Re: [Libguestfs] [PATCH libnbd v3 2/3] copy: Use preferred block size for copying
On Thu, Jun 30, 2022 at 05:38:14PM +0200, Laszlo Ersek wrote:
On 06/29/22 15:36, Richard W.M. Jones wrote:
> + * The invariant for '*i' is always an extent which starts before or
> + * equal to the current offset.
> + */
> +static bool
> +only_zeroes (const extent_list exts, size_t *i,
(5) I think it's a bit wasteful (or at least strange) to pass in the
entire vector structure; we certainly don't need the "cap" field. Other
functions in libnbd seem to take pointers to vectors (which is what I'd
expect).
Note it's only passing in 3 fields (24 bytes), not the entire array
(and I guess it should inline the whole function). Does that change
things?
> @@ -177,7 +229,10 @@ worker_thread (void *wp)
> extent_list exts = empty_vector;
>
> while (get_next_offset (&offset, &count)) {
> + struct command *command;
> size_t i;
> + bool is_zeroing = false;
> + uint64_t zeroing_start = 0;
(14) I think we should not initialize "zeroing_start". It suggests that
the initializer value is meaningful, but it is not.
GCC warns if you don't initialize it! It doesn't understand that
is_zeroing is related to the validity of zeroing_start.
Thanks for the other suggestions, I'll rework things.
Rich.
--
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