| Message ID | 1380721516-488-2-git-send-email-sakari.ailus@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 10/02/13 15:45, Sakari Ailus wrote: > From: Teemu Tuominen <teemux.tuominen@intel.com> > > Add check and return POLLERR from subdev_poll() in case of no events > subscribed and wakeup once the last event subscription is removed. > > This change is essentially done to add possibility to wakeup polling > with concurrent unsubscribe. > > Signed-off-by: Teemu Tuominen <teemux.tuominen@intel.com> > > Move the check after calling poll_wait(). Otherwise it's possible that we go > to sleep without getting notified if the subscription went away between the > two. > > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> > Tested-by: Teemu Tuominen <teemux.tuominen@intel.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Regards, Hans > --- > drivers/media/v4l2-core/v4l2-event.c | 15 +++++++++++++++ > drivers/media/v4l2-core/v4l2-subdev.c | 3 +++ > include/media/v4l2-event.h | 1 + > 3 files changed, 19 insertions(+) > > diff --git a/drivers/media/v4l2-core/v4l2-event.c b/drivers/media/v4l2-core/v4l2-event.c > index 86dcb54..b53897e 100644 > --- a/drivers/media/v4l2-core/v4l2-event.c > +++ b/drivers/media/v4l2-core/v4l2-event.c > @@ -107,6 +107,19 @@ static struct v4l2_subscribed_event *v4l2_event_subscribed( > return NULL; > } > > +bool v4l2_event_has_subscribed(struct v4l2_fh *fh) > +{ > + unsigned long flags; > + bool rval; > + > + spin_lock_irqsave(&fh->vdev->fh_lock, flags); > + rval = !list_empty(&fh->subscribed); > + spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); > + > + return rval; > +} > +EXPORT_SYMBOL(v4l2_event_has_subscribed); > + > static void __v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev, > const struct timespec *ts) > { > @@ -299,6 +312,8 @@ int v4l2_event_unsubscribe(struct v4l2_fh *fh, > fh->navailable--; > } > list_del(&sev->list); > + if (list_empty(&fh->subscribed)) > + wake_up_all(&fh->wait); > } > > spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c > index 996c248..7d72389 100644 > --- a/drivers/media/v4l2-core/v4l2-subdev.c > +++ b/drivers/media/v4l2-core/v4l2-subdev.c > @@ -382,6 +382,9 @@ static unsigned int subdev_poll(struct file *file, poll_table *wait) > if (v4l2_event_pending(fh)) > return POLLPRI; > > + if (!v4l2_event_has_subscribed(fh)) > + return POLLERR | POLLPRI; > + > return 0; > } > > diff --git a/include/media/v4l2-event.h b/include/media/v4l2-event.h > index be05d01..a9ca2b5 100644 > --- a/include/media/v4l2-event.h > +++ b/include/media/v4l2-event.h > @@ -121,6 +121,7 @@ struct v4l2_subscribed_event { > > int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event, > int nonblocking); > +bool v4l2_event_has_subscribed(struct v4l2_fh *fh); > void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev); > void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev); > int v4l2_event_pending(struct v4l2_fh *fh); > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/media/v4l2-core/v4l2-event.c b/drivers/media/v4l2-core/v4l2-event.c index 86dcb54..b53897e 100644 --- a/drivers/media/v4l2-core/v4l2-event.c +++ b/drivers/media/v4l2-core/v4l2-event.c @@ -107,6 +107,19 @@ static struct v4l2_subscribed_event *v4l2_event_subscribed( return NULL; } +bool v4l2_event_has_subscribed(struct v4l2_fh *fh) +{ + unsigned long flags; + bool rval; + + spin_lock_irqsave(&fh->vdev->fh_lock, flags); + rval = !list_empty(&fh->subscribed); + spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); + + return rval; +} +EXPORT_SYMBOL(v4l2_event_has_subscribed); + static void __v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev, const struct timespec *ts) { @@ -299,6 +312,8 @@ int v4l2_event_unsubscribe(struct v4l2_fh *fh, fh->navailable--; } list_del(&sev->list); + if (list_empty(&fh->subscribed)) + wake_up_all(&fh->wait); } spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c index 996c248..7d72389 100644 --- a/drivers/media/v4l2-core/v4l2-subdev.c +++ b/drivers/media/v4l2-core/v4l2-subdev.c @@ -382,6 +382,9 @@ static unsigned int subdev_poll(struct file *file, poll_table *wait) if (v4l2_event_pending(fh)) return POLLPRI; + if (!v4l2_event_has_subscribed(fh)) + return POLLERR | POLLPRI; + return 0; } diff --git a/include/media/v4l2-event.h b/include/media/v4l2-event.h index be05d01..a9ca2b5 100644 --- a/include/media/v4l2-event.h +++ b/include/media/v4l2-event.h @@ -121,6 +121,7 @@ struct v4l2_subscribed_event { int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event, int nonblocking); +bool v4l2_event_has_subscribed(struct v4l2_fh *fh); void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev); void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev); int v4l2_event_pending(struct v4l2_fh *fh);