| Message ID | 20210618183017.3340769-6-olteanv@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Improvement for DSA cross-chip setups | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for net-next |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | success | CCed 7 of 7 maintainers |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 71 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | Link |
On 6/18/2021 11:30 AM, Vladimir Oltean wrote: > From: Vladimir Oltean <vladimir.oltean@nxp.com> > > dsa_slave_change_mtu() calls dsa_port_mtu_change() twice: > - it sends a cross-chip notifier with the MTU of the CPU port which is > used to update the DSA links. > - it sends one targeted MTU notifier which is supposed to only match the > user port on which we are changing the MTU. The "propagate_upstream" > variable is used here to bypass the cross-chip notifier system from > switch.c > > But due to a mistake, the second, targeted notifier matches not only on > the user port, but also on the DSA link which is a member of the same > switch, if that exists. > > And because the DSA links of the entire dst were programmed in a > previous round to the largest_mtu via a "propagate_upstream == true" > notification, then the dsa_port_mtu_change(propagate_upstream == false) > call that is immediately upcoming will break the MTU on the one DSA link > which is chip-wise local to the dp whose MTU is changing right now. > > Example given this daisy chain topology: > > sw0p0 sw0p1 sw0p2 sw0p3 sw0p4 > [ cpu ] [ user ] [ user ] [ dsa ] [ user ] > [ x ] [ ] [ ] [ x ] [ ] > | > +---------+ > | > sw1p0 sw1p1 sw1p2 sw1p3 sw1p4 > [ user ] [ user ] [ user ] [ dsa ] [ dsa ] > [ ] [ ] [ ] [ ] [ x ] > > ip link set sw0p1 mtu 9000 > ip link set sw1p1 mtu 9000 # at this stage, sw0p1 and sw1p1 can talk > # to one another using jumbo frames > ip link set sw0p2 mtu 1500 # this programs the sw0p3 DSA link first to > # the largest_mtu of 9000, then reprograms it to > # 1500 with the "propagate_upstream == false" > # notifier, breaking communication between > # sw0p1 and sw1p1 > > To escape from this situation, make the targeted match really match on a > single port - the user port, and rename the "propagate_upstream" > variable to "targeted_match" to clarify the intention and avoid future > issues. > > Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h index b8b17474b72b..b0811253d101 100644 --- a/net/dsa/dsa_priv.h +++ b/net/dsa/dsa_priv.h @@ -84,7 +84,7 @@ struct dsa_notifier_vlan_info { /* DSA_NOTIFIER_MTU */ struct dsa_notifier_mtu_info { - bool propagate_upstream; + bool targeted_match; int sw_index; int port; int mtu; @@ -200,7 +200,7 @@ int dsa_port_vlan_filtering(struct dsa_port *dp, bool vlan_filtering, bool dsa_port_skip_vlan_configuration(struct dsa_port *dp); int dsa_port_ageing_time(struct dsa_port *dp, clock_t ageing_clock); int dsa_port_mtu_change(struct dsa_port *dp, int new_mtu, - bool propagate_upstream); + bool targeted_match); int dsa_port_fdb_add(struct dsa_port *dp, const unsigned char *addr, u16 vid); int dsa_port_fdb_del(struct dsa_port *dp, const unsigned char *addr, diff --git a/net/dsa/port.c b/net/dsa/port.c index 6379d66a6bb3..5c93f1e1a03d 100644 --- a/net/dsa/port.c +++ b/net/dsa/port.c @@ -567,11 +567,11 @@ int dsa_port_mrouter(struct dsa_port *dp, bool mrouter, } int dsa_port_mtu_change(struct dsa_port *dp, int new_mtu, - bool propagate_upstream) + bool targeted_match) { struct dsa_notifier_mtu_info info = { .sw_index = dp->ds->index, - .propagate_upstream = propagate_upstream, + .targeted_match = targeted_match, .port = dp->index, .mtu = new_mtu, }; diff --git a/net/dsa/slave.c b/net/dsa/slave.c index ac2ca5f75af3..5e668e529575 100644 --- a/net/dsa/slave.c +++ b/net/dsa/slave.c @@ -1586,14 +1586,15 @@ int dsa_slave_change_mtu(struct net_device *dev, int new_mtu) goto out_master_failed; /* We only need to propagate the MTU of the CPU port to - * upstream switches. + * upstream switches, so create a non-targeted notifier which + * updates all switches. */ - err = dsa_port_mtu_change(cpu_dp, cpu_mtu, true); + err = dsa_port_mtu_change(cpu_dp, cpu_mtu, false); if (err) goto out_cpu_failed; } - err = dsa_port_mtu_change(dp, new_mtu, false); + err = dsa_port_mtu_change(dp, new_mtu, true); if (err) goto out_port_failed; @@ -1607,7 +1608,7 @@ int dsa_slave_change_mtu(struct net_device *dev, int new_mtu) if (new_master_mtu != old_master_mtu) dsa_port_mtu_change(cpu_dp, old_master_mtu - dsa_tag_protocol_overhead(cpu_dp->tag_ops), - true); + false); out_cpu_failed: if (new_master_mtu != old_master_mtu) dev_set_mtu(master, old_master_mtu); diff --git a/net/dsa/switch.c b/net/dsa/switch.c index 8b601ced6b45..75f567390a6b 100644 --- a/net/dsa/switch.c +++ b/net/dsa/switch.c @@ -52,10 +52,13 @@ static int dsa_switch_ageing_time(struct dsa_switch *ds, static bool dsa_switch_mtu_match(struct dsa_switch *ds, int port, struct dsa_notifier_mtu_info *info) { - if (ds->index == info->sw_index) - return (port == info->port) || dsa_is_dsa_port(ds, port); + if (ds->index == info->sw_index && port == info->port) + return true; - if (!info->propagate_upstream) + /* Do not propagate to other switches in the tree if the notifier was + * targeted for a single switch. + */ + if (info->targeted_match) return false; if (dsa_is_dsa_port(ds, port) || dsa_is_cpu_port(ds, port))