linux/drivers/net/ethernet/mscc
Vladimir Oltean a14e6b69f3 net: mscc: ocelot: fix incorrect balancing with down LAG ports
Assuming the test setup described here:
https://patchwork.kernel.org/project/netdevbpf/cover/20210205130240.4072854-1-vladimir.oltean@nxp.com/
(swp1 and swp2 are in bond0, and bond0 is in a bridge with swp0)

it can be seen that when swp1 goes down (on either board A or B), then
traffic that should go through that port isn't forwarded anywhere.

A dump of the PGID table shows the following:

PGID_DST[0] = ports 0
PGID_DST[1] = ports 1
PGID_DST[2] = ports 2
PGID_DST[3] = ports 3
PGID_DST[4] = ports 4
PGID_DST[5] = ports 5
PGID_DST[6] = no ports
PGID_AGGR[0] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[1] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[2] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[3] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[4] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[5] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[6] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[7] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[8] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[9] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[10] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[11] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[12] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[13] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[14] = ports 0, 1, 2, 3, 4, 5
PGID_AGGR[15] = ports 0, 1, 2, 3, 4, 5
PGID_SRC[0] = ports 1, 2
PGID_SRC[1] = ports 0
PGID_SRC[2] = ports 0
PGID_SRC[3] = no ports
PGID_SRC[4] = no ports
PGID_SRC[5] = no ports
PGID_SRC[6] = ports 0, 1, 2, 3, 4, 5

Whereas a "good" PGID configuration for that setup should have looked
like this:

PGID_DST[0] = ports 0
PGID_DST[1] = ports 1, 2
PGID_DST[2] = ports 1, 2
PGID_DST[3] = ports 3
PGID_DST[4] = ports 4
PGID_DST[5] = ports 5
PGID_DST[6] = no ports
PGID_AGGR[0] = ports 0, 2, 3, 4, 5
PGID_AGGR[1] = ports 0, 2, 3, 4, 5
PGID_AGGR[2] = ports 0, 2, 3, 4, 5
PGID_AGGR[3] = ports 0, 2, 3, 4, 5
PGID_AGGR[4] = ports 0, 2, 3, 4, 5
PGID_AGGR[5] = ports 0, 2, 3, 4, 5
PGID_AGGR[6] = ports 0, 2, 3, 4, 5
PGID_AGGR[7] = ports 0, 2, 3, 4, 5
PGID_AGGR[8] = ports 0, 2, 3, 4, 5
PGID_AGGR[9] = ports 0, 2, 3, 4, 5
PGID_AGGR[10] = ports 0, 2, 3, 4, 5
PGID_AGGR[11] = ports 0, 2, 3, 4, 5
PGID_AGGR[12] = ports 0, 2, 3, 4, 5
PGID_AGGR[13] = ports 0, 2, 3, 4, 5
PGID_AGGR[14] = ports 0, 2, 3, 4, 5
PGID_AGGR[15] = ports 0, 2, 3, 4, 5
PGID_SRC[0] = ports 1, 2
PGID_SRC[1] = ports 0
PGID_SRC[2] = ports 0
PGID_SRC[3] = no ports
PGID_SRC[4] = no ports
PGID_SRC[5] = no ports
PGID_SRC[6] = ports 0, 1, 2, 3, 4, 5

In other words, in the "bad" configuration, the attempt is to remove the
inactive swp1 from the destination ports via PGID_DST. But when a MAC
table entry is learned, it is learned towards PGID_DST 1, because that
is the logical port id of the LAG itself (it is equal to the lowest
numbered member port). So when swp1 becomes inactive, if we set
PGID_DST[1] to contain just swp1 and not swp2, the packet will not have
any chance to reach the destination via swp2.

The "correct" way to remove swp1 as a destination is via PGID_AGGR
(remove swp1 from the aggregation port groups for all aggregation
codes). This means that PGID_DST[1] and PGID_DST[2] must still contain
both swp1 and swp2. This makes the MAC table still treat packets
destined towards the single-port LAG as "multicast", and the inactive
ports are removed via the aggregation code tables.

The change presented here is a design one: the ocelot_get_bond_mask()
function used to take an "only_active_ports" argument. We don't need
that. The only call site that specifies only_active_ports=true,
ocelot_set_aggr_pgids(), must retrieve the entire bonding mask, because
it must program that into PGID_DST. Additionally, it must also clear the
inactive ports from the bond mask here, which it can't do if bond_mask
just contains the active ports:

	ac = ocelot_read_rix(ocelot, ANA_PGID_PGID, i);
	ac &= ~bond_mask;  <---- here
	/* Don't do division by zero if there was no active
	 * port. Just make all aggregation codes zero.
	 */
	if (num_active_ports)
		ac |= BIT(aggr_idx[i % num_active_ports]);
	ocelot_write_rix(ocelot, ac, ANA_PGID_PGID, i);

So it becomes the responsibility of ocelot_set_aggr_pgids() to take
ocelot_port->lag_tx_active into consideration when populating the
aggr_idx array.

Fixes: 23ca3b727e ("net: mscc: ocelot: rebalance LAGs on link up/down events")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220107164332.402133-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-01-07 18:54:59 -08:00
..
Kconfig of: net: move of_net under net/ 2021-10-07 13:39:51 +01:00
Makefile net: ocelot: add FDMA support 2021-12-10 20:56:58 -08:00
ocelot.c net: mscc: ocelot: fix incorrect balancing with down LAG ports 2022-01-07 18:54:59 -08:00
ocelot.h net: ocelot: add support for ndo_change_mtu 2021-12-10 20:56:57 -08:00
ocelot_devlink.c net: update NXP copyright text 2021-09-17 13:52:17 +01:00
ocelot_fdma.c net: ocelot: use dma_unmap_addr to get tx buffer dma_addr 2021-12-13 14:51:21 +00:00
ocelot_fdma.h net: ocelot: add FDMA support 2021-12-10 20:56:58 -08:00
ocelot_flower.c flow_offload: add index to flow_action_entry structure 2021-12-19 14:08:47 +00:00
ocelot_io.c net: mscc: Fix non-GPL export of regmap APIs 2021-08-12 09:44:31 +01:00
ocelot_mrp.c net: mscc: ocelot: add the local station MAC addresses in VID 0 2021-10-21 12:14:29 +01:00
ocelot_net.c net: ocelot: add support to get port mac from device-tree 2021-12-15 10:29:41 +00:00
ocelot_police.c
ocelot_police.h
ocelot_ptp.c time64.h: Consolidated PSEC_PER_SEC definition 2021-04-06 16:32:17 -07:00
ocelot_qs.h
ocelot_rew.h
ocelot_vcap.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-11-26 13:45:19 -08:00
ocelot_vcap.h
ocelot_vsc7514.c net: ocelot: add FDMA support 2021-12-10 20:56:58 -08:00
vsc7514_regs.c net: mscc: ocelot: split register definitions to a separate file 2021-12-07 21:44:49 -08:00