Re: [Qemu-devel] [Qemu-block] [PATCH v3 04/16] block/mirror: Pull out mirror_perform()

[Jeff Cody <jcody@redhat.com>]

On Wed, Feb 28, 2018 at 07:04:55PM +0100, Max Reitz wrote:
> When converting mirror's I/O to coroutines, we are going to need a point
> where these coroutines are created.  mirror_perform() is going to be
> that point.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> Reviewed-by: Fam Zheng <famz@redhat.com>
> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  block/mirror.c | 51 +++++++++++++++++++++++++++++----------------------
>  1 file changed, 29 insertions(+), 22 deletions(-)
> 
> diff --git a/block/mirror.c b/block/mirror.c
> index f5bf620942..d197c8936e 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -82,6 +82,12 @@ typedef struct MirrorOp {
>      uint64_t bytes;
>  } MirrorOp;
>  
> +typedef enum MirrorMethod {
> +    MIRROR_METHOD_COPY,
> +    MIRROR_METHOD_ZERO,
> +    MIRROR_METHOD_DISCARD,
> +} MirrorMethod;
> +
>  static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read,
>                                              int error)
>  {
> @@ -321,6 +327,22 @@ static void mirror_do_zero_or_discard(MirrorBlockJob *s,
>      }
>  }
>  
> +static unsigned mirror_perform(MirrorBlockJob *s, int64_t offset,
> +                               unsigned bytes, MirrorMethod mirror_method)
> +{
> +    switch (mirror_method) {
> +    case MIRROR_METHOD_COPY:
> +        return mirror_do_read(s, offset, bytes);
> +    case MIRROR_METHOD_ZERO:
> +    case MIRROR_METHOD_DISCARD:
> +        mirror_do_zero_or_discard(s, offset, bytes,
> +                                  mirror_method == MIRROR_METHOD_DISCARD);
> +        return bytes;
> +    default:
> +        abort();
> +    }
> +}
> +
>  static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>  {
>      BlockDriverState *source = s->source;
> @@ -387,11 +409,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>          int ret;
>          int64_t io_bytes;
>          int64_t io_bytes_acct;
> -        enum MirrorMethod {
> -            MIRROR_METHOD_COPY,
> -            MIRROR_METHOD_ZERO,
> -            MIRROR_METHOD_DISCARD
> -        } mirror_method = MIRROR_METHOD_COPY;
> +        MirrorMethod mirror_method = MIRROR_METHOD_COPY;
>  
>          assert(!(offset % s->granularity));
>          ret = bdrv_block_status_above(source, NULL, offset,
> @@ -429,22 +447,11 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>          }
>  
>          io_bytes = mirror_clip_bytes(s, offset, io_bytes);
> -        switch (mirror_method) {
> -        case MIRROR_METHOD_COPY:
> -            io_bytes = io_bytes_acct = mirror_do_read(s, offset, io_bytes);
> -            break;
> -        case MIRROR_METHOD_ZERO:
> -        case MIRROR_METHOD_DISCARD:
> -            mirror_do_zero_or_discard(s, offset, io_bytes,
> -                                      mirror_method == MIRROR_METHOD_DISCARD);
> -            if (write_zeroes_ok) {
> -                io_bytes_acct = 0;
> -            } else {
> -                io_bytes_acct = io_bytes;
> -            }
> -            break;
> -        default:
> -            abort();
> +        io_bytes = mirror_perform(s, offset, io_bytes, mirror_method);
> +        if (mirror_method != MIRROR_METHOD_COPY && write_zeroes_ok) {
> +            io_bytes_acct = 0;
> +        } else {
> +            io_bytes_acct = io_bytes;
>          }
>          assert(io_bytes);
>          offset += io_bytes;
> @@ -638,7 +645,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
>                  continue;
>              }
>  
> -            mirror_do_zero_or_discard(s, offset, bytes, false);
> +            mirror_perform(s, offset, bytes, MIRROR_METHOD_ZERO);
>              offset += bytes;
>          }
>  
> -- 
> 2.14.3
> 
> 

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