block: Introduce bdrv_open_child()

It is the same as bdrv_open_image(), except that it doesn't only return
success or failure, but the newly created BdrvChild object for the new
child node.

As the BdrvChild object already contains a BlockDriverState pointer (and
this is supposed to become the only pointer so that bdrv_append() and
friends can just change a single pointer in BdrvChild), the pbs
parameter is removed for bdrv_open_child().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 8996baf..ec244b5 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -335,11 +335,11 @@ struct BdrvChildRole {
 extern const BdrvChildRole child_file;
 extern const BdrvChildRole child_format;
 
-typedef struct BdrvChild {
+struct BdrvChild {
     BlockDriverState *bs;
     const BdrvChildRole *role;
     QLIST_ENTRY(BdrvChild) next;
-} BdrvChild;
+};
 
 /*
  * Note: the function bdrv_append() copies and swaps contents of