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From: Ido Schimmel <idosch@OSS.NVIDIA.COM>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: <kbuild@lists.01.org>, <lkp@intel.com>, <kbuild-all@lists.01.org>,
	<linux-kernel@vger.kernel.org>, Jakub Kicinski <kuba@kernel.org>,
	Jiri Pirko <jiri@OSS.NVIDIA.COM>
Subject: Re: drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:3598 mlxsw_sp_nexthop_group_refresh() warn: missing error code 'err'
Date: Sat, 15 May 2021 18:48:40 +0300	[thread overview]
Message-ID: <YJ/tWBNKXrobK9RU@shredder> (raw)
In-Reply-To: <202105141823.Td2h3Mbi-lkp@intel.com>

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@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@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.

> 
> 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  }
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
> 

  reply	other threads:[~2021-05-15 16:03 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-14 14:35 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:3598 mlxsw_sp_nexthop_group_refresh() warn: missing error code 'err' Dan Carpenter
2021-05-15 15:48 ` Ido Schimmel [this message]
2021-05-15 16:53   ` Dan Carpenter
2021-05-15 16:56     ` Dan Carpenter
2021-05-16 10:28     ` Ido Schimmel

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