| Message ID | 0-v1-43ae3c759177+65-qib_type_jgg@nvidia.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Jason Gunthorpe |
| Headers | show |
| Series | IB/qib: Fix null pointer subtraction compiler warning | expand |
On 9/3/21 9:07 AM, Jason Gunthorpe wrote: >>> drivers/infiniband/hw/qib/qib_sysfs.c:411:1: warning: performing pointer subtraction with a null pointer has undefined behavior > +[-Wnull-pointer-subtraction] > QIB_DIAGC_ATTR(rc_resends); > ^~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' > .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ > > Use offsetof and accomplish the type check using static_assert. > > Fixes: 4a7aaf88c89f ("RDMA/qib: Use attributes for the port sysfs") > Reported-by: kernel test robot <lkp@intel.com> > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> > --- > drivers/infiniband/hw/qib/qib_sysfs.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/infiniband/hw/qib/qib_sysfs.c b/drivers/infiniband/hw/qib/qib_sysfs.c > index d57e49de6650be..452e2355d24eeb 100644 > --- a/drivers/infiniband/hw/qib/qib_sysfs.c > +++ b/drivers/infiniband/hw/qib/qib_sysfs.c > @@ -403,9 +403,11 @@ static ssize_t diagc_attr_store(struct ib_device *ibdev, u32 port_num, > } > > #define QIB_DIAGC_ATTR(N) \ > + static_assert(&((struct qib_ibport *)0)->rvp.n_##N != (u64 *)NULL); \ > static struct qib_diagc_attr qib_diagc_attr_##N = { \ > .attr = __ATTR(N, 0664, diagc_attr_show, diagc_attr_store), \ > - .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ > + .counter = \ > + offsetof(struct qib_ibport, rvp.n_##N) / sizeof(u64) \ > } > > QIB_DIAGC_ATTR(rc_resends); > > base-commit: 6a217437f9f5482a3f6f2dc5fcd27cf0f62409ac > Looks fine. Acked-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
On Fri, Sep 03, 2021 at 10:07:28AM -0300, Jason Gunthorpe wrote: > >> drivers/infiniband/hw/qib/qib_sysfs.c:411:1: warning: performing pointer subtraction with a null pointer has undefined behavior > +[-Wnull-pointer-subtraction] > QIB_DIAGC_ATTR(rc_resends); > ^~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' > .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ > > Use offsetof and accomplish the type check using static_assert. > > Fixes: 4a7aaf88c89f ("RDMA/qib: Use attributes for the port sysfs") > Reported-by: kernel test robot <lkp@intel.com> > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> > Acked-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> > --- > drivers/infiniband/hw/qib/qib_sysfs.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) Applied to for-rc Jason
diff --git a/drivers/infiniband/hw/qib/qib_sysfs.c b/drivers/infiniband/hw/qib/qib_sysfs.c index d57e49de6650be..452e2355d24eeb 100644 --- a/drivers/infiniband/hw/qib/qib_sysfs.c +++ b/drivers/infiniband/hw/qib/qib_sysfs.c @@ -403,9 +403,11 @@ static ssize_t diagc_attr_store(struct ib_device *ibdev, u32 port_num, } #define QIB_DIAGC_ATTR(N) \ + static_assert(&((struct qib_ibport *)0)->rvp.n_##N != (u64 *)NULL); \ static struct qib_diagc_attr qib_diagc_attr_##N = { \ .attr = __ATTR(N, 0664, diagc_attr_show, diagc_attr_store), \ - .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ + .counter = \ + offsetof(struct qib_ibport, rvp.n_##N) / sizeof(u64) \ } QIB_DIAGC_ATTR(rc_resends);