[2.6 patch] videobuf-core.c locking fixes

From: Adrian Bunk
Date: Wed Dec 12 2007 - 14:45:11 EST


On Wed, Dec 12, 2007 at 01:57:27PM -0500, Shane wrote:
> On Dec 12, 2007 11:37 AM, Shane <gnome42@xxxxxxxxx> wrote:
> > On Dec 12, 2007 9:21 AM, Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxx> wrote:
> > ...
> > > The proper solution is provided by this changeset:
> > > http://git.kernel.org/?p=linux/kernel/git/mchehab/v4l-dvb.git;a=commitdiff;h=19fb1457990b6b7e15586ec7331541a184233acc
> >
> > I applied this and it seems fine with a bttv card.
>
> Ugh, after further testing with a bttv card it seems this is not fine.
>
> vbi doesn't work anymore and my application gets stuck in a Zombie,
> unkillable, have to reboot state :(
>
> mythtv 3683 1 -3 2.4 0.0 0 0 ? Z<l 13:40:35
> 00:00:06 [mythbackend] <defunct>
>
> Reverting Mauro's patch above does fix the problem.

Thanks for testing, does the patch below fix it?

> Shane

cu
Adrian


<-- snip -->


After commit 19fb1457990b6b7e15586ec7331541a184233acc the callers in
videobuf-core.c that already hold the lock must call
__videobuf_read_start() instead of videobuf_read_start().

Signed-off-by: Adrian Bunk <bunk@xxxxxxxxxx>

---

drivers/media/video/videobuf-core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

e1f8b4a49d86746f699919531c17fd154787e308
diff --git a/drivers/media/video/videobuf-core.c b/drivers/media/video/videobuf-core.c
index 81f77d2..c8a5cb5 100644
--- a/drivers/media/video/videobuf-core.c
+++ b/drivers/media/video/videobuf-core.c
@@ -909,7 +909,7 @@ ssize_t videobuf_read_stream(struct videobuf_queue *q,
if (q->streaming)
goto done;
if (!q->reading) {
- retval = videobuf_read_start(q);
+ retval = __videobuf_read_start(q);
if (retval < 0)
goto done;
}
@@ -982,7 +982,7 @@ unsigned int videobuf_poll_stream(struct file *file,
struct videobuf_buffer, stream);
} else {
if (!q->reading)
- videobuf_read_start(q);
+ __videobuf_read_start(q);
if (!q->reading) {
rc = POLLERR;
} else if (NULL == q->read_buf) {

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