On Fri, Oct 09, 2015 at 02:15:32PM +0200, Kevin Wolf wrote:
> This is the final step in converting all of the BlockDriverState
> pointers that block drivers use to BdrvChild.
>
> After this patch, bs->children contains the full list of child nodes
> that are referenced by a given BDS, and these children are only
> referenced through BdrvChild, so that updating the pointer in there is
> enough for changing edges in the graph.
>
> Signed-off-by: Kevin Wolf <kw...@redhat.com>
> ---
> block.c | 105
> +++++++++++++++++++++++-----------------------
> block/io.c | 24 +++++------
> block/mirror.c | 6 +--
> block/qapi.c | 8 ++--
> block/qcow.c | 4 +-
> block/qcow2-cluster.c | 4 +-
> block/qcow2.c | 6 +--
> block/qed.c | 12 +++---
> block/stream.c | 8 ++--
> block/vmdk.c | 21 +++++-----
> block/vvfat.c | 6 +--
> blockdev.c | 4 +-
> include/block/block_int.h | 12 ++++--
> qemu-img.c | 4 +-
> 14 files changed, 115 insertions(+), 109 deletions(-)
>
[...]
> diff --git a/include/block/block_int.h b/include/block/block_int.h
> index 98936c9..90971c0 100644
> --- a/include/block/block_int.h
> +++ b/include/block/block_int.h
> @@ -378,8 +378,7 @@ struct BlockDriverState {
> QDict *full_open_options;
> char exact_filename[PATH_MAX];
>
> - BlockDriverState *backing_hd;
> - BdrvChild *backing_child;
> + BdrvChild *backing;
> BdrvChild *file;
>
> NotifierList close_notifiers;
> @@ -458,6 +457,11 @@ struct BlockDriverState {
> NotifierWithReturn write_threshold_notifier;
> };
>
> +static inline BlockDriverState *backing_bs(BlockDriverState *bs)
> +{
> + return bs->backing ? bs->backing->bs : NULL;
> +}
> +
Is there a good guideline regarding when you prefer backing_bs() to be
used, over accessing bs->backing->bs directly? There seems to be a
lot of mixed usage left in this patch, and I'm not sure if I am just
missing the intended distinction.
Thanks,
Jeff
