V4L/DVB (6601): V4L: videobuf-core locking fixes and comments

- Add comments to functions that require that caller hold q->lock
- Add __videobuf_mmap_free that doesn't hold q->lock for use within videobuf
- Add locking to videobuf_mmap_free
- Fix linux/drivers/media/common/saa7146_video.c which was holding lock around
  videobuf_read_stop
- Add locking to functions that operate on a queue
- Add videobuf_stop to take care of stopping in both the read and stream case

TODO: bttv still has an unsafe call to videobuf_queue_is_busy

Signed-off-by: Brandon Philips <bphilips@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/media/videobuf-core.h b/include/media/videobuf-core.h
index 0fa5d5912555..4fd5d0eaa935 100644
--- a/include/media/videobuf-core.h
+++ b/include/media/videobuf-core.h
@@ -208,6 +208,8 @@ int videobuf_cgmbuf(struct videobuf_queue *q,
 int videobuf_streamon(struct videobuf_queue *q);
 int videobuf_streamoff(struct videobuf_queue *q);
 
+void videobuf_stop(struct videobuf_queue *q);
+
 int videobuf_read_start(struct videobuf_queue *q);
 void videobuf_read_stop(struct videobuf_queue *q);
 ssize_t videobuf_read_stream(struct videobuf_queue *q,