sysdev: Do not register with sysdev when erroring on add

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>

diff --git a/drivers/base/sys.c b/drivers/base/sys.c
index b094e0d6139fa4f85b56206340d027a5e5a7d8ef..f6fb54741602b566f740400a3ff6a5861131e3bf 100644 (file)
--- 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