block: fix bdi vs gendisk lifetime mismatch

[deliverable/linux.git] / mm / backing-dev.c

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index efe2377420744d4d557b801ce4a265d3815cfb8f..8fde443f36d778ffae9e66643387575ce7be9307 100644 (file)
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -825,6 +825,20 @@ int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev)
 }
 EXPORT_SYMBOL(bdi_register_dev);
 
+int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner)
+{
+       int rc;
+
+       rc = bdi_register(bdi, NULL, "%u:%u", MAJOR(owner->devt),
+                       MINOR(owner->devt));
+       if (rc)
+               return rc;
+       bdi->owner = owner;
+       get_device(owner);
+       return 0;
+}
+EXPORT_SYMBOL(bdi_register_owner);
+
 /*
  * Remove bdi from bdi_list, and ensure that it is no longer visible
  */
@@ -849,6 +863,11 @@ void bdi_unregister(struct backing_dev_info *bdi)
                device_unregister(bdi->dev);
                bdi->dev = NULL;
        }
+
+       if (bdi->owner) {
+               put_device(bdi->owner);
+               bdi->owner = NULL;
+       }
 }
 
 void bdi_exit(struct backing_dev_info *bdi)