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Subject[PATCH 09/50] sysdev: Do not register with sysdev when erroring on add
Date
From: Borislav Petkov <borislav.petkov@amd.com>

When encountering an error while executing the driver's ->add method, we
should cancel registration and unwind what we've regged so far. The low
level ->add methods do return proper error codes but those aren't looked
at in sysdev_driver_register(). Fix that by sharing the unregistering
code.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/base/sys.c | 61 +++++++++++++++++++++++++++++++++++++--------------
1 files changed, 44 insertions(+), 17 deletions(-)
diff --git a/drivers/base/sys.c b/drivers/base/sys.c
index b094e0d..f6fb547 100644
--- a/drivers/base/sys.c
+++ b/drivers/base/sys.c
@@ -166,6 +166,36 @@ EXPORT_SYMBOL_GPL(sysdev_class_unregister);

static DEFINE_MUTEX(sysdev_drivers_lock);

+/*
+ * @dev != NULL means that we're unwinding because some drv->add()
+ * failed for some reason. You need to grab sysdev_drivers_lock before
+ * calling this.
+ */
+static void __sysdev_driver_remove(struct sysdev_class *cls,
+ struct sysdev_driver *drv,
+ struct sys_device *from_dev)
+{
+ struct sys_device *dev = from_dev;
+
+ list_del_init(&drv->entry);
+ if (!cls)
+ return;
+
+ if (!drv->remove)
+ goto kset_put;
+
+ if (dev)
+ list_for_each_entry_continue_reverse(dev, &cls->kset.list,
+ kobj.entry)
+ drv->remove(dev);
+ else
+ list_for_each_entry(dev, &cls->kset.list, kobj.entry)
+ drv->remove(dev);
+
+kset_put:
+ kset_put(&cls->kset);
+}
+
/**
* sysdev_driver_register - Register auxillary driver
* @cls: Device class driver belongs to.
@@ -175,9 +205,9 @@ static DEFINE_MUTEX(sysdev_drivers_lock);
* called on each operation on devices of that class. The refcount
* of @cls is incremented.
*/
-
int sysdev_driver_register(struct sysdev_class *cls, struct sysdev_driver *drv)
{
+ struct sys_device *dev = NULL;
int err = 0;

if (!cls) {
@@ -198,19 +228,27 @@ int sysdev_driver_register(struct sysdev_class *cls, struct sysdev_driver *drv)

/* If devices of this class already exist, tell the driver */
if (drv->add) {
- struct sys_device *dev;
- list_for_each_entry(dev, &cls->kset.list, kobj.entry)
- drv->add(dev);
+ list_for_each_entry(dev, &cls->kset.list, kobj.entry) {
+ err = drv->add(dev);
+ if (err)
+ goto unwind;
+ }
}
} else {
err = -EINVAL;
WARN(1, KERN_ERR "%s: invalid device class\n", __func__);
}
+
+ goto unlock;
+
+unwind:
+ __sysdev_driver_remove(cls, drv, dev);
+
+unlock:
mutex_unlock(&sysdev_drivers_lock);
return err;
}

-
/**
* sysdev_driver_unregister - Remove an auxillary driver.
* @cls: Class driver belongs to.
@@ -220,23 +258,12 @@ void sysdev_driver_unregister(struct sysdev_class *cls,
struct sysdev_driver *drv)
{
mutex_lock(&sysdev_drivers_lock);
- list_del_init(&drv->entry);
- if (cls) {
- if (drv->remove) {
- struct sys_device *dev;
- list_for_each_entry(dev, &cls->kset.list, kobj.entry)
- drv->remove(dev);
- }
- kset_put(&cls->kset);
- }
+ __sysdev_driver_remove(cls, drv, NULL);
mutex_unlock(&sysdev_drivers_lock);
}
-
EXPORT_SYMBOL_GPL(sysdev_driver_register);
EXPORT_SYMBOL_GPL(sysdev_driver_unregister);

-
-
/**
* sysdev_register - add a system device to the tree
* @sysdev: device in question
--
1.7.4.1


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