Re: [PATCH 10/21] migration: Use QAPI_CLONE_MEMBERS in query_migrate_parameters

[Peter Xu]

On Mon, Jun 02, 2025 at 10:37:59PM -0300, Fabiano Rosas wrote:
> QAPI_CLONE_MEMBERS is a better option than copying parameters one by
> one because it operates on the entire struct and follows pointers. It
> also avoids the need to alter this function every time a new parameter
> is added.
> 
> Note, since this is a deep clone, now we must free the TLS strings
> before assignment.
> 
> Signed-off-by: Fabiano Rosas <faro...@suse.de>
> ---
>  migration/options.c | 31 ++++---------------------------
>  1 file changed, 4 insertions(+), 27 deletions(-)
> 
> diff --git a/migration/options.c b/migration/options.c
> index dd62e726cb..0a2a3050ec 100644
> --- a/migration/options.c
> +++ b/migration/options.c
> @@ -918,7 +918,9 @@ static void tls_option_set_str(StrOrNull **dstp, 
> StrOrNull *src)
>  {
>      StrOrNull *dst = *dstp;
>  
> -    assert(!dst);
> +    if (dst) {
> +        qapi_free_StrOrNull(dst);
> +    }
>  
>      dst = *dstp = g_new0(StrOrNull, 1);
>      dst->type = QTYPE_QSTRING;
> @@ -975,42 +977,17 @@ MigrationParameters *qmp_query_migrate_parameters(Error 
> **errp)
>      MigrationParameters *params;
>      MigrationState *s = migrate_get_current();
>  
> -    /* TODO use QAPI_CLONE() instead of duplicating it inline */
>      params = g_malloc0(sizeof(*params));
>  
> -    params->throttle_trigger_threshold = 
> s->parameters.throttle_trigger_threshold;
> -    params->cpu_throttle_initial = s->parameters.cpu_throttle_initial;
> -    params->cpu_throttle_increment = s->parameters.cpu_throttle_increment;
> -    params->cpu_throttle_tailslow = s->parameters.cpu_throttle_tailslow;
> +    QAPI_CLONE_MEMBERS(MigrationParameters, params, &s->parameters);
>  
>      tls_option_set_str(&params->tls_creds, s->parameters.tls_creds);
>      tls_option_set_str(&params->tls_hostname, s->parameters.tls_hostname);
>      tls_option_set_str(&params->tls_authz, s->parameters.tls_authz);
>  
> -    params->max_bandwidth = s->parameters.max_bandwidth;
> -    params->avail_switchover_bandwidth = 
> s->parameters.avail_switchover_bandwidth;
> -    params->downtime_limit = s->parameters.downtime_limit;
> -    params->x_checkpoint_delay = s->parameters.x_checkpoint_delay;
> -    params->multifd_channels = s->parameters.multifd_channels;
> -    params->multifd_compression = s->parameters.multifd_compression;
> -    params->multifd_zlib_level = s->parameters.multifd_zlib_level;
> -    params->multifd_qatzip_level = s->parameters.multifd_qatzip_level;
> -    params->multifd_zstd_level = s->parameters.multifd_zstd_level;
> -    params->xbzrle_cache_size = s->parameters.xbzrle_cache_size;
> -    params->max_postcopy_bandwidth = s->parameters.max_postcopy_bandwidth;
> -    params->max_cpu_throttle = s->parameters.max_cpu_throttle;
> -    params->announce_initial = s->parameters.announce_initial;
> -    params->announce_max = s->parameters.announce_max;
> -    params->announce_rounds = s->parameters.announce_rounds;
> -    params->announce_step = s->parameters.announce_step;
>      params->block_bitmap_mapping =
>          QAPI_CLONE(BitmapMigrationNodeAliasList,
>                     s->parameters.block_bitmap_mapping);

Wouldn't the QAPI_CLONE_MEMBERS() have deep cloned this too?

> -    params->x_vcpu_dirty_limit_period = 
> s->parameters.x_vcpu_dirty_limit_period;
> -    params->vcpu_dirty_limit = s->parameters.vcpu_dirty_limit;
> -    params->mode = s->parameters.mode;
> -    params->zero_page_detection = s->parameters.zero_page_detection;
> -    params->direct_io = s->parameters.direct_io;
>  
>      /*
>       * query-migrate-parameters expects all members of
> -- 
> 2.35.3
> 

-- 
Peter Xu