[media] cx88: don't use atomic_t for core->mpeg_users

mpeg_users is always read or written with core->lock held except
in mpeg_release (where it looks like a bug). A plain int is simpler
and faster.

Tested-by: Andi Huber <[e-mail]>
Tested-by: Marlon de Boer <[e-mail]>
Signed-off-by: Jonathan Nieder <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/video/cx88/cx88-blackbird.c

···
 		return err;
 	}
 
-	if (!atomic_read(&dev->core->mpeg_users) && blackbird_initialize_codec(dev) < 0) {
+	if (!dev->core->mpeg_users && blackbird_initialize_codec(dev) < 0) {
 		drv->request_release(drv);
 		mutex_unlock(&dev->core->lock);
 		return -EINVAL;
···
 	cx88_set_scale(dev->core, dev->width, dev->height,
 			fh->mpegq.field);
 
-	atomic_inc(&dev->core->mpeg_users);
+	dev->core->mpeg_users++;
 	mutex_unlock(&dev->core->lock);
 	return 0;
 }
···
 	struct cx8802_dev *dev = fh->dev;
 	struct cx8802_driver *drv = NULL;
 
-	if (dev->mpeg_active && atomic_read(&dev->core->mpeg_users) == 1)
+	mutex_lock(&dev->core->lock);
+
+	if (dev->mpeg_active && dev->core->mpeg_users == 1)
 		blackbird_stop_codec(dev);
 
 	cx8802_cancel_buffers(fh->dev);
···
 
 	videobuf_mmap_free(&fh->mpegq);
 
-	mutex_lock(&dev->core->lock);
 	file->private_data = NULL;
 	kfree(fh);
 
···
 	if (drv)
 		drv->request_release(drv);
 
-	atomic_dec(&dev->core->mpeg_users);
+	dev->core->mpeg_users--;
 
 	mutex_unlock(&dev->core->lock);
 

drivers/media/video/cx88/cx88.h

···
 	/* various v4l controls */
 	u32                        freq;
 	atomic_t		   users;
-	atomic_t                   mpeg_users;
+	int                        mpeg_users;
 
 	/* cx88-video needs to access cx8802 for hybrid tuner pll access. */
 	struct cx8802_dev          *dvbdev;