Re: [Qemu-devel] [PATCH v3 05/20] commit: Switch commit_populate() to byte-based

[Jeff Cody <jcody@redhat.com>]

On Tue, Jun 27, 2017 at 02:24:43PM -0500, Eric Blake wrote:
> We are gradually converting to byte-based interfaces, as they are
> easier to reason about than sector-based.  Start by converting an
> internal function (no semantic change).
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>
> 

Reviewed-by: Jeff Cody <jcody@redhat.com>

> ---
> v2: no change
> ---
>  block/commit.c | 15 ++++++++-------
>  1 file changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/block/commit.c b/block/commit.c
> index 4cda7f2..6f67d78 100644
> --- a/block/commit.c
> +++ b/block/commit.c
> @@ -47,26 +47,25 @@ typedef struct CommitBlockJob {
>  } CommitBlockJob;
> 
>  static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base,
> -                                        int64_t sector_num, int nb_sectors,
> +                                        int64_t offset, uint64_t bytes,
>                                          void *buf)
>  {
>      int ret = 0;
>      QEMUIOVector qiov;
>      struct iovec iov = {
>          .iov_base = buf,
> -        .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
> +        .iov_len = bytes,
>      };
> 
> +    assert(bytes < SIZE_MAX);
>      qemu_iovec_init_external(&qiov, &iov, 1);
> 
> -    ret = blk_co_preadv(bs, sector_num * BDRV_SECTOR_SIZE,
> -                        qiov.size, &qiov, 0);
> +    ret = blk_co_preadv(bs, offset, qiov.size, &qiov, 0);
>      if (ret < 0) {
>          return ret;
>      }
> 
> -    ret = blk_co_pwritev(base, sector_num * BDRV_SECTOR_SIZE,
> -                         qiov.size, &qiov, 0);
> +    ret = blk_co_pwritev(base, offset, qiov.size, &qiov, 0);
>      if (ret < 0) {
>          return ret;
>      }
> @@ -193,7 +192,9 @@ static void coroutine_fn commit_run(void *opaque)
>          trace_commit_one_iteration(s, sector_num * BDRV_SECTOR_SIZE,
>                                     n * BDRV_SECTOR_SIZE, ret);
>          if (copy) {
> -            ret = commit_populate(s->top, s->base, sector_num, n, buf);
> +            ret = commit_populate(s->top, s->base,
> +                                  sector_num * BDRV_SECTOR_SIZE,
> +                                  n * BDRV_SECTOR_SIZE, buf);
>              bytes_written += n * BDRV_SECTOR_SIZE;
>          }
>          if (ret < 0) {
> -- 
> 2.9.4
>