[Libguestfs] [PATCH nbdkit v3 2/3] common: Introduce round up, down; and divide round up functions.

Eric Blake eblake at redhat.com
Wed Sep 19 14:28:22 UTC 2018


On 9/17/18 4:27 PM, Richard W.M. Jones wrote:
> This refactoring also fixes a bug spotted by Eric Blake:
> 
>    nbdkit --filter truncate pattern size=5G round-up=512
> 
> results in a 1G virtual disk.
> ---

> +/* Round up i to next multiple of n (n must be a power of 2).
> + */
> +#define ROUND_UP(i, n) ({                          \
> +      assert (is_power_of_2 (n));                  \
> +      ((i) + (n) - 1) & -((typeof (i))n);          \

Missing () around n here,

> +})
> +
> +/* Round down i to next multiple of n (n must be a power of 2).
> + */
> +#define ROUND_DOWN(i, n) ({                         \
> +      assert (is_power_of_2 (n));                   \
> +      (i) & -((typeof (i))(n));                     \

but not here. I pushed the obvious fix.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org




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