drm/i915: Keep refs on the object over the lifetime of vmas for GTT mmap.

This fixes potential fault at fault time if the object was unreferenced
while the mapping still existed.  Now, while the mmap_offset only lives
for the lifetime of the object, the object also stays alive while a vma
exists that needs it.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 25 insertions, 18 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 078858178832..ac534c9a2f81 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -607,8 +607,6 @@ int i915_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
         case -EAGAIN:
                 return VM_FAULT_OOM;
         case -EFAULT:
-        case -EBUSY:
-                DRM_ERROR("can't insert pfn??  fault or busy...\n");
                 return VM_FAULT_SIGBUS;
         default:
                 return VM_FAULT_NOPAGE;
@@ -684,6 +682,30 @@ out_free_list:
         return ret;
 }
 
+static void
+i915_gem_free_mmap_offset(struct drm_gem_object *obj)
+{
+        struct drm_device *dev = obj->dev;
+        struct drm_i915_gem_object *obj_priv = obj->driver_private;
+        struct drm_gem_mm *mm = dev->mm_private;
+        struct drm_map_list *list;
+
+        list = &obj->map_list;
+        drm_ht_remove_item(&mm->offset_hash, &list->hash);
+
+        if (list->file_offset_node) {
+                drm_mm_put_block(list->file_offset_node);
+                list->file_offset_node = NULL;
+        }
+
+        if (list->map) {
+                drm_free(list->map, sizeof(struct drm_map), DRM_MEM_DRIVER);
+                list->map = NULL;
+        }
+
+        obj_priv->mmap_offset = 0;
+}
+
 /**
  * i915_gem_get_gtt_alignment - return required GTT alignment for an object
  * @obj: object to check
@@ -2896,9 +2918,6 @@ int i915_gem_init_object(struct drm_gem_object *obj)
 void i915_gem_free_object(struct drm_gem_object *obj)
 {
         struct drm_device *dev = obj->dev;
-        struct drm_gem_mm *mm = dev->mm_private;
-        struct drm_map_list *list;
-        struct drm_map *map;
         struct drm_i915_gem_object *obj_priv = obj->driver_private;
 
         while (obj_priv->pin_count > 0)
@@ -2909,19 +2928,7 @@ void i915_gem_free_object(struct drm_gem_object *obj)
 
         i915_gem_object_unbind(obj);
 
-        list = &obj->map_list;
-        drm_ht_remove_item(&mm->offset_hash, &list->hash);
-
-        if (list->file_offset_node) {
-                drm_mm_put_block(list->file_offset_node);
-                list->file_offset_node = NULL;
-        }
-
-        map = list->map;
-        if (map) {
-                drm_free(map, sizeof(*map), DRM_MEM_DRIVER);
-                list->map = NULL;
-        }
+        i915_gem_free_mmap_offset(obj);
 
         drm_free(obj_priv->page_cpu_valid, 1, DRM_MEM_DRIVER);
         drm_free(obj->driver_private, 1, DRM_MEM_DRIVER);