[PATCH 3/6] RDMA/core: Remove uverbs_async_event_release()

[Jason Gunthorpe <jgg@nvidia.com>]

Instead of having an alternative fops release always use the standard
uverbs_uobject_fd_release() and route the special async behavior back up
through uverbs_obj_fd_type ops pointer.

This removes a dependency where the technically lower level rdma_core.c is
referring to a symbol from uverbs_std_types_async_fd.c.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/infiniband/core/rdma_core.c           | 30 ++++++++++++++++---
 drivers/infiniband/core/uverbs.h              |  1 -
 drivers/infiniband/core/uverbs_main.c         |  2 +-
 .../core/uverbs_std_types_async_fd.c          | 22 +++++---------
 drivers/infiniband/core/uverbs_uapi.c         | 13 ++++++++
 include/rdma/uverbs_types.h                   |  8 ++++-
 6 files changed, 54 insertions(+), 22 deletions(-)

diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c
index 5018ec837056ff..71e3d58d26e654 100644
--- a/drivers/infiniband/core/rdma_core.c
+++ b/drivers/infiniband/core/rdma_core.c
@@ -465,8 +465,8 @@ alloc_begin_fd_uobject(const struct uverbs_api_object *obj,
 
 	fd_type =
 		container_of(obj->type_attrs, struct uverbs_obj_fd_type, type);
-	if (WARN_ON(fd_type->fops && fd_type->fops->release != &uverbs_uobject_fd_release &&
-		    fd_type->fops->release != &uverbs_async_event_release)) {
+	if (WARN_ON(fd_type->fops &&
+		    fd_type->fops->release != &uverbs_uobject_fd_release)) {
 		ret = ERR_PTR(-EINVAL);
 		goto err_fd;
 	}
@@ -846,13 +846,35 @@ int uverbs_uobject_release(struct ib_uobject *uobj)
  */
 int uverbs_uobject_fd_release(struct inode *inode, struct file *filp)
 {
+	void (*release_cleanup)(struct ib_uobject *uobj) = NULL;
+	struct ib_uobject *uobj = filp->private_data;
+	int ret;
+
 	/*
 	 * This can only happen if the fput came from alloc_abort_fd_uobject()
 	 */
-	if (!filp->private_data)
+	if (!uobj)
 		return 0;
 
-	return uverbs_uobject_release(filp->private_data);
+	/*
+	 * uverbs_disassociate_api() can NULL type_attrs after disassociate, but
+	 * it won't if release_cleanup is used.
+	 */
+	if (uobj->uapi_object->type_attrs)
+		release_cleanup = container_of(uobj->uapi_object->type_attrs,
+					       struct uverbs_obj_fd_type, type)
+					  ->release_cleanup;
+	if (release_cleanup)
+		uverbs_uobject_get(uobj);
+
+	ret = uverbs_uobject_release(uobj);
+
+	if (release_cleanup) {
+		release_cleanup(uobj);
+		uverbs_uobject_put(uobj);
+	}
+
+	return ret;
 }
 EXPORT_SYMBOL(uverbs_uobject_fd_release);
 
diff --git a/drivers/infiniband/core/uverbs.h b/drivers/infiniband/core/uverbs.h
index e353e195a49c74..31ce2e77fa3a64 100644
--- a/drivers/infiniband/core/uverbs.h
+++ b/drivers/infiniband/core/uverbs.h
@@ -203,7 +203,6 @@ void ib_uverbs_init_event_queue(struct ib_uverbs_event_queue *ev_queue);
 void ib_uverbs_init_async_event_file(struct ib_uverbs_async_event_file *ev_file);
 void ib_uverbs_free_event_queue(struct ib_uverbs_event_queue *event_queue);
 void ib_uverbs_flow_resources_free(struct ib_uflow_resources *uflow_res);
-int uverbs_async_event_release(struct inode *inode, struct file *filp);
 
 int ib_alloc_ucontext(struct uverbs_attr_bundle *attrs);
 int ib_init_ucontext(struct uverbs_attr_bundle *attrs);
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 15d8387718c050..a937d276c5c076 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -338,7 +338,7 @@ const struct file_operations uverbs_async_event_fops = {
 	.owner	 = THIS_MODULE,
 	.read	 = ib_uverbs_async_event_read,
 	.poll    = ib_uverbs_async_event_poll,
-	.release = uverbs_async_event_release,
+	.release = uverbs_uobject_fd_release,
 	.fasync  = ib_uverbs_async_event_fasync,
 };
 
diff --git a/drivers/infiniband/core/uverbs_std_types_async_fd.c b/drivers/infiniband/core/uverbs_std_types_async_fd.c
index cc24cfdf7aee66..671f510bca496f 100644
--- a/drivers/infiniband/core/uverbs_std_types_async_fd.c
+++ b/drivers/infiniband/core/uverbs_std_types_async_fd.c
@@ -32,14 +32,9 @@ static void uverbs_async_event_destroy_uobj(struct ib_uobject *uobj,
 					NULL, NULL);
 }
 
-int uverbs_async_event_release(struct inode *inode, struct file *filp)
+static void uverbs_async_event_free_event_queue(struct ib_uobject *uobj)
 {
 	struct ib_uverbs_async_event_file *event_file;
-	struct ib_uobject *uobj = filp->private_data;
-	int ret;
-
-	if (!uobj)
-		return uverbs_uobject_fd_release(inode, filp);
 
 	event_file =
 		container_of(uobj, struct ib_uverbs_async_event_file, uobj);
@@ -50,11 +45,7 @@ int uverbs_async_event_release(struct inode *inode, struct file *filp)
 	 * release. The user knows it has reached the end of the event stream
 	 * when it sees IB_EVENT_DEVICE_FATAL.
 	 */
-	uverbs_uobject_get(uobj);
-	ret = uverbs_uobject_fd_release(inode, filp);
 	ib_uverbs_free_event_queue(&event_file->ev_queue);
-	uverbs_uobject_put(uobj);
-	return ret;
 }
 
 DECLARE_UVERBS_NAMED_METHOD(
@@ -66,11 +57,12 @@ DECLARE_UVERBS_NAMED_METHOD(
 
 DECLARE_UVERBS_NAMED_OBJECT(
 	UVERBS_OBJECT_ASYNC_EVENT,
-	UVERBS_TYPE_ALLOC_FD(sizeof(struct ib_uverbs_async_event_file),
-			     uverbs_async_event_destroy_uobj,
-			     &uverbs_async_event_fops,
-			     "[infinibandevent]",
-			     O_RDONLY),
+	UVERBS_TYPE_ALLOC_FD_RELEASE(sizeof(struct ib_uverbs_async_event_file),
+				     uverbs_async_event_destroy_uobj,
+				     uverbs_async_event_free_event_queue,
+				     &uverbs_async_event_fops,
+				     "[infinibandevent]",
+				     O_RDONLY),
 	&UVERBS_METHOD(UVERBS_METHOD_ASYNC_EVENT_ALLOC));
 
 const struct uapi_definition uverbs_def_obj_async_fd[] = {
diff --git a/drivers/infiniband/core/uverbs_uapi.c b/drivers/infiniband/core/uverbs_uapi.c
index 31b248295854bd..4e2e556c8119b5 100644
--- a/drivers/infiniband/core/uverbs_uapi.c
+++ b/drivers/infiniband/core/uverbs_uapi.c
@@ -718,12 +718,25 @@ void uverbs_disassociate_api(struct uverbs_api *uapi)
 		if (uapi_key_is_object(iter.index)) {
 			struct uverbs_api_object *object_elm =
 				rcu_dereference_protected(*slot, true);
+			const struct uverbs_obj_type *type_attrs =
+				object_elm->type_attrs;
 
 			/*
 			 * Some type_attrs are in the driver module. We don't
 			 * bother to keep track of which since there should be
 			 * no use of this after disassociate.
+			 *
+			 * release_cleanup is the exception because
+			 * uverbs_uobject_fd_release() needs it. In this case
+			 * the module reference held by the fops will guarentee
+			 * the type_class remains valid too.
 			 */
+			if (type_attrs &&
+			    type_attrs->type_class == &uverbs_fd_class &&
+			    container_of(type_attrs, struct uverbs_obj_fd_type,
+					 type)->release_cleanup)
+				continue;
+
 			object_elm->type_attrs = NULL;
 		} else if (uapi_key_is_attr(iter.index)) {
 			struct uverbs_api_attr *elm =
diff --git a/include/rdma/uverbs_types.h b/include/rdma/uverbs_types.h
index 6a253b7dc5ea66..5a07f9a6dcd1f6 100644
--- a/include/rdma/uverbs_types.h
+++ b/include/rdma/uverbs_types.h
@@ -147,6 +147,7 @@ struct uverbs_obj_fd_type {
 	struct uverbs_obj_type  type;
 	void (*destroy_object)(struct ib_uobject *uobj,
 			       enum rdma_remove_reason why);
+	void (*release_cleanup)(struct ib_uobject *uobj);
 	const struct file_operations	*fops;
 	const char			*name;
 	int				flags;
@@ -190,7 +191,8 @@ int uverbs_uobject_release(struct ib_uobject *uobj);
 
 #define UVERBS_BUILD_BUG_ON(cond) (sizeof(char[1 - 2 * !!(cond)]) -	\
 				   sizeof(char))
-#define UVERBS_TYPE_ALLOC_FD(_obj_size, _destroy_object, _fops, _name, _flags) \
+#define UVERBS_TYPE_ALLOC_FD_RELEASE(_obj_size, _destroy_object,	\
+				     _release_cleanup, _fops, _name, _flags) \
 	((&((const struct uverbs_obj_fd_type)				\
 	 {.type = {							\
 		.type_class = &uverbs_fd_class,				\
@@ -199,9 +201,13 @@ int uverbs_uobject_release(struct ib_uobject *uobj);
 					    sizeof(struct ib_uobject)), \
 	 },								\
 	 .destroy_object = _destroy_object,				\
+	 .release_cleanup = _release_cleanup,				\
 	 .fops = _fops,							\
 	 .name = _name,							\
 	 .flags = _flags}))->type)
+#define UVERBS_TYPE_ALLOC_FD(_obj_size, _destroy_object, _fops, _name, _flags) \
+	UVERBS_TYPE_ALLOC_FD_RELEASE(_obj_size, _destroy_object, NULL,	\
+				     _fops, _name, _flags)
 #define UVERBS_TYPE_ALLOC_IDR_SZ(_size, _destroy_object)	\
 	((&((const struct uverbs_obj_idr_type)				\
 	 {.type = {							\
-- 
2.43.0