IB/uverbs: Use uverbs_api to manage the object type inside the uobject
authorJason Gunthorpe <jgg@mellanox.com>
Fri, 10 Aug 2018 02:14:37 +0000 (20:14 -0600)
committerJason Gunthorpe <jgg@mellanox.com>
Fri, 10 Aug 2018 22:06:24 +0000 (16:06 -0600)
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>
drivers/infiniband/core/rdma_core.c
drivers/infiniband/core/rdma_core.h
drivers/infiniband/core/uverbs_ioctl.c
include/rdma/ib_verbs.h
include/rdma/uverbs_std_types.h
include/rdma/uverbs_types.h

index 4235b9ddc2adaf7fc1d5e1fc8963e46a4befaea5..2814228ead39f0d8eb13ed906cbfdc39048cf2a3 100644 (file)
@@ -97,7 +97,7 @@ static void uverbs_uobject_free(struct kref *ref)
        struct ib_uobject *uobj =
                container_of(ref, struct ib_uobject, ref);
 
-       if (uobj->type->type_class->needs_kfree_rcu)
+       if (uobj->uapi_object->type_class->needs_kfree_rcu)
                kfree_rcu(uobj, rcu);
        else
                kfree(uobj);
@@ -180,7 +180,7 @@ static int uverbs_destroy_uobject(struct ib_uobject *uobj,
        assert_uverbs_usecnt(uobj, UVERBS_LOOKUP_WRITE);
 
        if (uobj->object) {
-               ret = uobj->type->type_class->destroy_hw(uobj, reason);
+               ret = uobj->uapi_object->type_class->destroy_hw(uobj, reason);
                if (ret) {
                        if (ib_is_destroy_retryable(ret, reason, uobj))
                                return ret;
@@ -197,7 +197,7 @@ static int uverbs_destroy_uobject(struct ib_uobject *uobj,
        if (reason == RDMA_REMOVE_ABORT) {
                WARN_ON(!list_empty(&uobj->list));
                WARN_ON(!uobj->context);
-               uobj->type->type_class->alloc_abort(uobj);
+               uobj->uapi_object->type_class->alloc_abort(uobj);
        }
 
        uobj->context = NULL;
@@ -210,7 +210,7 @@ static int uverbs_destroy_uobject(struct ib_uobject *uobj,
        if (reason != RDMA_REMOVE_DESTROY)
                atomic_set(&uobj->usecnt, 0);
        else
-               uobj->type->type_class->remove_handle(uobj);
+               uobj->uapi_object->type_class->remove_handle(uobj);
 
        if (!list_empty(&uobj->list)) {
                spin_lock_irqsave(&ufile->uobjects_lock, flags);
@@ -268,13 +268,13 @@ out_unlock:
  * with a NULL object pointer. The caller must pair this with
  * uverbs_put_destroy.
  */
-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)
 {
        struct ib_uobject *uobj;
        int ret;
 
-       uobj = rdma_lookup_get_uobject(type, ufile, id, UVERBS_LOOKUP_DESTROY);
+       uobj = rdma_lookup_get_uobject(obj, ufile, id, UVERBS_LOOKUP_DESTROY);
        if (IS_ERR(uobj))
                return uobj;
 
@@ -292,27 +292,22 @@ struct ib_uobject *__uobj_get_destroy(const struct uverbs_obj_type *type,
  * on success (negative errno on failure). For use by callers that do not need
  * the uobj.
  */
-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)
 {
        struct ib_uobject *uobj;
 
-       uobj = __uobj_get_destroy(type, id, ufile);
+       uobj = __uobj_get_destroy(obj, id, ufile);
        if (IS_ERR(uobj))
                return PTR_ERR(uobj);
 
-       /*
-        * FIXME: After destroy this is not safe. We no longer hold the rwsem
-        * so disassociation could have completed and unloaded the module that
-        * backs the uobj->type pointer.
-        */
        rdma_lookup_put_uobject(uobj, UVERBS_LOOKUP_WRITE);
        return success_res;
 }
 
 /* alloc_uobj must be undone by uverbs_destroy_uobject() */
 static struct ib_uobject *alloc_uobj(struct ib_uverbs_file *ufile,
-                                    const struct uverbs_obj_type *type)
+                                    const struct uverbs_api_object *obj)
 {
        struct ib_uobject *uobj;
        struct ib_ucontext *ucontext;
@@ -321,7 +316,7 @@ static struct ib_uobject *alloc_uobj(struct ib_uverbs_file *ufile,
        if (IS_ERR(ucontext))
                return ERR_CAST(ucontext);
 
-       uobj = kzalloc(type->obj_size, GFP_KERNEL);
+       uobj = kzalloc(obj->type_attrs->obj_size, GFP_KERNEL);
        if (!uobj)
                return ERR_PTR(-ENOMEM);
        /*
@@ -331,7 +326,7 @@ static struct ib_uobject *alloc_uobj(struct ib_uverbs_file *ufile,
        uobj->ufile = ufile;
        uobj->context = ucontext;
        INIT_LIST_HEAD(&uobj->list);
-       uobj->type = type;
+       uobj->uapi_object = obj;
        /*
         * Allocated objects start out as write locked to deny any other
         * syscalls from accessing them until they are committed. See
@@ -368,7 +363,7 @@ static int idr_add_uobj(struct ib_uobject *uobj)
 
 /* Returns the ib_uobject or an error. The caller should check for IS_ERR. */
 static struct ib_uobject *
-lookup_get_idr_uobject(const struct uverbs_obj_type *type,
+lookup_get_idr_uobject(const struct uverbs_api_object *obj,
                       struct ib_uverbs_file *ufile, s64 id,
                       enum rdma_lookup_mode mode)
 {
@@ -401,15 +396,14 @@ free:
 }
 
 static struct ib_uobject *
-lookup_get_fd_uobject(const struct uverbs_obj_type *type,
+lookup_get_fd_uobject(const struct uverbs_api_object *obj,
                      struct ib_uverbs_file *ufile, s64 id,
                      enum rdma_lookup_mode mode)
 {
+       const struct uverbs_obj_fd_type *fd_type;
        struct file *f;
        struct ib_uobject *uobject;
        int fdno = id;
-       const struct uverbs_obj_fd_type *fd_type =
-               container_of(type, struct uverbs_obj_fd_type, type);
 
        if (fdno != id)
                return ERR_PTR(-EINVAL);
@@ -417,6 +411,11 @@ lookup_get_fd_uobject(const struct uverbs_obj_type *type,
        if (mode != UVERBS_LOOKUP_READ)
                return ERR_PTR(-EOPNOTSUPP);
 
+       if (!obj->type_attrs)
+               return ERR_PTR(-EIO);
+       fd_type =
+               container_of(obj->type_attrs, struct uverbs_obj_fd_type, type);
+
        f = fget(fdno);
        if (!f)
                return ERR_PTR(-EBADF);
@@ -436,18 +435,21 @@ lookup_get_fd_uobject(const struct uverbs_obj_type *type,
        return uobject;
 }
 
-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)
 {
        struct ib_uobject *uobj;
        int ret;
 
-       uobj = type->type_class->lookup_get(type, ufile, id, mode);
+       if (!obj)
+               return ERR_PTR(-EINVAL);
+
+       uobj = obj->type_class->lookup_get(obj, ufile, id, mode);
        if (IS_ERR(uobj))
                return uobj;
 
-       if (uobj->type != type) {
+       if (uobj->uapi_object != obj) {
                ret = -EINVAL;
                goto free;
        }
@@ -469,18 +471,19 @@ struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_obj_type *type,
 
        return uobj;
 free:
-       uobj->type->type_class->lookup_put(uobj, mode);
+       obj->type_class->lookup_put(uobj, mode);
        uverbs_uobject_put(uobj);
        return ERR_PTR(ret);
 }
 
-static struct ib_uobject *alloc_begin_idr_uobject(const struct uverbs_obj_type *type,
-                                                 struct ib_uverbs_file *ufile)
+static struct ib_uobject *
+alloc_begin_idr_uobject(const struct uverbs_api_object *obj,
+                       struct ib_uverbs_file *ufile)
 {
        int ret;
        struct ib_uobject *uobj;
 
-       uobj = alloc_uobj(ufile, type);
+       uobj = alloc_uobj(ufile, obj);
        if (IS_ERR(uobj))
                return uobj;
 
@@ -504,8 +507,9 @@ uobj_put:
        return ERR_PTR(ret);
 }
 
-static struct ib_uobject *alloc_begin_fd_uobject(const struct uverbs_obj_type *type,
-                                                struct ib_uverbs_file *ufile)
+static struct ib_uobject *
+alloc_begin_fd_uobject(const struct uverbs_api_object *obj,
+                      struct ib_uverbs_file *ufile)
 {
        int new_fd;
        struct ib_uobject *uobj;
@@ -514,7 +518,7 @@ static struct ib_uobject *alloc_begin_fd_uobject(const struct uverbs_obj_type *t
        if (new_fd < 0)
                return ERR_PTR(new_fd);
 
-       uobj = alloc_uobj(ufile, type);
+       uobj = alloc_uobj(ufile, obj);
        if (IS_ERR(uobj)) {
                put_unused_fd(new_fd);
                return uobj;
@@ -526,11 +530,14 @@ static struct ib_uobject *alloc_begin_fd_uobject(const struct uverbs_obj_type *t
        return uobj;
 }
 
-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)
 {
        struct ib_uobject *ret;
 
+       if (!obj)
+               return ERR_PTR(-EINVAL);
+
        /*
         * The hw_destroy_rwsem is held across the entire object creation and
         * released during rdma_alloc_commit_uobject or
@@ -539,7 +546,7 @@ struct ib_uobject *rdma_alloc_begin_uobject(const struct uverbs_obj_type *type,
        if (!down_read_trylock(&ufile->hw_destroy_rwsem))
                return ERR_PTR(-EIO);
 
-       ret = type->type_class->alloc_begin(type, ufile);
+       ret = obj->type_class->alloc_begin(obj, ufile);
        if (IS_ERR(ret)) {
                up_read(&ufile->hw_destroy_rwsem);
                return ret;
@@ -561,8 +568,8 @@ static int __must_check destroy_hw_idr_uobject(struct ib_uobject *uobj,
                                               enum rdma_remove_reason why)
 {
        const struct uverbs_obj_idr_type *idr_type =
-               container_of(uobj->type, struct uverbs_obj_idr_type,
-                            type);
+               container_of(uobj->uapi_object->type_attrs,
+                            struct uverbs_obj_idr_type, type);
        int ret = idr_type->destroy_object(uobj, why);
 
        /*
@@ -599,8 +606,8 @@ static void alloc_abort_fd_uobject(struct ib_uobject *uobj)
 static int __must_check destroy_hw_fd_uobject(struct ib_uobject *uobj,
                                              enum rdma_remove_reason why)
 {
-       const struct uverbs_obj_fd_type *fd_type =
-               container_of(uobj->type, struct uverbs_obj_fd_type, type);
+       const struct uverbs_obj_fd_type *fd_type = container_of(
+               uobj->uapi_object->type_attrs, struct uverbs_obj_fd_type, type);
        int ret = fd_type->context_closed(uobj, why);
 
        if (ib_is_destroy_retryable(ret, why, uobj))
@@ -633,8 +640,8 @@ static int alloc_commit_idr_uobject(struct ib_uobject *uobj)
 
 static int alloc_commit_fd_uobject(struct ib_uobject *uobj)
 {
-       const struct uverbs_obj_fd_type *fd_type =
-               container_of(uobj->type, struct uverbs_obj_fd_type, type);
+       const struct uverbs_obj_fd_type *fd_type = container_of(
+               uobj->uapi_object->type_attrs, struct uverbs_obj_fd_type, type);
        int fd = uobj->id;
        struct file *filp;
 
@@ -679,7 +686,7 @@ int __must_check rdma_alloc_commit_uobject(struct ib_uobject *uobj)
        int ret;
 
        /* alloc_commit consumes the uobj kref */
-       ret = uobj->type->type_class->alloc_commit(uobj);
+       ret = uobj->uapi_object->type_class->alloc_commit(uobj);
        if (ret) {
                uverbs_destroy_uobject(uobj, RDMA_REMOVE_ABORT);
                up_read(&ufile->hw_destroy_rwsem);
@@ -735,7 +742,7 @@ void rdma_lookup_put_uobject(struct ib_uobject *uobj,
                             enum rdma_lookup_mode mode)
 {
        assert_uverbs_usecnt(uobj, mode);
-       uobj->type->type_class->lookup_put(uobj, mode);
+       uobj->uapi_object->type_class->lookup_put(uobj, mode);
        /*
         * In order to unlock an object, either decrease its usecnt for
         * read access or zero it in case of exclusive access. See
@@ -995,23 +1002,26 @@ const struct uverbs_obj_type_class uverbs_fd_class = {
 EXPORT_SYMBOL(uverbs_fd_class);
 
 struct ib_uobject *
-uverbs_get_uobject_from_file(const struct uverbs_obj_type *type_attrs,
+uverbs_get_uobject_from_file(u16 object_id,
                             struct ib_uverbs_file *ufile,
                             enum uverbs_obj_access access, s64 id)
 {
+       const struct uverbs_api_object *obj =
+               uapi_get_object(ufile->device->uapi, object_id);
+
        switch (access) {
        case UVERBS_ACCESS_READ:
-               return rdma_lookup_get_uobject(type_attrs, ufile, id,
+               return rdma_lookup_get_uobject(obj, ufile, id,
                                               UVERBS_LOOKUP_READ);
        case UVERBS_ACCESS_DESTROY:
                /* Actual destruction is done inside uverbs_handle_method */
-               return rdma_lookup_get_uobject(type_attrs, ufile, id,
+               return rdma_lookup_get_uobject(obj, ufile, id,
                                               UVERBS_LOOKUP_DESTROY);
        case UVERBS_ACCESS_WRITE:
-               return rdma_lookup_get_uobject(type_attrs, ufile, id,
+               return rdma_lookup_get_uobject(obj, ufile, id,
                                               UVERBS_LOOKUP_WRITE);
        case UVERBS_ACCESS_NEW:
-               return rdma_alloc_begin_uobject(type_attrs, ufile);
+               return rdma_alloc_begin_uobject(obj, ufile);
        default:
                WARN_ON(true);
                return ERR_PTR(-EOPNOTSUPP);
index 55a687285b1daaa9007ee1ba6d8a6c60870baf01..d89569d87b1cff305b3bebff4f7f7a97a043a219 100644 (file)
@@ -89,7 +89,7 @@ void uverbs_close_fd(struct file *f);
  * uverbs_finalize_objects are called.
  */
 struct ib_uobject *
-uverbs_get_uobject_from_file(const struct uverbs_obj_type *type_attrs,
+uverbs_get_uobject_from_file(u16 object_id,
                             struct ib_uverbs_file *ufile,
                             enum uverbs_obj_access access, s64 id);
 
index 23ff698ab08ef658d0c05e38bf0913bcf9a117bd..8a052d0fdf2cc026904351a91bd0d377387b93a0 100644 (file)
@@ -57,7 +57,6 @@ static int uverbs_process_attr(struct ib_uverbs_file *ufile,
        const struct uverbs_attr_spec *spec;
        const struct uverbs_attr_spec *val_spec;
        struct uverbs_attr *e;
-       const struct uverbs_object_spec *object;
        struct uverbs_obj_attr *o_attr;
        struct uverbs_attr *elements = attr_bundle_h->attrs;
 
@@ -145,9 +144,6 @@ static int uverbs_process_attr(struct ib_uverbs_file *ufile,
                        return -EINVAL;
 
                o_attr = &e->obj_attr;
-               object = uverbs_get_object(ufile, spec->u.obj.obj_type);
-               if (!object)
-                       return -EINVAL;
 
                /* specs are allowed to have only one destroy attribute */
                WARN_ON(spec->u.obj.access == UVERBS_ACCESS_DESTROY &&
@@ -162,7 +158,7 @@ static int uverbs_process_attr(struct ib_uverbs_file *ufile,
                 * IDR implementation today rejects negative IDs
                 */
                o_attr->uobject = uverbs_get_uobject_from_file(
-                                       object->type_attrs,
+                                       spec->u.obj.obj_type,
                                        ufile,
                                        spec->u.obj.access,
                                        uattr->data_s64);
index 3b07201b9a804e214ca900163468107c9ac8d6a1..5d404c20b49f276590f509097fec1bd9249b3f29 100644 (file)
@@ -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 {
index 64ee2545dd3db34201c25d3bd0131f5c9c76cb92..3b00231cc084d7528e7052c4f8db78a1d0d1ca23 100644 (file)
@@ -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
 
index 1ab9a85eebd9f2a769e12c2a44c6c52fe7fc79bc..acb1bfa3cc99a5b2d82f70e547acce8ea93d5928 100644 (file)
@@ -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);