3 files changed, 34 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index 8ac7fbf..08d14df 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -300,6 +300,18 @@ static int drm_open_helper(struct inode *inode, struct file *filp,
 				goto out_free;
 			}
 		}
+		mutex_lock(&dev->struct_mutex);
+		if (dev->driver->master_set) {
+			ret = dev->driver->master_set(dev, priv, true);
+			if (ret) {
+				/* drop both references if this fails */
+				drm_master_put(&priv->minor->master);
+				drm_master_put(&priv->master);
+				mutex_unlock(&dev->struct_mutex);
+				goto out_free;
+			}
+		}
+		mutex_unlock(&dev->struct_mutex);
 	} else {
 		/* get a reference to the master */
 		priv->master = drm_master_get(priv->minor->master);
@@ -533,6 +545,8 @@ int drm_release(struct inode *inode, struct file *filp)
 
 		if (file_priv->minor->master == file_priv->master) {
 			/* drop the reference held my the minor */
+			if (dev->driver->master_drop)
+				dev->driver->master_drop(dev, file_priv, true);
 			drm_master_put(&file_priv->minor->master);
 		}
 	}
diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c
index adb864d..2c1b528 100644
--- a/drivers/gpu/drm/drm_stub.c
+++ b/drivers/gpu/drm/drm_stub.c
@@ -174,6 +174,8 @@ void drm_master_put(struct drm_master **master)
 int drm_setmaster_ioctl(struct drm_device *dev, void *data,
 			struct drm_file *file_priv)
 {
+	int ret = 0;
+
 	if (file_priv->is_master)
 		return 0;
 
@@ -188,6 +190,13 @@ int drm_setmaster_ioctl(struct drm_device *dev, void *data,
 		mutex_lock(&dev->struct_mutex);
 		file_priv->minor->master = drm_master_get(file_priv->master);
 		file_priv->is_master = 1;
+		if (dev->driver->master_set) {
+			ret = dev->driver->master_set(dev, file_priv, false);
+			if (unlikely(ret != 0)) {
+				file_priv->is_master = 0;
+				drm_master_put(&file_priv->minor->master);
+			}
+		}
 		mutex_unlock(&dev->struct_mutex);
 	}
 
@@ -204,6 +213,8 @@ int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
 		return -EINVAL;
 
 	mutex_lock(&dev->struct_mutex);
+	if (dev->driver->master_drop)
+		dev->driver->master_drop(dev, file_priv, false);
 	drm_master_put(&file_priv->minor->master);
 	file_priv->is_master = 0;
 	mutex_unlock(&dev->struct_mutex);
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 1b72a52..770772c 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -774,6 +774,15 @@ struct drm_driver {
 	/* Master routines */
 	int (*master_create)(struct drm_device *dev, struct drm_master *master);
 	void (*master_destroy)(struct drm_device *dev, struct drm_master *master);
+	/**
+	 * master_set is called whenever the minor master is set.
+	 * master_drop is called whenever the minor master is dropped.
+	 */
+
+	int (*master_set)(struct drm_device *dev, struct drm_file *file_priv,
+			  bool from_open);
+	void (*master_drop)(struct drm_device *dev, struct drm_file *file_priv,
+			    bool from_release);
 
 	int (*proc_init)(struct drm_minor *minor);
 	void (*proc_cleanup)(struct drm_minor *minor);