Re: [PATCH v4 3/3] acpi : acpi_bus_trim() stops removing devices when failing to remove the device
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
>
> ---
> 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.c2012-07-13 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);
> + ret = device_release_driver(>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(>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
[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
---
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);
+ ret = device_release_driver(>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.c2012-07-13 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(>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
[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.yasu...@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.c2012-07-13 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
Re: [PATCH v4 3/3] acpi : acpi_bus_trim() stops removing devices when failing to remove the device
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.yasu...@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.c2012-07-13 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
