drm/i915: Only close vma we open

The history of i915_vma_close() is confusing, as is its use. As the
lifetime of the i915_vma is currently bounded by the object it is
attached to, we needed a means of identify when a vma was no longer in
use by userspace (via the user's fd). This is further complicated by
that only ppgtt vma should be closed at the user's behest, as the ggtt
were always shared.

Now that we attach the vma to a lut on the user's context, the open
count does indicate how many unique and open context/vm are referencing
this vma from the user. As such, we can and should just use the
open_count to track when the vma is still in use by userspace.

It's a poor man's replacement for reference counting.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/1193
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200422190558.30509-1-chris@chris-wilson.co.uk

1 files changed, 10 insertions, 22 deletions

diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
index 5d2a02fcf595..2e471500a646 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
@@ -331,9 +331,6 @@ static void close_object_list(struct list_head *objects,
 		vma = i915_vma_instance(obj, vm, NULL);
 		if (!IS_ERR(vma))
 			ignored = i915_vma_unbind(vma);
-		/* Only ppgtt vma may be closed before the object is freed */
-		if (!IS_ERR(vma) && !i915_vma_is_ggtt(vma))
-			i915_vma_close(vma);
 
 		list_del(&obj->st_link);
 		i915_gem_object_put(obj);
@@ -591,7 +588,7 @@ static int walk_hole(struct i915_address_space *vm,
 				pr_err("%s bind failed at %llx + %llx [hole %llx- %llx] with err=%d\n",
 				       __func__, addr, vma->size,
 				       hole_start, hole_end, err);
-				goto err_close;
+				goto err_put;
 			}
 			i915_vma_unpin(vma);
 
@@ -600,14 +597,14 @@ static int walk_hole(struct i915_address_space *vm,
 				pr_err("%s incorrect at %llx + %llx\n",
 				       __func__, addr, vma->size);
 				err = -EINVAL;
-				goto err_close;
+				goto err_put;
 			}
 
 			err = i915_vma_unbind(vma);
 			if (err) {
 				pr_err("%s unbind failed at %llx + %llx  with err=%d\n",
 				       __func__, addr, vma->size, err);
-				goto err_close;
+				goto err_put;
 			}
 
 			GEM_BUG_ON(drm_mm_node_allocated(&vma->node));
@@ -616,13 +613,10 @@ static int walk_hole(struct i915_address_space *vm,
 					"%s timed out at %llx\n",
 					__func__, addr)) {
 				err = -EINTR;
-				goto err_close;
+				goto err_put;
 			}
 		}
 
-err_close:
-		if (!i915_vma_is_ggtt(vma))
-			i915_vma_close(vma);
 err_put:
 		i915_gem_object_put(obj);
 		if (err)
@@ -675,7 +669,7 @@ static int pot_hole(struct i915_address_space *vm,
 				       addr,
 				       hole_start, hole_end,
 				       err);
-				goto err;
+				goto err_obj;
 			}
 
 			if (!drm_mm_node_allocated(&vma->node) ||
@@ -685,7 +679,7 @@ static int pot_hole(struct i915_address_space *vm,
 				i915_vma_unpin(vma);
 				err = i915_vma_unbind(vma);
 				err = -EINVAL;
-				goto err;
+				goto err_obj;
 			}
 
 			i915_vma_unpin(vma);
@@ -697,13 +691,10 @@ static int pot_hole(struct i915_address_space *vm,
 				"%s timed out after %d/%d\n",
 				__func__, pot, fls64(hole_end - 1) - 1)) {
 			err = -EINTR;
-			goto err;
+			goto err_obj;
 		}
 	}
 
-err:
-	if (!i915_vma_is_ggtt(vma))
-		i915_vma_close(vma);
 err_obj:
 	i915_gem_object_put(obj);
 	return err;
@@ -778,7 +769,7 @@ static int drunk_hole(struct i915_address_space *vm,
 				       addr, BIT_ULL(size),
 				       hole_start, hole_end,
 				       err);
-				goto err;
+				goto err_obj;
 			}
 
 			if (!drm_mm_node_allocated(&vma->node) ||
@@ -788,7 +779,7 @@ static int drunk_hole(struct i915_address_space *vm,
 				i915_vma_unpin(vma);
 				err = i915_vma_unbind(vma);
 				err = -EINVAL;
-				goto err;
+				goto err_obj;
 			}
 
 			i915_vma_unpin(vma);
@@ -799,13 +790,10 @@ static int drunk_hole(struct i915_address_space *vm,
 					"%s timed out after %d/%d\n",
 					__func__, n, count)) {
 				err = -EINTR;
-				goto err;
+				goto err_obj;
 			}
 		}
 
-err:
-		if (!i915_vma_is_ggtt(vma))
-			i915_vma_close(vma);
 err_obj:
 		i915_gem_object_put(obj);
 		kfree(order);