Re: [PATCH v5 11/31] qcow2: Add offset_into_subcluster() and size_to_subclusters()

[Eric Blake <eblake@redhat.com>]

On 5/5/20 12:38 PM, Alberto Garcia wrote:
> Like offset_into_cluster() and size_to_clusters(), but for
> subclusters.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>   block/qcow2.h | 10 ++++++++++
>   1 file changed, 10 insertions(+)
> 
> diff --git a/block/qcow2.h b/block/qcow2.h
> index e68febb15b..8b1ed1cbcf 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -537,11 +537,21 @@ static inline int64_t offset_into_cluster(BDRVQcow2State *s, int64_t offset)
>       return offset & (s->cluster_size - 1);
>   }
>   
> +static inline int64_t offset_into_subcluster(BDRVQcow2State *s, int64_t offset)
> +{
> +    return offset & (s->subcluster_size - 1);
> +}
> +
>   static inline uint64_t size_to_clusters(BDRVQcow2State *s, uint64_t size)
>   {
>       return (size + (s->cluster_size - 1)) >> s->cluster_bits;
>   }

Pre-existing, but this could use DIV_ROUND_UP.

>   
> +static inline uint64_t size_to_subclusters(BDRVQcow2State *s, uint64_t size)
> +{
> +    return (size + (s->subcluster_size - 1)) >> s->subcluster_bits;
> +}

at which point, your addition could be:

return DIV_ROUND_UP(size, s->subcluster_size);

Either way,

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

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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