drm: Prune GEM vma entries

Hook the GEM vm open/close ops into the generic drm vm open/close so
that the private vma entries are created and destroy appropriately.
Fixes the leak of the drm_vma_entries during the lifetime of the filp.
Reported-by: Matt Mackall <mpm@selenic.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_gem.c

@@ -528,6 +528,10 @@ void drm_gem_vm_open(struct vm_area_struct *vma)
 	struct drm_gem_object *obj = vma->vm_private_data;
 
 	drm_gem_object_reference(obj);
+
+	mutex_lock(&obj->dev->struct_mutex);
+	drm_vm_open_locked(vma);
+	mutex_unlock(&obj->dev->struct_mutex);
 }
 EXPORT_SYMBOL(drm_gem_vm_open);
 
@@ -535,7 +539,10 @@ void drm_gem_vm_close(struct vm_area_struct *vma)
 {
 	struct drm_gem_object *obj = vma->vm_private_data;
 
-	drm_gem_object_unreference_unlocked(obj);
+	mutex_lock(&obj->dev->struct_mutex);
+	drm_vm_close_locked(vma);
+	drm_gem_object_unreference(obj);
+	mutex_unlock(&obj->dev->struct_mutex);
 }
 EXPORT_SYMBOL(drm_gem_vm_close);
 

drivers/gpu/drm/drm_vm.c

@@ -433,15 +433,7 @@ static void drm_vm_open(struct vm_area_struct *vma)
 	mutex_unlock(&dev->struct_mutex);
 }
 
-/**
- * \c close method for all virtual memory types.
- *
- * \param vma virtual memory area.
- *
- * Search the \p vma private data entry in drm_device::vmalist, unlink it, and
- * free it.
- */
-static void drm_vm_close(struct vm_area_struct *vma)
+void drm_vm_close_locked(struct vm_area_struct *vma)
 {
 	struct drm_file *priv = vma->vm_file->private_data;
 	struct drm_device *dev = priv->minor->dev;
@@ -451,7 +443,6 @@ static void drm_vm_close(struct vm_area_struct *vma)
 		  vma->vm_start, vma->vm_end - vma->vm_start);
 	atomic_dec(&dev->vma_count);
 
-	mutex_lock(&dev->struct_mutex);
 	list_for_each_entry_safe(pt, temp, &dev->vmalist, head) {
 		if (pt->vma == vma) {
 			list_del(&pt->head);
@@ -459,6 +450,23 @@ static void drm_vm_close(struct vm_area_struct *vma)
 			break;
 		}
 	}
+}
+
+/**
+ * \c close method for all virtual memory types.
+ *
+ * \param vma virtual memory area.
+ *
+ * Search the \p vma private data entry in drm_device::vmalist, unlink it, and
+ * free it.
+ */
+static void drm_vm_close(struct vm_area_struct *vma)
+{
+	struct drm_file *priv = vma->vm_file->private_data;
+	struct drm_device *dev = priv->minor->dev;
+
+	mutex_lock(&dev->struct_mutex);
+	drm_vm_close_locked(vma);
 	mutex_unlock(&dev->struct_mutex);
 }
 

include/drm/drmP.h

@@ -1175,6 +1175,7 @@ extern int drm_release(struct inode *inode, struct file *filp);
 extern int drm_mmap(struct file *filp, struct vm_area_struct *vma);
 extern int drm_mmap_locked(struct file *filp, struct vm_area_struct *vma);
 extern void drm_vm_open_locked(struct vm_area_struct *vma);
+extern void drm_vm_close_locked(struct vm_area_struct *vma);
 extern resource_size_t drm_core_get_map_ofs(struct drm_local_map * map);
 extern resource_size_t drm_core_get_reg_ofs(struct drm_device *dev);
 extern unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait);