We may end up in i915_ttm_bo_destroy() in an error path before the
object is fully initialized. In that case it's not correct to call
__i915_gem_free_object(), because that function
a) Assumes the gem object refcount is 0, which it isn't.
b) frees the placements which are owned by the caller until the
init_object() region ops returns successfully. Fix this by providing
a lightweight cleanup function i915_gem_object_fini() which is also
called by __i915_gem_free_object().
While doing this, also make sure we call dma_resv_fini() as part of
ordinary object destruction and not from the RCU callback that frees
the object. This will help track down bugs where the object is
incorrectly
locked from an RCU lookup.
Finally, make sure the object isn't put on the region list until it's
either locked or fully initialized in order to block list processing of
partially initialized objects.
Signed-off-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gem/i915_gem_object.c | 18 ++++++++++--
drivers/gpu/drm/i915/gem/i915_gem_object.h | 3 ++
drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 32 +++++++++++++---------
3 files changed, 38 insertions(+), 15 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c
b/drivers/gpu/drm/i915/gem/i915_gem_object.c
index 6fb9afb65034..244e555f9bba 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
@@ -89,6 +89,20 @@ void i915_gem_object_init(struct
drm_i915_gem_object *obj,
mutex_init(&obj->mm.get_dma_page.lock);
}
+/**
+ * i915_gem_object_fini - Clean up a GEM object initialization
+ * @obj: The gem object cleanup
+ *
+ * This function cleans up gem object fields that are set up by
+ * drm_gem_private_object_init() and i915_gem_object_init().
+ */
+void i915_gem_object_fini(struct drm_i915_gem_object *obj)
+{
+ mutex_destroy(&obj->mm.get_page.lock);
+ mutex_destroy(&obj->mm.get_dma_page.lock);
+ dma_resv_fini(&obj->base._resv);
+}
+
/**
* Mark up the object's coherency levels for a given cache_level
* @obj: #drm_i915_gem_object
@@ -174,7 +188,6 @@ void __i915_gem_free_object_rcu(struct rcu_head
*head)
container_of(head, typeof(*obj), rcu);
struct drm_i915_private *i915 = to_i915(obj->base.dev);
- dma_resv_fini(&obj->base._resv);
i915_gem_object_free(obj);
GEM_BUG_ON(!atomic_read(&i915->mm.free_count));
@@ -223,7 +236,6 @@ void __i915_gem_free_object(struct
drm_i915_gem_object *obj)
obj_link))) {
GEM_BUG_ON(vma->obj != obj);
spin_unlock(&obj->vma.lock);
-
__i915_vma_put(vma);
