IB/uverbs: Remove rdma_explicit_destroy() from the ioctl methods

The core code will destroy the HW object on behalf of the method, if the
method provides an implementation it must simply copy data from the stub
uobj into the response. Destroy methods cannot touch the HW object.
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/rdma_core.c

@@ -924,10 +924,7 @@ int uverbs_finalize_object(struct ib_uobject *uobj,
 		rdma_lookup_put_uobject(uobj, true);
 		break;
 	case UVERBS_ACCESS_DESTROY:
-		if (commit)
-			ret = rdma_remove_commit_uobject(uobj);
-		else
-			rdma_lookup_put_uobject(uobj, true);
+		rdma_lookup_put_uobject(uobj, true);
 		break;
 	case UVERBS_ACCESS_NEW:
 		if (commit)

drivers/infiniband/core/uverbs_ioctl.c

@@ -51,6 +51,7 @@ static int uverbs_process_attr(struct ib_uverbs_file *ufile,
 			       u16 attr_id,
 			       const struct uverbs_attr_spec_hash *attr_spec_bucket,
 			       struct uverbs_attr_bundle_hash *attr_bundle_h,
+			       struct uverbs_obj_attr **destroy_attr,
 			       struct ib_uverbs_attr __user *uattr_ptr)
 {
 	const struct uverbs_attr_spec *spec;
@@ -148,6 +149,12 @@ static int uverbs_process_attr(struct ib_uverbs_file *ufile,
 		if (!object)
 			return -EINVAL;
 
+		/* specs are allowed to have only one destroy attribute */
+		WARN_ON(spec->u.obj.access == UVERBS_ACCESS_DESTROY &&
+			*destroy_attr);
+		if (spec->u.obj.access == UVERBS_ACCESS_DESTROY)
+			*destroy_attr = o_attr;
+
 		/*
 		 * The type of uattr->data is u64 for UVERBS_ATTR_TYPE_IDR and
 		 * s64 for UVERBS_ATTR_TYPE_FD. We can cast the u64 to s64
@@ -235,6 +242,7 @@ static int uverbs_uattrs_process(struct ib_uverbs_file *ufile,
 				 size_t num_uattrs,
 				 const struct uverbs_method_spec *method,
 				 struct uverbs_attr_bundle *attr_bundle,
+				 struct uverbs_obj_attr **destroy_attr,
 				 struct ib_uverbs_attr __user *uattr_ptr)
 {
 	size_t i;
@@ -268,7 +276,8 @@ static int uverbs_uattrs_process(struct ib_uverbs_file *ufile,
 		attr_spec_bucket = method->attr_buckets[ret];
 		ret = uverbs_process_attr(ufile, uattr, attr_id,
 					  attr_spec_bucket,
-					  &attr_bundle->hash[ret], uattr_ptr++);
+					  &attr_bundle->hash[ret], destroy_attr,
+					  uattr_ptr++);
 		if (ret) {
 			uverbs_finalize_attrs(attr_bundle,
 					      method->attr_buckets,
@@ -322,9 +331,11 @@ static int uverbs_handle_method(struct ib_uverbs_attr __user *uattr_ptr,
 	int ret;
 	int finalize_ret;
 	int num_given_buckets;
+	struct uverbs_obj_attr *destroy_attr = NULL;
 
-	num_given_buckets = uverbs_uattrs_process(
-		ufile, uattrs, num_uattrs, method_spec, attr_bundle, uattr_ptr);
+	num_given_buckets =
+		uverbs_uattrs_process(ufile, uattrs, num_uattrs, method_spec,
+				      attr_bundle, &destroy_attr, uattr_ptr);
 	if (num_given_buckets <= 0)
 		return -EINVAL;
 
@@ -333,7 +344,18 @@ static int uverbs_handle_method(struct ib_uverbs_attr __user *uattr_ptr,
 	if (ret)
 		goto cleanup;
 
+	/*
+	 * We destroy the HW object before invoking the handler, handlers do
+	 * not get to manipulate the HW objects.
+	 */
+	if (destroy_attr) {
+		ret = rdma_explicit_destroy(destroy_attr->uobject);
+		if (ret)
+			goto cleanup;
+	}
+
 	ret = method_spec->handler(ibdev, ufile, attr_bundle);
+
 cleanup:
 	finalize_ret = uverbs_finalize_attrs(attr_bundle,
 					     method_spec->attr_buckets,

drivers/infiniband/core/uverbs_std_types_cq.c

@@ -179,21 +179,12 @@ static int UVERBS_HANDLER(UVERBS_METHOD_CQ_DESTROY)(struct ib_device *ib_dev,
 {
 	struct ib_uobject *uobj =
 		uverbs_attr_get_uobject(attrs, UVERBS_ATTR_DESTROY_CQ_HANDLE);
-	struct ib_uverbs_destroy_cq_resp resp;
-	struct ib_ucq_object *obj;
-	int ret;
-
-	if (IS_ERR(uobj))
-		return PTR_ERR(uobj);
-
-	obj = container_of(uobj, struct ib_ucq_object, uobject);
-
-	ret = rdma_explicit_destroy(uobj);
-	if (ret)
-		return ret;
-
-	resp.comp_events_reported  = obj->comp_events_reported;
-	resp.async_events_reported = obj->async_events_reported;
+	struct ib_ucq_object *obj =
+		container_of(uobj, struct ib_ucq_object, uobject);
+	struct ib_uverbs_destroy_cq_resp resp = {
+		.comp_events_reported = obj->comp_events_reported,
+		.async_events_reported = obj->async_events_reported
+	};
 
 	return uverbs_copy_to(attrs, UVERBS_ATTR_DESTROY_CQ_RESP, &resp,
 			      sizeof(resp));