From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mga02.intel.com ([134.134.136.20]:29627 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754412Ab3JBNos (ORCPT ); Wed, 2 Oct 2013 09:44:48 -0400 From: Sakari Ailus To: linux-media@vger.kernel.org Cc: hverkuil@xs4all.nl, laurent.pinchart@ideasonboard.com, teemux.tuominen@intel.com Subject: [RFC v2 1/4] v4l: return POLLERR on V4L2 sub-devices if no events are subscribed Date: Wed, 2 Oct 2013 16:45:13 +0300 Message-Id: <1380721516-488-2-git-send-email-sakari.ailus@linux.intel.com> In-Reply-To: <1380721516-488-1-git-send-email-sakari.ailus@linux.intel.com> References: <1380721516-488-1-git-send-email-sakari.ailus@linux.intel.com> Sender: linux-media-owner@vger.kernel.org List-ID: From: Teemu Tuominen 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 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 Tested-by: Teemu Tuominen --- 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); -- 1.8.3.2