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Date: Thu, 16 May 2013 11:14:21 +0200
From: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20130516091421.GJ1597@stefanha-thinkpad.redhat.com>
References: <1368618432-4431-1-git-send-email-kwolf@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] qemu-io: Fix 'map' output
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To: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-devel@nongnu.org

On Wed, May 15, 2013 at 01:47:12PM +0200, Kevin Wolf wrote:
> +static int map_is_allocated(int64_t sector_num, int64_t nb_sectors, int64_t *pnum)
> +{
> +    int num, num_checked;
> +    int ret, firstret;
> +
> +    num_checked = MIN(nb_sectors, INT_MAX);
> +    ret = bdrv_is_allocated(bs, sector_num, num_checked, &num);
> +    if (ret < 0) {
> +        return ret;
> +    }
> +
> +    firstret = ret;
> +    *pnum = num;
> +
> +    while (nb_sectors > 0 && ret == firstret) {
> +        sector_num += num;
> +        nb_sectors -= num;
> +
> +        num_checked = MIN(nb_sectors, INT_MAX);
> +        ret = bdrv_is_allocated(bs, sector_num, num_checked, &num);
> +        if (ret == firstret) {
> +            *pnum += num;
> +        } else {
> +            break;
> +        }

The break makes && ret == firstret redundant above.  I suggest just
while (nb_sectors > 0) { ... } which is easier to read.

Also, if you respin the patch please tweak the commit message.
"Coalesce 'map' output" is more specific than "Fix 'map' output" -
unless this really fixes a bug which you didn't mention in the commit
description.