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>

1 files changed, 44 insertions, 17 deletions

diff --git a/drivers/base/sys.c b/drivers/base/sys.c
index b094e0d6139f..f6fb54741602 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