[media] tm6000: fix resource locking (9efd85df) · Commits · jan.koester / Linux

drivers/staging/tm6000/tm6000-video.c

+42 −14

Original line number	Diff line number	Diff line
		@@ -788,25 +788,49 @@ static struct videobuf_queue_ops tm6000_video_qops = {
		IOCTL handling
		------------------------------------------------------------------*/

		static int res_get(struct tm6000_core dev, struct tm6000_fh fh)
		static bool is_res_read(struct tm6000_core dev, struct tm6000_fh fh)
		{
		/* is it free? */
		if (dev->resources)
		return 0;
		/* it's free, grab it */
		dev->resources =1;
		dprintk(dev, V4L2_DEBUG_RES_LOCK, "res: get\n");
		return 1;
		/* Is the current fh handling it? if so, that's OK */
		if (dev->resources == fh && dev->is_res_read)
		return true;

		return false;
		}

		static int res_locked(struct tm6000_core *dev)
		static bool is_res_streaming(struct tm6000_core dev, struct tm6000_fh fh)
		{
		return (dev->resources);
		/* Is the current fh handling it? if so, that's OK */
		if (dev->resources == fh)
		return true;

		return false;
		}

		static bool res_get(struct tm6000_core dev, struct tm6000_fh fh,
		bool is_res_read)
		{
		/* Is the current fh handling it? if so, that's OK */
		if (dev->resources == fh && dev->is_res_read == is_res_read)
		return true;

		/* is it free? */
		if (dev->resources)
		return false;

		/* grab it */
		dev->resources = fh;
		dev->is_res_read = is_res_read;
		dprintk(dev, V4L2_DEBUG_RES_LOCK, "res: get\n");
		return true;
		}

		static void res_free(struct tm6000_core dev, struct tm6000_fh fh)
		{
		dev->resources = 0;
		/* Is the current fh handling it? if so, that's OK */
		if (dev->resources != fh)
		return;

		dev->resources = NULL;
		dprintk(dev, V4L2_DEBUG_RES_LOCK, "res: put\n");
		}

		@@ -981,7 +1005,7 @@ 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))
		if (!res_get(dev, fh, false))
		return -EBUSY;
		return (videobuf_streamon(&fh->vb_vidq));
		}
		@@ -1310,7 +1334,7 @@ tm6000_read(struct file file, char __user data, size_t count, loff_t *pos)
		struct tm6000_fh *fh = file->private_data;

		if (fh->type==V4L2_BUF_TYPE_VIDEO_CAPTURE) {
		if (res_locked(fh->dev))
		if (!res_get(fh->dev, fh, true))
		return -EBUSY;

		return videobuf_read_stream(&fh->vb_vidq, data, count, pos, 0,
		@@ -1328,7 +1352,10 @@ tm6000_poll(struct file file, struct poll_table_struct wait)
		if (V4L2_BUF_TYPE_VIDEO_CAPTURE != fh->type)
		return POLLERR;

		if (res_get(fh->dev,fh)) {
		if (!!is_res_streaming(fh->dev, fh))
		return POLLERR;

		if (!is_res_read(fh->dev, fh)) {
		/* streaming capture */
		if (list_empty(&fh->vb_vidq.stream))
		return POLLERR;
		@@ -1356,6 +1383,7 @@ static int tm6000_release(struct file *file)

		dev->users--;

		res_free(dev, fh);
		if (!dev->users) {
		tm6000_uninit_isoc(dev);
		videobuf_mmap_free(&fh->vb_vidq);

drivers/staging/tm6000/tm6000.h

+3 −1

Original line number	Diff line number	Diff line
		@@ -189,7 +189,9 @@ struct tm6000_core {
		int users;

		/* various device info */
		unsigned int resources;
		struct tm6000_fh resources; / Points to fh that is streaming */
		bool is_res_read;

		struct video_device *vfd;
		struct tm6000_dmaqueue vidq;
		struct v4l2_device v4l2_dev;