block: clarify badblocks lifetime

The badblocks list attached to a gendisk is allocated by the driver
which equates to the driver owning the lifetime of the object.  Do not
automatically free it in del_gendisk(). This is in preparation for
expanding the use of badblocks in libnvdimm drivers and introducing
devm_init_badblocks().

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/block/badblocks.c b/block/badblocks.c
index fabf6b64c2d1..37e5c0a2ef69 100644
--- a/block/badblocks.c
+++ b/block/badblocks.c
@@ -555,6 +555,8 @@ EXPORT_SYMBOL_GPL(badblocks_init);
  */
 void badblocks_exit(struct badblocks *bb)
 {
+	if (!bb)
+		return;
 	kfree(bb->page);
 	bb->page = NULL;
 }