Re: [Qemu-devel] [PATCH v2 1/8] block: Change BDS parameter of bdrv_open() to **

[Kevin Wolf <kwolf@redhat.com>]

Am 08.02.2014 um 18:39 hat Max Reitz geschrieben:
> Make bdrv_open() take a pointer to a BDS pointer, similarly to
> bdrv_file_open(). If a pointer to a NULL pointer is given, bdrv_open()
> will create a new BDS with an empty name; if the BDS pointer is not
> NULL, that existing BDS will be reused (in the same way as bdrv_open()
> already did).
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  block.c               | 64 +++++++++++++++++++++++++++++++--------------------
>  block/blkdebug.c      |  1 +
>  block/blkverify.c     |  2 ++
>  block/qcow2.c         | 14 +++++++----
>  block/vmdk.c          |  5 ++--
>  block/vvfat.c         |  6 ++---
>  blockdev.c            | 20 ++++++++--------
>  hw/block/xen_disk.c   |  2 +-
>  include/block/block.h |  2 +-
>  qemu-img.c            | 10 ++++----
>  qemu-io.c             |  2 +-
>  qemu-nbd.c            |  2 +-
>  12 files changed, 72 insertions(+), 58 deletions(-)

> @@ -1160,6 +1158,10 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp)
>   * BlockdevRef.
>   *
>   * The BlockdevRef will be removed from the options QDict.
> + *
> + * As with bdrv_open(), if *pbs is NULL, a new BDS will be created with a
> + * pointer to it stored there. If it is not NULL, the referenced BDS will
> + * be reused.
>   */
>  int bdrv_open_image(BlockDriverState **pbs, const char *filename,
>                      QDict *options, const char *bdref_key, int flags,

There are no callers that make use of *pbs != NULL. Are you planning to
add such users? Otherwise, we could just assert() it here instead of
documenting behaviour that is never used.

Kevin