Re: [Qemu-devel] [Qemu-block] [PATCH v3 1/2] blockdev: Error out on negative throttling option values

[Max Reitz <mreitz@redhat.com>]

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On 14.01.2016 05:08, Fam Zheng wrote:
> The implicit casting from unsigned int to double changes negative values
> into large positive numbers and accepts them.  We should instead print
> an error.
> 
> Check the number range so this case is caught and reported.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  blockdev.c              |  3 ++-
>  include/qemu/throttle.h |  2 ++
>  util/throttle.c         | 16 ++++++----------
>  3 files changed, 10 insertions(+), 11 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>

> diff --git a/blockdev.c b/blockdev.c
> index 2df0c6d..1afef87 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -348,7 +348,8 @@ static bool check_throttle_config(ThrottleConfig *cfg, Error **errp)
>      }
>  
>      if (!throttle_is_valid(cfg)) {
> -        error_setg(errp, "bps/iops/maxs values must be 0 or greater");
> +        error_setg(errp, "bps/iops/maxs values must be within [0, %" PRId64
> +                         ")", (int64_t)THROTTLE_VALUE_MAX);

I personally would have liked a simpler %lli and no cast, but I can see
why you want an explicit int64_t here.

>          return false;
>      }
>  
> diff --git a/include/qemu/throttle.h b/include/qemu/throttle.h
> index 12faaad..d0c98ed 100644
> --- a/include/qemu/throttle.h
> +++ b/include/qemu/throttle.h
> @@ -29,6 +29,8 @@
>  #include "qemu-common.h"
>  #include "qemu/timer.h"
>  
> +#define THROTTLE_VALUE_MAX 1000000000000000LL

<pedantic>
But then you could use UINT64_C(1000000000000000) here.
</pedantic>


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