Re: [Qemu-devel] [PATCH 18/22] vmdk: implement .bdrv_detach/attach_aio_context()

[Fam Zheng <famz@redhat.com>]

On Thu, 05/01 16:54, Stefan Hajnoczi wrote:
> Implement .bdrv_detach/attach_aio_context() interfaces to propagate
> detach/attach to BDRVVmdkState->extents[].file.  The block layer takes
> care of ->file and ->backing_hd but doesn't know about our extents
> BlockDriverStates, which is also part of the graph.
> 
> Cc: Fam Zheng <famz@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  block/vmdk.c | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/block/vmdk.c b/block/vmdk.c
> index 06a1f9f..1ca944a 100644
> --- a/block/vmdk.c
> +++ b/block/vmdk.c
> @@ -2063,6 +2063,27 @@ static ImageInfoSpecific *vmdk_get_specific_info(BlockDriverState *bs)
>      return spec_info;
>  }
>  
> +static void vmdk_detach_aio_context(BlockDriverState *bs)
> +{
> +    BDRVVmdkState *s = bs->opaque;
> +    int i;
> +
> +    for (i = 0; i < s->num_extents; i++) {
> +        bdrv_detach_aio_context(s->extents[i].file);
> +    }
> +}
> +
> +static void vmdk_attach_aio_context(BlockDriverState *bs,
> +                                    AioContext *new_context)
> +{
> +    BDRVVmdkState *s = bs->opaque;
> +    int i;
> +
> +    for (i = 0; i < s->num_extents; i++) {
> +        bdrv_attach_aio_context(s->extents[i].file, new_context);
> +    }
> +}
> +
>  static QEMUOptionParameter vmdk_create_options[] = {
>      {
>          .name = BLOCK_OPT_SIZE,
> @@ -2118,6 +2139,8 @@ static BlockDriver bdrv_vmdk = {
>      .bdrv_has_zero_init           = vmdk_has_zero_init,
>      .bdrv_get_specific_info       = vmdk_get_specific_info,
>      .bdrv_refresh_limits          = vmdk_refresh_limits,
> +    .bdrv_detach_aio_context      = vmdk_detach_aio_context,
> +    .bdrv_attach_aio_context      = vmdk_attach_aio_context,
>  
>      .create_options               = vmdk_create_options,
>  };
> -- 

I'm wondering why we need to separate detach and attach as two functions, and
also add bdrv_set_aio_context in block.c, instead of a single
.bdrv_set_aio_context member which is called in bdrv_set_aio_context()? The
latter seems less code.

Thanks,
Fam