diff options
Diffstat (limited to 'drivers/gpu/drm/drm_gem.c')
-rw-r--r-- | drivers/gpu/drm/drm_gem.c | 47 |
1 files changed, 30 insertions, 17 deletions
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index 3c2d4ab..64353d4 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -763,7 +763,8 @@ EXPORT_SYMBOL(drm_gem_object_release); void drm_gem_object_free(struct kref *kref) { - struct drm_gem_object *obj = (struct drm_gem_object *) kref; + struct drm_gem_object *obj = + container_of(kref, struct drm_gem_object, refcount); struct drm_device *dev = obj->dev; WARN_ON(!mutex_is_locked(&dev->struct_mutex)); @@ -810,8 +811,6 @@ EXPORT_SYMBOL(drm_gem_vm_close); * drm_gem_mmap() prevents unprivileged users from mapping random objects. So * callers must verify access restrictions before calling this helper. * - * NOTE: This function has to be protected with dev->struct_mutex - * * Return 0 or success or -EINVAL if the object size is smaller than the VMA * size, or if no gem_vm_ops are provided. */ @@ -820,8 +819,6 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size, { struct drm_device *dev = obj->dev; - lockdep_assert_held(&dev->struct_mutex); - /* Check for valid size. */ if (obj_size < vma->vm_end - vma->vm_start) return -EINVAL; @@ -865,30 +862,46 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma) { struct drm_file *priv = filp->private_data; struct drm_device *dev = priv->minor->dev; - struct drm_gem_object *obj; + struct drm_gem_object *obj = NULL; struct drm_vma_offset_node *node; int ret; if (drm_device_is_unplugged(dev)) return -ENODEV; - mutex_lock(&dev->struct_mutex); + drm_vma_offset_lock_lookup(dev->vma_offset_manager); + node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager, + vma->vm_pgoff, + vma_pages(vma)); + if (likely(node)) { + obj = container_of(node, struct drm_gem_object, vma_node); + /* + * When the object is being freed, after it hits 0-refcnt it + * proceeds to tear down the object. In the process it will + * attempt to remove the VMA offset and so acquire this + * mgr->vm_lock. Therefore if we find an object with a 0-refcnt + * that matches our range, we know it is in the process of being + * destroyed and will be freed as soon as we release the lock - + * so we have to check for the 0-refcnted object and treat it as + * invalid. + */ + if (!kref_get_unless_zero(&obj->refcount)) + obj = NULL; + } + drm_vma_offset_unlock_lookup(dev->vma_offset_manager); - node = drm_vma_offset_exact_lookup(dev->vma_offset_manager, - vma->vm_pgoff, - vma_pages(vma)); - if (!node) { - mutex_unlock(&dev->struct_mutex); + if (!obj) return -EINVAL; - } else if (!drm_vma_node_is_allowed(node, filp)) { - mutex_unlock(&dev->struct_mutex); + + if (!drm_vma_node_is_allowed(node, filp)) { + drm_gem_object_unreference_unlocked(obj); return -EACCES; } - obj = container_of(node, struct drm_gem_object, vma_node); - ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT, vma); + ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT, + vma); - mutex_unlock(&dev->struct_mutex); + drm_gem_object_unreference_unlocked(obj); return ret; } |