Re: [PATCH v13 11/25] v4l: async: Introduce helpers for calling async ops callbacks

[Sakari Ailus]

Hi Laurent,

On Tue, Sep 19, 2017 at 03:01:14PM +0300, Laurent Pinchart wrote:
> Hi Sakari,
> 
> Thank you for the patch.
> 
> On Friday, 15 September 2017 17:17:10 EEST Sakari Ailus wrote:
> > Add three helper functions to call async operations callbacks. Besides
> > simplifying callbacks, this allows async notifiers to have no ops set,
> > i.e. it can be left NULL.
> > 
> > Signed-off-by: Sakari Ailus <sakari.ai...@linux.intel.com>
> > Acked-by: Hans Verkuil <hans.verk...@cisco.com>
> > ---
> >  drivers/media/v4l2-core/v4l2-async.c | 49 ++++++++++++++++++++++++--------
> >  include/media/v4l2-async.h           |  1 +
> >  2 files changed, 37 insertions(+), 13 deletions(-)
> > 
> > diff --git a/drivers/media/v4l2-core/v4l2-async.c
> > b/drivers/media/v4l2-core/v4l2-async.c index 7b2125b3d62f..c35d04b9122f
> > 100644
> > --- a/drivers/media/v4l2-core/v4l2-async.c
> > +++ b/drivers/media/v4l2-core/v4l2-async.c
> > @@ -25,6 +25,34 @@
> >  #include <media/v4l2-fwnode.h>
> >  #include <media/v4l2-subdev.h>
> > 
> > +static int v4l2_async_notifier_call_bound(struct v4l2_async_notifier *n,
> > +                                     struct v4l2_subdev *subdev,
> > +                                     struct v4l2_async_subdev *asd)
> > +{
> > +   if (!n->ops || !n->ops->bound)
> > +           return 0;
> > +
> > +   return n->ops->bound(n, subdev, asd);
> > +}
> > +
> > +static void v4l2_async_notifier_call_unbind(struct v4l2_async_notifier *n,
> > +                                       struct v4l2_subdev *subdev,
> > +                                       struct v4l2_async_subdev *asd)
> > +{
> > +   if (!n->ops || !n->ops->unbind)
> > +           return;
> > +
> > +   n->ops->unbind(n, subdev, asd);
> > +}
> > +
> > +static int v4l2_async_notifier_call_complete(struct v4l2_async_notifier *n)
> > +{
> > +   if (!n->ops || !n->ops->complete)
> > +           return 0;
> > +
> > +   return n->ops->complete(n);
> > +}
> > +
> 
> Wouldn't it be enough to add a single v4l2_async_notifier_call() macro ?
> 
> #define v4l2_async_notifier_call(n, op, args...) \
>       ((n)->ops && (n)->ops->op ? (n)->ops->op(n, ##args) : 0)

I actually had that in an earlier version but I changed it based on review
comments from Hans. A single macro isn't enough: some functions have int
return type. I think the way it is now is nicer.

> 
> Apart from that,
> 
> Reviewed-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> 
> >  static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev
> > *asd) {
> >  #if IS_ENABLED(CONFIG_I2C)
> > @@ -102,16 +130,13 @@ static int v4l2_async_match_notify(struct
> > v4l2_async_notifier *notifier, {
> >     int ret;
> > 
> > -   if (notifier->ops->bound) {
> > -           ret = notifier->ops->bound(notifier, sd, asd);
> > -           if (ret < 0)
> > -                   return ret;
> > -   }
> > +   ret = v4l2_async_notifier_call_bound(notifier, sd, asd);
> > +   if (ret < 0)
> > +           return ret;
> > 
> >     ret = v4l2_device_register_subdev(notifier->v4l2_dev, sd);
> >     if (ret < 0) {
> > -           if (notifier->ops->unbind)
> > -                   notifier->ops->unbind(notifier, sd, asd);
> > +           v4l2_async_notifier_call_unbind(notifier, sd, asd);
> >             return ret;
> >     }
> > 
> > @@ -123,8 +148,8 @@ static int v4l2_async_match_notify(struct
> > v4l2_async_notifier *notifier, /* Move from the global subdevice list to
> > notifier's done */
> >     list_move(&sd->async_list, &notifier->done);
> > 
> > -   if (list_empty(&notifier->waiting) && notifier->ops->complete)
> > -           return notifier->ops->complete(notifier);
> > +   if (list_empty(&notifier->waiting))
> > +           return v4l2_async_notifier_call_complete(notifier);
> > 
> >     return 0;
> >  }
> > @@ -210,8 +235,7 @@ void v4l2_async_notifier_unregister(struct
> > v4l2_async_notifier *notifier) list_for_each_entry_safe(sd, tmp,
> > &notifier->done, async_list) { v4l2_async_cleanup(sd);
> > 
> > -           if (notifier->ops->unbind)
> > -                   notifier->ops->unbind(notifier, sd, sd->asd);
> > +           v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
> >     }
> > 
> >     mutex_unlock(&list_lock);
> > @@ -300,8 +324,7 @@ void v4l2_async_unregister_subdev(struct v4l2_subdev
> > *sd)
> > 
> >     v4l2_async_cleanup(sd);
> > 
> > -   if (notifier->ops->unbind)
> > -           notifier->ops->unbind(notifier, sd, sd->asd);
> > +   v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
> > 
> >     mutex_unlock(&list_lock);
> >  }
> > diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
> > index 3c48f8b66d12..3bc8a7c0d83f 100644
> > --- a/include/media/v4l2-async.h
> > +++ b/include/media/v4l2-async.h
> > @@ -164,4 +164,5 @@ int v4l2_async_register_subdev(struct v4l2_subdev *sd);
> >   * @sd: pointer to &struct v4l2_subdev
> >   */
> >  void v4l2_async_unregister_subdev(struct v4l2_subdev *sd);
> > +
> >  #endif
> 
> 
> -- 
> Regards,
> 
> Laurent Pinchart
> 

-- 
Sakari Ailus
sakari.ai...@linux.intel.com