Re: [Qemu-devel] [PATCH 2/3] mirror: limit niov to IOV_MAX elements, again

[Eric Blake <eblake@redhat.com>]

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On 06/22/2016 01:51 PM, John Snow wrote:
> During the refactor of mirror_iteration in e5b43573,
> we regressed the fix introduced in cae98cb8.
> 
> This patch re-adds IOV_MAX checking to cases where we
> aren't checking alignment (and size) already.
> 
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>  block/mirror.c | 3 +++
>  1 file changed, 3 insertions(+)

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

> 
> diff --git a/block/mirror.c b/block/mirror.c
> index 2ba9642..377339d 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -231,11 +231,14 @@ static int mirror_do_read(MirrorBlockJob *s, int64_t sector_num,
>      int sectors_per_chunk, nb_chunks;
>      int ret;
>      MirrorOp *op;
> +    int max_sectors;
>  
>      sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
> +    max_sectors = sectors_per_chunk * s->max_iov;
>  
>      /* We can only handle as much as buf_size at a time. */
>      nb_sectors = MIN(s->buf_size >> BDRV_SECTOR_BITS, nb_sectors);
> +    nb_sectors = MIN(max_sectors, nb_sectors);
>      assert(nb_sectors);
>      ret = nb_sectors;
>  
> 

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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