linux/net/dsa
Vladimir Oltean c0a8a9c274 net: dsa: automatically bring user ports down when master goes down
This is not fixing any actual bug that I know of, but having a DSA
interface that is up even when its lower (master) interface is down is
one of those things that just do not sound right.

Yes, DSA checks if the master is up before actually bringing the
user interface up, but nobody prevents bringing the master interface
down immediately afterwards... Then the user ports would attempt
dev_queue_xmit on an interface that is down, and wonder what's wrong.

This patch prevents that from happening. NETDEV_GOING_DOWN is the
notification emitted _before_ the master actually goes down, and we are
protected by the rtnl_mutex, so all is well.

For those of you reading this because you were doing switch testing
such as latency measurements for autonomously forwarded traffic, and you
needed a controlled environment with no extra packets sent by the
network stack, this patch breaks that, because now the user ports go
down too, which may shut down the PHY etc. But please don't do it like
that, just do instead:

tc qdisc add dev eno2 clsact
tc filter add dev eno2 egress flower action drop

Tested with two cascaded DSA switches:
$ ip link set eno2 down
sja1105 spi2.0 sw0p2: Link is Down
mscc_felix 0000:00:00.5 swp0: Link is Down
fsl_enetc 0000:00:00.2 eno2: Link is Down

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-02-06 14:42:57 -08:00
..
dsa2.c net: dsa: allow changing the tag protocol via the "tagging" device attribute 2021-01-29 21:24:39 -08:00
dsa_priv.h net: dsa: fix SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING getting ignored 2021-02-03 18:25:49 -08:00
dsa.c net: dsa: allow changing the tag protocol via the "tagging" device attribute 2021-01-29 21:24:39 -08:00
Kconfig net: dsa: add a second tagger for Ocelot switches based on tag_8021q 2021-01-29 21:25:27 -08:00
Makefile net: dsa: add a second tagger for Ocelot switches based on tag_8021q 2021-01-29 21:25:27 -08:00
master.c net: dsa: allow changing the tag protocol via the "tagging" device attribute 2021-01-29 21:24:39 -08:00
port.c net: dsa: allow changing the tag protocol via the "tagging" device attribute 2021-01-29 21:24:39 -08:00
slave.c net: dsa: automatically bring user ports down when master goes down 2021-02-06 14:42:57 -08:00
switch.c net: dsa: allow changing the tag protocol via the "tagging" device attribute 2021-01-29 21:24:39 -08:00
tag_8021q.c net: dsa: tag_8021q: add helpers to deduce whether a VLAN ID is RX or TX VLAN 2021-01-29 21:24:30 -08:00
tag_ar9331.c net: dsa: tag_ar9331: let DSA core deal with TX reallocation 2020-11-02 17:41:17 -08:00
tag_brcm.c net: dsa: move the Broadcom tag information in a separate header file 2021-01-07 15:42:07 -08:00
tag_dsa.c net: dsa: tag_dsa: Support reception of packets from LAG devices 2021-01-14 17:11:56 -08:00
tag_gswip.c net: dsa: tag_gswip: let DSA core deal with TX reallocation 2020-11-02 17:41:16 -08:00
tag_hellcreek.c net: dsa: tag_hellcreek: Cleanup includes 2020-11-23 16:57:21 -08:00
tag_ksz.c net: dsa: tag_ksz: don't allocate additional memory for padding/tagging 2020-11-02 17:41:16 -08:00
tag_lan9303.c net: dsa: tag_lan9303: let DSA core deal with TX reallocation 2020-11-02 17:41:16 -08:00
tag_mtk.c net: dsa: tag_mtk: let DSA core deal with TX reallocation 2020-11-02 17:41:16 -08:00
tag_ocelot_8021q.c net: dsa: add a second tagger for Ocelot switches based on tag_8021q 2021-01-29 21:25:27 -08:00
tag_ocelot.c net: dsa: tag_ocelot: let DSA core deal with TX reallocation 2020-11-02 17:41:16 -08:00
tag_qca.c net: dsa: tag_qca: let DSA core deal with TX reallocation 2020-11-02 17:41:16 -08:00
tag_rtl4_a.c net: dsa: tag_rtl4_a: use the generic flow dissector procedure 2020-09-26 14:17:59 -07:00
tag_sja1105.c net: dsa: tag_sja1105: use a custom flow dissector procedure 2020-09-26 14:17:59 -07:00
tag_trailer.c net: dsa: trailer: don't allocate additional memory for padding/tagging 2020-11-02 17:41:16 -08:00
tag_xrs700x.c dsa: add support for Arrow XRS700x tag trailer 2021-01-15 15:36:31 -08:00