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    Subject[PATCH v4 3/3] acpi : acpi_bus_trim() stops removing devices when failing to remove the device
    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(-)

    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);


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