Re: drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:3598 mlxsw_sp_nexthop_group_refresh() warn: missing error code 'err'
From: Ido Schimmel
Date: Sat May 15 2021 - 12:04:01 EST
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 <lkp@xxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>
> 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.
>
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3599
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3600 ecmp_size = nhgi->sum_norm_weight;
> 425a08c67317ac Ido Schimmel 2017-10-22 3601 err = mlxsw_sp_fix_adj_grp_size(mlxsw_sp, &ecmp_size);
> 425a08c67317ac Ido Schimmel 2017-10-22 3602 if (err)
> 425a08c67317ac Ido Schimmel 2017-10-22 3603 /* No valid allocation size available. */
> 425a08c67317ac Ido Schimmel 2017-10-22 3604 goto set_trap;
> 425a08c67317ac Ido Schimmel 2017-10-22 3605
> 4b6b18692aec20 Jiri Pirko 2018-07-08 3606 err = mlxsw_sp_kvdl_alloc(mlxsw_sp, MLXSW_SP_KVDL_ENTRY_TYPE_ADJ,
> 4b6b18692aec20 Jiri Pirko 2018-07-08 3607 ecmp_size, &adj_index);
> 1312444374241f Arkadi Sharshevsky 2017-03-25 3608 if (err) {
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3609 /* We ran out of KVD linear space, just set the
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3610 * trap and let everything flow through kernel.
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3611 */
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3612 dev_warn(mlxsw_sp->bus_info->dev, "Failed to allocate KVD linear area for nexthop group.\n");
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3613 goto set_trap;
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3614 }
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3615 old_adj_index_valid = nhgi->adj_index_valid;
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3616 old_adj_index = nhgi->adj_index;
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3617 old_ecmp_size = nhgi->ecmp_size;
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3618 nhgi->adj_index_valid = 1;
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3619 nhgi->adj_index = adj_index;
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3620 nhgi->ecmp_size = ecmp_size;
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3621 mlxsw_sp_nexthop_group_rebalance(nhgi);
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3622 err = mlxsw_sp_nexthop_group_update(mlxsw_sp, nhgi, true);
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3623 if (err) {
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3624 dev_warn(mlxsw_sp->bus_info->dev, "Failed to update neigh MAC in adjacency table.\n");
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3625 goto set_trap;
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3626 }
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3627
> 8c5a5b9b9185e5 Ido Schimmel 2020-01-14 3628 mlxsw_sp_nexthop_group_offload_refresh(mlxsw_sp, nh_grp);
> 8c5a5b9b9185e5 Ido Schimmel 2020-01-14 3629
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3630 if (!old_adj_index_valid) {
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3631 /* The trap was set for fib entries, so we have to call
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3632 * fib entry update to unset it and use adjacency index.
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3633 */
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3634 err = mlxsw_sp_nexthop_fib_entries_update(mlxsw_sp, nh_grp);
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3635 if (err) {
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3636 dev_warn(mlxsw_sp->bus_info->dev, "Failed to add adjacency index to fib entries.\n");
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3637 goto set_trap;
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3638 }
> e3ddfb45bacdc6 Ido Schimmel 2020-11-17 3639 return 0;
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3640 }
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3641
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3642 err = mlxsw_sp_adj_index_mass_update(mlxsw_sp, nh_grp,
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3643 old_adj_index, old_ecmp_size);
> 4b6b18692aec20 Jiri Pirko 2018-07-08 3644 mlxsw_sp_kvdl_free(mlxsw_sp, MLXSW_SP_KVDL_ENTRY_TYPE_ADJ,
> 0304c00546fce7 Jiri Pirko 2018-07-08 3645 old_ecmp_size, old_adj_index);
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3646 if (err) {
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3647 dev_warn(mlxsw_sp->bus_info->dev, "Failed to mass-update adjacency index for nexthop group.\n");
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3648 goto set_trap;
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3649 }
> 77d964e66cfad0 Ido Schimmel 2017-08-02 3650
> e3ddfb45bacdc6 Ido Schimmel 2020-11-17 3651 return 0;
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3652
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3653 set_trap:
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3654 old_adj_index_valid = nhgi->adj_index_valid;
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3655 nhgi->adj_index_valid = 0;
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3656 for (i = 0; i < nhgi->count; i++) {
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3657 nh = &nhgi->nexthops[i];
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3658 nh->offloaded = 0;
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3659 }
> e3ddfb45bacdc6 Ido Schimmel 2020-11-17 3660 err2 = mlxsw_sp_nexthop_fib_entries_update(mlxsw_sp, nh_grp);
> e3ddfb45bacdc6 Ido Schimmel 2020-11-17 3661 if (err2)
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3662 dev_warn(mlxsw_sp->bus_info->dev, "Failed to set traps for fib entries.\n");
> 8c5a5b9b9185e5 Ido Schimmel 2020-01-14 3663 mlxsw_sp_nexthop_group_offload_refresh(mlxsw_sp, nh_grp);
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3664 if (old_adj_index_valid)
> 4b6b18692aec20 Jiri Pirko 2018-07-08 3665 mlxsw_sp_kvdl_free(mlxsw_sp, MLXSW_SP_KVDL_ENTRY_TYPE_ADJ,
> 7f7a417e6a11d7 Ido Schimmel 2020-11-13 3666 nhgi->ecmp_size, nhgi->adj_index);
> e3ddfb45bacdc6 Ido Schimmel 2020-11-17 3667 return err;
> a7ff87acd995e3 Jiri Pirko 2016-07-05 3668 }
>
> ---
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