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Date: Sun, 25 Sep 2016 12:42:29 +0200
From: Jiri Pirko <jiri@...nulli.us>
To: Ido Schimmel <idosch@...sch.org>
Cc: netdev@...r.kernel.org, davem@...emloft.net, idosch@...lanox.com,
eladr@...lanox.com, yotamg@...lanox.com, nogahf@...lanox.com,
ogerlitz@...lanox.com, roopa@...ulusnetworks.com,
nikolay@...ulusnetworks.com, linville@...driver.com,
andy@...yhouse.net, f.fainelli@...il.com, dsa@...ulusnetworks.com,
jhs@...atatu.com, vivien.didelot@...oirfairelinux.com,
andrew@...n.ch, ivecera@...hat.com, kaber@...sh.net,
john@...ozen.org
Subject: Re: [patch net-next v2 3/6] mlxsw: spectrum_router: Use FIB
notifications instead of switchdev calls
Sun, Sep 25, 2016 at 12:22:08PM CEST, idosch@...sch.org wrote:
>On Fri, Sep 23, 2016 at 11:22:12AM +0200, Jiri Pirko wrote:
>> From: Jiri Pirko <jiri@...lanox.com>
>>
>> Until now, in order to offload a FIB entry to HW we use switchdev op.
>> However that has limits. Mainly in case we need to make the HW aware of
>> all route prefixes configured in kernel. HW needs to know those in order
>> to properly trap appropriate packets and pass the to kernel to do
>> the forwarding. Abort mechanism is now handled within the mlxsw driver.
>>
>> Signed-off-by: Jiri Pirko <jiri@...lanox.com>
>
>[...]
>
>> static int
>> mlxsw_sp_router_fib4_entry_init(struct mlxsw_sp *mlxsw_sp,
>> - const struct switchdev_obj_ipv4_fib *fib4,
>> + const struct fib_entry_notifier_info *fen_info,
>> struct mlxsw_sp_fib_entry *fib_entry)
>> {
>> - struct fib_info *fi = fib4->fi;
>> + struct fib_info *fi = fen_info->fi;
>> + struct mlxsw_sp_rif *r;
>> + int nhsel;
>>
>> - if (fib4->type == RTN_LOCAL || fib4->type == RTN_BROADCAST) {
>> + if (fen_info->type == RTN_LOCAL || fen_info->type == RTN_BROADCAST) {
>> fib_entry->type = MLXSW_SP_FIB_ENTRY_TYPE_TRAP;
>> return 0;
>> }
>> - if (fib4->type != RTN_UNICAST)
>> + if (fen_info->type != RTN_UNICAST)
>> return -EINVAL;
>>
>> - if (fi->fib_scope != RT_SCOPE_UNIVERSE) {
>> - struct mlxsw_sp_rif *r;
>> + for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {
>> + const struct fib_nh *nh = &fi->fib_nh[nhsel];
>> +
>> + if (!nh->nh_dev)
>> + continue;
>> + r = mlxsw_sp_rif_find_by_dev(mlxsw_sp, nh->nh_dev);
>> + if (!r) {
>> + /* In case router interface is not found for
>> + * at least one of the nexthops, that means
>> + * the nexthop points to some device unrelated
>> + * to us. Set trap and pass the packets for
>> + * this prefix to kernel.
>> + */
>> + fib_entry->type = MLXSW_SP_FIB_ENTRY_TYPE_TRAP;
>> + return 0;
>> + }
>> + }
>>
>> + if (fi->fib_scope != RT_SCOPE_UNIVERSE) {
>> fib_entry->type = MLXSW_SP_FIB_ENTRY_TYPE_LOCAL;
>> - r = mlxsw_sp_rif_find_by_dev(mlxsw_sp, fi->fib_dev);
>> - if (!r)
>> - return -EINVAL;
>> fib_entry->rif = r->rif;
>> return 0;
>> }
>> +
>> fib_entry->type = MLXSW_SP_FIB_ENTRY_TYPE_REMOTE;
>> return mlxsw_sp_nexthop_group_get(mlxsw_sp, fib_entry, fi);
>> }
>
>[...]
>
>> +static int mlxsw_sp_router_fib4_add(struct mlxsw_sp *mlxsw_sp,
>> + struct fib_entry_notifier_info *fen_info)
>> {
>> - struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
>> - struct mlxsw_sp_router_fib4_add_info *info;
>> struct mlxsw_sp_fib_entry *fib_entry;
>> struct mlxsw_sp_vr *vr;
>> int err;
>>
>> - info = switchdev_trans_item_dequeue(trans);
>> - fib_entry = info->fib_entry;
>> - kfree(info);
>> + if (mlxsw_sp->router.aborted)
>> + return 0;
>> +
>> + fib_entry = mlxsw_sp_fib_entry_get(mlxsw_sp, fen_info);
>> + if (IS_ERR(fib_entry)) {
>> + dev_warn(mlxsw_sp->bus_info->dev, "Failed to get FIB4 entry being added.\n");
>> + return PTR_ERR(fib_entry);
>> + }
>>
>> if (fib_entry->ref_count != 1)
>> - return 0;
>> + goto skip_add;
>>
>> vr = fib_entry->vr;
>> err = mlxsw_sp_fib_entry_insert(vr->fib, fib_entry);
>> - if (err)
>> + if (err) {
>> + dev_warn(mlxsw_sp->bus_info->dev, "Failed to insert FIB4 entry being added.\n");
>> goto err_fib_entry_insert;
>> - err = mlxsw_sp_fib_entry_update(mlxsw_sp_port->mlxsw_sp, fib_entry);
>> + }
>> + err = mlxsw_sp_fib_entry_update(mlxsw_sp, fib_entry);
>> if (err)
>> goto err_fib_entry_add;
>> +
>> +skip_add:
>> + fib_info_offload_inc(fen_info->fi);
>
>This is called for every FIB that is added on the system. Even those
>going via management ports, so all the routes are marked as offloaded.
>Tested to make sure I'm not talking nonsense ^^
>
>$ ip r s
>default via 10.209.0.1 dev eno1
>10.209.0.0/23 dev eno1 proto kernel scope link src 10.209.1.6
>169.254.0.0/16 dev eno1 scope link metric 1002
>
>$ sudo ip r a 1.1.1.0/24 dev eno1
>$ ip r s
>default via 10.209.0.1 dev eno1
>1.1.1.0/24 dev eno1 scope link offload
>10.209.0.0/23 dev eno1 proto kernel scope link src 10.209.1.6
>169.254.0.0/16 dev eno1 scope link metric 1002
>
>I think we should only call fib_info_offload_inc() in
>mlxsw_sp_router_fib4_entry_init() if fib_entry->type !=
>MLXSW_SP_FIB_ENTRY_TRAP. It'll also solve another problem (see below).
Hmm, that makes sense. Will do that.
>
>> return 0;
>>
>> err_fib_entry_add:
>> @@ -1899,29 +1814,22 @@ err_fib_entry_insert:
>> return err;
>> }
>
>[...]
>
>> +static void mlxsw_sp_router_fib4_abort(struct mlxsw_sp *mlxsw_sp)
>> +{
>> + struct mlxsw_resources *resources;
>> + struct mlxsw_sp_fib_entry *fib_entry;
>> + struct mlxsw_sp_fib_entry *tmp;
>> + struct mlxsw_sp_vr *vr;
>> + int i;
>> + int err;
>> +
>> + resources = mlxsw_core_resources_get(mlxsw_sp->core);
>> + for (i = 0; i < resources->max_virtual_routers; i++) {
>> + vr = &mlxsw_sp->router.vrs[i];
>> + if (!vr->used)
>> + continue;
>> +
>> + list_for_each_entry_safe(fib_entry, tmp,
>> + &vr->fib->entry_list, list) {
>> + bool do_break = &tmp->list == &vr->fib->entry_list;
>> +
>> + fib_info_offload_dec(fib_entry->fi);
>
>We call fib_info_offload_inc() multiple times for an already existing
>FIB entry, but in abort we only call fib_info_offload_dec() once per
>entry.
>
>If we inc / dec in fib4_entry_init/fini, then this counter is called
>once per entry (upon creation / destruction).
Okay. Will do.
>
>> + mlxsw_sp_fib_entry_del(mlxsw_sp, fib_entry);
>> + mlxsw_sp_fib_entry_remove(fib_entry->vr->fib,
>> + fib_entry);
>> + mlxsw_sp_fib_entry_put_all(mlxsw_sp, fib_entry);
>> + if (do_break)
>> + break;
>> + }
>> + }
>> + mlxsw_sp->router.aborted = true;
>> + err = mlxsw_sp_router_set_abort_trap(mlxsw_sp);
>> + if (err)
>> + dev_warn(mlxsw_sp->bus_info->dev, "Failed to set abort trap.\n");
>> +}
>
>Besides that the patch looks really good to me.
Thanks for review.
>
>Thanks!
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