On Sat, May 15, 2021 at 06:48:40PM +0300, Ido Schimmel wrote:
> On Fri, May 14, 2021 at 05:35:00PM +0300, Dan Carpenter wrote:
> > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> > master
> > head: 315d99318179b9cd5077ccc9f7f26a164c9fa998
> > commit: e3ddfb45bacdc623eedea7f7bf9e7879257471d6 mlxsw: spectrum_router:
> > Allow returning errors from mlxsw_sp_nexthop_group_refresh()
> > config: x86_64-randconfig-m031-20210514 (attached as .config)
> > compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <l...@intel.com>
> > Reported-by: Dan Carpenter <dan.carpen...@oracle.com>
> >
> > smatch warnings:
> > drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:3598
> > mlxsw_sp_nexthop_group_refresh() warn: missing error code 'err'
> >
> > vim +/err +3598 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> >
> > e3ddfb45bacdc6 Ido Schimmel 2020-11-17 3555 static int
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3556
> > mlxsw_sp_nexthop_group_refresh(struct mlxsw_sp *mlxsw_sp,
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3557
> > struct mlxsw_sp_nexthop_group *nh_grp)
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3558 {
> > 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3559 struct
> > mlxsw_sp_nexthop_group_info *nhgi = nh_grp->nhgi;
> > eb789980d0aa6c Ido Schimmel 2017-10-22 3560 u16 ecmp_size,
> > old_ecmp_size;
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3561 struct
> > mlxsw_sp_nexthop *nh;
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3562 bool
> > offload_change = false;
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3563 u32 adj_index;
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3564 bool
> > old_adj_index_valid;
> > e3ddfb45bacdc6 Ido Schimmel 2020-11-17 3565 int i, err2,
> > err = 0;
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3566 u32
> > old_adj_index;
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3567
> > 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3568 if
> > (!nhgi->gateway) {
> > b3e8d1ebad2d04 Ido Schimmel 2017-02-08 3569
> > mlxsw_sp_nexthop_fib_entries_update(mlxsw_sp, nh_grp);
> > e3ddfb45bacdc6 Ido Schimmel 2020-11-17 3570 return
> > 0;
> > b3e8d1ebad2d04 Ido Schimmel 2017-02-08 3571 }
> > b3e8d1ebad2d04 Ido Schimmel 2017-02-08 3572
> > 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3573 for (i = 0; i <
> > nhgi->count; i++) {
> > 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3574 nh =
> > &nhgi->nexthops[i];
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3575
> > 56b8a9ed276bc1 Petr Machata 2017-07-31 3576 if
> > (nh->should_offload != nh->offloaded) {
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3577
> > offload_change = true;
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3578
> > if (nh->should_offload)
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3579
> > nh->update = 1;
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3580 }
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3581 }
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3582 if
> > (!offload_change) {
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3583 /*
> > Nothing was added or removed, so no need to reallocate. Just
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3584 *
> > update MAC on existing adjacency indexes.
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3585 */
> > 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3586 err =
> > mlxsw_sp_nexthop_group_update(mlxsw_sp, nhgi, false);
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3587 if
> > (err) {
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3588
> > dev_warn(mlxsw_sp->bus_info->dev, "Failed to update neigh MAC in adjacency
> > table.\n");
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3589
> > goto set_trap;
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3590 }
> > e3ddfb45bacdc6 Ido Schimmel 2020-11-17 3591 return
> > 0;
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3592 }
> > 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3593
> > mlxsw_sp_nexthop_group_normalize(nhgi);
> > 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3594 if
> > (!nhgi->sum_norm_weight)
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3595 /* No
> > neigh of this group is connected so we just set
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3596 * the
> > trap and let everthing flow through kernel.
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 3597 */
> > a7ff87acd995e3 Jiri Pirko 2016-07-05 @3598 goto
> > set_trap;
> >
> > The comments sort of imply that this is a success path so no error
> > code necessary. It's sort of hard to be positive though...
>
> Thanks for the report, Dan. This is indeed a success path. How do you
> suggest to handle it in order to avoid the warning on future smatch
> invocations? I regularly run smatch before submitting patches and I
> would like to keep it error/warning free.
>
You could move setting the error to within 4 lines of the goto:
err = 0;
goto set_trap;
This check basically assumes that if you have a cleanup block after
a return 0; then it should return a negative error code. It finds
quite a few bugs and I'm generally happy with it. But like this is
open source and all so I'm also always open to different ideas if you
have a way to improve the check.
regards,
dan carpenter
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