Re: [PATCH rdma-next v2 01/13] IB/uverbs: Add an ib_uobject getter to ioctl() infrastructure

[Jason Gunthorpe <jgg@ziepe.ca>]

On Tue, May 29, 2018 at 08:49:58PM +0000, Ruhl, Michael J wrote:
> >From: Jason Gunthorpe [mailto:jgg@mellanox.com]
> >Sent: Tuesday, May 29, 2018 4:21 PM
> >To: Ruhl, Michael J <michael.j.ruhl@intel.com>
> >Cc: Leon Romanovsky <leon@kernel.org>; Doug Ledford
> ><dledford@redhat.com>; Leon Romanovsky <leonro@mellanox.com>; RDMA
> >mailing list <linux-rdma@vger.kernel.org>; Boris Pismenny
> ><borisp@mellanox.com>; Matan Barak <matanb@mellanox.com>; Raed
> >Salem <raeds@mellanox.com>; Yishai Hadas <yishaih@mellanox.com>; Saeed
> >Mahameed <saeedm@mellanox.com>; linux-netdev
> ><netdev@vger.kernel.org>
> >Subject: Re: [PATCH rdma-next v2 01/13] IB/uverbs: Add an ib_uobject getter
> >to ioctl() infrastructure
> >
> >On Tue, May 29, 2018 at 07:31:22PM +0000, Ruhl, Michael J wrote:
> >> >-	struct ib_uverbs_destroy_cq_resp resp;
> >> > 	struct ib_uobject *uobj =
> >> >-		uverbs_attr_get(attrs,
> >> >UVERBS_ATTR_DESTROY_CQ_HANDLE)->obj_attr.uobject;
> >> >-	struct ib_ucq_object *obj = container_of(uobj, struct ib_ucq_object,
> >> >-						 uobject);
> >> >+		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);
> >> >+
> >>
> >> I remember a conversation that if an method attribute was mandatory, that
> >you did not need to
> >> test the uobj for error (since it was checked in the infrastructure).
> >
> >Yes.
> >
> >> Is this error check necessary?
> >
> >No
> >
> >But there is no way to check one way or the other at compile time
> >right now, and omitting the check makes smatch mad.
> 
> Is smatch going to get mad at (same patch):

Yes, this is where it already got mad, IIRC :( 

Fixing this whole thing is a todo on my list..

Jason