1 files changed, 16 insertions, 4 deletions

diff --git a/block/genhd.c b/block/genhd.c
index a9c516a8b37d..d252d29fe837 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -271,16 +271,17 @@ void blkdev_show(struct seq_file *seqf, off_t offset)
 /**
  * register_blkdev - register a new block device
  *
- * @major: the requested major device number [1..255]. If @major=0, try to
+ * @major: the requested major device number [1..255]. If @major = 0, try to
  *         allocate any unused major number.
  * @name: the name of the new block device as a zero terminated string
  *
  * The @name must be unique within the system.
  *
- * The return value depends on the @major input parameter.
+ * The return value depends on the @major input parameter:
+ *
  *  - if a major device number was requested in range [1..255] then the
  *    function returns zero on success, or a negative error code
- *  - if any unused major number was requested with @major=0 parameter
+ *  - if any unused major number was requested with @major = 0 parameter
  *    then the return value is the allocated major number in range
  *    [1..255] or a negative error code otherwise
  */
@@ -1060,8 +1061,19 @@ static struct attribute *disk_attrs[] = {
 	NULL
 };
 
+static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+	struct device *dev = container_of(kobj, typeof(*dev), kobj);
+	struct gendisk *disk = dev_to_disk(dev);
+
+	if (a == &dev_attr_badblocks.attr && !disk->bb)
+		return 0;
+	return a->mode;
+}
+
 static struct attribute_group disk_attr_group = {
 	.attrs = disk_attrs,
+	.is_visible = disk_visible,
 };
 
 static const struct attribute_group *disk_attr_groups[] = {
@@ -1352,7 +1364,7 @@ struct kobject *get_disk(struct gendisk *disk)
 	owner = disk->fops->owner;
 	if (owner && !try_module_get(owner))
 		return NULL;
-	kobj = kobject_get(&disk_to_dev(disk)->kobj);
+	kobj = kobject_get_unless_zero(&disk_to_dev(disk)->kobj);
 	if (kobj == NULL) {
 		module_put(owner);
 		return NULL;