Re: [PATCH RFC 06/10] vmstate: Introduce vmstate_save_field_with_vmdesc()

[Fabiano Rosas <farosas@suse.de>]

Peter Xu <peterx@redhat.com> writes:

> Introduce a helper to do both the JSON blob dump and vmstate dump.  This
> further shrinks the function a bit.  More importantly, we'll need to dump
> two fields in one loop very soon in the future with the JSON blob.
>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  migration/vmstate.c | 38 +++++++++++++++++++++++++++-----------
>  1 file changed, 27 insertions(+), 11 deletions(-)
>
> diff --git a/migration/vmstate.c b/migration/vmstate.c
> index caa7b50bce..5a6b352764 100644
> --- a/migration/vmstate.c
> +++ b/migration/vmstate.c
> @@ -514,6 +514,30 @@ static bool vmstate_save_field(QEMUFile *f, void *pv, size_t size,
>      return true;
>  }
>  
> +/*
> + * Dump a whole VMSD field, including its JSON blob separately when @vmdesc

Could do without the "dump" terminology all over the series. There's
already use for that term due to -dump-vmstate.

> + * is specified.
> + */
> +static inline bool
> +vmstate_save_field_with_vmdesc(QEMUFile *f, void *pv, size_t size,
> +                               const VMStateDescription *vmsd,
> +                               const VMStateField *field, JSONWriter *vmdesc,
> +                               int i, int max, Error **errp)
> +{
> +    uint64_t old_offset, written_bytes;
> +    bool ok;
> +
> +    vmsd_desc_field_start(vmsd, vmdesc, field, i, max);
> +
> +    old_offset = qemu_file_transferred(f);
> +    ok = vmstate_save_field(f, pv, size, field, vmdesc, errp);
> +    written_bytes = qemu_file_transferred(f) - old_offset;
> +
> +    vmsd_desc_field_end(vmsd, vmdesc, field, written_bytes);
> +
> +    return ok;
> +}
> +
>  static bool vmstate_save_vmsd_v(QEMUFile *f, const VMStateDescription *vmsd,
>                                  void *opaque, JSONWriter *vmdesc,
>                                  int version_id, Error **errp)
> @@ -542,7 +566,6 @@ static bool vmstate_save_vmsd_v(QEMUFile *f, const VMStateDescription *vmsd,
>              void *first_elem = opaque + field->offset;
>              int i, n_elems = vmstate_n_elems(opaque, field);
>              int size = vmstate_size(opaque, field);
> -            uint64_t old_offset, written_bytes;
>              JSONWriter *vmdesc_loop = vmdesc;
>              bool is_prev_null = false;
>  
> @@ -558,7 +581,6 @@ static bool vmstate_save_vmsd_v(QEMUFile *f, const VMStateDescription *vmsd,
>                  bool is_null;
>                  int max_elems = n_elems - i;
>  
> -                old_offset = qemu_file_transferred(f);
>                  if (field->flags & VMS_ARRAY_OF_POINTER) {
>                      assert(curr_elem);
>                      curr_elem = *(void **)curr_elem;
> @@ -606,15 +628,9 @@ static bool vmstate_save_vmsd_v(QEMUFile *f, const VMStateDescription *vmsd,
>                      }
>                  }
>  
> -                vmsd_desc_field_start(vmsd, vmdesc_loop, inner_field,
> -                                      i, max_elems);
> -
> -                ok = vmstate_save_field(f, curr_elem, size, inner_field,
> -                                        vmdesc_loop, errp);
> -
> -                written_bytes = qemu_file_transferred(f) - old_offset;
> -                vmsd_desc_field_end(vmsd, vmdesc_loop, inner_field,
> -                                    written_bytes);
> +                ok = vmstate_save_field_with_vmdesc(f, curr_elem, size, vmsd,
> +                                                    inner_field, vmdesc_loop,
> +                                                    i, max_elems, errp);
>  
>                  /* If we used a fake temp field.. free it now */
>                  if (is_null) {