From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Desaulniers Subject: Re: [PATCH] IB/mlx4: Avoid implicit enumerated type conversion Date: Mon, 24 Sep 2018 15:29:38 -0700 Message-ID: References: <20180924195716.30848-1-natechancellor@gmail.com> <20180924222737.GA26973@flashbox> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: <20180924222737.GA26973@flashbox> Sender: linux-kernel-owner@vger.kernel.org To: Nathan Chancellor Cc: dledford@redhat.com, jgg@ziepe.ca, linux-rdma@vger.kernel.org, LKML List-Id: linux-rdma@vger.kernel.org On Mon, Sep 24, 2018 at 3:27 PM Nathan Chancellor wrote: > > On Mon, Sep 24, 2018 at 03:24:36PM -0700, Nick Desaulniers wrote: > > On Mon, Sep 24, 2018 at 12:57 PM Nathan Chancellor > > wrote: > > > > > > Clang warns when one enumerated type is implicitly converted to another. > > > > > > drivers/infiniband/hw/mlx4/mad.c:1811:41: warning: implicit conversion > > > from enumeration type 'enum mlx4_ib_qp_flags' to different enumeration > > > type 'enum ib_qp_create_flags' [-Wenum-conversion] > > > qp_init_attr.init_attr.create_flags = MLX4_IB_SRIOV_TUNNEL_QP; > > > ~ ^~~~~~~~~~~~~~~~~~~~~~~ > > > > > > drivers/infiniband/hw/mlx4/mad.c:1819:41: warning: implicit conversion > > > from enumeration type 'enum mlx4_ib_qp_flags' to different enumeration > > > type 'enum ib_qp_create_flags' [-Wenum-conversion] > > > qp_init_attr.init_attr.create_flags = MLX4_IB_SRIOV_SQP; > > > ~ ^~~~~~~~~~~~~~~~~ > > > > > > The type mlx4_ib_qp_flags explicitly provides supplemental values to the > > > type ib_qp_create_flags. Make that clear to Clang by changing the > > > create_flags type to u32. > > > > > > Reported-by: Nick Desaulniers > > > Signed-off-by: Nathan Chancellor > > > --- > > > include/rdma/ib_verbs.h | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h > > > index e463d3007a35..f6f4d9e3c8ed 100644 > > > --- a/include/rdma/ib_verbs.h > > > +++ b/include/rdma/ib_verbs.h > > > @@ -1149,7 +1149,7 @@ struct ib_qp_init_attr { > > > struct ib_qp_cap cap; > > > enum ib_sig_type sq_sig_type; > > > enum ib_qp_type qp_type; > > > - enum ib_qp_create_flags create_flags; > > > + u32 create_flags; > > > > I think it might be better to just have explicit casts at the > > assignment. What do the maintainers think? > > > > That's fine with me, I tend to explicitly cast if it is only one > location but it certainly makes sense in this case as well. I'll > wait for the maintainers to weigh in before sending a v2. Yeah, I mean my opinion on this might seem arbitrary, but based on the pattern and the comment in ib_qp_create_flags, those enum values are reserved to be "subclassed" in a sense, so they should always be in sync or this code will have bigger problems. > > Thanks for the review, > Nathan > > > > > > > /* > > > * Only needed for special QP types, or when using the RW API. > > > -- > > > 2.19.0 > > > > > > > > > -- > > Thanks, > > ~Nick Desaulniers -- Thanks, ~Nick Desaulniers