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Date: Mon, 24 Nov 2008 10:47:00 -0600
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH 4/5] Cleanup {alloc|get}_cluster_offset().
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To: qemu-devel@nongnu.org

Gleb Natapov wrote:
> Move duplicated code into helper functions.
>
> Signed-off-by: Gleb Natapov <gleb@redhat.com>
> ---
>
>  block-qcow2.c |  160 +++++++++++++++++++++++++--------------------------------
>  1 files changed, 70 insertions(+), 90 deletions(-)
>
> diff --git a/block-qcow2.c b/block-qcow2.c
> index 7f99921..0771281 100644
> --- a/block-qcow2.c
> +++ b/block-qcow2.c
> @@ -61,6 +61,8 @@
>  
>  #define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
>  
> +#define SIZE2CLUSTERS(Q, S) (((S) + ((Q)->cluster_size - 1)) >> (Q)->cluster_bits)
>   

Please make this a static function.

> @@ -668,38 +693,23 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
>  
>      l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
>      cluster_offset = be64_to_cpu(l2_table[l2_index]);
> -    nb_available = s->cluster_sectors;
> -    l2_index++;
> -
> -    if (!cluster_offset) {
> -
> -       /* how many empty clusters ? */
> -
> -       while (nb_available < nb_needed && !l2_table[l2_index]) {
> -           l2_index++;
> -           nb_available += s->cluster_sectors;
> -       }
> -    } else {
> +    nb_clusters = SIZE2CLUSTERS(s, nb_needed << 9);
>  
> +    c = (!cluster_offset) ?
> +        /* how many empty clusters ? */
> +        count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]) :
>         /* how many allocated clusters ? */
> +        count_contiguous_clusters(nb_clusters, s->cluster_size,
> +                &l2_table[l2_index], QCOW_OFLAG_COPIED);
>   

Just use an if() here.

>          nb_available = nb_clusters << (s->cluster_bits - 9);
>          if (nb_available > n_end)
> @@ -951,6 +937,7 @@ static uint64_t alloc_cluster_offset(BlockDriverState *bs,
>  
>      cluster_offset = alloc_clusters(bs, nb_clusters * s->cluster_size);
>  
> +
>      /* we must initialize the cluster content which won't be
>         written */

Unnecessary whitespace.

Regards,

Anthony Liguori