Re: [PATCH 01/18] migration/vmstate: Document vmstate_dummy

[Philippe Mathieu-Daudé]

On 7/16/20 11:52 AM, Daniel P. Berrangé wrote:
> On Fri, Jul 03, 2020 at 10:18:54PM +0200, Philippe Mathieu-Daudé wrote:
>> vmstate_dummy is special and restricted to linux-user. See commit
>> c71c3e99b8 ("Add a vmstate_dummy struct for CONFIG_USER_ONLY").
>>
>> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>> ---
>>  include/migration/vmstate.h | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
>> index f68ed7db13..af7d80cd4e 100644
>> --- a/include/migration/vmstate.h
>> +++ b/include/migration/vmstate.h
>> @@ -194,7 +194,7 @@ struct VMStateDescription {
>>      const VMStateDescription **subsections;
>>  };
>>  
>> -extern const VMStateDescription vmstate_dummy;
>> +extern const VMStateDescription vmstate_dummy; /* Exclusively for 
>> linux-user */
> 
> Originally in the commit mentioned above, this was enforced at build time:
> 
>   +#ifdef CONFIG_USER_ONLY
>   +extern const VMStateDescription vmstate_dummy;
>   +#endif
> 
> 
> but this was removed in
> 
>   commit 6afc14e92ac81b29c25f097468f7751d5df1b5bc
>   Author: Stefan Weil <sw@weilnetz.de>
>   Date:   Fri Feb 6 22:43:10 2015 +0100
> 
>     migration: Fix warning caused by missing declaration of vmstate_dummy
>     
>     Warning from the Sparse static analysis tool:
>     
>     stubs/vmstate.c:4:26: warning:
>      symbol 'vmstate_dummy' was not declared. Should it be static?
> 
> 
> So if this is really intended to only be used by linux-user, then I
> suggest we put CONFIG_USER_ONLY back, and figure out a different
> way to address the undeclared symbol problem. I guess the problem
> was that stub code is shared both both user/softmmu builds. So
> perhaps we need to stub this in linux-user only code, instead of
> having it in the main stub library that is common.

Good idea, I'll look at it.

Thanks,

Phil.