diff mbox

[RFC,v2,6/7] V4L: Events: Sequence numbers

Message ID 1261500191-9441-6-git-send-email-sakari.ailus@maxwell.research.nokia.com (mailing list archive)
State RFC, archived
Headers

Commit Message

Sakari Ailus Dec. 22, 2009, 4:43 p.m. UTC 
  Add sequence numbers to events.

Signed-off-by: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
---
 drivers/media/video/v4l2-event.c |    8 ++++++++
 include/media/v4l2-event.h       |    1 +
 2 files changed, 9 insertions(+), 0 deletions(-)

Comments

Hans Verkuil Jan. 18, 2010, 12:48 p.m. UTC | #1 
Hi Sakari,

Some more review comments:

On Tue, 22 Dec 2009, Sakari Ailus wrote:

> Add sequence numbers to events.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
> ---
> drivers/media/video/v4l2-event.c |    8 ++++++++
> include/media/v4l2-event.h       |    1 +
> 2 files changed, 9 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/media/video/v4l2-event.c b/drivers/media/video/v4l2-event.c
> index 72fdf7f..cc2bf57 100644
> --- a/drivers/media/video/v4l2-event.c
> +++ b/drivers/media/video/v4l2-event.c
> @@ -58,6 +58,7 @@ void v4l2_event_init_fh(struct v4l2_fh *fh)
> 	INIT_LIST_HEAD(&events->subscribed);
>
> 	atomic_set(&events->navailable, 0);
> +	events->sequence = 0;

Why not make this atomic_t as well?

> }
> EXPORT_SYMBOL_GPL(v4l2_event_init_fh);
>
> @@ -158,10 +159,16 @@ void v4l2_event_queue(struct video_device *vdev, struct v4l2_event *ev)
>
> 	list_for_each_entry(fh, &vdev->fh, list) {
> 		struct _v4l2_event *_ev;
> +		u32 sequence;
>
> 		if (!v4l2_event_subscribed(fh, ev->type))
> 			continue;
>
> +		spin_lock(&fh->events.lock);
> +		sequence = fh->events.sequence;
> +		fh->events.sequence++;
> +		spin_unlock(&fh->events.lock);

Then you can use atomic_inc_return() here.

> +
> 		if (atomic_read(&fh->events.navailable) >= V4L2_MAX_EVENTS)
> 			continue;
>
> @@ -172,6 +179,7 @@ void v4l2_event_queue(struct video_device *vdev, struct v4l2_event *ev)
> 		_ev->event = *ev;
>
> 		spin_lock(&fh->events.lock);
> +		_ev->event.sequence = sequence;
> 		list_add_tail(&_ev->list, &fh->events.available);
> 		spin_unlock(&fh->events.lock);
>
> diff --git a/include/media/v4l2-event.h b/include/media/v4l2-event.h
> index 69305c6..5a778d4 100644
> --- a/include/media/v4l2-event.h
> +++ b/include/media/v4l2-event.h
> @@ -44,6 +44,7 @@ struct v4l2_events {
> 	spinlock_t		lock; /* Protect everything here. */
> 	struct list_head	available;
> 	atomic_t		navailable;
> +	u32			sequence;
> 	wait_queue_head_t	wait;
> 	struct list_head	subscribed; /* Subscribed events. */
> };
> -- 
> 1.5.6.5
>

Regards,

 	Hans
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diff mbox

Patch

diff --git a/drivers/media/video/v4l2-event.c b/drivers/media/video/v4l2-event.c
index 72fdf7f..cc2bf57 100644
--- a/drivers/media/video/v4l2-event.c
+++ b/drivers/media/video/v4l2-event.c
@@ -58,6 +58,7 @@  void v4l2_event_init_fh(struct v4l2_fh *fh)
 	INIT_LIST_HEAD(&events->subscribed);
 
 	atomic_set(&events->navailable, 0);
+	events->sequence = 0;
 }
 EXPORT_SYMBOL_GPL(v4l2_event_init_fh);
 
@@ -158,10 +159,16 @@  void v4l2_event_queue(struct video_device *vdev, struct v4l2_event *ev)
 
 	list_for_each_entry(fh, &vdev->fh, list) {
 		struct _v4l2_event *_ev;
+		u32 sequence;
 
 		if (!v4l2_event_subscribed(fh, ev->type))
 			continue;
 
+		spin_lock(&fh->events.lock);
+		sequence = fh->events.sequence;
+		fh->events.sequence++;
+		spin_unlock(&fh->events.lock);
+
 		if (atomic_read(&fh->events.navailable) >= V4L2_MAX_EVENTS)
 			continue;
 
@@ -172,6 +179,7 @@  void v4l2_event_queue(struct video_device *vdev, struct v4l2_event *ev)
 		_ev->event = *ev;
 
 		spin_lock(&fh->events.lock);
+		_ev->event.sequence = sequence;
 		list_add_tail(&_ev->list, &fh->events.available);
 		spin_unlock(&fh->events.lock);
 
diff --git a/include/media/v4l2-event.h b/include/media/v4l2-event.h
index 69305c6..5a778d4 100644
--- a/include/media/v4l2-event.h
+++ b/include/media/v4l2-event.h
@@ -44,6 +44,7 @@  struct v4l2_events {
 	spinlock_t		lock; /* Protect everything here. */
 	struct list_head	available;
 	atomic_t		navailable;
+	u32			sequence;
 	wait_queue_head_t	wait;
 	struct list_head	subscribed; /* Subscribed events. */
 };