drm: rip out dev->ioctl_count tracking

Now dev->ioctl_count tries to prevent the device from disappearing if
it's still in use. And if we'd actually need this code it would be
hopelessly racy and broken.

But luckily the vfs already takes care of this. So we can just rip it
out.

Signed-off-by: Daniel Vetter <[e-mail]>
Signed-off-by: Dave Airlie <[e-mail]>

drivers/gpu/drm/drm_drv.c

···
 	if (drm_device_is_unplugged(dev))
 		return -ENODEV;
 
-	atomic_inc(&dev->ioctl_count);
 	++file_priv->ioctl_count;
 
 	if ((nr >= DRM_CORE_IOCTL_COUNT) &&
···
 
 	if (kdata != stack_kdata)
 		kfree(kdata);
-	atomic_dec(&dev->ioctl_count);
 	if (retcode)
 		DRM_DEBUG("ret = %d\n", retcode);
 	return retcode;

drivers/gpu/drm/drm_fops.c

···
 	if (drm_core_check_feature(dev, DRIVER_MODESET))
 		return;
 
-	atomic_set(&dev->ioctl_count, 0);
 	atomic_set(&dev->vma_count, 0);
 
 	dev->sigdata.lock = NULL;
···
 	 */
 
 	if (!--dev->open_count) {
-		if (atomic_read(&dev->ioctl_count)) {
-			DRM_ERROR("Device busy: %d\n",
-				  atomic_read(&dev->ioctl_count));
-			retcode = -EBUSY;
-		} else
-			retcode = drm_lastclose(dev);
+		retcode = drm_lastclose(dev);
 		if (drm_device_is_unplugged(dev))
 			drm_put_dev(dev);
 	}

include/drm/drmP.h

···
 	/** \name Usage Counters */
 	/*@{ */
 	int open_count;			/**< Outstanding files open */
-	atomic_t ioctl_count;		/**< Outstanding IOCTLs pending */
 	atomic_t vma_count;		/**< Outstanding vma areas open */
 	int buf_use;			/**< Buffers in use -- cannot alloc */
 	atomic_t buf_alloc;		/**< Buffer allocation in progress */