Re: [Qemu-devel] [PATCH v2 01/13] block: Make essential BlockDriver objects public

[Kevin Wolf <kwolf@redhat.com>]

Am 27.11.2014 um 15:48 hat Max Reitz geschrieben:
> There are some block drivers which are essential to QEMU and may not be
> removed: These are raw, file and qcow2 (as the default non-raw format).
> Make their BlockDriver objects public so they can be directly referenced
> throughout the block layer without needing to call bdrv_find_format()
> and having to deal with an error at runtime, while the real problem
> occured during linking (where raw, file or qcow2 were not linked into
> qemu).
> 
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  block/qcow2.c             | 4 ++--
>  block/raw-posix.c         | 4 ++--
>  block/raw-win32.c         | 4 ++--
>  block/raw_bsd.c           | 4 ++--
>  include/block/block_int.h | 8 ++++++++
>  5 files changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 8b9ffc4..0eeba36 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -2847,7 +2847,7 @@ static QemuOptsList qcow2_create_opts = {
>      }
>  };
>  
> -static BlockDriver bdrv_qcow2 = {
> +BlockDriver *bdrv_qcow2 = &(BlockDriver){

As you correctly guessed, I like the looks of this syntax, but it leaves
us with some bdrv_<format> objects being pointers, and most others still
directly being the BlockDriver object.

I think it would be better to define a public BlockDriver here and use
&bdrv_qcow2 where necessary. Perhaps not a blocker, but in case you need
to send a v3.

Kevin