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

[Fabiano Rosas]

Peter Xu <pet...@redhat.com> writes:

> 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?
>

Hmm, I think it should. But it definitely broke something without this
line. I'll double check.

>> -    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
>>