diff options
Diffstat (limited to 'target/linux/generic/backport-5.15/719-v5.12-net-dsa-automatically-bring-up-DSA-master-when-openi.patch')
| -rw-r--r-- | target/linux/generic/backport-5.15/719-v5.12-net-dsa-automatically-bring-up-DSA-master-when-openi.patch | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/target/linux/generic/backport-5.15/719-v5.12-net-dsa-automatically-bring-up-DSA-master-when-openi.patch b/target/linux/generic/backport-5.15/719-v5.12-net-dsa-automatically-bring-up-DSA-master-when-openi.patch new file mode 100644 index 0000000000..3b630377f9 --- /dev/null +++ b/target/linux/generic/backport-5.15/719-v5.12-net-dsa-automatically-bring-up-DSA-master-when-openi.patch @@ -0,0 +1,85 @@ +From 9d5ef190e5615a7b63af89f88c4106a5bc127974 Mon Sep 17 00:00:00 2001 +From: Vladimir Oltean <vladimir.oltean@nxp.com> +Date: Fri, 5 Feb 2021 15:37:10 +0200 +Subject: [PATCH] net: dsa: automatically bring up DSA master when opening user + port + +DSA wants the master interface to be open before the user port is due to +historical reasons. The promiscuity of interfaces that are down used to +have issues, as referenced Lennert Buytenhek in commit df02c6ff2e39 +("dsa: fix master interface allmulti/promisc handling"). + +The bugfix mentioned there, commit b6c40d68ff64 ("net: only invoke +dev->change_rx_flags when device is UP"), was basically a "don't do +that" approach to working around the promiscuity while down issue. + +Further work done by Vlad Yasevich in commit d2615bf45069 ("net: core: +Always propagate flag changes to interfaces") has resolved the +underlying issue, and it is strictly up to the DSA and 8021q drivers +now, it is no longer mandated by the networking core that the master +interface must be up when changing its promiscuity. + +From DSA's point of view, deciding to error out in dsa_slave_open +because the master isn't up is +(a) a bad user experience and +(b) knocking at an open door. +Even if there still was an issue with promiscuity while down, DSA could +still just open the master and avoid it. + +Doing it this way has the additional benefit that user space can now +remove DSA-specific workarounds, like systemd-networkd with BindCarrier: +https://github.com/systemd/systemd/issues/7478 + +And we can finally remove one of the 2 bullets in the "Common pitfalls +using DSA setups" chapter. + +Tested with two cascaded DSA switches: + +$ ip link set sw0p2 up +fsl_enetc 0000:00:00.2 eno2: configuring for fixed/internal link mode +fsl_enetc 0000:00:00.2 eno2: Link is Up - 1Gbps/Full - flow control rx/tx +mscc_felix 0000:00:00.5 swp0: configuring for fixed/sgmii link mode +mscc_felix 0000:00:00.5 swp0: Link is Up - 1Gbps/Full - flow control off +8021q: adding VLAN 0 to HW filter on device swp0 +sja1105 spi2.0 sw0p2: configuring for phy/rgmii-id link mode +IPv6: ADDRCONF(NETDEV_CHANGE): eno2: link becomes ready +IPv6: ADDRCONF(NETDEV_CHANGE): swp0: link becomes ready + +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> +--- + Documentation/networking/dsa/dsa.rst | 4 ---- + net/dsa/slave.c | 7 +++++-- + 2 files changed, 5 insertions(+), 6 deletions(-) + +--- a/Documentation/networking/dsa/dsa.rst ++++ b/Documentation/networking/dsa/dsa.rst +@@ -273,10 +273,6 @@ will not make us go through the switch t + the Ethernet switch on the other end, expecting a tag will typically drop this + frame. + +-Slave network devices check that the master network device is UP before allowing +-you to administratively bring UP these slave network devices. A common +-configuration mistake is forgetting to bring UP the master network device first. +- + Interactions with other subsystems + ================================== + +--- a/net/dsa/slave.c ++++ b/net/dsa/slave.c +@@ -68,8 +68,11 @@ static int dsa_slave_open(struct net_dev + struct dsa_port *dp = dsa_slave_to_port(dev); + int err; + +- if (!(master->flags & IFF_UP)) +- return -ENETDOWN; ++ err = dev_open(master, NULL); ++ if (err < 0) { ++ netdev_err(dev, "failed to open master %s\n", master->name); ++ goto out; ++ } + + if (!ether_addr_equal(dev->dev_addr, master->dev_addr)) { + err = dev_uc_add(master, dev->dev_addr); |