diff options
author | Vladimir Oltean <vladimir.oltean@nxp.com> | 2021-06-21 19:42:18 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2021-06-21 12:50:20 -0700 |
commit | 88faba20e2100c1f367133af56612742ad37df08 (patch) | |
tree | 54b39a59d69c8c7294bf675f0e91520f27fce15d /net/dsa/port.c | |
parent | 4e4ab7950044d195f6e3d4dac328f506badb6efa (diff) |
net: dsa: targeted MTU notifiers should only match on one port
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dsa/port.c')
-rw-r--r-- | net/dsa/port.c | 4 |
1 files changed, 2 insertions, 2 deletions
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, }; |