IB/uverbs: Use uverbs_api to manage the object type inside the uobject

Currently the struct uverbs_obj_type stored in the ib_uobject is part of
the .rodata segment of the module that defines the object. This is a
problem if drivers define new uapi objects as we will be left with a
dangling pointer after device disassociation.

Switch the uverbs_obj_type for struct uverbs_api_object, which is
allocated memory that is part of the uverbs_api and is guaranteed to
always exist. Further this moves the 'type_class' into this memory which
means access to the IDR/FD function pointers is also guaranteed. Drivers
cannot define new types.

This makes it safe to continue to use all uobjects, including driver
defined ones, after disassociation.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

3 files changed, 22 insertions, 19 deletions

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 3b07201b9a80..5d404c20b49f 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1524,7 +1524,7 @@ struct ib_uobject {
 	atomic_t		usecnt;		/* protects exclusive access */
 	struct rcu_head		rcu;		/* kfree_rcu() overhead */
 
-	const struct uverbs_obj_type *type;
+	const struct uverbs_api_object *uapi_object;
 };
 
 struct ib_udata {
diff --git a/include/rdma/uverbs_std_types.h b/include/rdma/uverbs_std_types.h
index 64ee2545dd3d..3b00231cc084 100644
--- a/include/rdma/uverbs_std_types.h
+++ b/include/rdma/uverbs_std_types.h
@@ -54,14 +54,15 @@ static inline const struct uverbs_object_tree_def *uverbs_default_get_objects(vo
  */
 #define _uobj_check_id(_id) ((_id) * typecheck(u32, _id))
 
-#define uobj_get_type(_object) UVERBS_OBJECT(_object).type_attrs
+#define uobj_get_type(_ufile, _object)                                         \
+	uapi_get_object((_ufile)->device->uapi, _object)
 
 #define uobj_get_read(_type, _id, _ufile)                                      \
-	rdma_lookup_get_uobject(uobj_get_type(_type), _ufile,                  \
+	rdma_lookup_get_uobject(uobj_get_type(_ufile, _type), _ufile,          \
 				_uobj_check_id(_id), UVERBS_LOOKUP_READ)
 
 #define ufd_get_read(_type, _fdnum, _ufile)                                    \
-	rdma_lookup_get_uobject(uobj_get_type(_type), _ufile,                  \
+	rdma_lookup_get_uobject(uobj_get_type(_ufile, _type), _ufile,          \
 				(_fdnum)*typecheck(s32, _fdnum),               \
 				UVERBS_LOOKUP_READ)
 
@@ -76,20 +77,21 @@ static inline void *_uobj_get_obj_read(struct ib_uobject *uobj)
 		uobj_get_read(_type, _id, _ufile)))
 
 #define uobj_get_write(_type, _id, _ufile)                                     \
-	rdma_lookup_get_uobject(uobj_get_type(_type), _ufile,                  \
+	rdma_lookup_get_uobject(uobj_get_type(_ufile, _type), _ufile,          \
 				_uobj_check_id(_id), UVERBS_LOOKUP_WRITE)
 
-int __uobj_perform_destroy(const struct uverbs_obj_type *type, u32 id,
+int __uobj_perform_destroy(const struct uverbs_api_object *obj, u32 id,
 			   struct ib_uverbs_file *ufile, int success_res);
 #define uobj_perform_destroy(_type, _id, _ufile, _success_res)                 \
-	__uobj_perform_destroy(uobj_get_type(_type), _uobj_check_id(_id),      \
-			       _ufile, _success_res)
+	__uobj_perform_destroy(uobj_get_type(_ufile, _type),                   \
+			       _uobj_check_id(_id), _ufile, _success_res)
 
-struct ib_uobject *__uobj_get_destroy(const struct uverbs_obj_type *type,
+struct ib_uobject *__uobj_get_destroy(const struct uverbs_api_object *obj,
 				      u32 id, struct ib_uverbs_file *ufile);
 
 #define uobj_get_destroy(_type, _id, _ufile)                                   \
-	__uobj_get_destroy(uobj_get_type(_type), _uobj_check_id(_id), _ufile)
+	__uobj_get_destroy(uobj_get_type(_ufile, _type), _uobj_check_id(_id),  \
+			   _ufile)
 
 static inline void uobj_put_destroy(struct ib_uobject *uobj)
 {
@@ -124,11 +126,11 @@ static inline void uobj_alloc_abort(struct ib_uobject *uobj)
 	rdma_alloc_abort_uobject(uobj);
 }
 
-static inline struct ib_uobject *__uobj_alloc(const struct uverbs_obj_type *type,
-					      struct ib_uverbs_file *ufile,
-					      struct ib_device **ib_dev)
+static inline struct ib_uobject *
+__uobj_alloc(const struct uverbs_api_object *obj, struct ib_uverbs_file *ufile,
+	     struct ib_device **ib_dev)
 {
-	struct ib_uobject *uobj = rdma_alloc_begin_uobject(type, ufile);
+	struct ib_uobject *uobj = rdma_alloc_begin_uobject(obj, ufile);
 
 	if (!IS_ERR(uobj))
 		*ib_dev = uobj->context->device;
@@ -136,7 +138,7 @@ static inline struct ib_uobject *__uobj_alloc(const struct uverbs_obj_type *type
 }
 
 #define uobj_alloc(_type, _ufile, _ib_dev)                                     \
-	__uobj_alloc(uobj_get_type(_type), _ufile, _ib_dev)
+	__uobj_alloc(uobj_get_type(_ufile, _type), _ufile, _ib_dev)
 
 #endif
 
diff --git a/include/rdma/uverbs_types.h b/include/rdma/uverbs_types.h
index 1ab9a85eebd9..acb1bfa3cc99 100644
--- a/include/rdma/uverbs_types.h
+++ b/include/rdma/uverbs_types.h
@@ -37,6 +37,7 @@
 #include <rdma/ib_verbs.h>
 
 struct uverbs_obj_type;
+struct uverbs_api_object;
 
 enum rdma_lookup_mode {
 	UVERBS_LOOKUP_READ,
@@ -81,14 +82,14 @@ enum rdma_lookup_mode {
  * alloc_abort returns.
  */
 struct uverbs_obj_type_class {
-	struct ib_uobject *(*alloc_begin)(const struct uverbs_obj_type *type,
+	struct ib_uobject *(*alloc_begin)(const struct uverbs_api_object *obj,
 					  struct ib_uverbs_file *ufile);
 	/* This consumes the kref on uobj */
 	int (*alloc_commit)(struct ib_uobject *uobj);
 	/* This does not consume the kref on uobj */
 	void (*alloc_abort)(struct ib_uobject *uobj);
 
-	struct ib_uobject *(*lookup_get)(const struct uverbs_obj_type *type,
+	struct ib_uobject *(*lookup_get)(const struct uverbs_api_object *obj,
 					 struct ib_uverbs_file *ufile, s64 id,
 					 enum rdma_lookup_mode mode);
 	void (*lookup_put)(struct ib_uobject *uobj, enum rdma_lookup_mode mode);
@@ -128,12 +129,12 @@ struct uverbs_obj_idr_type {
 					   enum rdma_remove_reason why);
 };
 
-struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_obj_type *type,
+struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_api_object *obj,
 					   struct ib_uverbs_file *ufile, s64 id,
 					   enum rdma_lookup_mode mode);
 void rdma_lookup_put_uobject(struct ib_uobject *uobj,
 			     enum rdma_lookup_mode mode);
-struct ib_uobject *rdma_alloc_begin_uobject(const struct uverbs_obj_type *type,
+struct ib_uobject *rdma_alloc_begin_uobject(const struct uverbs_api_object *obj,
 					    struct ib_uverbs_file *ufile);
 void rdma_alloc_abort_uobject(struct ib_uobject *uobj);
 int __must_check rdma_alloc_commit_uobject(struct ib_uobject *uobj);