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Commit ba32bd95 authored by Brandon Philips's avatar Brandon Philips Committed by Mauro Carvalho Chehab
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V4L/DVB (6275): V4L: vivi.c remove the "resource" locking 



The "resource" locking in vivi isn't needed since
streamon/streamoff/read_stream do mutual exclusion using
q->reading/q->streaming.

Plus it is sort of broken:

a) res_locked() use in vivi_read() is racey.
b) res_free() calls mutex_lock twice causing streamoff to break

Signed-off-by: default avatarBrandon Philips <bphilips@suse.de>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
parent 85c7c70b

drivers/media/video/vivi.c

+4 −44
Original line number Diff line number Diff line
@@ -170,7 +170,6 @@ struct vivi_dev { 
	int                        users;



	/* various device info */

	unsigned int               resources;

	struct video_device        vfd;



	struct vivi_dmaqueue       vidq;
@@ -726,40 +725,6 @@ static struct videobuf_queue_ops vivi_video_qops = { 
	.buf_release    = buffer_release,

};



/* ------------------------------------------------------------------

	IOCTL handling

   ------------------------------------------------------------------*/





static int res_get(struct vivi_dev *dev, struct vivi_fh *fh)

{

	/* is it free? */

	mutex_lock(&dev->lock);

	if (dev->resources) {

		/* no, someone else uses it */

		mutex_unlock(&dev->lock);

		return 0;

	}

	/* it's free, grab it */

	dev->resources =1;

	dprintk(1,"res: get\n");

	mutex_unlock(&dev->lock);

	return 1;

}



static int res_locked(struct vivi_dev *dev)

{

	return (dev->resources);

}



static void res_free(struct vivi_dev *dev, struct vivi_fh *fh)

{

	mutex_lock(&dev->lock);

	dev->resources = 0;

	dprintk(1,"res: put\n");

	mutex_lock(&dev->lock);

}



/* ------------------------------------------------------------------

	IOCTL vidioc handling

   ------------------------------------------------------------------*/
@@ -913,9 +878,7 @@ static int vidioc_streamon(struct file *file, void *priv, enum v4l2_buf_type i) 
	if (i != fh->type)

		return -EINVAL;



	if (!res_get(dev,fh))

		return -EBUSY;

	return (videobuf_streamon(&fh->vb_vidq));

	return videobuf_streamon(&fh->vb_vidq);

}



static int vidioc_streamoff(struct file *file, void *priv, enum v4l2_buf_type i)
@@ -928,10 +891,7 @@ static int vidioc_streamoff(struct file *file, void *priv, enum v4l2_buf_type i) 
	if (i != fh->type)

		return -EINVAL;



	videobuf_streamoff(&fh->vb_vidq);

	res_free(dev,fh);



	return (0);

	return videobuf_streamoff(&fh->vb_vidq);

}



static int vidioc_s_std (struct file *file, void *priv, v4l2_std_id *i)
@@ -1096,10 +1056,10 @@ static ssize_t 
vivi_read(struct file *file, char __user *data, size_t count, loff_t *ppos)

{

	struct vivi_fh        *fh = file->private_data;

	struct vivi_dev        *dev = fh->dev;

	struct videobuf_queue *q = &fh->vb_vidq;



	if (fh->type==V4L2_BUF_TYPE_VIDEO_CAPTURE) {

		if (res_locked(fh->dev))

			return -EBUSY;

		return videobuf_read_stream(&fh->vb_vidq, data, count, ppos, 0,

					file->f_flags & O_NONBLOCK);

	}