| Message ID | 4FFFE1EC.6040003@jp.fujitsu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 2012-07-13 at 17:53 +0900, Yasuaki Ishimatsu wrote: > acpi_bus_trim() stops removing devices, when acpi_bus_remove() return error > number. But acpi_bus_remove() cannot return error number correctly. > acpi_bus_remove() only return -EINVAL, when dev argument is NULL. Thus even if > device cannot be removed correctly, acpi_bus_trim() ignores and continues to > remove devices. acpi_bus_hot_remove_device() uses acpi_bus_trim() for removing > devices. Therefore acpi_bus_hot_remove_device() can send "_EJ0" to firmware, > even if the device is running on the system. In this case, the system cannot > work well. So acpi_bus_trim() should check whether device was removed or not > correctly. The patch adds error check into some functions to remove the device. > > device_release_driver() can return error value by the patch. But the change > does not impact other caller function excluding acpi_bus_trim(), since all > of them does not check return value of device_releae_driver(). I think potential risk here is that __device_release_driver() now performs rollback in case of error from driver's remove interface. I agree with doing the rollback, but this leads to a different situation if the caller does not check error from device_release_driver() and proceeds the operation. So, we will need to make sure that: - Other driver's remove interfaces do not fail (or very unlikely to fail), or - If other driver's remove interfaces failed, their end results are no worse than today. Thanks, -Toshi > Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> > > --- > drivers/acpi/scan.c | 15 ++++++++++++--- > drivers/base/dd.c | 22 +++++++++++++++++----- > include/linux/device.h | 2 +- > 3 files changed, 30 insertions(+), 9 deletions(-) > > Index: linux-3.5-rc6/drivers/acpi/scan.c > =================================================================== > --- linux-3.5-rc6.orig/drivers/acpi/scan.c 2012-07-13 15:10:46.136790418 +0900 > +++ linux-3.5-rc6/drivers/acpi/scan.c 2012-07-13 15:12:41.364349387 +0900 > @@ -425,12 +425,17 @@ static int acpi_device_remove(struct dev > { > struct acpi_device *acpi_dev = to_acpi_device(dev); > struct acpi_driver *acpi_drv = acpi_dev->driver; > + int ret; > > if (acpi_drv) { > if (acpi_drv->ops.notify) > acpi_device_remove_notify_handler(acpi_dev); > - if (acpi_drv->ops.remove) > - acpi_drv->ops.remove(acpi_dev, acpi_dev->removal_type); > + if (acpi_drv->ops.remove) { > + ret = acpi_drv->ops.remove(acpi_dev, > + acpi_dev->removal_type); > + if (ret) > + return ret; > + } > } > acpi_dev->driver = NULL; > acpi_dev->driver_data = NULL; > @@ -1208,11 +1213,15 @@ static int acpi_device_set_context(struc > > static int acpi_bus_remove(struct acpi_device *dev, int rmdevice) > { > + int ret; > + > if (!dev) > return -EINVAL; > > dev->removal_type = ACPI_BUS_REMOVAL_EJECT; > - device_release_driver(&dev->dev); > + ret = device_release_driver(&dev->dev); > + if (ret) > + return ret; > > if (!rmdevice) > return 0; > Index: linux-3.5-rc6/drivers/base/dd.c > =================================================================== > --- linux-3.5-rc6.orig/drivers/base/dd.c 2012-07-13 15:10:46.136790418 +0900 > +++ linux-3.5-rc6/drivers/base/dd.c 2012-07-13 15:14:13.895193383 +0900 > @@ -464,9 +464,10 @@ EXPORT_SYMBOL_GPL(driver_attach); > * __device_release_driver() must be called with @dev lock held. > * When called for a USB interface, @dev->parent lock must be held as well. > */ > -static void __device_release_driver(struct device *dev) > +static int __device_release_driver(struct device *dev) > { > struct device_driver *drv; > + int ret = 0; > > drv = dev->driver; > if (drv) { > @@ -482,9 +483,11 @@ static void __device_release_driver(stru > pm_runtime_put_sync(dev); > > if (dev->bus && dev->bus->remove) > - dev->bus->remove(dev); > + ret = dev->bus->remove(dev); > else if (drv->remove) > - drv->remove(dev); > + ret = drv->remove(dev); > + if (ret) > + goto rollback; > devres_release_all(dev); > dev->driver = NULL; > klist_remove(&dev->p->knode_driver); > @@ -494,6 +497,12 @@ static void __device_release_driver(stru > dev); > > } > + > + return ret; > + > +rollback: > + driver_sysfs_add(dev); > + return ret; > } > > /** > @@ -503,16 +512,19 @@ static void __device_release_driver(stru > * Manually detach device from driver. > * When called for a USB interface, @dev->parent lock must be held. > */ > -void device_release_driver(struct device *dev) > +int device_release_driver(struct device *dev) > { > + int ret; > /* > * If anyone calls device_release_driver() recursively from > * within their ->remove callback for the same device, they > * will deadlock right here. > */ > device_lock(dev); > - __device_release_driver(dev); > + ret = __device_release_driver(dev); > device_unlock(dev); > + > + return ret; > } > EXPORT_SYMBOL_GPL(device_release_driver); > > Index: linux-3.5-rc6/include/linux/device.h > =================================================================== > --- linux-3.5-rc6.orig/include/linux/device.h 2012-07-13 15:10:46.137790406 +0900 > +++ linux-3.5-rc6/include/linux/device.h 2012-07-13 15:12:41.371349562 +0900 > @@ -827,7 +827,7 @@ static inline void *dev_get_platdata(con > * for information on use. > */ > extern int __must_check device_bind_driver(struct device *dev); > -extern void device_release_driver(struct device *dev); > +extern int device_release_driver(struct device *dev); > extern int __must_check device_attach(struct device *dev); > extern int __must_check driver_attach(struct device_driver *drv); > extern int __must_check device_reprobe(struct device *dev); > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Index: linux-3.5-rc6/drivers/acpi/scan.c =================================================================== --- linux-3.5-rc6.orig/drivers/acpi/scan.c 2012-07-13 15:10:46.136790418 +0900 +++ linux-3.5-rc6/drivers/acpi/scan.c 2012-07-13 15:12:41.364349387 +0900 @@ -425,12 +425,17 @@ static int acpi_device_remove(struct dev { struct acpi_device *acpi_dev = to_acpi_device(dev); struct acpi_driver *acpi_drv = acpi_dev->driver; + int ret; if (acpi_drv) { if (acpi_drv->ops.notify) acpi_device_remove_notify_handler(acpi_dev); - if (acpi_drv->ops.remove) - acpi_drv->ops.remove(acpi_dev, acpi_dev->removal_type); + if (acpi_drv->ops.remove) { + ret = acpi_drv->ops.remove(acpi_dev, + acpi_dev->removal_type); + if (ret) + return ret; + } } acpi_dev->driver = NULL; acpi_dev->driver_data = NULL; @@ -1208,11 +1213,15 @@ static int acpi_device_set_context(struc static int acpi_bus_remove(struct acpi_device *dev, int rmdevice) { + int ret; + if (!dev) return -EINVAL; dev->removal_type = ACPI_BUS_REMOVAL_EJECT; - device_release_driver(&dev->dev); + ret = device_release_driver(&dev->dev); + if (ret) + return ret; if (!rmdevice) return 0; Index: linux-3.5-rc6/drivers/base/dd.c =================================================================== --- linux-3.5-rc6.orig/drivers/base/dd.c 2012-07-13 15:10:46.136790418 +0900 +++ linux-3.5-rc6/drivers/base/dd.c 2012-07-13 15:14:13.895193383 +0900 @@ -464,9 +464,10 @@ EXPORT_SYMBOL_GPL(driver_attach); * __device_release_driver() must be called with @dev lock held. * When called for a USB interface, @dev->parent lock must be held as well. */ -static void __device_release_driver(struct device *dev) +static int __device_release_driver(struct device *dev) { struct device_driver *drv; + int ret = 0; drv = dev->driver; if (drv) { @@ -482,9 +483,11 @@ static void __device_release_driver(stru pm_runtime_put_sync(dev); if (dev->bus && dev->bus->remove) - dev->bus->remove(dev); + ret = dev->bus->remove(dev); else if (drv->remove) - drv->remove(dev); + ret = drv->remove(dev); + if (ret) + goto rollback; devres_release_all(dev); dev->driver = NULL; klist_remove(&dev->p->knode_driver); @@ -494,6 +497,12 @@ static void __device_release_driver(stru dev); } + + return ret; + +rollback: + driver_sysfs_add(dev); + return ret; } /** @@ -503,16 +512,19 @@ static void __device_release_driver(stru * Manually detach device from driver. * When called for a USB interface, @dev->parent lock must be held. */ -void device_release_driver(struct device *dev) +int device_release_driver(struct device *dev) { + int ret; /* * If anyone calls device_release_driver() recursively from * within their ->remove callback for the same device, they * will deadlock right here. */ device_lock(dev); - __device_release_driver(dev); + ret = __device_release_driver(dev); device_unlock(dev); + + return ret; } EXPORT_SYMBOL_GPL(device_release_driver); Index: linux-3.5-rc6/include/linux/device.h =================================================================== --- linux-3.5-rc6.orig/include/linux/device.h 2012-07-13 15:10:46.137790406 +0900 +++ linux-3.5-rc6/include/linux/device.h 2012-07-13 15:12:41.371349562 +0900 @@ -827,7 +827,7 @@ static inline void *dev_get_platdata(con * for information on use. */ extern int __must_check device_bind_driver(struct device *dev); -extern void device_release_driver(struct device *dev); +extern int device_release_driver(struct device *dev); extern int __must_check device_attach(struct device *dev); extern int __must_check driver_attach(struct device_driver *drv); extern int __must_check device_reprobe(struct device *dev);
acpi_bus_trim() stops removing devices, when acpi_bus_remove() return error number. But acpi_bus_remove() cannot return error number correctly. acpi_bus_remove() only return -EINVAL, when dev argument is NULL. Thus even if device cannot be removed correctly, acpi_bus_trim() ignores and continues to remove devices. acpi_bus_hot_remove_device() uses acpi_bus_trim() for removing devices. Therefore acpi_bus_hot_remove_device() can send "_EJ0" to firmware, even if the device is running on the system. In this case, the system cannot work well. So acpi_bus_trim() should check whether device was removed or not correctly. The patch adds error check into some functions to remove the device. device_release_driver() can return error value by the patch. But the change does not impact other caller function excluding acpi_bus_trim(), since all of them does not check return value of device_releae_driver(). Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> --- drivers/acpi/scan.c | 15 ++++++++++++--- drivers/base/dd.c | 22 +++++++++++++++++----- include/linux/device.h | 2 +- 3 files changed, 30 insertions(+), 9 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html