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Message-ID: <50779D35.3040600@jp.fujitsu.com>
Date: Fri, 12 Oct 2012 13:31:49 +0900
From: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
To: Toshi Kani <toshi.kani@...com>
CC: <linux-acpi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<lenb@...nel.org>, <wency@...fujitsu.com>,
<vasilis.liaskovitis@...fitbricks.com>
Subject: Re: [PATCH v2] acpi : acpi_bus_trim() stops removing devices when
failing to remove the device
Hi Toshi,
2012/10/11 22:58, Toshi Kani wrote:
> On Thu, 2012-10-11 at 19:12 +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.
>>
>> Vasilis hit the bug at memory hotplug and reported it as follow:
>> https://lkml.org/lkml/2012/9/26/318
>>
>> 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.
>>
>> Applying the patch, acpi_bus_trim() stops removing devices when failing
>> to remove the device. But I think there is no impact with the
>> exceptionof CPU and Memory hotplug path. Because other device also fails
>> but the fail is an irregular case like device is NULL.
>>
>> v1->v2
>> - add a rollback for reinstalling a notify handler.
>>
>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
>
> Thanks for the update. Looks good.
>
> Reviewed-by: Toshi Kani <toshi.kani@...com>
Thank you for reviewing.
Thanks,
Yasauaki Ishimatsu
> -Toshi
>
>>
>> ---
>> drivers/acpi/scan.c | 21 ++++++++++++++++++---
>> drivers/base/dd.c | 22 +++++++++++++++++-----
>> include/linux/device.h | 2 +-
>> 3 files changed, 36 insertions(+), 9 deletions(-)
>>
>> Index: linux-3.6/drivers/acpi/scan.c
>> ===================================================================
>> --- linux-3.6.orig/drivers/acpi/scan.c 2012-10-11 18:31:40.189019503 +0900
>> +++ linux-3.6/drivers/acpi/scan.c 2012-10-11 18:42:35.669041641 +0900
>> @@ -445,18 +445,29 @@ 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)
>> + goto rollback;
>> + }
>> }
>> acpi_dev->driver = NULL;
>> acpi_dev->driver_data = NULL;
>>
>> put_device(dev);
>> return 0;
>> +
>> +rollback:
>> + if (acpi_drv->ops.notify)
>> + acpi_device_install_notify_handler(acpi_dev);
>> +
>> + return ret;
>> }
>>
>> struct bus_type acpi_bus_type = {
>> @@ -1226,11 +1237,15 @@ 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-3.6/drivers/base/dd.c
>> ===================================================================
>> --- linux-3.6.orig/drivers/base/dd.c 2012-10-11 18:31:40.191019505 +0900
>> +++ linux-3.6/drivers/base/dd.c 2012-10-11 18:31:46.873020548 +0900
>> @@ -475,9 +475,10 @@ 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) {
>> @@ -493,9 +494,11 @@ 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;
>> dev_set_drvdata(dev, NULL);
>> @@ -506,6 +509,12 @@ static void __device_release_driver(stru
>> dev);
>>
>> }
>> +
>> + return ret;
>> +
>> +rollback:
>> + driver_sysfs_add(dev);
>> + return ret;
>> }
>>
>> /**
>> @@ -515,16 +524,19 @@ 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-3.6/include/linux/device.h
>> ===================================================================
>> --- linux-3.6.orig/include/linux/device.h 2012-10-11 18:31:40.194019508 +0900
>> +++ linux-3.6/include/linux/device.h 2012-10-11 18:31:46.881020556 +0900
>> @@ -834,7 +834,7 @@ 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);
>>
>
>
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