Re: [PATCH v3 4/4] block: Mark 'block_resize' as coroutine

[Markus Armbruster]

Kevin Wolf <address@hidden> writes:

> Am 16.01.2020 um 10:45 hat Markus Armbruster geschrieben:
>> Kevin Wolf <address@hidden> writes:
>> > block_resize is safe to run in a coroutine, so use it as an example for
>> > the new 'coroutine': true annotation in the QAPI schema.
>> >
>> > Signed-off-by: Kevin Wolf <address@hidden>
>> > Reviewed-by: Marc-André Lureau <address@hidden>
>
>> > diff --git a/blockdev.c b/blockdev.c
>> > index 8e029e9c01..b5e5d1e072 100644
>> > --- a/blockdev.c
>> > +++ b/blockdev.c
>> > @@ -3161,9 +3161,9 @@ void hmp_drive_del(Monitor *mon, const QDict *qdict)
>> >      aio_context_release(aio_context);
>> >  }
>> >  
>> > -void qmp_block_resize(bool has_device, const char *device,
>> > -                      bool has_node_name, const char *node_name,
>> > -                      int64_t size, Error **errp)
>> > +void coroutine_fn qmp_block_resize(bool has_device, const char *device,
>> > +                                   bool has_node_name, const char 
>> > *node_name,
>> > +                                   int64_t size, Error **errp)
>> >  {
>> >      Error *local_err = NULL;
>> >      BlockBackend *blk = NULL;
>> 
>> Pardon my ignorant question: what exactly makes a function a
>> coroutine_fn?
>
> When Stefan requested adding the coroutine_fn marker, it seemed to make
> sense to me because the QMP dispatcher will always call it from
> coroutine context now, and being always run in coroutine context makes a
> function a coroutine_fn.
>
> However, it's also called from hmp_block_resize(), so at least for now
> coroutine_fn is actually wrong.

This answers the question when we mark a function a coroutine_fn.  I
meant to ask what conditions the function itself must satisfy to be
eligible for this mark.