind_driver(dev); return 0; } @@ -385,7 +389,10 @@ void driver_attach(struct device_driver void device_release_driver(struct device * dev) { - struct device_driver * drv = dev->driver; + struct device_driver * drv; + + down(&dev->sem); + drv = dev->driver; if (drv) { sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj)); sysfs_remove_link(&dev->kobj, "driver"); @@ -394,6 +401,7 @@ void device_release_driver(struct device drv->remove(dev); dev->driver = NULL; } + up(&dev->sem); } diff --git a/drivers/base/core.c b/drivers/base/core.c --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -212,6 +212,7 @@ void device_initialize(struct device *de INIT_LIST_HEAD(&dev->driver_list); INIT_LIST_HEAD(&dev->bus_list); INIT_LIST_HEAD(&dev->dma_pools); + init_MUTEX(&dev->sem); } /** diff --git a/drivers/base/power/resume.c b/drivers/base/power/resume.c --- a/drivers/base/power/resume.c +++ b/drivers/base/power/resume.c @@ -22,6 +22,9 @@ extern int sysdev_resume(void); int resume_device(struct device * dev) { + int error = 0; + + down(&dev->sem); if (dev->power.pm_parent && dev->power.pm_parent->power.power_state) { dev_err(dev, "PM: resume from %d, parent %s still %d\n", @@ -31,9 +34,10 @@ int resume_device(struct device * dev) } if (dev->bus && dev->bus->resume) { dev_dbg(dev,"resuming\n"); - return dev->bus->resume(dev); + error = dev->bus->resume(dev); } - return 0; + up(&dev->sem); + return error; } diff --git a/drivers/base/power/suspend.c b/drivers/base/power/suspend.c --- a/drivers/base/power/suspend.c +++ b/drivers/base/power/suspend.c @@ -39,6 +39,7 @@ int suspend_device(struct device * dev, { int error = 0; + down(&dev->sem); if (dev->power.power_state) { dev_dbg(dev, "PM: suspend %d-->%d\n", dev->power.power_state, state); @@ -58,7 +59,7 @@ int suspend_device(struct device * dev, dev_dbg(dev, "suspending\n"); error = dev->bus->suspend(dev, state); } - + up(&dev->sem); return error; } diff --git a/include/linux/device.h b/include/linux/device.h --- a/include/linux/device.h +++ b/include/linux/device.h @@ -264,6 +264,10 @@ struct device { struct kobject kobj; char bus_id[BUS_ID_SIZE]; /* position on parent bus */ + struct semaphore sem; /* semaphore to synchronize calls to + * its driver. + */ + struct bus_type * bus; /* type of bus device is on */ struct device_driver *driver; /* which driver has allocated this device */