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| author | Hans Verkuil <hverkuil@xs4all.nl> | 2010-09-26 13:47:38 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2010-10-21 05:06:14 +0200 |
| commit | ee6869afc922a9849979e49bb3bbcad794872fcb (patch) | |
| tree | 2266050d01da694d04b533a6509873888327108b /include/media/v4l2-dev.h | |
| parent | V4L/DVB: v4l2-dev: remove get_unmapped_area (diff) | |
| download | linux-ee6869afc922a9849979e49bb3bbcad794872fcb.tar.xz linux-ee6869afc922a9849979e49bb3bbcad794872fcb.zip | |
V4L/DVB: v4l2: add core serialization lock
Drivers can optionally set a pointer to a mutex in struct video_device.
The core will use that to lock before calling open, read, write, unlocked_ioctl,
poll, mmap or release.
Updated the documentation as well and ensure that v4l2-event knows about the
lock: it will unlock it before doing a blocking wait on an event and relock it
afterwards.
Ensure that the 'video_is_registered' check is done when the lock is held:
a typical disconnect will take the lock as well before unregistering the
device nodes, so to prevent race conditions the video_is_registered check
should also be done with the lock held.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'include/media/v4l2-dev.h')
| -rw-r--r-- | include/media/v4l2-dev.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h index ba236ff35c8a..15802a067a12 100644 --- a/include/media/v4l2-dev.h +++ b/include/media/v4l2-dev.h @@ -94,6 +94,9 @@ struct video_device /* ioctl callbacks */ const struct v4l2_ioctl_ops *ioctl_ops; + + /* serialization lock */ + struct mutex *lock; }; /* dev to video-device */ |