Re: [PATCH v2 23/53] migration/rdma: Fix QEMUFileHooks method return values

[Markus Armbruster]

Juan Quintela <quintela@redhat.com> writes:

> Markus Armbruster <armbru@redhat.com> wrote:
>> The QEMUFileHooks methods don't come with a written contract.  Digging
>> through the code calling them, we find:
>>
>> * save_page():
>>
>>   Negative values RAM_SAVE_CONTROL_DELAYED and
>>   RAM_SAVE_CONTROL_NOT_SUPP are special.  Any other negative value is
>>   an unspecified error.
>>
>>   qemu_rdma_save_page() returns -EIO or rdma->error_state on error.  I
>>   believe the latter is always negative.  Nothing stops either of them
>>   to clash with the special values, though.  Feels unlikely, but fix
>>   it anyway to return only the special values and -1.
>>
>> * before_ram_iterate(), after_ram_iterate():
>>
>>   Negative value means error.  qemu_rdma_registration_start() and
>>   qemu_rdma_registration_stop() comply as far as I can tell.  Make
>>   them comply *obviously*, by returning -1 on error.
>>
>> * hook_ram_load:
>>
>>   Negative value means error.  rdma_load_hook() already returns -1 on
>>   error.  Leave it alone.
>>
>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>> Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
>
> Reviewed-by: Juan Quintela <quintela@redhat.com>
>
> Changed idea.  Will include this and rebase mines on top.

Thanks!