Re: [PATCH 6/8] block-backend: inline bdrv_co_get_geometry

[Eric Blake]

On Fri, Apr 07, 2023 at 05:33:01PM +0200, Paolo Bonzini wrote:
> bdrv_co_get_geometry is only used in blk_co_get_geometry.  Inline it in
> there, to reduce the number of wrappers for bs->total_sectors.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  block.c                  | 10 ----------
>  block/block-backend.c    |  8 ++++++--
>  include/block/block-io.h |  3 ---
>  3 files changed, 6 insertions(+), 15 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

> 
> diff --git a/block.c b/block.c
> index 9de50ac7c811..dbbc8de30c24 100644
> --- a/block.c
> +++ b/block.c
> @@ -5879,16 +5879,6 @@ int64_t coroutine_fn 
> bdrv_co_getlength(BlockDriverState *bs)
>      return ret * BDRV_SECTOR_SIZE;
>  }
>  
> -/* return 0 as number of sectors if no device present or error */
> -void coroutine_fn bdrv_co_get_geometry(BlockDriverState *bs,
> -                                       uint64_t *nb_sectors_ptr)
> -{
> -    int64_t nb_sectors = bdrv_co_nb_sectors(bs);
> -    IO_CODE();

Pre-patch, we called bdrv_co_nb_sectors() before the IO_CODE guard...

> +/* return 0 as number of sectors if no device present or error */
>  void coroutine_fn blk_co_get_geometry(BlockBackend *blk,
>                                        uint64_t *nb_sectors_ptr)
>  {
> +    BlockDriverState *bs = blk_bs(blk);
> +
>      IO_CODE();
>      GRAPH_RDLOCK_GUARD();
>  
> -    if (!blk_bs(blk)) {
> +    if (!bs) {
>          *nb_sectors_ptr = 0;
>      } else {
> -        bdrv_co_get_geometry(blk_bs(blk), nb_sectors_ptr);
> +        int64_t nb_sectors = bdrv_co_nb_sectors(bs);

...post-patch the order swaps.  That actually feels better to me, (the
guard is supposed to do sanity checks to detect coding bugs at the
soonest possible moment; if we have a bug, doing the work and only
later failing the check is not as safe as failing fast) - but probably
no impact to correctly written code.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
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