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Re: [Qemu-devel] [PATCH v4 05/26] qcow2: Use unsigned addend for update_
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH v4 05/26] qcow2: Use unsigned addend for update_refcount() |
Date: |
Thu, 11 Dec 2014 10:58:39 +0000 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Wed, Dec 03, 2014 at 02:37:25PM +0100, Max Reitz wrote:
> @@ -530,8 +530,16 @@ found:
> }
>
> /* XXX: cache several refcount block clusters ? */
> +/* In order to decrease refcounts, set @addend to the two's complement
> (giving a
> + * negative value and letting the implicit cast handle it is enough) and set
> + * @decrease to true. @decrease must be false if the refcount should be
> + * increased. */
The first time I read this patch I missed this quirk and thought that a
lot of places seemed to be doing the wrong thing with addend.
This is likely to cause confusion, why not make uint16_t addend truly
unsigned and leave the sign to bool decrease, as suggested by the
function prototype?
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