Re: [Qemu-devel] [PATCH v3 21/44] block: Switch blk_write_zeroes() to byte interface

["Denis V. Lunev" <den@openvz.org>]

On 04/23/2016 02:40 AM, Eric Blake wrote:
> Sector-based blk_write() should die; convert the one-off
> variant blk_write_zeroes().
>
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>   include/sysemu/block-backend.h | 4 ++--
>   block/block-backend.c          | 8 ++++----
>   block/parallels.c              | 3 ++-
>   qemu-img.c                     | 3 ++-
>   4 files changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
> index 662a106..1246699 100644
> --- a/include/sysemu/block-backend.h
> +++ b/include/sysemu/block-backend.h
> @@ -96,8 +96,8 @@ int blk_pread_unthrottled(BlockBackend *blk, int64_t offset, uint8_t *buf,
>                             int count);
>   int blk_write(BlockBackend *blk, int64_t sector_num, const uint8_t *buf,
>                 int nb_sectors);
> -int blk_write_zeroes(BlockBackend *blk, int64_t sector_num,
> -                     int nb_sectors, BdrvRequestFlags flags);
> +int blk_pwrite_zeroes(BlockBackend *blk, int64_t offset,
> +                     int count, BdrvRequestFlags flags);
>   BlockAIOCB *blk_aio_write_zeroes(BlockBackend *blk, int64_t sector_num,
>                                    int nb_sectors, BdrvRequestFlags flags,
>                                    BlockCompletionFunc *cb, void *opaque);
> diff --git a/block/block-backend.c b/block/block-backend.c
> index 5513b6f..ae08bd2 100644
> --- a/block/block-backend.c
> +++ b/block/block-backend.c
> @@ -816,11 +816,11 @@ int blk_write(BlockBackend *blk, int64_t sector_num, const uint8_t *buf,
>                     blk_write_entry, 0);
>   }
>
> -int blk_write_zeroes(BlockBackend *blk, int64_t sector_num,
> -                     int nb_sectors, BdrvRequestFlags flags)
> +int blk_pwrite_zeroes(BlockBackend *blk, int64_t offset,
> +                      int count, BdrvRequestFlags flags)
>   {
> -    return blk_rw(blk, sector_num, NULL, nb_sectors, blk_write_entry,
> -                  flags | BDRV_REQ_ZERO_WRITE);
> +    return blk_prw(blk, offset, NULL, count, blk_write_entry,
> +                   flags | BDRV_REQ_ZERO_WRITE);
>   }
>
>   static void error_callback_bh(void *opaque)
> diff --git a/block/parallels.c b/block/parallels.c
> index 2d8bc87..95bfc32 100644
> --- a/block/parallels.c
> +++ b/block/parallels.c
> @@ -516,7 +516,8 @@ static int parallels_create(const char *filename, QemuOpts *opts, Error **errp)
>       if (ret < 0) {
>           goto exit;
>       }
> -    ret = blk_write_zeroes(file, 1, bat_sectors - 1, 0);
> +    ret = blk_pwrite_zeroes(file, BDRV_SECTOR_SIZE,
> +                            (bat_sectors - 1) << BDRV_SECTOR_BITS, 0);
>       if (ret < 0) {
>           goto exit;
>       }
> diff --git a/qemu-img.c b/qemu-img.c
> index 2e4646e..376107c 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -1601,7 +1601,8 @@ static int convert_write(ImgConvertState *s, int64_t sector_num, int nb_sectors,
>               if (s->has_zero_init) {
>                   break;
>               }
> -            ret = blk_write_zeroes(s->target, sector_num, n, 0);
> +            ret = blk_pwrite_zeroes(s->target, sector_num << BDRV_SECTOR_BITS,
> +                                    n << BDRV_SECTOR_BITS, 0);
>               if (ret < 0) {
>                   return ret;
>               }
Acked-by: Denis V. Lunev <den@openvz.org>