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Re: [Qemu-block] [Qemu-devel] [PATCH 1/2] qemu-io: Use correct range lim
From: |
Eric Blake |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH 1/2] qemu-io: Use correct range limitations |
Date: |
Mon, 20 Jun 2016 09:23:58 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
On 06/20/2016 08:26 AM, Max Reitz wrote:
> create_iovec() has a comment lamenting the lack of SIZE_T_MAX. Since
> there actually is a SIZE_MAX, use it.
>
> Two places use INT_MAX for checking the upper bound of a sector count
> that is used as an argument for a blk_*() function (blk_discard() and
> blk_write_compressed(), respectively). BDRV_REQUEST_MAX_SECTORS should
> be used instead.
>
> And finally, do_co_pwrite_zeroes() used to similarly check that the
> sector count does not exceed INT_MAX. However, this function is now
> backed by blk_co_pwrite_zeroes() which takes bytes as an argument
> instead of sectors. Therefore, it should be the byte count that does not
> exceed INT_MAX, not the sector count.
>
> Signed-off-by: Max Reitz <address@hidden>
> ---
> qemu-io-cmds.c | 13 ++++++-------
> 1 file changed, 6 insertions(+), 7 deletions(-)
>
> @@ -500,7 +499,7 @@ static int do_write_compressed(BlockBackend *blk, char
> *buf, int64_t offset,
> {
> int ret;
>
> - if (count >> 9 > INT_MAX) {
> + if (count >> 9 > BDRV_REQUEST_MAX_SECTORS) {
Worth s/9/BDRV_SECTOR_BITS/ while touching it? But not a show-stopper
either way.
Reviewed-by: Eric Blake <address@hidden>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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