Messages in this thread | | | Date | Fri, 13 Jul 2012 16:16:09 +0900 | From | Yasuaki Ishimatsu <> | Subject | Re: [PATCH v3 3/3] acpi : acpi_bus_trim() stops removing devices when failing to remove the device |
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2012/07/13 1:50, Toshi Kani wrote: > On Thu, 2012-07-12 at 20:28 +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. >> >> 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 2012-07-12 20:11:37.316443808 +0900 >> +++ linux-3.5-rc6/drivers/acpi/scan.c 2012-07-12 20:17:17.927185231 +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 2012-07-12 20:11:37.316443808 +0900 >> +++ linux-3.5-rc6/drivers/base/dd.c 2012-07-12 20:17:17.928185218 +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; >> >> 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; > > ret is uninitialized when !drv.
Thanks! I'll update it.
> >> + >> +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) > > I agree with this change as driver's remove interface can fail. > However, there are other callers to this function, which do not check > the return value. I suppose there is no impact to the other paths since > you only changed the CPU hotplug path to fail properly, but please > confirm this is the case. I recommend documenting this change to the > change log.
Thank you for your agreement. As you know, there are other callers. I believe the patch does not impact to them, since all of them does not check return value of device_release_driver().
I will write it to the patch.
Thanks, Yasuaki Ishimatsu
> Thanks, > -Toshi > > >> { >> + 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 2012-07-12 20:11:37.317443779 +0900 >> +++ linux-3.5-rc6/include/linux/device.h 2012-07-12 20:17:17.936185118 +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 >
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