Re: [Qemu-devel] [PATCH v4 03/11] savevm: add error parameter to qemu_savevm_state_begin()

[Markus Armbruster <armbru@redhat.com>]

Markus Armbruster <armbru@redhat.com> writes:

> Markus Armbruster <armbru@redhat.com> writes:
>
>> Pavel Hrdina <phrdina@redhat.com> writes:
>>
>>> Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
>>> Reviewed-by: Eric Blake <eblake@redhat.com>
>>> ---
>>>  include/sysemu/sysemu.h | 3 ++-
>>>  migration.c             | 2 +-
>>>  savevm.c                | 5 +++--
>>>  3 files changed, 6 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
>>> index 6578782..2f35a05 100644
>>> --- a/include/sysemu/sysemu.h
>>> +++ b/include/sysemu/sysemu.h
>>> @@ -74,7 +74,8 @@ void qemu_announce_self(void);
>>>  
>>>  bool qemu_savevm_state_blocked(Error **errp);
>>>  void qemu_savevm_state_begin(QEMUFile *f,
>>> -                             const MigrationParams *params);
>>> +                             const MigrationParams *params,
>>> +                             Error **errp);
>>>  int qemu_savevm_state_iterate(QEMUFile *f);
>>>  void qemu_savevm_state_complete(QEMUFile *f);
>>>  void qemu_savevm_state_cancel(void);
>>> diff --git a/migration.c b/migration.c
>>> index 7fb2147..d517dd6 100644
>>> --- a/migration.c
>>> +++ b/migration.c
>>> @@ -505,7 +505,7 @@ static void *migration_thread(void *opaque)
>>>      bool old_vm_running = false;
>>>  
>>>      DPRINTF("beginning savevm\n");
>>> -    qemu_savevm_state_begin(s->file, &s->params);
>>> +    qemu_savevm_state_begin(s->file, &s->params, NULL);
>>>  
>>>      while (s->state == MIG_STATE_ACTIVE) {
>>>          int64_t current_time;
>>> diff --git a/savevm.c b/savevm.c
>>> index dc1f4a4..56da096 100644
>>> --- a/savevm.c
>>> +++ b/savevm.c
>>> @@ -1731,7 +1731,8 @@ bool qemu_savevm_state_blocked(Error **errp)
>>>  }
>>>  
>>>  void qemu_savevm_state_begin(QEMUFile *f,
>>> -                             const MigrationParams *params)
>>> +                             const MigrationParams *params,
>>> +                             Error **errp)
>>>  {
>>>      SaveStateEntry *se;
>>>      int ret;
>>> @@ -1921,7 +1922,7 @@ static int qemu_savevm_state(QEMUFile *f)
>>>      }
>>>  
>>>      qemu_mutex_unlock_iothread();
>>> -    qemu_savevm_state_begin(f, &params);
>>> +    qemu_savevm_state_begin(f, &params, NULL);
>>>      qemu_mutex_lock_iothread();
>>>  
>>>      while (qemu_file_get_error(f) == 0) {
>>
>> Unlike PATCH 01+02, this one only adds Error parameters, no actual
>> errors.  Do they come later in the series?
>
> Unlikely, because qemu_savevm_state_begin() can't fail.  Why add an
> Error parameter then?

Bear with me, I'm confused...

Actually, it can fail, sort of: it calls qemu_file_set_error() then.
But you don't return that error via your new Error parameter.  Perhaps
that comes later in the series.